THE OFFICIAL TECHNI

March 1988

PAID Permit No. 7867 Indianapolis, Ind.

PUBLICATION OF THE UNITED STATES GYMNASTICS FEDERATION

Vol. 8, No.1

March 1988

2

Inside This Issue

4-6 McDonald's American Cup Men's Technical Report

8-9 Somersault Trajectory Differences: Foam Block Versus Coil Spring Floor

10-12 Implementation Of A Profiling Prediction Test Battery In The Screening Of Elite Gymnasts

14 USGF Calendar Of Events 15 Safety Certification Schedule

By Robert Cowan Men's Program

Administrator By W.A. Sands University of Utah

G.S. George Ph.D. University of SW

Louisiana St. By Mark D. Grabiner,

Ph.D. University of Southern

California Robert McKelvain,

Ph.D. Harding University

16 Rhythmic Gymnastics From F.I.G.

17 Update

Survey To Help Loss Of Athletes

18-20 An Insight Into The Biomechanics Of Twisting

Cover photo © 1988 USGF, by Dave Black

D.J. Milem Age Group Chair.,

Region VIII By Hardy Fink University of British

Columbia

CHANGE OF ADDRESS AND SUBSCRIPTION INQUIRIES: In order to ensure uninterrupted delivery of TECHNIQUE magazine. notice of change of address should be made six to eight weeks in advance. For fastest service. please enclose your present mailing label. Direct all subscription mail to TECHNIQUE SUBSCRtPTIONS. Pan American Plaza. 201 S. Capitol Ave .. Suite 300. Indianapolis. IN 46225. POSTMASTER: Send address change to TECHNIQUE. Pan American Plaza. 201 S. Capitol Ave .. Suite 300. Indianapolis. IN 46225.

TECHNIQUE is published quarterly for $12.00 by the United States Gymnastics Federation. Pan American Plaza. 201 S. Capitol Ave .. Suite 300. Indianapolis. IN 46225 (Phone: 317-237-5050). Third class postage paid at Indianapolis. IN . Subscription price: $12.00 per year in United States; all other countries $24.00 per year. Back issue single ca­pies $2.00 plus $1 .00 postage/handling. All reasonable care will be taken. but no responsibility can be assumed for unsolicited material; enclose return postage. ©1987 by USGF and Technique. All rights reserved. Printed in USA.

FIG BULLETIN If you would like to subscribe to the FIG BULLETIN, please indicate your interest in writing by JANUARY 31, 1988. Due to the fluctuating currency exchange, the subscription price has not been determined. Last years price was $25.00. Send requests to: John Hewett, 201 S. Capitol Ave., Suite 300, Indianapolis, IN 46225.

Vol. 8, No.1

Publisher Mike Jacld

Education/Safety Editor Dr. Gerald George

Production Michael G. Botkin

UNITED STATES GYMNASTICS FEDERA­TION BOARD OF DIRECTORS: Executive Director: Mike Jacki. Athlete Representatives: Lydia Bree; Peter Vidmar; Linda Kardos; Tom Beach; Kathy Johnson; Tim Daggett; Kelly Garri­son. Amateur Athletic Union: Jerry Hardy. Amer­ican Sokol Organization: Norma Zabka. Amer­ican Turners: Harry Warnken. Members at Large: Linda Chencinski. NCAA Gymnastics Coaches­Men: Fred Roethlisberger, University of Minneso­ta . NCAA Gymnastics Coaches-Women: Judi Avener, Penn State University. National Associa­tion for Girls and Women In Sports: Dr. Mimi Murray, Sprin~field College. National Associa­tion of Women s Gymnastics Judges: Dale Brown. NCAA: Sylvia Moore, Oregon State University; Gail Davis, Rhode Island College; Jerry Miles, do NCAA; Wayne Young, Brigham Young Universi­ty. NAIA: Bonnie Morrow. NHSGCA: John Brink­worth. National Federation of State High School Athletic Assoc. : Sharon Wilch; Susan True . National Jewish Welfare Board: Courtney Shank­en. NJCAA: Dave Rowlands, Tru man College.

"NGJA: Mike Milidonis. USAIGC: Ed Knepper. Men's Elite Coaches Assoc.: Jim Howard, Uni­versity of Nebraska. USECA for Women: Roe Kreutzer; Steve Whitlock. Youn~ Men's Christian Assoc.: Cliff Lothery. Jr. Boy s Gym. Coaches Assoc.: Rich Boccia. President: Mike Donahue.

EXECUTIVE COMMITTEE : President: Mike Donahue. Secretary: Judi Avener. Vice President: Jim Howard. Executive Director: Mike Jacki. FIG Technical Committee: Jackie Fie. FIG Rhythmic Technical Comm.: Andrea Schmid. FIG Men's Technical Committee: Bill Roetzheim. Vice Presi­dent for Women: Sue Ammerman. President Emeritus: Bud Wilkinson. Athlete Representa­tives: Kathy Johnson; Peter Vidmar; Larry Gerald. Members at Large: Mike Milidonis; Linda Chen­cinski.

Associate Contrnt Editors SPORTS MEDICINE COMMITTH Merrill A. Ritter, M.D. SAFETY COMMITTEE Dr. Marc Rabinoff EDUCATION COMMllTEE Dr. Carland O'Quinn BIOMECHANICS COMMITTEE Dr. Marlene Adrian, Director SPORTS PSYCHOLOGY COMMITTEE Dr. Keith Henschen, Ph.D. EXERCISE PHYSIOLOGY COMMITTEE Dr. Pat Eisenman. Ph.D.

Unless expressly identified to the contrary. all articles, statements and views printed herein are 3uributed soley to the author and the United States Gymnastics Federation expresses no opin­ion thereon and ass umes no responsibility thereof.

Technique

Call tollfree for orden'ng information

1-800-345-4087 In PA , AK, HI, and Canada, call collect, 215 -376-6522.

With the help of some of tile best gymnasts in tile country, Elite/ Gym-Kin has developed new Sleek Fit, the ultimate fit in competitive leotards. Elite/Gym-Kin's new Sleek Fit hugs the contours of your body, mirroring your move­ments, creating long flowing lines of grace.

VVINNERS VVEAR

l1lere's more! Elite/Gym-Kin has also developed a new Shadow­proof Lining, optional on any special order leotard, that elim­inates "show-through."

New Sleek Fit. New Shadow­proof Lining. And much, much more. All in our new 56 page, 1987-88 catalog. Send for yours today!

Coaches/ Instructors: send catalog request on school or business letterhead. All others, send $3.50 to: The Elite/Gym-Kin, 1230 Spruce Street, Reading, PA 19602

American Cup Men's Technical Report

By Robert Cowan USGF Men's Program Administrator

The 13th American Cup proved to be "lucky 13" for Kevin Davis as he led all the American males on the day of finals . However, on

Saturday in the preliminaries, the day belonged to Dan Hayden who fin­ished 1st.

The 1988 American Cup in Fairfax, V A was in many ways, one of the more exciting competitions in recent years. While the competitive field was quite narrow relative to athletes who actually were capable of winning, the level of performance was extremely high. In other words, very few ath­letes could put 6 GREAT routines together, but all of the athletes were world class on at least three or four events .

Saturday's competition came down to those people who did not fall off or fall down moving into Sunday . Charles Lakes-USA, Scott Johnson­USA, Li Ning-CHN, Mike Inglis­CAN, Liubomir Geuraskov-BUL, Laszlo Boda-HUN, Alejandro Pineche­MEX, and Jeong Sik Lee-KOR; ALL fell on at least one event and some fell two and three times. Dan Hayden won the event on Saturday with 58.05, with Kevin Davis in 4th with 57.70, Scott Johnson was 6th with 57.50 and Charles Lakes was 14th with 55.85. However, due to the two man rule ad­vancing, Scott was not in the Sunday event.

Dan Hayden certainly has the inter­national experience and visibility to win the American Cup, IF he is con­sistent . Kevin Davis has the gymnas­tics skills and execution, but exposure at this level would have kept him from winning, or made it very difficult .

Eight athletes advanced to the finals on Sunday which is of course a total­ly new meet. It is all around again, and scores do not carry.

The event on Sunday for all intents and purposes proved my theory. Dan touched down on FX, did a 9.4 vault which scored 9.4 and finished 4th .

4

Kevin Davis was rock solid during both the McDonald's American Cup and International Mixed Pairs taking third and first respectively. Davis scored a 9.90 on pommel horse during the Mixed Pairs to lead his team to victory. (All photos © 1988 USGF, by Dave Black).

Kevin Davis was rock solid, besting his Saturday total to 58 .15 and finished 3rd. Other than wishing Dan had a 9.6 vault and had not made the error on FX, you could not have asked for more out of either gymnast.

Finalists included Marius Toba­ROM, Igor Korobchinsky-USSR, Sven Tippelt-GDR, Antonio Trecate-ITA, Casimiro Suarez-CUB, Takahiro Yamada-JPN and of course, Hayden and Davis .

Toba was very impressive en route to the 58.45 total which edged the Soviet by .25 and earned him the first Romanian title of American Cup Champion . In fact, it was exactly 13 years before when a Romanian (Nadia Comaneci) and an American (Bart

Conner) shared American Cup Cham­pion honors. This year it was Toba and Phoebe Mills-USA.

A listing of the routines for the top eight gymnasts follows this report.

MIXED PAIRS

The Mixed Pairs were held in Allen­town and hosted by the Par­kettes/Gymnastrum. 19 pairs started in the first round with Kevin Davis paired with Phoebe Mills, Dan Hay­den with Chelle Stack, Scott Johnson with Brandy Johnson and Charles Lakes with Hope Spivey. There were also some Parkette girls paired with Gymnastrum and International Gym­nastics school boys to give some local interest to the event.

Technique

Dan Hayden's early routines were hindered by a stiff neck but he recovered to perfectly execute his half-in, half-out over the bar dis­mount on high bar.

Only two American pairs can ad­vance and Charles Lakes and Hope Spivey got underscored on their first event (HB and V), and thus were eliminated. Only Kevin and Phoebe advanced to the final round which witnessed the Romanian pair, the Soviet pair and the USA pair battle for the Mixed Pairs title. Actually Kevin and Phoebe came in to the final round with 0.075 lead, but this was soon eliminated by first the Romanian pair who got 9.6 on FX and 9.7 on BM. Next came the Soviet pair and Baito­va went 9.9 on FX (although under­rotating a 3/1 dismount) and Korob­chinsky went 9.9 on PB with a routine which had at least 0.2 in execution decluctions .

For my money, the meet was over and it appeared the " fix " was in for the Soviets. However, nobody told Phoebe and Kevin. Phoebe did a great FX set, even though she dismounted 2/1 instead of double back and scored 9.9. Kevin did an excellent PH set with 4 D' s and flawless execution and scored 9.9!! The USA won.

Technique

AMERICAN CUP FINALIST ROUTINES

Floor Exercise Antonio Trecate-Italy-Double lay­

out-straddled arabian 1 %-flairs to handstand-wide arm press-tuck dou­ble dismount

Takahiro Yamada-Japan-Tucked full in-11h to punch front-front front­tucked double dismount

Marius Toba-Romania-Piked full in­double back punch front step out, round off, flip flop , 111 punch front-Ill side-2/1 punch front dis­mount

Igor Korobchinsky-USSR-Double layout, flip flop tucked back-Arabian 1 %-Wide arm press-tucked double dismount

Kevin Davis-USA-Tucked full in-2/1-break dance sequence-side sorni-tucked double dismount

Casimiro Suarez-Cuba-Double layout-tucked III in-Layout punch

Phoebe Mills teamed with Kevin Davis to win the International Mixed Pairs competition. Mills, originally not scheduled to compete in these events, seized the opportunity to win them both.

front 11f4 -tucked double dismount Dan Hayden-USA-Arabian double

front, headspring out-Front through to Double back-wide arm press-layout back-tucked double back dismount

Sven Tippelt-GDR-Layout/pike double-Arabian 1 %-layout back punch front-flairing spindle-wide arm press­tucked double back dismount

Pommel Horse Toba-Back kip cross-pullout-yam­

awaki-yamawaki-whippet-handstand­back giant-cross-straightl straight press (straddled)-double layout

Vault Davis-Cuervo Suarez-1 arm straddle layout tsuk

III Hayden-Handspring front piked Tippelt-Piked Cuervo Yamada-Piked Cuervo Toba-Layout tsuk III Korobchinsky-Layout tsuk III Trecate-Cartwheel pike front

Parallel Bars Hayden-Peach Ih -giant Ih -giant­

front rise-back pirouette-" V" -Press straight straight-Stutz hand-back toss hand-back toss hand stutz hand­tucked double

5

Tippelt-Peach hand-giant-giant % to end-giant glide reverse cut-swing hand-healey-front pirouette-stutz­giant glide to end-double front dismount

Yamada-Peach hand-pirouette forward-stutz % turn to one rail-glide from side _" V" -press-1f4 turn in­diamidov-front rise-swing hand-stutz­tucked double dismount

Toba-Glide on end- flairs-straddle planche-giant cast-healey-swing handstand-healey-front 11f4 cutback swing handstand-stutz-tucked double dismount

Korobchinsky-Cast support-back pirouette-giant-stutz-healey down­back stutz-hop pirouette-stutz­diamidov-tucked double dismount

Trecate-Glide-reverse cut-peach­reverse cut-handstand-reverse pirou­ette-diamidov-diamidov with % turn­side glide up to straddle-press handstand- % turn in-stutz-"V"­double front

Davis-From side-glide-straddle "L"­press-pirouette into diamidov-healey­healey-% pirouette down to back stutz-front roll-cuts to ilL" -press­tucked double

Suarez-Peach hand-stutz-gienger­fron t rise-" L' , -press-diamidov -back

toss-back toss-stutz-tucked double dismount

Horizontal Bar Yamada-Stemme-stalder-inside

stalder-pirouette-tkachev with legs together-jam eagle, eagle, pirouette­double layout

Toba-Back rise hand-stalder-blind­endo-pirouette-tkachev-higgins to eagles-double double

Korobchinsky-Back rise hand-Ill

Igor Korobchinsky's parallel bars rou­tine was one of his best .

• scrl-e

gienger-kip change-higgins to inverts­yeager-triple back

Trecate-Stemme pirouette to 1 arm-I arm tkachev-catch with 1 arm-healey­jam eagles-pirouette-double layout

Davis-Stemme stalder-1 arm healey-1 arm giant-1 arm tkachev-jam eagle­inverts-pirouette-double layout

Suarez-Stemme pirouette- 1% gienger- III spin to 1 arm- gienger­higgins-eagle- layout III in

Hayden-Back rise hand-stalder­blind-eagles-kovacs-endo-pirouette­full twisting kovacs

Tippelt-Mixed grip stemme-pirou­ette-1 arm tkachev-tkachev-blind change-1 arm giant-pirouette-jam­eagle-inverts-barani in

OTHER UNUSUAL SKILLS

Laszlo Boda-Hungary-FX-Excellent 3/1-double back punch front to round off flip flop 1% twister to punch barani Also did handspring, front flip flop, front flip flop to 1 % dive roll. Li Ning­China-Did piked double double at least 1 mile high .

Boda-Hungary-SR-did Guczoghy into immediate triple flyaway

Penichi-Mexico-Vault-did III twist­ing cuervo

ow TechniqUe gives the gymnastics professional, as well as the enthusiast, a clear jump on the rest

* ~~ ~"'@i.~ lib 1m \!® r~~!&W W'\

of the community. As you know, education in our fast-paced sport is essential to the development of a safe and effective program. Technique gives you that vital information. Take advantage of this most important resource. Subscribe today.

Please enter my subscription immediately. o Enclosed is $12 check or

money order for 4 issues

6

.L ..&:JV.&.&...l.. &~ U ~ THE OFFICIAL TECHNICAL PUBLICATION OF THE UNITED STATES GYMNASTICS FEDERATION

Name

Address

City, State, Zip

Phone Check one 0 Gymnast/Age_ o Parent 0 Coach 0 Other __

USGF Department of Education & Safety Pan American Plaza Suite 300 201 South Capitol Ave. Indianapolis, IN 46225

Technique

Insure your success with the nation's strongest program of gymnastics memberships, to insure your club, your staff and your students.

2 CLUB MEMBERSHIP PROGRAMS

D 100% CLUB MEMBERSHIP

Add members to your club insurance by name as they join your club.

*** No minimum number to join

*** One fee for all, reduced in quarterly increments for those joining your club later during the policy year.

*** Technique

• PEAK ENROLLMENT MEMBERSHIP

No reporting of names. Fees based on highest number of staff and .students during your peak month of year.

*** 100 student minimum

*** Reduced rate for age 6 and under

*** Fees based upon quarter in which your club joins program.

***

New Quarterly Fee Reductions

*** New Non-Gymnastics Coverage Available to Memoer Clubs

*** Trampoline Coverage Included

*** Master Policy Based on June 1 to June 1 Year

*** Liability & Medical Benefits for your club, your staff and students include:

• $1,000,000 Comprehensive General Liability Coverage

• $50,000 Excess Accident Medical Benefit ($250 deductible)

• $10,000 Accidental Death and Dismemberment Coverage

• Lifetime Catastrophic Medical Insurance Program

• Owners, Landlords and Tenants Liability Coverage

• Hired and Non-Owned Auto Liability • Personal Injury Liability • Independent Contractors Coverage • Extended Bodily Injury Liability

Coverage • Premises Medical Payments

For more information on these out­standing Club Membership programs, call or write .

USGF Member Services Pan American Plaza Suite 300 201 South Capitol Indianapolis,lN 46225 1-800-345-4719

7

Somersault Trajectory Differences: Foam Bloc Versus Coil Spring Floor

W.A. Sands, Ph.D. Assistant Women's Program Administrator Human Performance Research Laboratory

University of Utah

G.S. George, Ph.D. Biomechanics Consultant

Women's National Program University of South Western Louisiana

Concern was voiced by and other running mechanics have coaches of the 1987 World been shown to be affected by running Championships team that surface (McMahon, 1985; MacMahon our national team gym- & Greene, 1978; McMahon & Green, nasts had a great deal of 1979). Floor exercise areas involving

trouble staying within the floor exer- conical and cylindrical springs have cise boundaries during performance. been compared showing differing The deductions for going out of the characteristics and resulting in differ­boundaries can be a considerable drain ing muscular innervation patterns on the team and individual scores. The (Gormley, 1982) . floor exercise surface varies in differ- The purpose of this investigation ent competitions, but the boundary was to determine if trajectory lengths dimensions remain the same . of a layout somersault were different Moreover, since a tumbling pass con- when performed on a coil spring floor sists of multiple alternating floor con- exercise surface or a foam block floor tacts and flight phases, the study of exercise surface. The design and con­the length of trajectories on different struction of these two types of floor ex­floor surfaces seemed warranted. The ercise surfaces are quite common in nature of the flight phase of a somer- the United States and abroad. Athletes sault or other airborne skill can be de- may train on one particular style of fined closely by knowing the quanti- floor and then compete on the oppo­ties of the horizontal and vertical com- site style . If floors have different per­ponents of velocity at the moment of formance characteristics, it is imp or­departure from the floor surface (Hay, tant that coaches and athletes know 1973) . These quantities are partially or what these variable charactertistics completely determined by the are. Moreover, these characteristics strength of the athlete, velocity of the should be identified so that the expect­body at contact with the floor, specif- ed performance could be more ac­ic take off actions, and the qualities of curately predicted. the floor surface .

The variables of strength and tech­nique require rather indepth analysis using sophisticated instrumentation and preclude generalizable conclu­sions for the majority of national team members . The large amount of time invested in such investigations make them largely impractical for team wide generalizations. Varying floor area conditions in elasticity and loading qualities could be a major contributing factor to jumping ability. Stride length

8

METHODS

DUring the Senior Nation­al Training Camp in Al­tamonte Springs, Florida the gymnasts (N = 26) of the senior national team

were divided into three groups for physiological and biomechanical test­ing . As the three groups rotated to each testing station they received a series of physical performance tests .

One of these stations was the layout somersault trajectory distance test. Two groups of gymnasts began on the foam floor surface, and one group be­gan on the coil spring surface. Each group was asked to perform a run to round off, flip flop, and layout somer­sault as they would perform their first major floor exercise tumbling pass . Each gymnast performed three trials on each floor surface. Two skilled coaches present at the camp visually noted the take off and landing inden­tations in the matting surface and im­mediately measured the length of the trajectory with a metric tape measure.

The trials data were subjected to reliability analysis using Cronbach's Alpha model to determine if there were any trends across the trials. Fol­lowing this determination the average of the trials was used for the final data value (Henry, 1967). These values were then assessed by a matched pairs ! test, and a Pearson product moment correlation coefficient (!).

RESULTS

Reliability analysis using Cronbach's Alpha model showed that there were no significant differences between the trials on either

the coil floor (f(25,2) = 0.67, p>.05) or the foam floor (f(25,2 = .020, £>.05). The Alpha values for reliability were .85 for the coil floor and .89 for the foam floor. Both of these values indi­cated that the reliability of the trials was quite high . Following this analy­sis the data were reduced by calculat­ing the mean of the three trials as the data for analysis.

Table I shows the descriptive statis­tics for the population of senior na­tional team members.

Technique

Table I Descriptive Statistics

Item Mean Std Deviation

Height (cm) 152.47 6.95 Weight (kg) 45.15 5.94 Foam Trajectory

Distance (cm) 175.18 23.71 Coil Trajectory

Distance (cm) 168.58 20.47

The results of the matched pairs! test showed that there was a differ­ence between the floor types (!(25) = 2.20, £<.05) . The Pearson product moment correlation coefficient reached!: = .77 (£<.05). The corre­lation coefficient indicated that ap­proximately 59% of the variability in one trajectory length on one floor sur­face type could be predicted by know­ing the other trajectory length .

DISCUSSION

The difference between the mean values of trajectory lengths indicates approxi­mately a 4.15% increase in distance on the foam block

type of floor. This translates to only a 6.6 cm increase (approximately 2.6 inches). This distance would appear to be hardly worth worrying about. However, one must consider that there are several other trajectories in the entire tumbling pass. If the 4.15% increase in distance of the somersault can be translated to the entire pass this could become a very significant figure . The length of the diagonal of the floor exercise area is 16.97 m . Taking 4.15% of this distance returns 0.70 m . (ap­proximately 27.6 inches) or slightly more than two feet.

The 0.70 m distance probably

represents an inflated value due to the differences in the goals of each of the trajectories of a tumbling pass. For ex­ample, running steps, snap downs, flip flops, etc. are of lower height. Our best approximation of the increase in length for the total tumbling pass is 30.5-45.75 cm (12-18 inches). We offer for consideration that the corner boundaries be modified for those ath­letes who train normally on a coil spring floor and are going to compete on a foam block floor. Figure 1 shows a possible modification scheme.

In conclusion, it appears that the na­ture of the construction of the floor ex­ercise surface may have an impact on the length of a somersault trajectory. Moreover, the length of the entire tumbling pass may be affected by the same phenomenon. This effect may be further exaggerated by placement of the floor exercise surface on the com­petition podium. A theoretical cause of the differences in trajectory lengths may lie in the restitution characteris­tics of the tumbling surfaces. RECOMMENDATIONS/COACHES

TRANSLATION:

A softer and therefore slower floor means that performers will be in contact with the tum­bling surface for a longer

duration of time . This means that their rebound angles for virtually any air­borne skill will be greater than on harder/springier surfaces. A greater rebound angle will cause the perform­er to travel further relative to a stiffer surface. The net result is that the potential for landing out of bounds is increased. To compensate for this potential tendency it is recommended

Figure 1

r ------ I \. 15-23.5cm. I

// 6-121nclles ~

I

\r--~ Modified Floor Exer. Boundary Area Standard (rupe)

IL Boundary'

I I

--'

Technique

that the corner boundaries be moved in 15-23.5 cm (6-12 inches) on coil spring floors during the routine prepa­ration preceding competition on a foam block floor.

OBSERVATION

Visual observation and comments made by Europeans-their arm lift is similar to ours for back rotation, BUT, they drop their arms behind them with a neurtral head position giving a quicker rotation and more control dur­ing the skill and in the landing. Best advice, slow down the film of the re­cent meets and study the position of ' the set-up for double backs and dou­ble layouts. It becomes more obvious. It looks awkward, but appears to be effective.

During the training sessions that the vaulting board was used to a great deal during training for certain drills.

1. Handstand pushups with the coach "sculpturing" the body at the top and the bottom.

2. Back tucks off board with empha­sis on sticking-also pikes-back 1/2

3. Handstand snapdown from board-hs snap down back-back pike­back layout-back with 1/2 etc .

4. Athletes squatting on board with the coach sitting on their back/shoul­ders and bouncing the board slowly. When questioned-reply was it strengthens and stretches the achilles.

REFERENCES

Gormley, J. T. (1982). An investigation of two spring floor type characteristics and the muscular response in gymnasts of different body mass and skill perfor­mance levels. Underdale: South Aus­tralia . South Australia College of Advanced Education. Author.

Hay, J. G . (1973) . The Biomechanics of Sports Techniques. Englewood Cliffs, NJ: Prentice Hall.

Henry, F.M. (1967) . " Best" versus "average" individual scores. Research Quarterly, 38, 317-320.

McMahon, T.A. (1985). The role of compliance in mammalian running gaits . Journal of Experimental Biology, 115, 263-285 .

McMahon, T.A., & Greene, P .R. (1978) . Fast running tracks. Scientific American, 239, 148-163.

McMahon, T.A. & Greene, P .R. (1979) . The influence of track com­pliance on running. Journal of Bi­omechanics, 12, 893-904.

9

Implementation Of A Profiling Prediction Test Battery In The Screening Of Elite Gymnasts

By Mark D. Grabiner, Ph.D.

University of Southern California and

Robert McKelvain, Ph.D. Harding University

This research has been supported, in part, by travel grants from the Unit­ed States Gymnastic Federation. This project is part of the United States Gymnastic Federation Men's Junior Olympic Sport Sciences Program.

Introduction

The international success of the sports sciences pro­grams of the Soviet Union and Soviet-block countries has been related by some

as being most directly to the selection of the most able and talented young individuals and the creation of an en­vironment that makes possible the at­tainment of athletic mastery (Schneid­man, 1978) .

One may assume that the status of training environments worldwide is the less disparate of the two. The so­lution to the questions regarding the selection of those young athletes that are predisposed to successful athletic participation in high-level competition has represented an elusive quarry to sports scientists for nearly a century . Any number of physiological, bi­omechanical, or anthropometric models of elite athletes have been reported, however, the implementa­tion of such data remains, for the most part, limited . That is, they have not been administered on what may be considered a large scale. Grabiner and Dillman (1982) proposed a method by which athletes could be profiled based upon performance in 14 standardized fitness tasks and morphological data .

It was assumed that performance on the tasks, which were selected to yield information regarding a metabolic

10

energy source continuum, would correlate well with the athletes' body­type and therefore allow objective counseling with respect to a specific group or type of activities. A modifi­cation of the original test battery, which was reduced to seven timed performance tasks and whose calculat­ed output variable represented aver­age power output per unit body weight, was reported by Grabiner and Dillman (1984).

The average power output was stan­dardized (Z-scores) so as to partial out the effects of individual body weight and height. Each of seven tasks, chos­en to represent most of the body's major joint actions were performed by a group of 40 college-aged males (Mean: age = 22.1 years, height = 179 cm, weight = 75.3 kg) for 60 seconds. The tests that were administered were pushups, situps, pullups, dips, verti­cal jumps (12 inches), handstand pushups, and squat thrusts . The num­ber of correctly performed repetitions during the 60 seconds were recorded and used as input to a computer pro­gram which, based upon the athletes sex, height, and weight, calculated the vertical displacement of the overall body center of mass during each repe­tition, the work performed against gravity during each repetition, and ul­timately the average power output during the performance period per unit of body weight (W/N).

It was discovered that athletes of various activities displayed specific profiles that qualitatively differentiat­ed between groups and were consis­tent within groups. Represented in Figure 1 are the standardized scores of wrestlers (N = 3), an elite college base­ball pitcher (currently professional), and a female intercollegiate middle­distance swimmer (scores represent­ing deviations from a female test population. More notable than differ­ences in any particular score, is the Civerall profile, or shape, generated by the continuum of scores .

Methods

The possible role that such a testing/ screening proce­dure could serve attracted the attention of the USGF Mens' Jr. Elite Program

and two separate groups of young ath­letes were tested with a modified bat­tery at the USOC Training Center in Colorado Springs . The modification of the battery included stiff-stiffs (on the parallel bars) in lieu of squat thrusts. The first group was tested during the 1985 Spring Training Camp (N = 15, Mean: age = 16.5 years, weight = 50.7 kg, height = 164.33 cm). The tests for this group were administered in "random" (athletes' preferred) order. Athletes were allowed essentially as much rest between tests as they desired.

With the exception of the stiff-stiffs, the test battery was also administered to a control group of athletes (non­gymnasts) all older than 12 years old (N = 62, Mean: height = 169.92 cm, weight = 62.7 kg) . The results from this group were implemented as base­line values against which the gym­nasts scores could be plotted so as to generate the gymnast profile.

The testing of the second group of USGF athletes during the 1985 Sum­mer Training camp (N = 27, Mean: age = 14.76 years, weight = 51.39 kg, height = 158.47 cm) was conductedm such a way so as to control for the two factors which were free to vary in the first group. These two factors were the order of test administration and the amount of rest allowed between tests. The test order was pullups, pushups, situps, dips, vertical jump, handstand pushups, and stiff-stiffs. Each athlete had eleven minutes of recovery be­tween tests.

By selecting the best athletes, the United States could push themselves to the top of the gymnastics world like they did during the recent Pan American Games. (USGF photo © 1987, by Dave Black).

Technique

Results

Results of the first data set illustrate that the gym­nasts are more homogene­ous than the control group with respect to the per-

formance tasks. The average coeffi­cient of variation for the six tests was 31 .28 percent versus the 59.0 percent for the control group. Additionally, and perhaps more importantly, the means of the gymnasts' scores were found to be an average 2.05 standard deviations above the control group's mean values.

Results of the second group of USGF athletes tested illustrated two notable points. Firstly were the similarities in scores and profiles from one group to the other (!: = .92). Again, the mean of the normalized scores was 2 .04 standard deviations above those of the control group . Se­condly, the possible effects of controll­ing for the order of test administration and amount of rest was observed. The coefficient of variability, 31.28 percent in the first group of athletes was reduced to 24.71 percent (Table 1) .

Technique

Table 1 Descriptive statistics for the gymnas-tics and control groups.

USGF Group #1

Test Mean (W/kg) SD CV

pullups 97.56 31.34 32 situps 201.04 28.55 14 pushups 191.21 75 .33 39 handstand

pushups 38.82 11.77 30 dips 186.70 66.40 35 vertical jump 14.64 4.80 33 stiff-stiffs 61.66 22.40 36

USGF Group #271

pullups 93.57 15.67 17 situps 197.47 19.27 10 pushups 292.54 45.76 16 handstand

pushups 27.29 8.97 33 dips 163.41 41.12 25 vertical jump 17.68 4.39 25 stiff-stiffs 30.48 14.40 47

Control group

pullups 37.74 24.60 65 situps 119.92 24.10 20 pushups 150.79 68.51 45 handstand

pushups 10.97 10.83 99 dips 52.14 40.27 77 vertical jumps 14.47 6.92 48

The predictive capabilities of the test battery with respect to performance was investigated using multiple regression. Overall national ranking of the second group of athletes, ranging from 12 to 64, was used as the depen­dent variable and the power output scores were used as independent vari­ables. The equation, using stan­dardized regression coefficients, Overall rank = - 28.96 + .222 * X,

- .009 * X2 + .705 * X3 - .626 * X4 - .204 * Xs - .009 * X6 + .065 * X7

where, Xl = pullup power output X2 = situp power output X3 = pushup power output X4 = handstand pushup power

output Xs = dip power output X6 = vertical jump power output X7 = stiff-stiff power output,

accounted for 44.02 percent of the var­iance associated with overall rank (R = .6635).

Conclusions

The gymnast profile is markedly different than any other profile previous­ly encountered (Grabiner and Dillman, 1984) . It

11

seems conservatively reasonable to suggest that junior elite gymnasts demonstrate levels of average power output that distinguish them from average/normal athletes of similar age range. Despite the relative insensitiv­ity of inherent in the measurement of average power output values, know­ledge of these parameters seems to al­low some discrimination of gymnas­tic ability without so much as any gymnastics measures. It remains to be seen, however, as to the predictive value of the test battery with respect to an "unknown" population. That is,

having only the power output scores, whether the model will allow for prediction of overall placement of gymnasts. Of significant value is whether, given scores of young, gymnastically- untrained individuals the model can suggest gymnastics potential. This, then, could be the sounding board for a program whose focus is the selection and prediction of athletes and their future level of suc­cess within a given athletic activity.

References Schniedman, N. (1978) . The Soviet

Rad to Olympus - Theory and prac-

Figure 1

tice of Soviet Physical Culture and Sport. Ontario: Ontario Institute tor Studies in Education.

Grabiner, M. D. and Dillman, C. J. (1982) . A program of athletic profil­ing and counseling. Proposal pre­pared at the University of illinois Bi­omechanics Research Laboratory.

Grabiner, M. D . and Dillman, C. J. (1984) . Athletic profiling and counseling- A feasibility report. In Proceedings of "Children to Cham­pions" , An International pre­Olympic Symposium, (J . Calla­ghan, Ed .). University of Southern California Press.

Re prese ntative profiles f o r differe nt athl e t e s

12

V1 <lJ

5 <.,

Vl I

N

3.5

2.5

1.5

.5

- .5

-1.5

-2.5

Athlete

~~ Swimnler

mu Baseball

~ Wrestler

- 3.5 .1...-_ -<-_-+--_--+-_---+ __ 1 __ ....--""''_+___---1

3 .5

2. 5

1 .5

~ .5 a u

Vl I

N -.5

-1.5

- 2.5

pus.hups h.s.p.u. s i tups vert .

dips pullups squat thru s ts Perfo rmance Tasks

Figure 2 The Junior E lite Gymnast Profi le

-3.5 L-_ _ ~--__ -----+---~--~---+----~

pullups situps pushups h.s . p.u. d i ps vert j Performo n ce Task

Technique

THE ROAD TO SEOUL STARTS IN SALT LAKE

PRE SEN T N G:

u.s. OLYMPIC GYMNASTICS TRIALS JULY 29 THROUGH AUGUST 6,1988

S ee the best of America in the Salt Palace as Salt Lake City hosts the top 60 Olympic hopefuls. A men's and

women's gymnastics team, along with a rhythmic gymnastics team, will be selected to go for the gold as the United States Olympic Gymnastics Team in Seoul, Korea! Gymnasts will compete in a broad variety of events, including floor exercise, pommel horse, still rings, vaulting, parallel bars, horizontal bar, balance beam, and uneven parallel bars. In addition, enjoy the elegance of rhythmiC gymnasts competing for a spot on the Olympic squad.

SCHEDULE OF EVENTS: Rhythmic Preliminaries .. . . July 29 Rhythmic Finals . .. .. . .... July 30 Practice Days . ...... August 1 & 2 Men's Compulsories . ... . August 3 Women's Compulsories .. August 4 Men's Finals . ......... . August 5 Women's Finals ..... . .. August 6

Note: Tentative schedule - dates may VB/}'.

HOSTED BY:

FOR TICKETS: 1-800-888-SHOW TICKET INFORMATION: 1-801-363-7681 HEADQUARTERS: Little America Hotel 1-8QO.453-9450 VISITOR INFORMATION: 1-800-831-4332

U S F U oited States Gymnastics Fedemtion

EVENT SCHEDULE (Dates & Events subject to change or cancellation)

1988 April 1-2 USGF Collegiate Nat'l Springfield,

(Division II&III-MIW) MA 5-11 International Tournament 01 Cottbus, GDR

Cottbus (M) 8-10 U.S. Rhythmic Gymnastics San Ralel, CA

Championships 8-18 USA vs Spain (Junior Boys) Madrid, Spain 9-10 NCAA Regionals rNl Various Sites 15-16 NCAA National Champion- Lincoln , NE

ships (M) 15-17 Class I State Championships Various Sites

rNl 16-21 MoSCCIN News (R) Moscow,

USSR 20-26 Messe Cup (MIWIR) Hannover, W.

Gennany 21-26 Training in Moscow (R) Moscow,

USSR 22-23 NCAA National Champion- Sa~ Lake

ships rNl City, UT 23 McDonald's Challenge - Phoenix, ftZ

USA/USSR (MIW) 24 USA/USSR Exhibition Los Angeles,

CA 24-May 1 International Tournament 01 Beijing, China

Beijing (M) 27-May 1 Senior Men's Training Camp Colorado

Springs, CO 29-May 1 Class I Regionals rNl Various Sites 3O-May 7World Sports Fair (M) Tokyo, Japan

14

~m~mu CALENDAR

May 20-23 Junior Olympic Boys NationaisAlbuquerque, 6-8 Regional Elite Qualifying Various Sites (M) NM

Meets rNl 21-28 Moncada Cup (MIW) Santiago City, 13-14 J.O . East Championships Worthington, Cuba

(Class Q OH 23-26 JRlSR Training Camp - a as- TBA 13-14 J .O . West Championships San Jose, CA sic Qualifier rNl

(Class I) TBA Canadian Classic rNl Canada 13-15 Corbeil Essones (R) Corbeil,

July France

21-23 American Classic Nationals Phoenix, ftZ 1-8 Jr. Pan American Games Puerto Rico

rNl (MIWIR)

14-Jun 5 Four Continents Training TBA 7-10 McDonald's U.S. GymnastiCS Houston, TX

Champs (MIW)

25-30

25-30 27-28 28-30

June 3-5

3-5

3-5

3-8

5-12

18-19 20-24

Camp (R) Golden Sands (MIW) Varna,

14-19 1989-92 JR Olympic Compul- Indianapolis,

Bulgaria sory Routine Filming IN

Grand Prix 01 Madrid (MIW) Madrid, Spain 19-26 SR Elite Training Camp (R) Marquette, MI 26-Aug 2 JR Elite Training Camp (R) Marquette, MI

Brother Cup (R) Japan Junior Olympic Nationals rNl Forest View

August H.S.-IL

2-9 Class I Training Camp (R) Marquette, MI 4-7 Olympic Trials (MIWIR) Salt Lake

Sr. Elite Regionals (M) Ohio State City, UT

5-7 JR. Intemational Invitational Cuba University 01

(MIW) Iowa Arizona State

9-16 Class II Training Camp (R) Marquette, MI

Elite East Qualifying Meet rNl Wilbraham, 13 Jefferson Pilot Olympic Charlotte, NC

Promotion NJ

Elite West Qualifying Meet rNlFort Worth, • - Tentative Dates or Sites TX TBA - to Be Announced

Jefferson Pilot Olympic Las Vegas, .. - Proposed Event Promotion NV (M) - Men Four Continents Champion- Toronto, rNl - Women ships (R) Canada (R) - Rhythmic U.S. Classic Nationals rNl TBA (C) - Children 'SR Womens Training Camp TBA (J) - Junior

rNl

USGF Me rchandise P .O. Box 5562

Indianapolis, IN 46255-5562

(S) - Senior

Microcomputer software for gymnastics scoring, written exclusively for the United States Gymnastics Federation. • For IBM and IBM 100% compatable micro­

computers (with 2 floppy d isc drives or hard d rive)

• H andles 60 teams and 999 gymnas ts pe r com­pe tition

• All USG F J r. O lympic age group divisions • Compulsory O nly or Compulsory/Optiona l

COmpetitIOns • T ea m scoring • All-Around Results page includes a ll gymnas ts'

placings on all events • Configured for your hardware • Program suppo rt and service provided by

I/O Databasics on all sales

o Women's Version 1.0 (Order# 3011) . $325.00 o Men's Version 1.0 (Order# 3021) . .. $325.00

All pnres indude shipping ond hondling

r-------------I

Name ________________________________________ _

Address ______________________________________ __

I C ity, State, Z ip ________________ _ Phone ____________________ _

I Co mputer make _______ model

I I

Printe r make ________________ model

For credit card only, call 0 Visa

317/237-5060 0 Maste rCa rd Ca rd N umbe r _______ ____ Exp. ___ _

Technique

U.S. GYMNASTICS FEDERATION

SAFETY CERTIFICATION TESTING

Everyone Needs To Be Safety Certified 1. Promotes a safer teachingllearning environment. 2. Reduces insurance premIUms. 3. Identifies your commitment to your profession, your sport and

your athletes. 4. Implementation of stricter safety practices will help reduce the

chances of accidents and/or injuries . 5. Helps in membership recruitment.

General Points of Information

1. The text book for the Certification Course is the USGF GYM­NASTICS SAFETY MANUAL. This text/reference manual is to be purchased and studied prior to course participation.

2. The course will take approximately six hours, including the test .

3. The Course fee is $100.00 (retest cost is $25.00). 4. Certification is good for four years.

Participation Registration Form Name: Mr.!Mrs .!Ms.

Address: _______________ _

City: ________ State.: _______ _

Telephone: 1.!.(H.!..)L-____ --'(l-"'B:.J...) _____ _

Course Director: ____________ _

Course Location: ________ -'='D~a~te'-'-: __ _

Organization Represented: ________ _

If USGF Member, List Type and Number: ___ _ Form of Payment:

Check Visa Mastercard ___ _

Name on Card: ____________ _

Number: _______________ _

Expiration Date: __ Signature: ______ _

Please make checks payable in full to: USGF SAFETY CERTIFICATION Mail Registration Form and Payment to Respective Course Contact.

'~O NOT WRITE BELOW THIS LINE - FOR OFFICE USE ONLY'

Registration Form Received: ________ _

Confirmation Mailed: __________ _

Saturday, April 9, 1988 Thcson, Arizona - 8:00am-3:00pm Thcson Parks and Recreation 900 South Randolph Way Thcson, AZ 85716 Course Director: Stormy Eaton - 602-941-3496 Local Contact: Ray Hoyt - 602-791-4870/4879

Sunday, May 1, 1988 Boont<m, New Jersey - 1O:00am-5:00pm Sokol USA 301 Pine Street Boonton, NJ 07005 201-538-2817 Course Director: Cathy Finkel - 201-263-1534 Course Contact: Geri Johnston - 201-762-5222

Friday, May 13, 1988 Bartlesville, Oklahoma - 2:00-9:00pm Park Inn Hotel, Corral Room - 918-333-2100 222 S.E. Washington Blvd. (US 75 near 60 West) Bartlesville, OK 74006 Course Director: Eddie Smith - 501-443-1902 This course will be conducted during the Region III Men's Regional Championships.

Saturday, June 4, 1988 Memphis, Thnnessee - 9:00am-5:00pm Lausanne School Library (adjacent to gym) 1381 Massey Road Memphis, TN 901-683-5233 Course Director: David Neel - 901-362-3466 Course Contact: Karen Wener - 901-362-3466 This course will be held in conjunction with the Thnnessee State Coaches Meet.

Saturday, June 5, 1988 Pittsburgh, Pennsylvania - 10:00am-6:00pm National School of Gymnastics 97 Thrence Drive Pittsburgh, PA 15236 412-655-0424 Course Director: Jeannette Jay - 412-563-4161

Friday & Saturday, June lO & 11, 1988 Fort Worth, Thxas - 7:00-1O:00pm both evenings L.D. Bell High School Course Director: Dr. Gerald George -318-988-1220 Local Contact: Jerry Milan - 817-571-0271 x 265 This course will be conducted concurrent with the 1988 USGF International Coaching Summit.

Thesday & Wednesday, June 14 & 15, 1988 East Stroudsburg, Pennsylvania - 7:00-10:00pm both evenings International Gymnastics Center Course Director: Dr. Gerald George -318-988-1220 Course Contact: Bruno Klaus - 717-629-0244 This course will be conducted concurrent with the 1988 USGF International Coaching Summit.

Dates, Times and Locations will all be listed in USA G.YMNASTICS and USGF TECHNIQUE. They can also be checked by calling the USGF Department of Safety

and Education at (317) 237-5050

Rhythmic Gymnastics Update Group Exercises: With 3 Hoops And 3 Ribbons

Following questions were raised by some Federations regarding the group exercise with 3 ribbons and 3 hoops, the Technical Committee of RSG/FIG would like to clarify the following: 1. The composition of the group exer­

cise must clearly represent the ele­ments specific to these apparatus and the body movements specific for each apparatus.

2. Regarding the ribbons: 2.1. the individual gymnast can

perform movements of the rib­bon by holding the apparatus by the stick and by a part of the ribbon, with one or two hands. Consequently, the gymnasts of the group can perform move­ments of the ribbon in which a gymnast holds the apparatus by the stick while another gymnast holds it by the ribbon.

2.2 The norms regarding the use of the apparatus as a decora­tion or the static use of the ap­paratus are still valid. How­ever, a stretched ribbon (or

stretched ribbons), held by one, two or several gymnasts in order to obtain geometrical designs without specific move­ment of the ribbon, can be tolerated under the following conditions: - the static and choreographic

use of the ribbon (or ribbons) can be justified by specific moves of the hoops. If this is not the case, it constitutes a non-authorized choreo­graphic element, for which a penalty of 0.30 point is applicable.

- the static and choreographic element of the ribbon must be very momentary. If this is not the case, it constitutes a static use of the apparatus, for which a penalty of 0.20 points is applicable.

2.3 A maximum of three such ele­ments will be tolerated in the composition. Penalty: 0.20 point for each supplementary element.

USGF Official Gymnastics Safety Manual. "' - Official manual for USGF

Safety Certifica tion Program

- Designed to raise the level of safety awareness in the entire industry.

U.S. G~ASTICS FEDERATION

Group Exercises: Musical Accompaniment

Subsequent to certain errors noted at the 1987 World Championships at Varna in the utilization of the new possibilities of accompaniment for the group exercises, the TC-RSG-FIG points out that the use of 2 or 3 differ­ent musics is acceptable .

However, where it is a question of arrangements, of music specially re­written for the exercise or of musical "editing", the following rules must be observed:

1. The different musical themes must be linked and their co-existence must be as unified as possible.

2. An interruption of the music be­tween 2 different themes is not permitted.

3. In the case of "editing", the tonal­ities of the various musical themes must be respected as well as the phrases and the musical themes themselves.

- Includes chapters on: The Need for Safety; Legal

Responsibility of Instructor; Accident

Prevention

A Must For Every Serious Gymnastics Professional

Edit ed by Gera ld S. George, Ph .D.

16

To order eithe r th e Gym nas tics or Trampoline Sa fe ty Man uals, se nd check or money order to:

USGF Merchandis ing P.O. Box 5562 Ind ianapol is, India na 46255-5562

#6001 USGF Safety manu al (quant. ) __ x $16.45 = __

#6002 Trampoline Safe ty Man ual (quant. ) __ x $ 9.95 = _ _

A llow 4-6 weeks for delivery. Total amount enclosed __ Edited by Wi llia m Allison

Technique

Survey To Help Loss of Athletes DEAR GYMNAST,

As the Age Group Chairman for Region VIII, I am extremely concerned with the loss of high level com­petitors from our sport . As a result of this concern, I have devised the enclosed questionnaire for yourself and your parents to fill out and return to me.

I am not asking you to consider returning to com­petitive gymnastics, but to possibly identify some of the causes that led to your leaving.

All responses will be marked confidential, and your

name, parents name, coach or gym name will not be mentioned. Please enter your Region and State ab­breviation for your code number, for example 4-IA if you are from Iowa (Region IV).

Thank you for your help, we all miss you and wish you well in your future endeavors.

Please send this form to me at 730 St. John's Bluff Road, Jacksonville, FL 32211 (904) 641-9966.

D.J. Milem Regional Jo Development Chairman

CODE NUMBER _____ _

(NOTE: Please use separate sheet of paper for additional comments)

1. Your present age? _____ _ 2. How long were you in gymnastics (Classes, etc.), _________________________ _ 3. How long were you in competitive gymnastics? _________________________ _ 4. Your highest level of competitive gymnastics (Elite, Class I, etc.), ___________________ _ 5. What was your most enjoyable level? _____________________________ _ 6. Why do you consider this the most enjoyable? __________________________ _

7. Time spent at your last competitive level? ____________________________ _ 8. Why did you move up/down to your last competitive level (coaches decision, mandate, your friends all moved up,

mom & dad wanted it, etc.)? _________________________________ _

9. Your age when you quit? _____ _ 10. Your grade in school when you quit? _____ _ 11. Were your grades in school affected by the time spent in gym? Y - N 12. How many hours per day did you spend in the gym? _____ _ 13. How many days per week? _____ _ 14. Did you have weekend workouts? Y - N - SOMETIMES 15. If Y, did you have to attend or did you have a choice? ______________________ _

16. How did your friends (other than friends in the gym) view your time spent in the gym? Felt that you spent too much time doing gymnastics. Thought that it was neat that you could do that stuff, etc . ___________ _

17. Were you a cheerleader in your school prior to quitting gymnastics? Y - N 18. Do you have brothers and sisters? Y - N No. Brothers Sisters ___ _ 19. If Y, did your brothers or sisters seem to resent the fact that you took up so much of your parents time (driving

to gym, going to meets, etc.?) Y - N 20. Did you feel that the difficulty level at the last competitive level was too hard? Y - N 21 . Were you injured prior to your decision to quit? Y - N 22. Was that one of the reasons you quit? Y - N 23. Was your weight one of the reasons you quit? Y - N 24. Did it seem that all of your team mates and the little kids got tricks easier than you did? Y - N 25. Did your coach seem to ignore you, and favor the others? Y - N 26. Did you change gyms before you decided to quit? Y - N 27. Did gymnastics just not seem "FUN" anymore? Y - N 28. Did any of your team mates decide to quit with you? Y - N 29. Were you hoping to use your gymnastics to get a college scholarship? Y - N 30. Any other reasons for your decision to quit? __________________________ _

Technique 17

An Insight Into The Biomechanics Of Twisting

By: Hardy Fink Department of Physical Education

University of British Columbia

Introduction

An understanding of how a gymnast twists in the air is still not complete, even in the minds of physicists and mathematicians; however, the past decade has seen much progress in identifying probable mechanisms and in

identifying which of these mechanisms are most effec­tive or contributory to successful twisting.

A major problem has been that, although the human body must obey the laws of physics, it does not act as a rigid system and therefore is not easily analyzed. In fact, a recent survey (Frohlich, 1979) of the 59 physicists who responded to a questionnaire, more than 56% believed that a somersaulting diver could not initiate a twist after having left the board; something we practitioners have known to be readily possible for some time.

Ten years earlier a paper was published (Leigh & Ben­gerter, 1967) which attempted, with the use of cinematog­raphy, to demonstrate that coaches were poorly prepared in basic theory because all in the study believed (proba­bly correctly) their divers and trampolists to have initiat­ed their twists in the air, contrary to what the authors believed the film to show.

The reasons for past difficulties are not hard to under­stand. All "knew" that according to the principle of con­servation of angular momentum rotation could not be in­itiated in the absence of an applied torque. Also, until the late '60's not many aerial performances, in the sense of multiple somersaults with delayed multiple twist, had been seen; the common appearance of which finally did challenge theoreticians to explain. Finally it may well be, and the issue is far from resolved, that as many as three or four twisting mechanisms are active during one per­formance and that these mechanisms may interact throughout a complicated twisting and somersaulting performance.

Twisting Mechanisms

For purposes of Simplification, validated twisting mechanisms may be identified in the following manner:

18

A. Torque twists B. Non-torque twists

I. Zero Angular Momentum Mechanisms a) "cat twist" or two axis theorem b) "hula hoop" or conical twist

II . Non-Zero Angular Momentum Mechanisms a) " tilt twist"

Understanding Angular Momentum

The principle of the conservation of angular momen­tum is most simply stated as:

Angular momentum = moment of inertia x angular velocity

or AM = Iw

For meaningful discussion the forgoing relationship must be understood completely.

1. Angular momentum can be viewed as the quantity of rotation a body has about some given axis as a result of its speed of rotation and the distribution of mass about the axis.

Technique

2. Moment of Inertia (I) is a measure of how the mass of a body is distributed about the axis of rotation. The further the mass is away from the object the larg­er the I and vice versa. In fact I increases as the square of the distance of the mass and therefore small increases in distance can result in relatively large increases in I.

3. Angular velocity (w) is simply the speed of rotation about the axis of rotation.

4. Since AM must be conserved (unless an external force or torque is applied) the product of I and W must stay constant. However the human body can change position in the air whch has the effect of changing I and thus w. If a gymnast tucks up in the air I will decrease and then, so that AM be con­served, W will increase accordingly and vice versa.

5. No discussion of rotation is meaningful unless the axis of rotation is specified.

Angular momentum can be created only by the appli­cation of an eccentric force - that is, a force that acts at some distance from the axis of rotation . Such a force is known as a torque and is most effective the further that it is applied from the axis.

Twisting Mechanisms

A. Torque twists: Clearly the most effective twisting mechanism is to

apply a large torque relative to the longitudinal axis during take-off. The gymnast will then have a con­siderable twisting AM in the air and then if the arms have been held wide (large I) W can be increased quite significantly simply by pulling the arms in (small I) .

For most twisting gymnastics skills the application of a torque during take-off is the major twisting mechanism.

B. Non-torque twists: Two conditions can occur: The gymnast can begin

with total body AM equal to zero about all axes or the gymnast can begin with some quantity of AM about one of the non-twisting axes (ie. somersaulting or cartw heeling). 1. Zero AM Twisting Mechanism: Two quite differ­

ent mechanisms have been identified that provide for a body twist without violating the principle of conservation of angular momentum. a) "Cat-twist" or two axis theorem

It is possible to perform a limited twist by vary­ing the relative moments of inertia of the upper and lower body - in essence successively twist­ing one part of the body with small I against one with large I which will therefore twist less in the opposite direction.

b) "Hula-hoop" or conical twist theory The simplest explanation is that if a body part is used to introduce an extraneous component of AM the total body must turn in the opposite direction to maintain the total AM at zero . The hand or arms could be rotated overhead but more effective because of its mass is to use the trunk in a "hula-hoop" fashion. The total body will respond by twisting in the opposite direction about the longitudinal axis .

It is important to recognize that these mechan­isms, under conditions of zero total body AM, provide only for a reorientation of the body in

Technique

space while certain body parts are moved and that the twisting action ceases immediately that the body actions are stopped.

II. Non-zero AM Twisting Mechanism a) "Tilt twist"

If a gymnast has considerable angular momen­tum about the tranverse (somersaulting) axis it has now been established that the most effective mechanism for initiating a non-torque sustained twist is what is commonly referred to as the "tilt twist ." This took many years to "discover" be­cause it had been neglected that AM is a vector quantity - that is, it has a magnitude component and a directional component. For AM to be con­served both components must be conserved. The direction of the angular momentum vector dur­ing a somersault is along the axis of rotation (left for forward "somies" and vice versa) .

The tilt mechanism requires the gymnast to shorten one side of the body relative to the other (by throwing the arms-one up, one down - or by side flexion or both). This has the effect if tilting the somersaulting axis away from the AM vec­tor which direction, in order to be conserved, re­quires the body to undertake a compensating sustained twist about the longitudinal axis as long as the "tilt" exists.

Though this is not a mathematical paper, the simpli­fied mathematics of what occurs can be very enlightening.

AMt = AMs sinO (1) Itwt = IswssinB Wt = Ws (Is I It) sinO (2)

where t = twist, s = somersault, a = angle of tilt

Equation (1) gives the relationship of how much twist­ing AM is induced by a given degree of tilt, but Equa­tion (2) is especially useful once it is understood. If we assume that we wish to maximize the speed of the twist (Wt) then the equation tells us the following :

1. Wt will be larger the larger the Ws (the speed of the initial somersault) .

2. Wt will be largest if the somersaults are performed in the layout position since the value of IslIs is max­imized if the numerator is maximized and the denominator minimized (a layout position in each case).

3. Wt will be greatest the greater the amount of tilt or the greater the amount one side is shortened rela­tive to the other since the value of sine increases from a to 1.0 as the angle e approaches 90°. In other words if the body tilts sideways (8 = 90°; sine = 1) complete­ly then the total somersault is converted to twist.

The message should be clear. One of the most effec­tive uses of the tilt twist mechanism is in multiple layout somersaults with late twists (i .e. double layout with full out) which gives a large value of WSt maximizes the value of Is/It and perhaps of sinO because of the arch to hollow body position change.

It has been demonstrated that in backward somersaults the feasible tile of 10° will result in a twisting speed of 3 twists for each somersault. Forwards the feasible tilt is 20° which can result in 5% twists per somersault.

19

Conclusion

It is likely that in most twisting gymnastics skills there is an interaction of the various twisting mechanisms. Although the "cat twist" and the " hula hoop" mechan­isms were explained in reference to zero angular momen­tum twists, it is clear that they may also be active in non­zero angular momentum twists. In these cases the " cat twist" likely assists in initiating twist and the "hula hoop" mechanism assists in and may be sufficient for sus­taining it although it is not clear if these actions can be maintained consciously throughout a complex performance.

In all cases - other things being equal - a torque twist is the most effective twisting method provided it does not aesthetically detract from the performance or result in the modification of other performance parameters (i.e . height or somersaulting AM). In delayed non-zero AM twists the "tilt twist" mechanism is the most effective and the only one that can create a sustained twist . It is also the only in air mechanism that is certainly under conscious control during the initiation and maintenance of compli­cated twisting skills .

REFERENCES

Bartee, H . & Dowell, L (1982) "A cinematographical anal­ysis of twisting about the longitudinal axis when per­formers are free of support," Journal of Human Move-4~ ~ _ • • .L C'L • . ..J; __ 0 . .41 r:A jij.Cfi. ... 0,"&4Uj.£:.':; , U • ..i.. - •

Fink, H. (1985) "A critical review of biomechanical research in the sport of gymnastics," University of Brit­ish Columbia, unpublished paper.

Fink, H. (1986) "The principle of the conservation of an­gular momentum and its application to gymnastics, " Coaching Review, March, 1986.

Frohlich, C. (1979) "Do springboard divers violate angular momentum conservation?" American Journal of Phys­ics, 47(7) : 583-592.

Leigh, L. & Bangerter, B. (1967) "A cinematographic anal­ysis comparing techniques and mechanics of selected forward and backward twisting somersaults in com­petitive diving and rebound tumbling." Paper to A .A.H.P.E .R., March 13, 1967.

Liu, Z. & Nelson, R. (1985) " Analysis of twisting somer­sault dives using computer diagnostics" in BI­OMECHANICS IX-B

Frohlich, C. (1980) "The physics of somersaulting and twisting," Scientific American, March, 1980.

Van Gheluwe, B. (1981) " A biomechanical simulation model for airborne twist in backward somersaults" Journal of Human Movement Studies, 7:1-22.

Van Gheluwe, B. & Duquet, W. (1977) "A cinemato­graphic evaluation of two twisting theories in the back­ward somersault," Journal of Human Movement Studies, 3:5-20.

Yeadon, M. & Atha, J. (1985) "The production of a sus­tained aerial twist during a somersault without the use of asymmetrical arm action" in Biomechanics IX-B (ed. by Winter et al), pp . 395-400.

20 Technique

e NATIONAL USGF TEAM T·SHIRT LOGO PIN Wear your sport on your shirt. The new national team logos are presented in Red and Navy on a 50/50 cotton t-shirt. 9101-9107 Women's National

TeamT 9201-9207 Men's National

TeamT 9301-9307 Rhythmic

NationalTeamT $7.95

USA SWEATSHIRT This soft white sweatshirt is embroidered with USA in red and Gymnastics in blue. Per­fect for your favorite gymnast. 5311-5317 $22.95

TRAVEL KIT The USGF logo is presented on a navy, nylon travel kit. Perfect for your grips and over­night trips .

The USGF Logo Pin is red, white and blue under soft enamel-1". 4201 $2.00

NATIONAL TEAM PINS Select your team pin and show the sport you support! The new logo pins are 1" x 1" with the particu lar event displayed in red, white and blue. 4203 Women's National

Team 4204 Men's National Team 4205 Rhythmic National

Team $2.50

USA GYMNASTICS COFFEE MUG

------------------- 5551 $6.50 Your favorite hot drink will have an extra twist with a USA Gym­nastics Coffee Mug. USA Gymnastics is in red on a white ceramic mug.

Orde r # O\'l' GO\O~ SIl-e Description Total : OFFICIAL

I WORKOUT I BAG

Aoparel & T-Shirts digit of order #

. gnates the size desired Adult sizes XL L M S Last Digit 1 2 3 4

USGF Merchandise P.O. Box 5562 Indianapolis , IN 46255-5562

Total Amount Name ________________________ __

Address ______________________ _

City. State , Zip __________ _ Phone, _______________________ _

For credit card only, ca ll

317-237-5060

D VISA

o MasterCard Card Number ____________________ _

My card expires __________________ _

I I I I I I I I I

Perfect for carrying all your stuff to the gym. This navy nylon bag is 18 x 10 with white straps and the USGF logo in red and white. 5421 $9.95

4601 $6.00

TOWEL The USGFTowel is 34" x 60" and displays the USGF logo in red and blue . Perfect for the shower or for the beach . 5701 $20.00

I INTERNATIONAL I I COACHING SUMMIT I

Featuring Men's And Women's Gymnastics

Come participate in a three-day coaching seminar for men's and womf>n's 2:vmnastics with

top- clinicians from th~ United States and Soviet Union.

FEATURES • Two coaches and gymnasts from the United States and Soviet Union present at all sessions. • Major emphasis: Teaching Progressions • Learn the Soviet's advanced and elite level teaching and training techniques . • Learn how to adopt these same training techniques for your beginning and intermediate programs from the U.S.'s major clinicians.

TWO SESSIONS June 10-11-12, 1988 Ft. Worth, Texas L.D. Bell High School

COSt: $150.00* *Doesn't include meals and lodging Local Contact: Emil and Jerry Milan Men's Major Clinician: James Hartung, 1984 Olympic Gold Medalist

June 14-15-16, 1988 East Stroudsburg, P A International Gymnastics Center

COSt: $210.00* *Does include meals and lodging Local Contact: Bruno Klaus Men's Major Clinician: Gene Watson

Robert Cowan USGF Men's Program Administrator Pan American Plaza, Suite 300, 201 S. Capitol Avenue

Indianapolis, Indiana 46225 • (317) 237-5050

GYMNASTICS SAFETY

FI SECQ

1

1\LWAYS VIDEO

I n an effort to upgrade safety awareness in the gymnastics community, the United States

Gymnastics Federation has developed a safety video, that gives athletes, coaches and club owners easy and enjoyable method of disseminating safety .!_J:. ~ __ L..!~_ 1J.lJ.VJ.J.llQUV.ll.

Featuring Olympic gold medalist Bart Conner and Peter Vidmar, along with silver medalist Kathy Johnson, Abie Grossfeld, Greg Marsden, Judy A vener and Bela Karolyi. Truely a state of the art method to teach gymnastic safety and awareness. Delivered price: $29.95 to USGF Members*

$39.95 to non-members *Please provide membership number to receive discount.

Name ____________________________________ __

Address __________________________________ ___

City __________________ State __ Zip ___ _

Ph one

Order # Qty .

2601

USGF Merchandise P.O. Box 5562 Indianapolis, IN 46255-5562

Description Total

Safety Video

Member $29.95

Non Member $39.95

Total Amount

For credit card only, call

(317)-237-5060 o VISA 0 MasterCard

Card Number ____________ _

My card expires ____________ _

American Athletic, an official spon­sor of the United States Gymnastics Federa­tion, is the all-around favorite. The one selected for use in the Olympics, and the Olympic Trials, the World Gymnastics Championships, the Pan American Games, the World University Games ... and many other major tours and meets.

Why this unequaled popularity? Because our concern rests with the athlete. Because we believe gymnastic apparatus should enhance an athlete's performance, never hinder it.

ATAI

It's no wonder American Athletic is the choice of champions. Shouldn't it be your choice, too? Bring out the best in your athletes, bring out MI American.

For information about the complete line, call Ken Cysewski at 1-800-247-3978 toll-free today. Telex 910-520-1031.

I ~AJ American 200 American Avenue Jefferson, Iowa 50129, U.S.A.

Official Supplier of Gymnastic Equipment to the United States Gymnastics Federation

U.S. OLYMPIC TEAM VISA® CARD Preferred Application

To be considered for this account you must be able to answer YES to these questions: Do you have a minimum income or at ieast $15,0007 r--l ' , ,---, ... ,

U Ie!:) U I\lU

If no, you may wish to consider a Co-A pplicant whose income may also be included. Is your credit history clear of any bankruptcies, legal actions or delinquent accounts? D Yes 0 No Please complete the following:

Full Name

Apartment Number a nd Na me

Stree t Address

Socia l Secu rit y Nu mber

D Own 0 Re nt 0 Li ve with Parents

Previous Address

Sta te Zip

Length of Residence

Date of Birth

$ Mont hly Mo rtgage or Re nt

S ta te Zip

$

Years

~B-us~in-e-s-s ~N~a-m-e-o-r~E~n-,p-"'lo-y-e-r----------- Annual Income

Business Add ress

Sta te Zip

Yea rs =7.'"-:-::----------­~B,-u"'"'si-n-es-'-s·P""h-o-n-e----- '"'Ye'-a-rs~' T~I"',eC!.:re'- Position

O ther Income" Source

YeMs Previous Employer Years There

Position Previous Business Address

Cit y Sta te Zip

Ap plica nt 's Signatu re Date

Please mail this application to: U.S. Olympic Team VISA Card CORESTATES BANK OF DELAWARE, NA P.O. Box 8847, Wilmington, DE 19885-9409 1085-11 -S01 Only residents of the Continental United States arc eligible fo r this o ffer.

Complete this section if you would like a Joint Account.

Fu ll Na me of CO-Applica nt

Address (If different from applicant's)

Socia l Secu rit y Number Date of Birth $

nB-us~in-e-s-s'N'a-m-e-o-rrE'-m-r7Io-y-e-r------ ~A-n-n-u~a l~l-nc-o-m-e--------

Business Stree t Address

Cit y (

Business Phone

$ O the r Income'

S ta te Zip

Years Years There Position

SOUTce

Co-Applicant's Signature Date

'Alimony, child support, or separate maintenance need not be revealed if you do not wish to have it considered as a basis for repaying this obligation .

We may obtain a credit report in connection with your applica tion . If you aSK, we will tell you whether we have obta ined a credit report and the name of the credit bureau that 'supplied it.

For Bank Purpose Only: Code CL Date CoreStates Credit Account Disclosure

Annual Variable Annual Grace Percent- Rate Index Member- Period are Rate and ship for

APR) Spread Fee Purchases 15.9% TheAPRmd' $25 Finance

Cash increase, an charges will wi ll be d e ter- Late no t accrue

Advance mined by add-Fee on new rur-

Fee ing 6% to the chases i you Pnme Rate

$15' pay your en-

None of The tire balance

Trans- Philadel~hia National ank. Over-The- by the pay-

ment du e date action As of 1/1 /88, Limit shown on

Fee the APR was Fee your monthly

None 15.9%.

$15* s tatement.

,Excep t in Colorado, Ida ho, IndIa na, Iowa, Kansa s, Maine, Oklah oma, South Carolina, Utah and Wyoming where fees are waived.