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Medicine of Cycling – Anatomy of the Knee

Common Cycling Knee Disorders

Knee Structure

• Hinge joint

• Possesses the largest sesamoidbone in the body- patella

• Caught between 2 multi-axial joints above and below

• The knee moves in 3 dimensional space and must be assessed as such when it comes to quantifying cycling specific patterns of movement

Anterior Knee Pain

• Multifactorial

• Joint- patella tracking:

influenced by bony structure

and mm control.

• Mm length.

• Soft tissue- pat tendon >

quad tendon. (strength v

mechanical advantage)

• Medial Retinaculum/ ligamentous structures

• Medial Patella-femoral Ligament

• Pes Anserine Tendonitis / Bursitis

• Off bike assessment of mm length and strength – functional movement patterns e.g. valgus knee collapse in single leg squat and assess knee tracking through 3D tracking under load

• Plan appropriate distal or proximal control

Medial Knee Pain

Lateral Knee Pain

• Assess muscular system in terms

of mm length and strength.

• Saddle type and stability- both

intrinsic and extrinsic factors.

• Assess accurate biomechanics

when rider is under load.

• Does the rider overextend?

Appropriate for that riders

flexibility.

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• Pes Anserine( more medial but common insertion)

• Biceps Tendonitis(lateral)- assess mm length. On bike look at combination of saddle height and fore/aft-possible rearward position

• Gastrocnemius- proximal calf- can be deep ache- assess pedal technique/ankle drive/ cleat position fore/aft

Posterior Knee Pain

Cycling for Rehab

• low impact rehabilitation tool.

• positive and potentially negative impact.

• The ‘knee’ is the most common lower limb cycling injury.

• Location of symptoms + quantify movement + determining the primary pathology = interventions to an appropriate treatment plan

• Range of Motion- total joint range at hip, knee and foot

• Joint Angles- at different points of the pedal stroke

• Alignments- 3D

• Movement Patterns- how the rider functions as a result of

intrinsic and extrinsic factors

Cycling Kinematics

Determining optimal position on a bicycle while the

individual is riding under a normal physiological load.

What is Dynamic Fit?

Dynamic Fitting Tools

• 2D

• 3D

• Power

Zin Technology

• Digitizes a bike

• Accurate fit coordinates

• Frame geometry

Retül Müve

• Dynamic Fit Bike

Frame Finder Technology

• Frame, Equipment & Fit Database

Retül Fit and Sizing System

Static vs. Dynamic Fit

Static

• Limited joint angles

• KOPS

• No pedal stroke analysis

• No video

• No power

Dynamic

• Full body joint angles and different points of pedal stroke

• Knee forward of foot replaces KOPS

• 3D pedal stroke analysis

• Video

• Power

• Enables a holistic assessment of riders mvt patterns and interaction with the bikes contact points

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Range Of Motion

Road TT

Ankle 23.6 +/- 5.2 24.9 +/- 5.3

Knee 74.3 +/- 3.5 74.1 +/- 3.3

Hip 44.1 +/- 2.7 44.3 +/- 2.5

Variability in Positioning

R² = 0.8738

650

700

750

800

850

900

750 770 790 810 830 850 870 890 910 930 950

SA

DD

LE H

EIG

HT

(M

M)

TOTAL LEG LENGTH (MM)

Saddle height vs Leg Length

Knee Angle Flexion

98

100

102

104

106

108

110

112

114

116

118

KN

EE

AN

GLE

FLE

XIO

N (

DE

GR

EE

S)

Knee angle flexion: road

Road: 111 +/- 2.9°

TT: 111.3 +/- 2.9°

Knee Angle Extension

Road: 36.7 +/- 4.0°

TT: 37.1 +/- 3.6°

25

30

35

40

45

50

KN

EE

AN

GLE

EX

TE

NS

ION

(DE

GR

EE

S)

Knee Angle Extension

Ankle Angle Minimum

Road: 72.6 +/- 6.1°

TT: 68.0 +/- 4.9°

50

55

60

65

70

75

80

85

90

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Ankle angle min

Ankle Angle Maximum

Road: 96.1 +/- 5.3°

TT: 92.4 +/- 4.8°

80

85

90

95

100

105

110

Ankle angle max: road

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Knee Fore/Aft of Foot (Pedal Spindle)

Road: 5.2 +/- 18.2 mm

TT: 77.8 +/- 19.8 mm

-40

-30

-20

-10

0

10

20

30

40

50

60

70

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

KF

F (

MM

)

Knee forward of foot: road

Intrinsic and Extrinsic Factors in Knee

Pain• INTRINSIC

• (Rider Biomechanical Functional Faults and Riding Technique)

• Dysfunctional Joints- Pathology/ ROM/ Instability

• Lack of Appropriate Strength: ‘Robustness’

• Pelvic Asymmetry

• Anatomical Variation e.g. hip retro or ante version

• Pre-fit assessment informs the clinician on the Rider dysfunctional system

• Look for those significant side to side differences

• If bilaterally weak and symptoms are unilateral is the weakness significant

Primary Dysfunctions

Obvious off bike Assessment Movement Faults

• All joints are participating in contributing to lower limb kinematics.

• Altered knee position will occur due to foot orientation in relation to ‘neutral knee’

• Genu Varum v. Valgus-influences patella tracking:

• Must assess the mm system

Intrinsic and Extrinsic Factors in Knee Pain

Intrinsic and Extrinsic Factors in Knee Pain

• EXTRINSIC

• Component choice- saddle too wide/narrow/uncomfortable

• Crank Length **

• The general fit of the bike- self selected of fitted poorly

• Influence of coach on training load prescription/ early season etc

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Knee is caught in the middle….

Proximal

• Saddle shape and

type

• Stability at pelvis

• Mm length and

strength at the hip

• Mm pattern

coordination

Distal

• Bottom up support

• Foot mechanics

• Shoe support

• Shoe type

• Cleat position

Adaptability

MACRO ABSORBERS

Clinical Application

• The same bike fitting interventions affect

different individuals on a spectrum of

effectiveness from productive to damaging

depending on the riders ability to adapt to

change.

• The fit process itself should be dynamic and

open to change.

• Outliers of fit

• Avoid recipe fit procedures.

• Bike is a fixed environmental constraint but is adjustable

• Human is flexible organism but adaptable on a spectrum

Clinical Application

Impact of Changing Position on Kinetic Chain

• Not so simple

• Explains why some people react immediately to changes….. And some resist

• Why some do not change

• Why some change but not has we expected

• Why bike fit for some is important and for others not….

Movement Pathology

Movement Pathology:

• Biomechanical Plotting Often Highlights

Asymmetries

• Frontal Plane

• Transverse Plane

How to Manage the Fit:

• Creating Neutral Position

• Addressing Rider Complaints

• Conducting Mechanical or

Biomechanical Corrections

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Professional vs. Amateur Riders

Novice Riders Can Exert Abnormal Joint &

Muscular Loads – Always Symptomatic?

Summary

• The Knee is the Link in the Chain

• Don’t get side tracked by local symptoms.

• Assess Lower Limb Anatomical Structure and Function and any predisposing factors that may limit a ‘neutral’ fit being achieved.

• Assess individual biomechanical movement patterns to make informed and clinically appropriate fit interventions