does strength training change your movement patterns?

Does strength training change your movement patterns?

By Chris Beardsley, S&C Research columnist

Most of us in this industry believe that good movement patterns make someonea better athlete, as well making them less likely to get injured. Unsurprisingly,therefore, a lot of programs have been put together to help you improve yourmovement patterns.

Early on, these programs tended to involve mainly just stretching tight muscles,and then strengthening weaker ones with special exercises.

These days, much of the research is being done into the effects of movementpractice with feedback, where a risky movement (like a drop landing) isperformed regularly, but altered over time using cues.

But taking one step back, how much does a standard, off-the-peg strengthtraining program change your movement patterns anyway, even without anyexpert input, stretching, foam rolling, special exercises, or cues?

Let’s find out!

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What do you mean by “movement patterns?”

The expression “movement patterns” is one of those concepts that everyoneimmediately recognizes, but no-one has ever managed to put forward an exactdefinition that sticks in the memory.

Sadly, I am not going to fix that particular problem today.

Even so, this is not too big a problem, because we can all agree in the meantimethat movements are built up of single joint angle rotations. And the amount ofrotation at a joint (called the joint range of motion or ROM) can change, whenmeasured before and after a training program.

And if joint ROM changes, then movement patterns must change.–

So for the purposes of this article, I am just going to look at whether maximum

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joint ROM changes in a variety of sporting movements, after no-frills strengthtraining. I am going to limit myself to the hip and knee joints in lower bodymovements (because it is what I know best).

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What do you mean by “strength training?”

Bear with me for just a second, we need to clarify this quickly.

We all know what strength training is, but the research has some complexities.

This is because most studies that have assessed changes in movement patternsafter training programs have done so to try and figure out a way toprevent injuries. As a result, the kitchen sink tends to get thrown in.

In these “kitchen sink” training programs, the subjects end up doing a wholetheme park of strength training (with or without internal cues), balance,plyometrics, core stability, static stretching, and anything else the researcherscan come up with, all in a concerted effort to produce some kind of injury-prevention effect.

This is, of course, totally understandable.

We need to find something that works. However, if we want to figure out howstrength training changes movement patterns, then looking at studiesinvestigating these kind of programs does not help, because the otherinterventions prevent us seeing the wood for the trees.

So while there is a ton of literature out there assessing the effects of varioustraining programs on movement patterns, I have had to be verycautious about which studies to include in the analysis, to tease out the effectsof strength training alone. Sometimes you can start reading a study that soundslike it only used strength training, and get halfway through the method sectionand find that there was static stretching, plyometrics, or balance exercises inthere as well (e.g. Lephart et al. 2005).

So just to be clear, in this article, when I refer to a “strength training” programand its effects on movement patterns, I literally just mean the kind of strengthtraining that anyone can perform on their own in a gym, and not anything else.


So as well as leaving out the combined training studies, I’ve ignored studiesusing feedback, movement practice, and attentional focus, even though there issome interesting work being done there (e.g. Gokeler et al. 2015; Welling et al.2016).

But wait a minute!

We try to change movement patterns for two reasons: improving sportsperformance, and reducing injury risk. And while we know that strength trainingimproves sports performance, is there any evidence that standard strengthtraining can reduce your risk of injury?

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Does strength training reduce injury risk?

Although it has not been widely researched, one or two studies do suggest thatperforming standard strength training programs (without anything else as well)could indeed reduce the incidence of injuries in general.

Way back at the dawn of time, Hejna et al. (1982) performed a case-controlanalysis of high-school athletes who were using weight training, and comparedthem to those who were not. The rate of injuries was lower among athletes whoused weight training compared to those who did not (26.2 vs. 72.4%). Whilepromising, this result was not really followed up.

Much later, Lehnhard et al. (1996) recorded injuries in a men’s college soccerteam over a 4-year period. In the first 2 years none of the athletes did anystrength training. In years 3 and 4, all of the athletes performed strength trainingthroughout the year. Injury incidence decreased from 15.2 to 8.0 injuries per1,000 exposures. Again, while very promising, this result was not really chaseddown in detail.

Much more recently, we find similar research appearing. Zouita et al. (2016)assessed the effects of a 12-week period of strength training in elite youngsoccer players (13 – 14 years old). The non-strength training group incurred 13injuries, which was more than the 4 injuries sustained in the strength traininggroup.


In the intervening 20 years, with the sole exception of hamstring muscle strains,most research has erred towards investigating combined (kitchen sink) programsfor injury prevention. While this approach may well have been beneficial, insofaras throwing everything possible at injury prevention has almostcertainly produced a larger reduction in injuries, and a larger effect is mucheasier to detect, it also has two downsides.

Firstly, it has made it much harder for other researchers to figure out themechanisms by which any of the interventions are reducing injury incidence. Soit is hard to tell from these trials whether the risk reductions come from athletesgetting stronger, or from them improving eccentric-specific strength, balance,flexibility, or movement patterns.

Secondly, it has made injury prevention harder to access for the average athlete.Most athletes are going to the gym and performing some strength traininganyway, and in such cases a standard but well-constructed strength trainingprogram can be learned and followed fairly easily. On the other hand, specifyinga need for a wide range of different modalities, some of which require specialequipment, we have moved the focus of the evidence base (probably correctly,but perhaps a little too hastily) away from what an average athlete without alarge coaching staff is reasonably able to do.

This is why I think it is essential to look at strength training on its own. It is a loteasier to do on your own without special equipment, which means that morepeople are likely to do it, which means fewer injuries (assuming it works).

With that being said, let’s jump right in, by looking at drop jumps.

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Why look at drop jumps?

Although we can just as easily look at joint angle movements during single-legsquats, lateral cutting maneuvers, and running, drop jumps are a useful way tostudy how strength training affects movement patterns, for two reasons.

Firstly, the difficulty of the landing phase is always identical, being from a fixedheight. Other jumping tasks are affected by distance, speed, or height jumped,which are a function of muscular strength, which obviously changes with


strength training. Secondly, landings are often identified as the point at whichacute, non-contact injuries occur because of poor mechanics (Mason-Mackay etal. 2015), so that makes them a useful movement to study.

So in this article, although I will discuss a few other movements, most of theresearch I will analyze involves drop jumps.

When looking at drop jumps, soft landings are thought to be beneficial. Softlandings involve more knee flexion than stiff landings, and lower vertical groundreaction force (VGRF), and allow more energy absorption by the hip andknee (DeVita & Skelly, 1992). Since strength training can indeed improve theability of muscles to absorb energy in eccentric contractions, it seemsplausible that strength training will increase knee flexion in drop landings.

This is important, as high levels of VGRF in drop landings likely increases the riskof anterior cruciate ligament (ACL) injury (Yeow et al. 2010; 2011). So makinglandings softer could perhaps help prevent some ACL injuries.

In contrast, although one study has linked low levels of hip abduction, kneeflexion, and knee extension strength with increased knee valgus in single-legsquats (Claiborne et al. 2006), the trend is for no association between kneestrength and knee valgus in most squat movements, and only a small associationbetween hip strength and knee valgus (Cronström et al. 2016). Poor ankledorsiflexion mobility seems a more likely cause of knee valgus (Bell et al. 2013;Malloy et al. 2015; Mason-Mackay et al. 2015).

Therefore, although knee valgus is also considered a risk factor for ACL injuryand knee injury in general (Weiss & Whatman, 2015), it is unlikely that we will seea change in knee valgus as a result of strength training in the following analysis,but if we do see any effect, it is most likely that it will be in single-leg squats(Claiborne et al. 2006).

So let’s see how strength training changes movement patterns!

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Does strength training knee flexion in drop jumps?

Standard strength training does seem to increase peak knee flexion angle


in drop jumps (McCurdy et al. 2012; Kondo & Someya, 2016), but suchimprovements do not always occur (Arabatzi & Kellis, 2012).

Where it happens, it means that the landing is “softer” than it was beforetraining, because the greater knee bend upon contact with the ground creates alonger joint ROM through which to absorb the impact (Pollard et al. 2010;McCurdy et al. 2012).

Using traditional barbell exercises in a group of female athletes with 4.3 years ofresistance training experience, McCurdy et al. (2012) reported an increase inpeak knee flexion in their strength training group, while the control group thatstopped their resistance training for the duration of the study displayed theopposite trend, as shown in the chart below.

Knee flexion increases in drop jumps with strength training

And using manual resistance for hip abduction (side-lying hip abduction) and hipexternal rotation (side-lying clam) with the load fixed by hand-helddynamometry, Kondo & Someya (2016) found that knee flexion increased by 7.5degrees at the point of greatest difference, although there was a trend forgreater knee bend at all points in the drop jump measured, shown in the chartbelow.


Knee flexion increases in drop jumps with strength training

In a group of male athletes with resistance training (but not Olympicweightlifting) experience, Arabatzi & Kellis (2012) observed conflicting trendsacross drop jump tests from 20cm, 40cm, and 60cm after standardstrength training, and a similar set of conflicting trends after Olympicweightlifting, which makes their results hard to interpret.

And for what it is worth, Lephart et al. (2005) reported an increase in kneeflexion of 8 degrees, but they used a couple of static stretching and balanceexercises in their program, as well as strength training. This was accompanied bya reduction in peak knee net joint moment, confirming the idea that a softerlanding strategy reduces the impact, probably by extending the impulse (force• time) over a longer time period.

Finally, in a similar but not identical task to the drop jump (the horizontal stopjump), Herman et al. (2008) failed to find any change in peak knee flexion anglesin a group of recreational female athletes. However, despite involving athletes,the training program used elastic resistance similar to those used inrehabilitation settings, and therefore may not have used sufficient load toproduce meaningful adaptations.


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Does strength training hip flexion in drop jumps?

Strength training seems to cause an increase in peak hip flexion angle in dropjumps (Arabatzi & Kellis, 2012; McCurdy et al. 2012; Kondo & Someya, 2016), butsuch increases do not always occur (Arabatzi & Kellis, 2012).

Such an increase has similarly been interpreted to mean that the landing is“softer” than it was before training (Pollard et al. 2010), because the greatertrunk ROM upon contact with the ground allows a smaller peak force, asdecelerating the inertial load of the upper body happens over a longer timeperiod.

Using traditional barbell exercise in a group of female athletes with 4.3 years ofresistance training experience, McCurdy et al. (2012) reported an increase in hipflexion, although this result did not reach statistical significance, even though thegroup that stopped resistance training for the duration of the study displayed theopposite trend, as shown in the chart below.

Hip flexion in drop jumps increases with strength training


Using manual resistance for hip abduction (side-lying hip abduction) and hipexternal rotation (side-lying clam) with the load determined by hand-helddynamometry, Kondo & Someya (2016) found that hip flexion in a drop jumpincreased by 15 degrees upon landing, and by 16 degrees at the point of impactabsorption.

Hip flexion in drop jumps increases with strength training

And in their group of male athletes who had some resistance training (but notOlympic weightlifting) experience, Arabatzi & Kellis (2012)found conflicting results after strength training, when they tested drop jumpsfrom 20cm, 40cm, and 60cm box heights, which again makes their results hardto interpret.

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Does strength training knee flexion in lateral cutting?

Moving away from drop jumps briefly, to look at lateral cutting, we can see thatCochrane et al. (2010) set out on an ambitious plan to assess the effects of fourdifferent training protocols on knee movements during sidestepping to 30 and


60 degrees, crossover cutting to 30 degrees, and straight line running, underboth preplanned and unanticipated circumstances.

Even so, the only finding in respect of peak knee flexion was that free weightstraining (but not machine weights training) actually reduced knee flexion in thecutting maneuvers. This result might be taken to infer that strength trainingis disadvantageous for injury-related movement patterns during lateral cutting,but this is difficult to assess based on a single study.

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Does strength training knee valgus in drop jumps?

Strength training alone does not tend to reduce knee valgus during drop jumps,at least when performed without the benefit of cues or guided coaching (McGinnet al. 2006; McCurdy et al. 2012; Kondo & Someya, 2016). Whether this isbecause the change is too small to notice, or because there is genuinely noeffect is less clear. Similarly, there is also no effect on knee valgus after strengthtraining in horizontal stop jumps, which are similar to drop jumps (Herman et al.2008).

On the other hand, when coupled with feedback regarding proper movement,which is a form of deliberate practice, strength training is effective at increasinghip abduction angle, and also shows a trend towards reducing knee valgus in ahorizontal stop jump. Interestingly, feedback alone is not effective (Hermann etal. 2009).

This suggests that both strength training and jumping practice might have clearand distinct contributory roles in improving key movement patterns in dropjumps, including knee valgus.

If you think about it, this could explain why plyometrics (with and withoutfeedback) are generally more reliable at improving movement patterns injumping movements compared to strength training (Lephart et al. 2005; Stearns& Powers, 2014; Nyman & Armstrong, 2015), as they essentially integratestrength training and some movement practice into one type of exercise.

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Does strength training knee valgus in single-leg squats?

In a very well-constructed study, which they should be extremely proud of,Dawson & Herrington, (2015) compared the effects of ground-based hipstrength training (gluteus maximus and medius) with movement practice on kneevalgus in single-leg squats. They found that the frontal plane projection anglereduced by around 6.5 degrees in both training groups, and hip adduction angleimproved by around 4.0 degrees, with no differences between groups.

This suggests that even very simple hip strengthening (quadruped hipextensions and side-lying hip abductions) can improve knee valgus in single-legsquats, even though strength training appears not to benefit knee valgus duringdrop jumps.

It also vindicates the findings of Claiborne et al. (2006) to a certain extent, whoreported an association between hip and knee strength, and knee valgus duringa single-leg squat, although based on the above analysis we should be cautiousabout assuming that the same applies for landings or squats using both legs.

Finally, in some support of these findings, similar results were reported by Willy& Davis (2011) in respect of hip adduction angle in the single-leg squat, and byOlson et al. (2011) for frontal plane projection angle in the single-leg step down,albeit in both cases after using a combined strength training and visual feedbackprogram, and not just a strength training program on its own.

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Does strength training knee valgus while running?

To date, the research is fairly clear in showing that while strength trainingmight have beneficial effects in improving running economy for enduranceathletes, it does not seem to alter knee valgus during running (Snyder et al.2009; Willy & Davis, 2011; Earl & Hoch, 2011; Ferber et al. 2011; Sheerin et al.2012).

Why strength training should produce an effect on knee valgus during single-legsquats, but not on knee valgus during running is a very interesting question,which I will not venture to try and address here.


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How does this all tie together?

There are several effects of strength training on movement patterns, but theseeffects seem to differ depending on which movement we measure (drop jumps,single-leg squats, lateral cutting, and running).

We might have anticipated this, as we know that an athlete’s joint anglemotions do not correlate perfectly across different tests, such as single-leglandings, single-leg squats, a two-leg landings, and two-leg squats (Donohue etal. 2015).

So while some beneficial joint angle motion changes might occur automaticallyas a result of a strength training program in some movements (such as softerdrop landings), this may mean that other risky movement patterns (such as kneevalgus) will likely require addressing with other methods, which might includeplyometrics, movement practice, and various types of feedback.

Also, as Donohue et al. (2015) suggest, we can see that “individuals are likely todemonstrate different profiles of injury risks when screened using differenttasks” and even when strength training has improved knee flexion or knee valgusin one test, it may not necessarily change it during another test. This may requireseveral tests of movement patterns to be performed, and not just one!

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Conclusions

Yes, strength training does change your movement patterns, at least by alteringpeak joint angles during several athletic movements, BUT theeffect differs depending on which movement is tested (e.g. drop jumps, single-leg squats, lateral cutting, running).

Strength training seems to increase peak hip and knee flexion angles in dropjumps, making the landing “softer” through greater absorption of the impactforces. However, it does not seem to reduce knee valgus in either drop jumps orrunning, although it might reduce knee valgus during single-leg squats.

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References

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