Change of direction (COD) ability is a key component of agility. Biomechanics research can help us identify which factors lead to better change of direction performances.
In a comparison of rugby athletes, starters were able to accomplish the same COD tasks in a shorter period of time.
Importantly, it was the deceleration phase (the time before the knee starts extending) that was the main contributor to this difference. So deceleration ability (which is determined by eccentric strength) may be a key factor.
One final comparison of athletes found that the horizontal propulsive force in a final step was positively associated with faster COD ability, while the vertical braking force was negatively associated.
This finding also supports the role of a more horizontally-directed force vector for optimal COD performance.
Taken together, these studies imply that certain strength qualities are very important for COD ability.
Eccentric strength, maximum strength, horizontally-directed strength, and strength at long muscle lengths may all therefore transfer very well to change of direction performance.
Long-term training studies are still catching up with these biomechanical investigations, but we can already see that eccentric strength is able to improve force production preferentially in the deceleration phase of COD tasks, which may be key to enhancing agility.
Hopefully, future studies will also investigate the impact of other specific strength qualities, such as maximum strength, horizontally-directed strength, and strength at long muscle lengths, so that we can identify all the essential strength qualities that transfer best.
Chris Beardsley is the Director at Strength & Conditioning Research Limited where he breaks down scientific research for practitioners. View more of his great infographics on his Instagram account and more articles on his LinkedIn account.
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