Do stiffness and asymmetries predict change of direction performance?

ABSTRACT

Change of direction speed (CODS) underpins performance in a wide range of sports but little is known about how stiffness and asymmetries affect CODS. Eighteen healthy males performed unilateral drop jumps to determine vertical, ankle, knee and hip stiffness, and a CODS test to evaluate left and right leg cutting performance during which ground reaction force data were sampled. A step-wise regression analysis was performed to ascertain the determinants of CODS time. A two-variable regression model explained 63% (R² = 0.63; P = 0.001) of CODS performance. The model included the mean vertical stiffness and jump height asymmetry determined during the drop jump. Faster athletes (n = 9) exhibited greater vertical stiffness (F = 12.40; P = 0.001) and less asymmetry in drop jump height (F = 6.02; P = 0.026) than slower athletes (n  = 9); effect sizes were both “large” in magnitude. Results suggest that overall vertical stiffness and drop jump height asymmetry are the strongest predictors of CODS in a healthy, non-athletic population.

KEYWORDS:

• Agility
• cutting
• leg-spring behaviour
• spring-mass model
• torsional spring model

Acknowledgements

No benefits in any form have been or will be received from any commercial party or grant body related directly or indirectly in relation to this manuscript. The results of the current study do not constitute the endorsement of any product by the authors.

Disclosure statement

No potential conflict of interest was reported by the authors.