Knee and ankle biomechanics in 90° side cutting on synthetic turf with shock pad

Abstract

The purpose of this study was to examine differences in knee and ankle biomechanics on synthetic turf with and without a shock pad in two approach velocities during a 90° cutting movement. Twelve recreational male American football or soccer players performed five trials of 90° side cutting in each of four conditions: turf only and turf with shock pad at approach velocity of 3.0 and 4.0 m/s. A two-way (surface × approach velocity) ANOVA was used to analyse selected variables. Knee and ankle variables were generally similar across surface conditions. However, peak knee frontal-plane loading eccentric power was greater (p = 0.013) while peak knee frontal-plane push-off eccentric power was reduced on the shock pad (p = 0.020). A surface × approach velocity interaction was detected for peak knee sagittal-plane eccentric power (p = 0.018), and a post-hoc analysis found a significant increase of peak knee sagittal-plane eccentric power at a faster approach speed on the turf only condition compared to the turf with the shock pad. There were increases in the knee extension moments (p = 0.004), peak push-off medial ground reaction force (GRF, p = 0.025), peak ankle eversion moment (p < 0.001), and ankle inversion ROM (p = 0.001) as approach velocity increased while peak push-off vertical GRF decreased (p = 0.011). The effects of the inclusion of a shock pad on lower extremity loading during a 90° cutting movement are limited. The results indicate that the turf with the shock pad absorbs more kinetic energy as speed increases than the turf alone.

Keywords:

• Artificial turf
• shock pad
• cutting
• injury
• biomechanics
• joint moment

Acknowledgements

The research project was supported financially in part by a gift from Brock International. The results of this study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation.

Disclosure statement

No potential conflict of interest was reported by the author(s).