Biomechanical responses to changes in friction on a clay court surface. Issue 5 (May 2017)

• Record Type: Journal Article
• Authors: Starbuck, Chelsea; Stiles, Victoria; Urà, Daniel; Carré, Matt; Dixon, Sharon
• Is Part Of: Journal of science and medicine in sport. Volume 20:Issue 5(2017)
• Page Start: 459
• Page End: 463
• Publication Date: 2017-05
• Subjects: Kinematics -- Loading rate -- Sliding -- Lower limb -- Injury risks; Sports sciences -- Periodicals; Sports medicine -- Periodicals; Exercise -- Physiological aspects -- Periodicals; Sports -- physiology -- Periodicals; Sports Medicine -- Periodicals; Sportgeneeskunde; 617.102705
• DOI: 10.1016/j.jsams.2016.08.019
• Languages: English
• ISSNs: 1440-2440

Abstract

Abstract: Objectives: To examine the influence of clay court frictional properties on tennis players' biomechanical response. Design: Repeated measures. Methods: Lower limb kinematic and force data were collected on sixteen university tennis players during 10 × 180° turns (running approach speed 3.9 ± 0.20 m s −1 ) on a synthetic clay surface of varying friction levels. To adjust friction levels the volume of sand infill above the force plate was altered (kg per m 2 surface area; 12, 16 and 20 kg m −2 ). Repeated measures ANOVA and Bonferroni's corrected alpha post-hoc analyses were conducted to identify significant differences in lower limb biomechanics between friction levels. Results: Greater sliding distances ( η p 2 = 0.355, p = 0.008) were observed for the lowest friction condition (20 kg m −2 ) compared to the 12 and 16 kg m −2 conditions. No differences in ankle joint kinematics and knee flexion angles were observed. Later peak knee flexion occurred on the 20 kg m −2 condition compared to the 12 kg m −2 ( η p 2 = 0.270, p = 0.023). Lower vertical ( η p 2 = 0.345, p = 0.027) and shear ( η p 2 = 0.396, p = 0.016) loading rates occurred for the 20 kg m 2 condition compared to the 16 kg m 2 . Conclusions: Lower loading rates and greater sliding distances when clay surface friction was reduced suggests load was more evenly distributed over time reducing players' injury risks. The greater sliding distances reported were accompanied with later occurrence of peak knee flexion, suggesting longer time spent braking and a greater requirement for muscular control increasing the likelihood of fatigue.