Decreased hip strength has been suggested to contribute to landing biomechanics that increase the risk of ACL injuries. However, the relationship between hip strength and landing biomechanics is conflicting. Previous studies are limited to examining the peak torque produced during isometric or isokinetic assessments of hip strength. Understanding how the isokinetic torque production of the hip through a range of motion may help clarify the role of hip strength in landing biomechanics.
PURPOSE: To examine the influence of hip isokinetic eccentric (ECC) and concentric (CON) work on landing biomechanics in male and female basketball players.
METHODS: Twenty- three male (N=11, 20.5±1.4 yrs, 189.2±8.0 cm, 90.2±10.4 kg) and female (N=12, 19.9±1.4 yrs, 172.4±6.8 cm, 78.9±13.8 kg) Division 1 basketball players participated. Using an isokinetic dynamometer, 5 repetitions of isokinetic CON and ECC hip extension torque were measured at 60 deg/s, with the work per repetition of the middle 3 repetitions used for analyses. Established 3D motion analysis techniques were used to collect three trials of a drop vertical jump and quantify the left limb’s sagittal, frontal, and transverse plane hip and knee joint excursions and peak external joint moments, normalized to body weight and height (BWHT). Separate step-wise, linear regressions determined the extent to which CON and ECC work predicted landing biomechanics in males and females.
RESULTS: In males, the average ECC and CON work per repetition was 0.98±0.15 J/BWHT and 0.92±0.18 J/BWHT, respectively. In females, the average ECC and CON work per repetition was 0.91±0.25 J/BWHT and 0.94±0.21 J/BWHT, respectively. Greater ECC work predicted less hip adduction moment (0.40±0.29 Nm/BWHT, R2=0.411, P=0.025) in females. ECC and CON work was not predictive of any other hip or knee joint excursions or peak moments in males or females (all P>0.05).
CONCLUSIONS: With the exception of hip adduction moment in females, ECC and CON hip strength was not predictive of landing biomechanics. This suggests that a combination of neuromuscular factors at the hip, such as muscle activation, combine to predict lower extremity biomechanics during dynamic activities. Further work is needed to clarify this relationship in more demanding tasks.