Does isolated hip abductor fatigue lead to biomechanical changes of trunk, pelvis and lower leg during single-leg landing? Yu Iwama 1, Kengo Harato 1, Satoshi Imai 2, Aiko Sakurai 1, Yutaro Morishige 1, Kazuya Kaneda 1, Shu Kobayashi 1, Yasuo Niki 1, Takeo Nagura 1,3 1) Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo, Japan 2) Institute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, Japan 3) Department of Clinical Biomechanics, Keio University School of Medicine, Tokyo, Japan
Yu Iwama, MD I have no financial conflicts to disclose.
Background Weakness of the hip abductors is responsible for the increases in range of motion of knee abduction and knee adductor moments [1]. Little attention has been paid to the relationship between hip abductor fatigue and the wholebody biomechanics. The purpose of the present study was to examine and to clarify the effects of hip abductor fatigue on the trunk, pelvis and lower leg biomechanics during single-leg landing (SLL) in male recreational level athletes.
Subjects & Motion Analysis System 15 male recreational level athletes (mean age = 20.0±1.5 yrs). Tegner activity scales were level 7. Motion analysis system was consisted of 8 cameras (120 frames/s; Pro-reflex, Qualisys, Sweden), 2 force plates (frequency 600 Hz; AM6110, Bertec, Columbus, OH, USA), and 46 retro-reflective markers. All methods and procedures were approved by Institutional Review Board of our university.
Methods The subjects performed single-leg landing (SLL), which was jumping from a 30-cm high box to a distance of 25% of their height away from the box, down to force plates. 25% of height 30cm
Methods Isolated hip abductor fatigue protocol 1The dominant leg (20 right) was chosen for the fatigue protocol. 2Abduction movement using a weight of 10 kg wrapped around the distal part of the lower leg in a lateral position until they could not raise up the lower leg. 3It was replaced with a weight of 5 kg and continued until they were unable to raise up the lower leg again. 42 trials were recorded for each subject before and after the protocol.
Methods The motion of markers was recorded by Qualisys Track Manager Software (version 2.7). To calculate trunk, pelvis, and lower leg biomechanics, Visual 3D (C-motion Company, Rockville, MD, USA) was utilized. Three-dimensional kinematics and kinetics were evaluated. As a statistical analysis, the data were compared between before and after the fatigue protocol in each group using two-tailed Paired t-test. The statistical significance level was set at P=0.05.
Results Peak values of each parameter during landing phase (mean±sd) a Values obtained using two-tailed Paired t-test
Results Biomechanical parameters at the timing of peak vgrf (mean±sd) a Values obtained using two-tailed Paired t-test
Discussion Literature Review Increased knee valgus on landing to be a risk factor for ACL injury [2]. Simulated hip abductor weakness increased knee abduction ROM during a jumping task [3].
Discussion From the present study After fatigue Peak values of each parameter during lading phase Knee abduction angle Knee internal rotation angle Left pelvic inclination Right trunk inclination Weakness of the hip abductor muscle might cause Trendelenburg like movement of the pelvis and compensatory movement of the trunk.
Conclusions Larger ipsilateral knee abduction were observed after fatigue. Weakness of the hip abductor muscle might cause Trendelenburg like movement of the pelvis and compensatory movement of trunk. Male recreational level athletes are likely to have the increased risk of ipsilateral knee ligament injury after isolated hip abductor fatigue during SLL.
References [1] McLeish RD, et al. J Biomech. 1970;3(2):191 209. [2] Hewett TE, et al. Am J Sports Med. 2005;33(4):492 501. [3] Geiser CF, et al. Med Sci Sports Exerc. 2010;42(3):535-45.