title: A resistance band increased internal hip abduction moments and gluteus medius activation during pre-landing and early-landing.
abstract: An increased knee abduction angle during jump-landing has been identified as a risk factor for anterior cruciate ligament injuries. Activation of the hip abductors may decrease the knee abduction angle during jump-landing. The purpose of this study was to examine the effects of a resistance band on the internal hip abduction moment and gluteus medius activation during the pre-landing (100ms before initial contact) and early-landing (100ms after initial contact) phases of a jump-landing-jump task. Thirteen male and 15 female recreational athletes (age: 21.1±2.4yr; mass: 73.8±14.6kg; height: 1.76±0.1m) participated in the study. Subjects performed jump-landing-jump tasks with or without a resistance band applied to their lower shanks. During the with-band condition, subjects were instructed to maintain their movement patterns as performing the jump-landing task without a resistance band. Lower extremity kinematics, kinetics, and gluteus medius electromyography (EMG) were collected. Applying the band increased the average hip abduction moment during pre-landing (p<0.001, Cohen׳s d (d)=2.8) and early-landing (p<0.001, d=1.5), and the average gluteus medius EMG during pre-landing (p<0.001, d=1.0) and early-landing (p=0.003, d=0.55). Applying the band decreased the initial hip flexion angle (p=0.028, d=0.25), initial hip abduction angle (p<0.001, d=0.91), maximum knee flexion angle (p=0.046, d=0.17), and jump height (p=0.004, d=0.16). Applying a resistance band provides a potential strategy to train the strength and muscle activation for the gluteus medius during jump-landing. Additional instructions and feedback regarding hip abduction, hip flexion, and knee flexion may be required to minimize negative changes to other kinematic variables.
authors.affiliation: Division of Kinesiology and Health, University of Wyoming, Laramie, USA. Electronic address: bdai@uwyo.edu.
authors.forename: Boyi
authors.initials: B
authors.lastname: Dai
authors.affiliation: Division of Kinesiology and Health, University of Wyoming, Laramie, USA.
authors.forename: Erika M
authors.initials: EM
authors.lastname: Heinbaugh
authors.affiliation: Department of Industrial and Management Systems Engineering, West Virginia University, Morgantown, WV, USA.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Ning
authors.affiliation: Division of Kinesiology and Health, University of Wyoming, Laramie, USA.
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhu
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D016059:Range of Motion, Articular; D055815:Young Adult
keywords: ACL injuries; EMG; Hip abductors; Jumping; Kinematics; Kinetics