Although anterior cruciate ligament (ACL) sprains usually occur during the initial phase of the landing cycle (less than 40�� knee flexion), the literature has focused on peak values of knee angles, vertical ground reaction force (VGRF), and muscle activity even though it is unclear what occurs during the initial phase of landing.
Objectives
The objectives of this study were to determine the effects of sex (male and female) and fatigue (prefatigue/post-fatigue) on knee flexion angles at the occurrence of peak values of biomechanical variables [knee valgus angle, VGRF, and normalized electromyographic amplitude (NEMG) of the quadriceps and hamstring muscles] during a bilateral drop landing task.
Methods
Knee valgus angle, VGRF, and NEMG of the quadricep and hamstring muscles were collected during bilateral drop landings for twenty-nine recreational athletes before and after a fatigue protocol.
Results
Peak values of knee valgus, VGRF, and NEMG of medial and lateral hamstring muscles occurred during the late phase of the landing cycle (>40�� of knee flexion). Females in the post-fatigue condition exhibited peak VGRF at significantly less knee flexion than in the pre-fatigue condition. Males in the post-fatigue condition exhibited peak lateral hamstring muscles NEMG at significantly higher knee flexion than in the pre-fatigue condition.
Discussion and conclusion
Peak values of biomechanical variables that have been previously linked to ACL injury did not occur during the initial phase of landing when ACL injuries occur. No biomechanical variables peaked during the initial phase of landing; therefore, peak values may not be an optimal indicator of the biomechanical factors leading to ACL injury during landing tasks.
Pappas, E., Hagins, M., Sheikhzadeh, A., Nordin, M., & Rose, D. (2009). Peak biomechanical variables during bilateral drop landings: comparisons between sex (female/male) and fatigue (pre-fatigue/post-fatigue).. North American journal of sports physical therapy : NAJSPT, 4(2), 83-91.
Identity
Web Of Science Accession Number
Additional Document Info
Start Page
83
End Page
91
Volume
4
Issue
2
Place Of Publication
Overview
Abstract
Background
Although anterior cruciate ligament (ACL) sprains usually occur during the initial phase of the landing cycle (less than 40�� knee flexion), the literature has focused on peak values of knee angles, vertical ground reaction force (VGRF), and muscle activity even though it is unclear what occurs during the initial phase of landing.
Objectives
The objectives of this study were to determine the effects of sex (male and female) and fatigue (prefatigue/post-fatigue) on knee flexion angles at the occurrence of peak values of biomechanical variables [knee valgus angle, VGRF, and normalized electromyographic amplitude (NEMG) of the quadriceps and hamstring muscles] during a bilateral drop landing task.
Methods
Knee valgus angle, VGRF, and NEMG of the quadricep and hamstring muscles were collected during bilateral drop landings for twenty-nine recreational athletes before and after a fatigue protocol.
Results
Peak values of knee valgus, VGRF, and NEMG of medial and lateral hamstring muscles occurred during the late phase of the landing cycle (>40�� of knee flexion). Females in the post-fatigue condition exhibited peak VGRF at significantly less knee flexion than in the pre-fatigue condition. Males in the post-fatigue condition exhibited peak lateral hamstring muscles NEMG at significantly higher knee flexion than in the pre-fatigue condition.
Discussion and conclusion
Peak values of biomechanical variables that have been previously linked to ACL injury did not occur during the initial phase of landing when ACL injuries occur. No biomechanical variables peaked during the initial phase of landing; therefore, peak values may not be an optimal indicator of the biomechanical factors leading to ACL injury during landing tasks.
Pappas, E., Hagins, M., Sheikhzadeh, A., Nordin, M., & Rose, D. (2009). Peak biomechanical variables during bilateral drop landings: comparisons between sex (female/male) and fatigue (pre-fatigue/post-fatigue).. North American journal of sports physical therapy : NAJSPT, 4(2), 83-91.
