Publication Date


Document Type


Committee Members

Andrew Froehle (Advisor), Drew Pringle (Committee Member), Larry Ream (Committee Member)

Degree Name

Master of Science (MS)


Anterior cruciate ligament (ACL) injury is 4-8 times more likely to occur in females than in males and is associated with significant morbidity. The mechanism underlying the gender disparity in non-contact ACL injuries is likely multifactorial, and may be influenced by a variety of risk factors. This study examines the influence of age at menarche and neuromuscular fatigue of the hamstrings muscles on knee biomechanics. Twelve female athletes performed drop vertical jump (DVJ) tasks before and after a fatiguing protocol utilizing a glute-ham bench. Knee kinematics and kinetics were recorded during the contact phase of the DVJ. The results of this study found a significant decrease in knee abduction angle in the dominant leg after fatigue (P = 0.05), and a significant decrease in peak vertical ground reaction force (vGRF) after fatigue. The findings of this study do not support our hypotheses that (1) age at menarche is correlated with greater dynamic knee valgus, (2) that knee valgus is greater after fatigue, or (3) that the effects of fatigue are exacerbated in females with earlier age at menarche. We concluded that because the glute-ham raise targeted fatigue of the lateral hamstrings (biceps femoris), the exercise caused a decrease in potentially harmful valgus knee angles and moments. The reduction in peak vGRF after fatigue may be a result of an altered landing strategy in order to reduce impact forces and to maintain overall landing mechanics. Understanding the factors that affect knee biomechanics is critical for the development of more effective injury prevention strategies.

Page Count


Department or Program

Department of Neuroscience, Cell Biology and Physiology

Year Degree Awarded


Included in

Anatomy Commons