Fatigue affects dynamic knee joint stability in women

Female athletes often sustain knee injuries, so physiologists investigated knee stability in fatigued and non-fatigued conditions. Researchers from the School of Health Professions at the University of Puerto Rico-Medical Sciences Center recently published an article in the NSCA’s Journal of Strength and Conditioning Research, stating that fatigue can increase the risk of knee injury in female athletes by decreasing dynamic knee joint stability.

Fifteen young women (mean age: 24.6 +/- 2.6 years) performed two tasks in a non-fatigued test session and a fatigued session. During both sessions, knee landing flexion, knee extension, joint angles and muscle activity of the quadriceps and hamstrings were measured. The first task was a single-leg drop jump from a 40-cm box, and the second was a repeated up/down hop on a 20-cm box. An anaerobic Wingate protocol was used to induce fatigue. Participants had greater knee injury-predisposing factors during the fatigued session. Specifically, a decrease in knee flexion during the up/down hop was statistically significant (p = 0.028).

The bottom line is that fatigue can increase the risk of injury. To mitigate this risk, athletes should incorporate strength-endurance components with emphasis on dynamic knee stability to increase control of body movements even when fatigued.

Read an abstract of the article here.