Much of the literature on hormones and ligament laxity has focused on the knee, but a study from James Madison University suggests that an interaction between hormone levels and fatigue may also affect laxity at the ankle.
Researchers analyzed ankle ligament laxity in 24 female college athletes during barefoot walking, running and cutting for four weeks, before and after a fatigue protocol that included stair running followed by a modified hurdle beep test. They found that the effect of fatigue on ligament laxity was significantly greater in week 4 and significantly lower in week 2 than in the other weeks, suggesting an interactive effect.
However, week 2 was associated with the highest levels of ligament laxity. In addition, fatigue increased midfoot pressures during weeks 1 and 2, but had the opposite effect in weeks 3 and 4. The authors hypothesized that increased laxity allows for midfoot collapse and reduced load under the metatarsal heads, particularly under fatigued conditions.
The findings were presented in August at the emed Scientific Meeting.