Protecting Ligaments from Overuse Injuries with Periodic Rest and Recovery

Ligaments play a critical role in joint stability by guiding smooth articulations and preventing excessive or abnormal joint loads. These soft connective tissues experience millions of cyclic loads annually, making them susceptible to mechanical fatigue and failure. Despite the widespread impact of ligament fatigue damage, the optimal rest durations required to mitigate cumulative damage and enhance recovery remain poorly understood. This study quantifies the effect of periodic rest on ligament fatigue behavior using bovine medial collateral ligaments (MCL). Samples were prepared using a Print-A-Punch to create standardized dumbbell specimens and kept hydrated in saline throughout testing. Ligaments underwent cyclic tensile loading at 30% of their predicted ultimate tensile strength (UTS) for 10,000 cycles at 3 Hz, with intermittent rest periods of 1, 5, or 10 hours. Three rest configurations—1-5-10, 5-10-1, and 10-1-5—were tested to assess the impact of rest order on recovery. Mechanical analysis using MATLAB quantified creep deformation and viscoelastic recovery. Results showed no significant differences in recovery across rest durations, suggesting that moderate rest alone may not fully reset tissue length. These findings highlight the need for further research on how loading history and rest influence ligament recovery and injury prevention.