Cryotherapy and Muscle Function in Immediate Return-to Scenarios

Abstract

Purpose This study aimed to investigate the effects of cold spray and cold pack applications on the biomechanical properties, muscle strength, and activity of the quadriceps femoris muscle. Methods Fifty-three male participants aged 18 to 25 were included in this randomised controlled study. Participants were randomly assigned to two groups: cold spray (n=27) and cold pack (n=26). The cold spray group received a 10-second application to the quadriceps, whereas the cold pack group received a 5-minute application. Measurements included skin surface temperature, muscle mechanical properties (MyotonPRO), isometric muscle strength (Lafayette dynamometer), and muscle activity (surface EMG). These measurements were conducted at three time points: before the intervention (baseline), immediately after the application, and five minutes post-application. Results Participant characteristics were similar between groups (p>0.05). Both groups showed time-dependent changes in muscle properties. Myoton-F, -S, and -D increased following the application, while Myoton-R decreased. Strength increased only in the cold spray group (p<0.05). The mean EMG workload was higher at baseline in the cold spray group (p<0.05), but no time-related change was observed in either group. EMG onset time decreased over time in the cold pack group (p<0.05). Skin temperature dropped significantly in both groups after the application (p<0.05), with a greater and more prolonged effect in the cold spray group (p<0.05). Conclusion These findings suggest that both cold spray and cold pack can induce short-term changes in quadriceps muscle function by altering the muscle's mechanical properties. Cold spray appears to improve muscle strength, while cold pack may influence the timing of muscle activation.