Dose-dependency of massage-like compressive loading on recovery of active muscle properties following eccentric exercise: rabbit study with clinical relevance.

BACKGROUND: Optimal strategies for massage and its use in athletes have not been conclusively demonstrated. PURPOSE/STUDY
DESIGN: Effects of varying duration, frequency and magnitude of massage-like compressive loading (MLL) on recovery of skeletal muscle active properties (torque angle (T-Θ) relationship) following exercise-induced muscle injury were studied.
METHODS: Twenty-four New Zealand White rabbits were surgically instrumented with bilateral peroneal nerve cuffs for stimulation of hindlimb tibialis anterior muscles. Following a bout of eccentric exercise (EEX), rabbits were randomly assigned to a MLL protocol of 0.25 or 0.5 Hz at 5 or 10 N for 15 or 30 min. T-Θ was obtained for 21 tibiotarsal joint angles pre- and post-EEX and post 4 consecutive days of MLL. Muscle wet weight and H&E sections were obtained following final treatments.
RESULTS: EEX produced an average 61.8%±2.1 decrease in peak isometric torque output. Differences in torque recovery were found between magnitudes (5 and 10 N; p=0.004, n=12) and frequencies (0.25 and 0.5 Hz; p=0.012, n=12), but no difference for durations (15 and 30 min) with the 0.5 Hz, 10 N, 15 min protocol showing greatest recovery 4 days post-EEX. MLL muscle (n=12) wet weight was 3.22±0.18 g, while no MLL tissue (n=9) weighed 3.74±0.22 g (p=0.029). Histological analysis showed a difference in torn fibres between low-parameter and high-parameter MLL (6.5±1.04 vs 0.5±0.29 per 0.59 mm(2), p=0.005).
CONCLUSIONS: Results showed a dose-response effect for magnitude and frequency of MLL on recovery of active muscle properties following EEX. Future studies will investigate underlying biological mechanisms for this enhanced recovery of muscle function.