Exercise-induced mechanical hypoalgesia in musculotendinous tissues of the lateral elbow

The aim of this study was to investigate mechanical sensitivity responses at the lateral elbow to repeated weekly bouts of low load exercise in healthy subjects. Thirteen young men (n=6) and women participated in 4 weeks of exercise. Arms were randomly allocated to an eccentric-only exercise protocol (ECC: 5 sets of 20 contractions) or to a concentric-eccentric protocol (CON-ECC: 5 sets of 10 eccentric/10 concentric contractions) performed at 30% maximal wrist extension force. Arms were exercised consecutively within each supervised weekly session. Quantitative measures of pressure pain threshold (PPT) recorded at three sites and maximal force for grip and wrist extension were assessed at baseline, and immediately pre/post exercise at each session. Muscle endurance during 100 maximal grip contractions force was assessed at baseline and one week following the final exercise session. Results showed that regardless of protocol, repeated low load exercise resulted in a time-dependent increase in PPT at all sites post exercise Weeks 3 and 4 and persisting at follow up Week 5 (P<0.02). No significant difference between protocols was evident for any measure. Muscle force and endurance were not significantly augmented compared with baseline. In conclusion mechanical hypoalgesia is induced by repeated low load exercises regardless of exercise mode, and this may prove beneficial if replicated clinically.