Only women report increase in pain threshold following fatiguing contractions of the upper extremity.

PURPOSE: The perception of pain in response to a noxious stimulus can be markedly reduced following an acute bout of exercise [exercise-induced hypoalgesia (EIH)]. Sex differences in EIH frequently occur after exercise but may be confounded by the sex differences in muscle fatigue. The purpose was to determine if sex differences in pain relief occur after an exercise protocol when muscle fatigue is similar for both young and older men and women. METHODS: Pain perception of 33 men (15 young) and 31 women (19 young) was measured using a pressure pain stimulus on the left index finger before and after maximal velocity concentric contractions of knee extensors or elbow flexors (separate days). During the 2-min pressure pain test, participants verbally indicated the onset of pain (pain threshold) and reported pain intensity (0-10) every 20 s. RESULTS: Only women experienced an increase in pain threshold (30 ± 27 to 41 ± 32 s) following elbow flexor exercise (trial × sex: p = 0.03). Neither men nor women experienced an increase in pain threshold following knee extensor exercise, and pain ratings were unchanged after exercise with either limb (p > 0.05). The pain response to exercise was similar in young and older adults (trial × age: p > 0.05), despite older adults demonstrating greater fatigability than young adults for the elbow flexor and knee extensor exercise tasks. CONCLUSIONS: Under controlled conditions where muscle fatigue is similar, sex differences in EIH occur in young and older adults that is site specific (upper extremity). Only women experience EIH following acute single limb high-velocity contractions.

Utilizing exercise to affect the symptomology of fibromyalgia: a pilot study.

UNLABELLED: Fibromyalgia (FM), a rheumatological disorder of unknown origin, is characterized by both physical and psychological symptoms. Although inconclusive results have been reported for most treatment modalities, exercise appears to have universal support for decreasing the myriad of symptoms associated with FM. Weaknesses in the literature, however, prevent conclusive statements regarding exercise prescription and concomitant impact on FM symptomology. PURPOSE: The current pilot study attempted to examine the effect of a 24-wk walking program at predetermined intensities on FM. METHODS: Initial design was a randomized control trial with high- and low-intensity exercise groups, and a control group. Subsequent nonrandomized control trials were based on actual exercise behavior. RESULTS: No differences between initial groups were identified. By collapsing groups, heart rate (HR) decreased (P < 0.05) weeks 0-12. Functional impairments were reduced 54% weeks 0-24, with exercise having a large impact (omega2 = 0.30) on this decrease. By reassigning groups, impact of FM on current health status decreased in the low-intensity group (P < 0.05) and increased in the high-intensity group (P < 0.02) weeks 0-24. Omega squared indicated strong influence of exercise on pain (omega2 = 0.51), with greater pain in the high-intensity group. CONCLUSIONS: A larger number of subjects and direct supervision of the training program to increase compliance is necessary to clarify the effects of a walking program on the manifestations of FM. Results indicate that intensity of the walking program is an important consideration. Individuals with FM can adhere to low-intensity walking programs two to three times per week, possibly reducing FM impact on daily activities.