Acute Heavy-resistance Exercise-induced Pain and Neuromuscular Fatigue in Elderly Women with Fibromyalgia and in Healthy Controls: Effects of Strength Training

Objective: To examine heavy-resistance exercise-induced acute neuromuscular fatigue, blood lactate concentration, and muscle pain in elderly women with fibromyalgia (FM) and in healthy controls before and after a period of strength training.

Methods: Thirteen elderly women with FM (mean+/-SD age 60+/-2 years) and 10 healthy women (mean+/-SD age 64+/-3 years) performed a heavy-resistance fatiguing protocol (5 sets of leg presses with 10 repetitions maximum) before and after a 21-week strength training period. Maximal isometric force and electromyography (EMG) activity of leg extensors and blood lactate concentration were measured during the loading. Pain was assessed by visual analog scale.

Results: The strength training led to large increases in maximal force and EMG activity of the muscles and contributed to the improvement in loading performance (average load/set) at week 21. The fatiguing loading sessions typically applied in strength training before and after the experimental period caused remarkable and comparable acute decreases in maximal force and increases in blood lactate concentration in both groups. Acute exercise-induced muscle pain increased similarly in both groups, and the pain level in women with FM was lowered after the 21-week training period.

Conclusion: The increased strength in women with FM improved high-load performance and also seemed to attenuate perceived pain. Acute exercise-induced neuromuscular changes and the time course of muscle pain in women with FM were comparable with findings in healthy controls, which suggests a typical fatiguing process and a similar trainability of the muscles in elderly women with FM.