Changes in knee extension and flexion force, EMG and functional capacity during strength training in older females with fibromyalgia and healthy controls

Abstract

Objective. To investigate the effects of strength training on neuromuscular functions in elderly females with fibromyalgia (FM). Methods. Thirteen females with fibromyalgia [group FMt; mean age (S.D.) 60.2 (2.5) years] and 11 healthy controls [group HCt; 64.2 (2.7) yr] carried out supervised strength training twice a week for 21 weeks. Thirteen FM patients [group FMc; 59.1 (3.5) yr] served as non-training controls. Maximal isometric force and electromyographic (EMG) activity of the right quadriceps femoris in knee extension and flexion actions, maximal 10-m walking speed, and 10-step stair-climbing time were measured. Tender points were assessed by palpation, subjectively perceived symptoms with a visual analogue scale, and the self-reported physical function capacity by Health Assessment Questionnaire (HAQ). Results. The mean (S.D.) increases in maximal extension force during the training period in groups FMt and in HCt were 32 (33)% (P < 0.001) and 24 (12)% (P < 0.001) respectively and those of flexion were 13 (20)% (P < 0.05) and 24 (17)% (P < 0.01). Explosive force of the extensors increased in both FMt and in HCt. The integrated EMGs of the vastus lateralis and medialis muscles increased in both FMt and HCt. Muscle forces and EMGs in group FMc remained at the basal level. Walking speed, stair-climbing time and the HAQ index improved in group FMt. The changes in the number of tender points and in perceived symptoms were in favour of the training group FMt. Conclusions. The data support the hypothesis that elderly female FM patients have normal neuromuscular function. Supervised strength training also suits elderly FM patients, has positive effects on perceived symptoms and improves functional capacity without complications.