Objective: To analyse the influence of chronic pain on muscle strength.
Design: Muscle strength of patients with unilateral nonspecific chronic pain, in an upper or lower limb, were measured according to a standardized protocol using a hand-held dynamometer. Before and after muscle strength measurement, a visual analogue scale for pain intensity was assessed.
Results: Forty patients were measured and the muscle strength of the painful side was 20-30% less than that of the nonpainful side. Strength reduction was seen in the whole limb. A significant correlation between pain intensity and reduced muscle strength in the painful limb existed for hip flexion, knee flexion, knee extension and three-point grip.
Conclusions: A strength reduction of 20-30% in a painful limb seems to be 'normal' in chronic pain patients.