Investigation of muscular strength in peripheral arterial disease

This study identified differences in muscular strength of the plantarflexors in patients with peripheral arterial disease (PAD) as compared to healthy controls. PAD is characterized by atherosclerosis in the lower extremity and results in claudication pain. Patients with PAD have a limited ability to generate power at the ankle, required to propel the body forward during walking. Patients with PAD (n=16) and matched healthy controls (n=16) performed maximal isometric contractions. Patients with PAD performed two conditions: pain and pain free. The resulting force curves were analyzed for the following variables: area under the curve, peak torque, time to peak torque, duration of the linear region, average torque during linear region, standard deviation of torque during linear region, and loading rate. Independent t-tests were performed to compare between-group means and dependent t-tests were used to compare conditions. There were significant differences between healthy controls and patients with PAD during pain for area under the curve, average torque during the linear region, and peak torque. Peak torque was reduced in patients with PAD during the pain free condition compared to healthy controls. There were no differences between pain free and pain conditions in patients with PAD. Results showed that the plantarflexor muscles are weaker in patients with PAD. However, peak strength of the muscle is unaffected by ischemic conditions. Damage at the cellular level is likely responsible for baseline decreases in strength. The decreases in strength are likely contributing to the gait deficits previously identified in these patients.