Heart Patients Advised to Exercise Calf Muscles

A new study reveals that chronic heart failure (CHF) patients have greater reliance on the ankle compared to the hip when walking, especially at faster speeds.

Researchers at the University of Western Australia (UWA; Crawley, Australia) conducted a study to better identify the mechanisms underlying reduced walking capacity, a hallmark of CHF which is strongly correlated with hospitalization and morbidity. To do so, they performed a detailed biomechanical gait analysis in six men and four women with CHF as they walked on a treadmill at different speeds, and then compared the results against 11 controls, including 8 men and 3 women.

The results showed no difference in preferred speed between groups, possibly explained by an optimization of the mechanical cost of transport in both groups. The majority of limb kinematics and kinetics were also similar between groups, with the exception of greater ankle dorsiflexion angles during stance in CHF. The researchers did find that over two times greater ankle plantarflexion work was required per given triceps surae muscle volume in CHF patients, an observation that could explain the high correlation between triceps surae muscle volume and exercise capacity in CHF. The study was published in the November 2014 issue of the Journal of Biomenchanics.

“Because we found some specific differences in muscles with people with heart failure compared with healthy people who just exercise less, we believe some specificity of this disease affects soleus muscles more than other muscles. We speculate that …. the fact that their calf is working very close to their maximum work capacity is what limits their exercise ability,” said lead author UWA sports biomechanics scientist Fausto Panizzolo, PhD. “Considering the key role played by the plantar flexors in powering walking and their association with exercise capacity, our findings strongly suggest that exercise-based rehabilitation in CHF should not omit the ankle muscle group.”

The triceps surae is composed of a pair of muscles; the superficial portion (the gastrocnemius) gives off two heads attaching to the base of the femur directly above the knee. The deep mass of muscle (the soleus) forms the remaining head, which attaches to the superior posterior area of the tibia. Both muscles also insert into the calcaneus, the bone of the heel of the human foot, and form the major part of the muscle of the posterior leg, commonly known as the calf muscle. Contraction of the triceps surae induces plantar flexion and stabilization of the ankle complex.

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University of Western Australia