Resistance exercises may help muscles recover after prolonged inactivity: Study

Resistance exercises such as leg press can help build muscle strength while recovering from prolonged inactivity that may result from years of hospitalisation, according to a study.

Earlier studies had revealed that the thigh muscles of individuals with an amputation below the knee are used less during movement, and therefore become weak.

The current study, published in the journal Experimental Physiology, examined the muscles of below-knee amputees to observe changes that happen with long-term inactivity.

The researchers, including those from the University of Roehampton in the UK, said similar changes might happen in the muscles of people who are hospitalised, sedentary, or travelling in space.

They assessed the maximum capacity of the muscles in the amputees for producing force, and their muscles' ability to quickly produce "explosive" force -- a process relevant during many daily activities such as recovering from a loss of balance, avoiding joint injuries, and when playing sports.

When the team compared the maximum and explosive strength among the amputees, they found that the participants had lost comparatively more explosive strength.

The researchers also found that the muscular changes accompanying reduction in explosive strength could not have been anticipated from the short-term bed rest studies.

The changes were specific to the type of strength examined, they said.

According to the study, rehabilitation regimens for amputees, or other patients experiencing prolonged inactivity should be tailored to help them recover explosive strength specifically.

"This research has exciting potential to help people who have been inactive long-term, due to hospitalisation for example, regain the strength they need for daily activities such as avoiding falls," said Amy Sibley, study co-author from the University of Roehampton.

"To achieve this aim, clinicians need to be specific about the type of strength training they use, for example typical resistance exercises (e.g., leg press) should be performed with the intention of lifting the resistance as rapidly as possible," Sibley said.