Study finds you could reap double the benefits by exercising just one arm

Oct 24, 2020
Training one arm can improve strength and decrease muscle loss in the other arm. Source: Getty.

It’s a fact well-documented that physical exercise can benefit the body in a number of ways, from preventing general aches and pains, to improving cognitive health and maintaining a healthy weight and general wellbeing. But now a new study has shed some light on the role of training in relation to muscle wastage and loss of strength – both of which can happen due to ageing.

New research carried out by Edith Cowan University (ECU) found that by training one arm, a person can actually improve strength and decrease muscle loss in their other arm.

Thirty participants (aged 18-34) took part in the study and had their non-dominant arms immobilised for four weeks. The group was then split into three, with some performing no exercise, some performing a mix of eccentric (causing muscles to elongate) and concentric (causing muscles to shorten) exercise and the rest performing eccentric exercise only.

The study found that the group who used a heavy dumbbell to perform only eccentric exercise on their active arm showed an increase in strength and a decrease in muscle atrophy, or wastage, in their immobilised arm.

“Participants who did eccentric exercise had the biggest increase in strength in both arms, so it has a very powerful cross-transfer effect,” Professor Ken Nosaka from ECU said. “This group also had just two per cent muscle wastage in their immobilised arm, compared with those who did no exercise who had a 28 per cent loss of muscle.

“This means that for those people who do no exercise, they have to regain all that muscle and strength again.”

Nosaka said that the findings could improve outcomes for post-injury and stroke patients. “I think this could change the way we approach rehabilitation for people who have temporarily lost the use of one arm or one leg,” he said.

“By starting rehab and exercise in the uninjured limb right away, we can prevent muscle damage induced by exercise in the other limb and also build strength without moving it at all.”

Starts at 60 previously spoke to Nick Rizzo, training director at RunRepeat, about the benefits that weight training offers for older people, after he published an article, based on 126 peer-reviewed studies, outlining the 78 science-backed benefits of weightlifting for seniors.

Weight or strength training not only helps with weight control by burning calories, it can also help you maintain muscle mass and stronger bones as people age, making it possible to live independently for longer. Lifting weights may also help ease general aches and pain that come with getting older and reduce pain in osteoarthritis-affected joints, Rizzo adds. It can give people more energy and help to do simple things more easily, such as walking to the shops or getting ready in the morning.

“The most obvious one is that it can help you more physically capable to do whatever you need to do,” he says. “Whether it is carrying groceries, moving furniture, playing a sport and everything in-between.”

On top of being able to move around with greater agility and less pain, weight training also improves mental, emotional and cognitive health. And it can increase longevity! According to the National Health Interview Survey (NHIS), adults 65 years and older who strength trained twice a week had a 46 per cent lower mortality rate.

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