Should exercise be an every day activity or a weekly goal?

Does it make a difference to muscle strength and mass if we exercise in one longer session or do a little every day? A new study published in the Scandinavian Journal of Medicine and Science in Sports aimed to find out.
The study

Researchers from Edith Cowan University, Niigata University and Nishi Kyushu University in Japan divided 36 young people into three groups and asked them to perform biceps curls on a machine which measures muscle strength.

At the end of the four-week programme the researchers measured changes in muscle strength and muscle thickness.

The first group did one set of six eccentric contractions once a week; the second group did one set of six eccentric contractions a day for five days a week; the third group meanwhile jammed five sets of six eccentric contractions into one a day in a week.

An eccentric contraction occurs when the muscle in question is lengthening, for example when lowering a heavy dumbbell in a biceps curl.

Should exercise be an every day activity or a weekly goal
The findings

After four weeks, the group doing six contractions once a week did not show any changes in muscle strength and muscle thickness.

The group who stuffed 30 contractions into a single day did not show any increase in muscle strength, although muscle thickness (an indicator of increase in muscle size or mass) increased 5.8 per cent.

The group who did six contractions a day for five days a week experienced significant increases in muscle strength – more than 10 per cent – together with an increase in muscle thickness of 4.4 per cent.

Interestingly, the increase in muscle strength in this group was similar to a group in a previous study that performed only one three-second maximal eccentric contraction per day for five days a week for four weeks.

Professor Ken Nosaka, from the Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, observes that such studies suggest that regular manageable amounts of exercise can have a real impact on muscle strength: “People think they have to do a lengthy session of resistance training in the gym, but that’s not the case…just lowering a heavy dumbbell slowly once or six times a day is enough.”

And he believes other muscle groups could derive equal benefit from resistance exercises designed to target them: “We only used the bicep curl exercise in this study, but we believe this would be the case for other muscles also, at least to some extent,” says Professor Nosaka.

Furthermore, while the study reported required participants to exert maximum effort, early findings from current, ongoing research suggest that similar results may be achieved for less effort.

“Muscle strength is important to our health. This could help prevent a decrease in muscle mass and strength with ageing,” says Professor Nosaka.

The reason why the body responds better to resistance exercises with eccentric contractions in smaller doses rather than bigger loads less often is still a mystery. However Professor Nosaka surmises it may relate to how often the brain is asked to make a muscle perform in a particular manner.

Should exercise be an every day activity or a weekly goal
What it means to you

Loss of muscle mass and strength (sarcopenia) is implicated in many chronic diseases that afflict us as we get older, such as heart and circulatory disease, type 2 diabetes, some cancers, dementia and musculoskeletal problems such as arthritis and osteoporosis.

This research suggests that you don’t have to go overboard to help stave off sarcopenia and so help protect yourself against these diseases.

The study also underlines the importance of rest. The group who experienced the greatest benefits had two days off a week.

Professor Nosaka observes: “Muscle adaptions occur when we are resting; if someone was able to somehow train 24 hours a day, there would actually be no improvement at all.

“Muscles need rest to improve their strength and their muscle mass, but muscles appear to like to be stimulated more frequently.”

He also points out that if you are unable to exercise for any reason – for example because of illness – there is no point trying to make up by doing a longer session when you resume training.

“If someone’s sick and can’t exercise for a week, that’s fine, but it is better to just return to regular exercise routine when you’re feeling better,” he said.

Current UK advice for older adults is to engage in 150 minutes of moderate activity or 75 minutes of vigorous activity a week and to include strength (resistance) training sessions on at least two days a week.

Professor Nosaka argues that there should be more emphasis on making exercise a daily activity, rather than hitting a weekly minute goal.

“If you’re just going to the gym once a week, it’s not as effective as doing a bit of exercise every day at home,” he said.

“This research, together with our previous study, suggests the importance of accumulating a small amount of exercise a week, rather than spending hours exercising once a week.

“We need to know that every muscle contraction counts, and it’s how regularly you perform them that counts.”

About Patsy Westcott

Patsy Westcott MSc is a freelance writer specialising in health and nutrition, and writes regularly for various print and online publications. She has a Master’s degree in Nutritional Medicine and has contributed to more than 40 health and nutrition books.