Many health-conscious people engaged in regular workout regimens, and even the so-called fitness coaches, are stumped when asked whether it is better to exercise for a short period each day, or exercise for longer once a week.
Researchers at Edith Cowan University in Australia have now come up with what they say is a definitive answer to this dilemma, at least when it comes to muscle strength — it could be more beneficial to exercise for a while each day than to put it off for a longer about once a week.
The Australian researchers in collaboration with scientists at Niigata University and Nishi Kyushu University in Japan, conducted a four-week training study. Participants in the study were separated into three groups performing an arm resistance exercise, while their changes in muscle strength and muscle thickness were measured and compared.
The exercise consisted of ‘maximal voluntary eccentric bicep contractions’ — an eccentric contraction is when the muscle is lengthening, such as when lowering a heavy dumbbell in a bicep curl.The exercise was performed on a machine that measures muscle strength in each muscle contraction.
Two groups performed 30 contractions per week, with one of the two groups doing six contractions a day for five days a week (6×5 group), while the other crammed all 30 into a single day, once a week (30×1 group). The third group only performed six contractions one day a week.
After four weeks, the group doing 30 contractions in a single day did not show any increase in muscle strength, although muscle thickness (an indicator of increase in muscle size) increased 5.8 percent.
The group doing six contractions once a week did not show any changes in muscle strength and muscle thickness.
However, the 6×5 group saw significant increases in muscle strength — more than 10 percent — with an increase in muscle thickness similar to the 30×1 group.
Importantly, the increase in muscle strength of the 6×5 group was similar to the group in a previous study that performed only one three-second maximal eccentric contraction per day for five days a week for four weeks.
The scientists also noted that while their study required participants to exert maximum effort, early findings from ongoing research indicated similar results could be achieved without needing to push as hard as possible. Additionally, while the study participants only used the bicep curl exercise for the arm, further studies have shown that this is the case with other muscles also.
The researchers said their studies suggest that easily manageable amounts of exercise done regularly can have a real effect on muscle strength, which is important to overall health and wellbeing. Muscle strength has been shown to prevent the decrease in muscle mass and strength that happens with aging. A decrease in muscle mass has also been implicated as a factor in many chronic diseases such as cardiovascular disease, type 2 diabetes, some cancers, dementia, plus musculoskeletal problems such as osteoporosis.
It is not yet known precisely why the body responds better to resistance exercises with eccentric contractions in smaller doses rather than bigger loads less frequently. The researchers postulated it may relate to how often the brain is asked to make a muscle perform in a particular manner. They also stressed that it was important to include rest in any exercise regimen.
Muscles need rest to improve their strength and their muscle mass, as muscle adaptations occur when we are resting. Also, muscles respond better when they are stimulated more frequently; if someone was able to somehow train 24 hours a day, there would actually be no improvement at all.
There needs to be more emphasis on the importance of making exercise a daily activity, rather than hitting a weekly minute goal, said the study team. Current Australian Government guidelines already indicate adults should try to be active every day and perform around three hours of moderate physical activity per week.
