Greater effects of performing a small number of eccentric contractions daily than a larger number once a week Summary Our previous study found that a maximal voluntary eccentric contraction (MVC-ECC) performed daily for 5 days a week for 4 weeks increased the MVC-ECC, isometric (MVC-ISO), and concentric contraction (MVC-CON) torque of the elbow flexors more than 10%. The present study investigated the effects of six maximal voluntary eccentric contractions on MVC torques and biceps brachii and brachii (MT) muscle thickness. Thirty-six healthy young adults were assigned to one of three groups (N = 12 per group); the 6 × 1 group that performed a series of six contractions once a week, the 6 × 5 group that performed a series of six contractions a day for 5 days a week, and the 30 × 1 group that performed five sets of six contractions a day in a week. The duration of training was 4 weeks for all groups, and changes in MVC-ECC, MVC-CON and MVC-ISO torque, and MT before and after the 4-week training were compared between the groups. The 6 × 1 group showed no significant changes in muscle strength and MT. Significant increases (p < 0.05) in MVC-ECC (13.5 ± 11.5%), MVC-ISO (9.3 ± 5.5%), MVC-CON torque (11.1 ± 7.4%) were evident for the 6 × 5 group only, and the Increases in MT were found for the 6 × 5 (10.4 ± 4.4%) and 30 × 1 (8.0 ± 5.8%) groups with no significant difference. These results suggest that performing a small number of eccentric contractions 5 days a week is more effective in increasing muscle strength than performing a greater volume of eccentric contractions once a week. However, it seems that training volume is a factor in muscle hypertrophy in short-duration training. |
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Response to exercise: Research shows it’s how often you do it, not how much
We all know exercise is important, but is it better to do a little every day or a lot a few times a week? New research from Edith Cowan University indicates that one is much more beneficial than the other.
So...should I exercise a little every day or exercise longer once a week?
It’s a dilemma many health-conscious people face, and new research from Edith Cowan University (ECU) is answering the question. This latest research indicates that a little daily activity may well be the most beneficial approach, at least for muscle strength. And happily, it also suggests that you don’t have to put in a mountain of work every day.
In collaboration with Niigata University and Nishi Kyushu University in Japan, the four-week training study had three groups of participants perform an arm strength exercise and changes in muscle strength and muscle thickness were measured and compared.
The exercise consisted of “maximum voluntary eccentric biceps contractions” performed on a machine that measures muscle strength in each muscle contraction you would do in the gym. An eccentric contraction is when the muscle is lengthening; in this case, like lowering a heavy dumbbell in a biceps curl.
Two groups performed 30 contractions per week, one group performed six contractions a day for five days a week (6x5 group), while the other squeezed all 30 into a single day, once a week (30x1 group). Another group only had six contractions one day a week.
After four weeks, the group that performed 30 contractions in a single day showed no increase in muscle strength, although muscle thickness (an indicator of increased muscle size) increased by 5.8 percent.
The group that performed six contractions once a week showed no change in muscle strength and muscle thickness.
However, the 6x5 group saw significant increases in muscle strength, more than 10 percent, with a similar increase in muscle thickness to the 30x1 group.
Frequency, not volume
Importantly, the increase in muscle strength of the 6x5 group was similar to the group in a previous study that performed only a maximum eccentric contraction of three seconds per day for five days a week for four weeks.
ECU Sports and Exercise Science Professor Ken Nosaka said these studies continue to suggest that very manageable amounts of exercise performed regularly can have a real effect on people’s strength.
“People think they have to do a long strength training session in the gym, but that’s not the case,” he said. “Simply lowering a heavy dumbbell slowly once or six times a day is enough.”
Professor Nosaka said that while the study required participants to exert maximum effort , early findings from current and ongoing research indicated that similar results could be achieved without requiring maximum effort. "We only used the biceps curl exercise in this study, but we believe this would also be the case for other muscles, at least to some extent," he said. “Muscle strength is important for our health. This could help prevent a decline in muscle mass and strength with aging.
“Decreased muscle mass is the cause of many chronic diseases, such as cardiovascular diseases, type 2 diabetes, some types of cancer, dementia and musculoskeletal problems such as osteoporosis.”
Rest
It is still not known precisely why the body responds better to strength exercises with eccentric contractions in smaller doses rather than larger loads less frequently. Professor Nosaka said it may relate to how often the brain is asked to make a muscle work in a particular way. However, he emphasized that it was also important to include rest in an exercise regimen.
“In this study, the 6x5 group had two days off a week,” he said. “Muscular adaptations occur when we are resting ; If someone could somehow train 24 hours a day, there would really be no improvement. “Muscles need to rest to improve their strength and muscle mass, but muscles seem to like to be stimulated more frequently.” He also stressed that if someone couldn’t exercise for a period, it wasn’t worth trying to "compensate" with a longer session later. “If someone is sick and can’t exercise for a week, that’s fine, but it’s better to return to a regular exercise routine when you feel better,” he said.
Clarifying advice
Current Australian government guidelines already indicate that adults should aim to be active every day and get 2.5 to 5 hours of moderate physical activity a week. Professor Nosaka said there needed to be more emphasis on the importance of making exercise a daily activity, rather than reaching a goal of weekly minutes.
“If you only go to the gym once a week, it’s not as effective as doing a little exercise every day at home,” he said. “This research, along with our previous study, suggests the importance of building up a small amount of exercise each week, rather than simply spending hours exercising once a week. “We need to know that every muscle contraction counts, and what counts is the regularity with which you perform them.” "Greater effects of performing a small number of eccentric contractions daily than a larger number of them once a week" was published in the Scandinavian Journal of Medicine and Science in Sports .
