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Research suggests that short bursts of daily exercise may be more beneficial for muscles. The Good Brigade/Getty Images
  • A new study finds that exercising briefly five days a week may be superior to an extended exercise session once a week.
  • The study’s participants who did just six arm-resistance exercises five days a week improved muscle strength and muscle thickness.
  • The study involved maximum-strength exercises, but researchers are seeing evidence in ongoing studies that suggests less strenuous resistance exercise may also work.

It can be hard to find time to exercise daily, even though it is an important activity for maintaining one’s health. For some, it is easier to carve out a bit of time each day, while others find that longer periods of exercise once or twice a week are more doable. A question to be asked is whether the two approaches are equally beneficial.

A new study from researchers at Edith Cowan University in Perth, Australia, and Japan’s Niigata University and Nishi Kyushu University found that they are not.

The researchers found that small amounts of exercise five days a week improved muscle more than a single extended weekly exercise session.

The corresponding author of the study, Dr. Masatoshi Nakamura, told Medical News Today:

“We believe 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.”

“It is also good to keep up a hard workout at the gym. However, I think it is a hurdle for many people,” Dr. Nakamura added.

The gains were the result of a single set of six eccentric resistance exercises, performed each weekday.

Strength training exercises usually include three phases: a concentric phase, an isometric phase, and an eccentric phase.

The concentric phase focuses on shortening the target muscle, reaching its peak contraction to overcome gravity or some other form of resistance load. The isomeric phase corresponds to the transition point of an exercise in which the muscle is stationary following the concentric phase. Finally, the eccentric phase follows the isometric phase, in which the muscle is lengthened under load to return to its starting position.

Eccentric training focuses on lengthening your muscles under tension, usually by slowing it down as a means to increase the intensity and illicit certain benefits.

Professor Paul Arciero, of the Human Physiological Sciences Department at Skidmore College, who was not involved in the study, told MNT:

“The positive benefit of this study showed a very small training stimulus (time commitment) produced a significant increase in strength.”

The study is published in the Scandinavian Journal of Medicine and Science in Sports.

The researchers divided 36 participants into three groups that exercised for four weeks:

  • The 6 x 5 group — performed six contractions a day five days a week.
  • The 30 x 1 group — performed all 30 contractions during a single weekly session.
  • The 6 x 1 group — performed just six contractions once a week.

The 6 x 5 group were the only participants to have built both muscle strength and thickness at the end of the study period.

The 30 x 1 group built muscle thickness, but not muscle strength. The 6 x 1 group showed no improvement.

The contractions participants performed were maximal, forcing the muscle to work as hard as possible.

“In order to perform maximal eccentric contractions, as used in the study, very expensive equipment is required called an isokinetic dynamometer, which greatly limits the application of the findings because not everyone has access to this specialized equipment at home or in a gym/fitness center,” Prof. Arciero noted.

Furthermore, he said, “This type of maximal eccentric exercise produces a significant increase in muscle soreness which may deter many people from doing it, including the elderly and young children who may be at increased risk for injury.”

“Muscle soreness and increase injury risk are major reasons to avoid exercise,” he pointed out.

It is not clear if the level of exertion explored in the study is required to achieve the reported benefit. Fortunately, “Ongoing research indicates similar results could be achieved without maximum-effort exercise,” said Dr. Nakamura.

Prof. Arciero proposed additional research “that uses submaximal eccentric contractions that can be performed using traditional resistance equipment such as dumbbells, barbells, cables, body weight, bands, etc., to determine whether it produces the same benefit. This would allow a much larger segment of the population to benefit from this form of training.”

MNT asked Dr. Nakamura if such exercise could be expanded to other muscle groups for a more comprehensive workout that does not take too much time out of the day.

“Unfortunately, we haven’t investigated other muscles yet, but we believe that the benefit of six muscle contractions daily could apply to the other muscles,” he said.

“[I]f we find the six muscle contractions daily rule also applies to other muscles, then you might be able to do a whole-body exercise in less than five minutes.”
— Dr. Masatoshi Nakamura

“Performing similar maximal eccentric movements for all the other muscles of the body may prove to be a time-efficient full-body workout,” said Prof. Arciero. “However, it’s unknown whether other muscles of the upper body, trunk, and lower limbs produce similar gains in strength.”

Dr. Nakamura also drew attention to the frequency and length of rest days or resting periods.

“Muscle adaptions occur when we are resting, regardless of training volume. However, the improvement effect may be lost if the rests are too long and training is done once a week. Muscles need rest to improve their strength and their muscle mass, but muscles appear to like to be stimulated more frequently,” he said.

“We also would like to highlight if someone was unable to exercise for a period, there was no value in trying to ‘make up’ for it with a longer session later.”
— Dr. Masatoshi Nakamura

“In my professional opinion,” concluded Dr. Arciero, “to benefit the most from exercise, you should perform exercise that you enjoy or at least be most likely to perform consistently in order to benefit from it.”

“I always recommend an… exercise routine that is time-efficient, multi-modal — includes variety and is fun! — performed outside in nature, and benefits the body in many different ways,” he said.