Researchers from McMaster University in Hamilton, Ontario, have concluded that lifting lighter weights is just as effective for gaining muscle mass and strength as lifting heavier weights, a result which stands contrary to collective wisdom and may help persuade more people to adopt exercise programs.
The common assumption has long been that exercising with heavier weights -doing repetitions with weights that are between 70 and 85 per cent of a person’s maximum for one repetition- is the most efficient pathway to putting on muscle mass and increasing muscle fibre size (both indicators of strength), but a new study appearing in the Journal of Applied Physiology finds otherwise.
“Fatigue is the great equalizer here,” says Stuart Phillips, professor in McMaster’s Department of Kinesiology and senior author of the study. “Lift to the point of exhaustion and it doesn’t matter whether the weights are heavy or light.”
Researchers tracked two groups of experienced weight lifters over a 12-week program. One group lifted weights equivalent to 50 per cent of their maximum strength in sets of 20 to 25 repetitions and the other group lifted up to 90 per cent of their maximum for eight to 12 reps, with both groups lifting to the point of failure.
Upon analysis, gains in muscle mass and fibre size were virtually identical in both groups, with even slightly better results from exercising with lighter weights on the bench press. The research team also concluded that post-exercise levels of hormones did not play a role in stimulating growth in muscle mass and overall strength.
“For the ‘mere mortal’ who wants to get stronger, we’ve shown that you can take a break from lifting heavy weights and not compromise any gains,” says Phillips. “It’s also a new choice which could appeal to the masses and get people to take up something they should be doing for their health.”
As most of us know, regular exercise is vitally important for heart health and longevity. But a recent study has concluded that exercising can also improve your memory, if it’s done four hours after learning.
Researchers at the Radboud University Medical Center in the Netherlands tested three groups of people on their ability to remember simple picture-location associations, with one group exercising immediately after the memory session, another exercising four hours later and the third not exercising at all. Two days later, the group exercising four hours after the session retained the information better than the other two, a result which researchers attribute to elevations of the chemical compounds dopamine and norephinephrine in the brain that come from physical exercise. “Our results suggest that appropriately timed physical exercise can improve long-term memory and highlight the potential of exercise as an intervention in educational and clinical settings,” say the study’s authors.
The Canadian Physical Activity Guidelines recommend for adults a minimum of 150 minutes of moderate to vigorous physical activity per week in bouts of ten minutes or more and that they participate in muscle and bone strengthening activities at least two times a week. For children and youth, the recommendations suggest at least 60 minutes of moderate to vigorous physical activity a day with muscle and bone strengthening activities at least three times a week.
According to a Canadian health Measures Survey, 93 per cent of Canadian children and youth between the ages of five and 17 do not attain the recommended amounts of daily exercise.
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