Tagged Weight Lifting

Lifting Lighter Weights Can Be Just as Effective as Heavy Ones

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Upending conventions about how best to strength train, a new study finds that people who lift relatively light weights can build just as much strength and muscle size as those who grunt through sessions using much heftier weights — if they plan their workouts correctly.

Strength training has long been dominated by the idea that to develop a physique like that of Charles Atlas or even Zac Efron, we — and I include women here — must load our barbells or machines with almost as much weight as we can bear.

In traditional weight training programs, in fact, we are told to first find the heaviest amount of weight that we possibly can lift one time. This is our one-repetition maximum weight. We then use this to shape the rest of the program by lifting 80 to 90 percent of that amount eight to 10 times, until our affected arms or legs shake with fatigue.

This approach to weight training is very effective, says Stuart Phillips, a professor of kinesiology at McMaster University in Hamilton, Ontario, who has long studied muscles and exercise. It builds muscle strength and size, possibly, many experts believe, by sparking a surge in the body’s production of testosterone and human growth hormone.

But many people find lifting such heavy weights to be daunting or downright unpleasant, which can discourage them from taking up or continuing with a resistance-training program, Dr. Phillips says.

So in recent years, he and his colleagues have been looking into the effects of a different type of weight training, which employs much lighter weights hefted through as many as 25 repetitions.

Since 2010, his lab has published several studies in which volunteers followed either the traditional regimen using heavy weights or an alternative that employed much slighter weight stacks. In general, the lifters’ results were comparable.

But those studies had been small and featured volunteers who were new to the gym, potentially skewing the outcomes, Dr. Phillips says. Almost everyone who takes up weight training shows significant improvements in strength and muscle size, making it difficult to tease out the impacts of one version of training versus another.

So for the new study, which was funded by the Natural Sciences and Engineering Research Council of Canada and published this month in the Journal of Applied Physiology, he and his colleagues recruited 49 young men who had been weight training for a year or more. (The scientists plan to study women and older people in future studies.)

All completed tests of strength, fitness, hormone levels and muscular health, then were randomly divided into two groups.

One group was assigned to follow the standard regimen, in which weights were set at between 75 and 90 percent of the man’s one-repetition maximum and the volunteer lifted until he could not lift again, usually after about 10 repetitions.

The other volunteers began the lighter routine. Their weights were set at between 30 and 50 percent of each man’s one-repetition maximum, and he lifted them as many as 25 times, until the muscles were exhausted.

All of the volunteers performed three sets of their various lifts four times per week for 12 weeks.

Then they returned to the lab to have muscle strength, size and health reassessed and their hormone levels re-measured.

The results were unequivocal. There were no significant differences between the two groups. All of the men had gained muscle strength and size, and these gains were almost identical, whether they had lifted heavy or light weights.

Interestingly, the scientists found no connection between changes in the men’s hormone levels and their gains in strength and muscle size. All of the men had more testosterone and human growth hormone flowing through their bodies after the workouts. But the degree of those changes in hormone levels did not correlate with their gains in strength.

Instead, the key to getting stronger for these men, Dr. Phillips and his colleagues decided, was to grow tired. The volunteers in both groups had to attain almost total muscular fatigue in order to increase their muscles’ size and strength.

That finding suggests, Dr. Phillips says, that there is something about the cellular mechanisms jump-started in muscle tissue by exhaustion that enables you to develop arms like the first lady’s.

This data does not prove, though, that one approach to lifting weights is necessarily better than the other, Dr. Phillips says.

“But some people will find it much easier or less intimidating” to lift lighter weights, he says, even though they need to complete more repetitions in order to tire their muscles. They also may experience fewer injuries, he says, although that possibility has not yet been tested.

For now, someone hoping to strengthen his or her muscles should choose a weight that feels tolerable and then lift it repeatedly until the effort of the final lift is at least an eight on a scale of one to 10, Dr. Phillips says. “There should be some discomfort,” he says, “but the dividends on the back side” in terms of stronger, healthier muscles “are enormous.”

Ask Well: Why Daily Weight Lifting Can Be Dangerous

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David Abusheik, 18, lifts weights for two hours a day, six days a week at Dolphin Fitness in Fort Hamilton, Brooklyn.

David Abusheik, 18, lifts weights for two hours a day, six days a week at Dolphin Fitness in Fort Hamilton, Brooklyn.Credit Béatrice de Géa for The New York Times

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Which Type of Exercise Is Best for the Brain?

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Some forms of exercise may be much more effective than others at bulking up the brain, according to a remarkable new study in rats. For the first time, scientists compared head-to-head the neurological impacts of different types of exercise: running, weight training and high-intensity interval training. The surprising results suggest that going hard may not be the best option for long-term brain health.

As I have often written, exercise changes the structure and function of the brain. Studies in animals and people have shown that physical activity generally increases brain volume and can reduce the number and size of age-related holes in the brain’s white and gray matter.

Exercise also, and perhaps most resonantly, augments adult neurogenesis, which is the creation of new brain cells in an already mature brain. In studies with animals, exercise, in the form of running wheels or treadmills, has been found to double or even triple the number of new neurons that appear afterward in the animals’ hippocampus, a key area of the brain for learning and memory, compared to the brains of animals that remain sedentary. Scientists believe that exercise has similar impacts on the human hippocampus.

These past studies of exercise and neurogenesis understandably have focused on distance running. Lab rodents know how to run. But whether other forms of exercise likewise prompt increases in neurogenesis has been unknown and is an issue of increasing interest, given the growing popularity of workouts such as weight training and high-intensity intervals.

So for the new study, which was published this month in the Journal of Physiology, researchers at the University of Jyvaskyla in Finland and other institutions gathered a large group of adult male rats. The researchers injected the rats with a substance that marks new brain cells and then set groups of them to an array of different workouts, with one group remaining sedentary to serve as controls.

Some of the animals were given running wheels in their cages, allowing them to run at will. Most jogged moderately every day for several miles, although individual mileage varied.

Others began resistance training, which for rats involves climbing a wall with tiny weights attached to their tails.

Still others took up the rodent equivalent of high-intensity interval training. For this regimen, the animals were placed on little treadmills and required to sprint at a very rapid and strenuous pace for three minutes, followed by two minutes of slow skittering, with the entire sequence repeated twice more, for a total of 15 minutes of running.

These routines continued for seven weeks, after which the researchers microscopically examined brain tissue from the hippocampus of each animal.

They found very different levels of neurogenesis, depending on how each animal had exercised.

Those rats that had jogged on wheels showed robust levels of neurogenesis. Their hippocampal tissue teemed with new neurons, far more than in the brains of the sedentary animals. The greater the distance that a runner had covered during the experiment, the more new cells its brain now contained.

There were far fewer new neurons in the brains of the animals that had completed high-intensity interval training. They showed somewhat higher amounts than in the sedentary animals but far less than in the distance runners.

And the weight-training rats, although they were much stronger at the end of the experiment than they had been at the start, showed no discernible augmentation of neurogenesis. Their hippocampal tissue looked just like that of the animals that had not exercised at all.

Obviously, rats are not people. But the implications of these findings are provocative. They suggest, said Miriam Nokia, a research fellow at the University of Jyvaskyla who led the study, that “sustained aerobic exercise might be most beneficial for brain health also in humans.”

Just why distance running was so much more potent at promoting neurogenesis than the other workouts is not clear, although Dr. Nokia and her colleagues speculate that distance running stimulates the release of a particular substance in the brain known as brain-derived neurotrophic factor that is known to regulate neurogenesis. The more miles an animal runs, the more B.D.N.F. it produces.

Weight training, on the other hand, while extremely beneficial for muscular health, has previously been shown to have little effect on the body’s levels of B.D.N.F., Dr. Nokia said, which could explain why it did not contribute to increased neurogenesis in this study.

As for high-intensity interval training, its potential brain benefits may be undercut by its very intensity, Dr. Nokia said. It is, by intent, much more physiologically draining and stressful than moderate running, and “stress tends to decrease adult hippocampal neurogenesis,” she said.

These results do not mean, however, that only running and similar moderate endurance workouts strengthen the brain, Dr. Nokia said. Those activities do seem to prompt the most neurogenesis in the hippocampus. But weight training and high-intensity intervals probably lead to different types of changes elsewhere in the brain. They might, for instance, encourage the creation of additional blood vessels or new connections between brain cells or between different parts of the brain.

So if you currently weight train or exclusively work out with intense intervals, continue. But perhaps also thread in an occasional run or bike ride for the sake of your hippocampal health.

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