Most of us know by now that staying fit doesn’t just mean “aerobic” exercise, when you get out of breath – it should also involve strength training, which is known as resistance exercises.
These days it’s no longer just body builders who are found lifting weights at the gym – the machines may be used by all.
But there is a bewildering array of activities that count as resistance exercise, and a cornucopia of videos, podcasts and websites that tell us exactly how we should be doing it.
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Now, though, the American College of Sports Medicine has completed a major review of the scientific research on resistance exercise, for the average person – as opposed to professional athletes – and their conclusions might be surprising.
Here are four ways that the US experts say most people should rethink their approach to strength training.
Training to failure is out
“Training to failure” means instead of doing a certain exercise – like lifting a weight – a set number of times, you do it until your muscles are so tired you feel that you cannot do it a single time more. You then rest, and repeat the process a couple more times.
The approach is claimed to help build more muscle mass, because it triggers release of certain hormones and other biochemicals.
But there is no evidence that training to failure does, in fact, lead to bigger muscles, according to the US guidelines.
And a previous study found the approach slowed down recovery after the exercise. “Avoiding failure would allow athletes to be in a better neuromuscular condition to undertake a new training session or competition in a shorter period of time,” that study concluded.
“The closer you go to failure, probably the more risk you are at of getting injured,” said Dr Jonathan Taylor, a senior lecturer in sport and exercise at Teesside University, who was not involved in the guidelines.
No need to slow down
Another trend is to slow down movements, to increase the “time under tension” experienced by muscles. This is claimed to increase stress on muscle fibres. But again, it has not been found to help build muscles.
“The theory is it increases metabolic stress,” said Dr Taylor. “The more well trained people become, you have to change the stimulus to get further gain.”
But this is not needed for most people, he said.
Workouts don’t have to be complicated
Different advice sources may recommend complex routines, like alternating sets – groups of repetitions – with heavy loads, followed by sets with lighter loads.
Or people may break traditional sets into smaller mini-sets, separated by preplanned rests. The idea is that this reduces muscle fatigue, allowing more work overall.
But none of this is necessary, according to the guidelines. “The best resistance training program is probably not the most complicated one. It is the one you can do consistently, progress sensibly, and stick with over time,” said Professor Stuart Phillips, a muscle researcher at McMaster University in Ontario, who is one of the guideline authors.
You don’t even need to go to the gym
Gyms usually have much better equipment than people can have in their homes – and can be social places too.
But home workouts are also fine, say the guidelines. “Elastic bands, bodyweight training and home-based routines offer clear and measurable improvements in strength, muscle size and functional performance,” the authors said.
This is worth stressing for people who currently do little or zero strength training and may be reluctant to join a gym, said Professor Lindsay Bottoms, a sports scientist at the University of Hertfordshire. “If you’re sedentary, don’t be put off by thinking you have got to go the gym. Anything that’s muscle building will help you.”
The key takeaways
So much for we shouldn’t do – what should we be doing?
“For strength, the evidence points to a few variables that matter most,” said Prof Phillips. “Train at least two times per week; use heavier loads; lift through a full range of motion; perform about two to three sets; and place key lifts at the beginning of the session.
“Training all major muscle groups at least twice a week matters far more than chasing the idea of a perfect or complex training plan.
The benefits to health from resistance training include a lower risk of heart disease, cancer, diabetes and depression, as well as better sleep quality. “The big headline is resistance training works,” said Prof Phillips.
The guidelines were published in the journal Medicine & Science in Sports & Exercise.