Gym culture is changing. Once the preserve of musclemen whose veins looked ready to pop, now muscle-strengthening activities are being advised by the NHS for those aged 19-64 at least twice a week. That’s because an increasing body of evidence links strength work with wellbeing and longevity, including a 2024 study that showed 90 minutes of strength training a week resulted in four years less biological ageing. Maybe that’s why about 15% of the UK population is now a member of a gym. Part of the appeal is accessibility – it’s not as technical as swimming, for example – but despite its simplicity, there’s a huge amount of misinformation and conflicting advice.
Low or high reps?
Strength-training exercises are structured into a number of sets made up of repetitions. For instance, eight lifts, rest, followed by eight further lifts equates to two sets of eight. Finding the optimal combination of sets, reps and rest for gaining strength is a well-worn gym debate, but science is beginning to settle on an answer.
“Building muscle – hypertrophy – can occur across all rep ranges, from low, moderate and high,” says Chris Peden, a former Royal Navy physical training instructor and now a strength and conditioning coach to professional and amateur athletes. “However, the optimum range appears to be in the moderate range of 6-12 reps and with a moderate intensity of load between 65% and 85% of an individual’s one-rep maximum.”
Peden adds that finding your one rep maximum (1RM) isn’t essential for beginners, especially as you could strain a muscle through inexperience. Just go on what feels tough but not dangerously so. Alternatively, you can use an app such as Hevy or Stronglifts to create a programme, calculate your 1RM, track your progress and suggest when you’re ready to upgrade to a heavier weight.
Peden stresses that a high rep number isn’t the most efficient way to increase strength. A 2015 study in the Journal of Strength and Conditioning Research that compared a high-rep (25-35 reps), low-weight group and a higher-weight, lower-rep (8-12) group, and discovered that muscle size for both groups was similar. However, the heavier-weight group enjoyed the greatest strength gains because of the greater recruitment of muscle fibres.
Muscle building happens ‘across all rep ranges’ and with higher and lower weights’, says personal trainer Chris Peden. Photograph: Hiraman/Getty Images
How much rest do I need?
When it comes to strength gains, what you do between lifts matters as much as what you do during them. “Generally, you should enjoy 90-150 seconds’ rest between sets for hypertrophy and 3-5 minutes’ rest for building strength,” says Peden. “If time isn’t an issue, I’d recommend resting a little longer if you can because it cranks up quality across all reps and sets. Rest as required; in other words, rest until you feel ready to go again and not by a strict timer.”
Free weights or machines?
When it comes to choosing machines or free weights, take heed of the legend of Milo of Croton, a six-time Olympic champion wrestler in the sixth-century BC, whose training is said to have involved lifting a calf over his head every day until it became a fully grown cow. Milo’s beefy exploits show that your workload needs to progress if you want to keep on improving, and also indicate that the precise usage of specific equipment isn’t the be-all and end-all.
“A mix of machines and free weights usually works best for strength and building muscle, though free weights help train the body in a more rounded fashion, incorporating stabiliser muscles,” says Peden. “This has its advantages in sporting settings and everyday life.”
Dumbbells and barbells that aren’t connected to a pulley deliver a greater benefit because you’re forced to balance your entire body while performing an exercise. For example, a standing biceps curl, which engages not only the biceps but also your back, abdominals and even your quadriceps to keep your body upright. This multimuscle engagement is more reflective of the real world, whether hitting a forehand on the tennis court or easing yourself in and out of a car.
Aren’t body-weight exercises sufficient?
Do you really have to spend on gym membership if crunches, press-ups and so on will give similar results? “Body-weight exercises kickstart the process of getting stronger and building muscle,” says Peden, “but ultimately it becomes harder to progress as you’ll lack the meaningful level of resistance to sufficiently stress the muscular system.”
A fundamental weakness of body-weight exercises is that the stress (your weight) stays the same (or even decreases) while your strength increases. That said, you can adjust the difficulty of home-based exercises; with press-ups, you can put your feet on a chair or use just one arm.
Body-weight exercises ‘kickstart’ the process of building strength and muscle. Photograph: Djordje Krstic/Getty Images
How should I balance weights and cardio?
The benefits of strength work are unequivocal, but what if you wish to tap into cardio work, too? One school of thought said that they’re unhappy bedfellows, each minimising the impact of the other. But a recent study revealed that people who took the NHS’s recommended 150 minutes of moderate exercise a week lived longer than those who didn’t, while those who combined regular aerobic exercise with muscle-strengthening activities once or twice a week fared even better.
Am I too old to start?
Thinking of hitting the gym but put off by your advancing years? Don’t be. “It’s never too late to start,” says Peden. “We can still build muscle and grow stronger in later life, which helps to offset the rate of the ageing process. Weights are great for maintaining quality of life.”
Muscle mass declines with age – a process that can begin in your 30s – and the resulting reduction in strength can lead to frailty and falls. But studies have shown that strength training can reverse this process and is associated with a variety of other benefits, including reductions in belly fat and blood pressure, and improved cholesterol readings.
Additionally, strength training has been shown to slow age-related decline in testosterone in men. And resistance training increases bone density – particularly beneficial for women at risk of osteoporosis.
Older gym-goers should think about increasing their protein intake. This is important for all ages but especially the over-60s because of an age-related anabolic resistance to protein. One study showed that protein absorption and assimilation was much slower in those over 60 compared with 20-to25-year-olds, leading to reduced strength gains. Evidence suggests a minimum of 1 gram of protein for every kilogram of bodyweight is a good starting point as you age.
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