Gym culture is evolving. Once dominated by bodybuilders, muscle-strengthening activities are now recommended for all adults at least twice a week by the UK’s chief medical officer. A growing body of evidence links strength work with wellbeing and longevity, including a 2024 study showing that 90 minutes of strength training per week resulted in four years less biological ageing. Around 15% of the UK population is now a gym member, drawn by accessibility, but misinformation persists.
When it comes to reps and sets, science is settling on an answer. Chris Peden, a former Royal Navy physical training instructor, explains that muscle hypertrophy can occur across all rep ranges, but the optimum is 6-12 reps with a load of 65-85% of your one-rep maximum (1RM). Beginners don't need to find their 1RM; just go on what feels tough but not dangerous. A 2015 study in the Journal of Strength and Conditioning Research found that a heavier-weight, lower-rep group (8-12 reps) gained more strength than a high-rep, low-weight group (25-35 reps), despite similar muscle size gains.
Rest between sets is crucial. Peden recommends 90-150 seconds for hypertrophy and 3-5 minutes for strength. “Rest until you feel ready to go again, not by a strict timer,” he advises. Longer rest improves quality across all reps and sets.
On equipment, a mix of machines and free weights works best. Free weights train the body more holistically, engaging stabiliser muscles. For example, a standing biceps curl also works your back, abdominals and quadriceps. This multimuscle engagement reflects real-world movements.
Body-weight exercises can kickstart strength gains, but progression becomes harder without added weight. Peden notes that eventually you’ll lack the meaningful load needed to continue building muscle. For optimal results, incorporate weights or resistance.
