There's a common belief that once you hit 40, you need to take some plates off the bar. Heavy sets are often swapped for lighter weights and higher reps, supposedly offering an easier way to build muscle.
But coach Alain Gonzalez argues that automatically dropping the weight could be a mistake. 'After 40, the question isn't simply, "Can this build muscle?" The better question is, "Which approach builds muscle with the least recovery cost, the least unnecessary joint stress, and the greatest long-term return?"'
Heavy vs. Light Weights for Muscle Growth
Research has shown that muscle can be built across a wide range of loads and rep ranges,provided your sets are taken sufficiently close to failure
'Both heavy and light weights can produce similar muscle growth,' Gonzalez says. 'But while both methods can get you to the same destination, they take very different paths to get there.'
He explains that the difference partly comes down to motor unit recruitment. Heavier loads require high levels of force, recruiting larger, high-threshold motor units early in the set.
However, when we work with lighter weights, Gonzalez says those high-threshold motor units only tend to be brought in towards the end of the set as fatigue builds.
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That means that, taking a set with lighter weights sufficiently close to failure can still recruit those fibres and provide a potent muscle building stimulus, you'll probably have to perform considerably more reps to get there.
Why Lifting Heavier After 40 Could Mean Less Fatigue
Gonzalez then explains why lifting heavier could be a more efficient option for people over 40.
'With lighter weights, you have to perform far more repetitions and get much closer to failure before your body recruits those larger high-threshold motor units,' he says. 'That means you're relying on fatigue to create the same growth stimulus that heavier weights create almost immediately.'
Higher-rep sets can also bring more muscle burn, breathlessness and general discomfort into the equation, potentially increasing perceived exertion.
'You're often ending the set not because the target muscle can't produce any more force, but because everything else gave out first,' says Gonzalez. 'You're paying a much higher fatigue cost to reach the same destination.'
While lighter and heavier loads can produce similar muscle growth, heavier loads generally have the edge when it comes to maximising strength. That doesn't mean you need to work to failure. Gonzalez recommends spending most of your training in the 6-12 rep range, keeping compound lifts towards the lower end and isolation exercises towards the higher end.
Gonzalez also warns, 'Heavy doesn't mean reckless.'
So, work within your capabilities, be sensible and leave the ego lifting behind.
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