Wondering how much weight you should be lifting in the gym to build strength? Dr Stacy Sims says that not going heavy enough could be the biggest mistake women are making in their workouts.
What strength training looks like might differ (for example, some prefer callisthenics over classic weight training) for some, but one thing is clear – it needs to be a challenge.
This is something exercise scientist Dr Stacy Sims was keen to emphasise to journalist Clare Johnston on a recent episode of her podcast, The Honest Channel. The pair discussed why intensity really matters for women when they’re strength training, rather than just doing the same exercise for as many sets or reps as possible.
Article continues below
Dr Sims says she believes many women don’t push themselves enough when working out, which is why we might not see results as quickly as we want. “There’s an inherent difference between building muscle and building strength. So we know that again, one of the first things that will come is strength, but how are we actually maximising that for women?” she says.
How much weight should I lift?
Dr Sims recommends lifting a weight you can complete for a maximum of six to eight repetitions, leaving just one or two in reserve. As she says in her video on perimenopause and resistance training: if it doesn’t challenge you, it doesn’t change you.
Doing lots of repetitions with lighter dumbbells or other weights won’t have the same effect, she warns. Doing many reps over time improves your muscles’ endurance, but not how fibres within the muscle are working and how tightly they’re contracting, which is what you need to build strength – especially in perimenopause.
“When we start having changes in oestrogen, one of the first things that goes is pure power and strength because oestrogen affects our contractile proteins actin and myosin,” she says. She explains that adding load (lifting heavier) means actin and myosin “hold onto each other a lot harder and to have a very strong and tight contraction – that’s what strength and power are”. This means that if you’re not challenging your muscles to work harder through progressive overload, you won’t see the results you may be aiming for, because the proteins in your muscles are only ever contracting lightly.
“It’s not just about building lean mass, it’s about how strong that muscle is as we go about building it. How do we go about preserving strength and fast-twitch fibres and all the things women need to conserve as we get older to have a really good health span,” Dr Sims explains.
Fast-twitch muscle fibres are needed for heavy weight lifting, sprinting and reaction ability, but they can fatigue quickly and reduce in size and number as we age. This is because of the fall in oestrogen we experience as we enter perimenopause. Men don’t have this problem because their testosterone levels stay more stable throughout their lives.
Taking supplements like creatine, alongside regular exercise, has been shown to improve this as well.
Dr Sims says lifting heavy weights and doing plyometric exercises – explosive, high-intensity exercises such as jumping or hopping – helps women increase and maintain their fast-twitch muscle fibres. She says if we focus on lifting heavy weights for fewer reps, there’s no need to be in the gym for hours every week – welcome news for all of us.
As for how often you should lift weights, she suggests at least three sessions every week with active recovery days between them. This should include mobility exercises and zone 2 exercise, such as a walking workout.
If you’re new to strength training, remember to speak to a trained professional first to ensure you avoid injury.
