When it comes to building size, gym lore holds that more is better. But should that be more volume, or more kilos? Or, is there a third, better option for both size and strength?

Gym culture might have us believe it’s all about heavier weights, bigger gains. But is that strictly true? After all, not all of us are training to get as massive as we can.

What if you want to be strong but slim? What if you’re training for a specific sport that doesn’t require biceps the size of Christmas hams?

Might a more balanced approach – a mix of heavy weights and higher reps – offer even more beneficial results?

We consulted the experts and analysed the science to settle the debate.

The benefits of lifting heavy

Bodybuilding protocol holds that if you’re looking to build muscle, you need to force your muscles to adapt by testing them with increasingly heavier loads.

For example, if you’re looking to bulk out your arms, you might do four sets of 8 - 10 bicep curls, progressively overloading the muscles with increasingly heavier dumbbells. You might even push past four sets and work to failure, when you physically can’t lift anything else.

“Lifting heavy means putting stress on your muscles, which damages them, causing micro-tears in the muscle fibres which then repair themselves both bigger and stronger, resulting in strength and size over time,” explains Rowan Clift, training specialist at AI-based fitness app Freeletics.

It sounds exhausting, but there are benefits to this tried and tested approach.
Bigger muscles not only help you lift more, they also help protect your bones, thereby reducing your chances of injury as you age. Lifting heavy may also help predict cognitive aging, and improve endurance, with one study finding heavier weights are more beneficial to cardio fitness than lighter ones.

Farren Morgan, former paratrooper and founder of the Tactical Athlete training method calls heavy weights “an indispensable component of any comprehensive training plan,” adding that compound exercises like squats, deadlifts, and bench presses should form the foundation of heavy lifting programs.

The benefits of higher reps

While traditional thinking argues that heavier weights are best for building muscle, higher reps at lower weights are thought to be best for toning up. Looking to define those triceps? You might do four sets on the rope pull down, aiming for 25 plus reps at a fairly light weight. Not too taxing at first, but you’ll feel the burn as you progress.

Morgan calls high rep training “a standard in fitness, particularly for individuals seeking to enhance muscular endurance and functional strength.”

He explains that high reps don’t just help you look chiseled, but also help your muscles withstand fatigue, findings backed up by a 2022 meta review which found that ‘local muscular endurance’ can be improved by 15 or repetitions per set. In other words, high reps aren’t just for show.

A 2021 study set out to challenge the idea that heavier weights lead to increased strength and found that both heavier weights and higher reps can build size. Interestingly, the study authors called heavy load training “ inefficient from a time standpoint” as it requires more sets, and could increase the potential for joint-related stresses and overtraining.

In other words, high reps may be lower impact, but they get the job done, and with a reduced risk of injury.

Another study, published in the Journal of Sports Science & Medicine also challenged the idea that lifting heavy equals bigger and stronger muscles. Looking at 19 male volunteers between the ages of 18-35, all of them experienced weight lifters, the study authors tracked their lifts and found heavy weights are best for increasing strength, while moderate weights at higher reps are best for increasing hypertrophy, or muscle size…

Higher reps or heavier weights... the verdict:

When it comes to higher reps vs heavier weights, Clift says it’s difficult to claim one method is superior, as not only will each of us react differently to a given training plan, but we all have different goals too.

One meta analysis of eight relevant studies did confirm that heavy reps performed to failure are better for strength gains, but as mentioned earlier, exercising this way brings an increased risk of injury and discomfort.

Yes, you’ll get stronger, but you’ll likely need to spend even more time doing stretches and accessory work to strengthen your joints so that 20kg dumbbell curl doesn’t put your elbow out of action for the next month. All of which must be considered when it comes to outlining a solid fitness routine.

“[Fitness] principles should stay fluid, and never rigid,” Clift says. “Mixing up your routine is what will help you excel in fitness.”

Morgan agrees, saying individualism is the most important factor in a given workout routine. Instead of choosing between high reps or heavy weights, he likes to integrate the two to optimise results.

As far as muscle growth goes, it doesn’t really seem to matter which method you favour, at least according to a 2016 study. In this instance, 49 men with an average of four years lifting experience underwent a whole body resistance training program with the results finding that both light weights and heavy weights elicited equal amounts of muscle growth – findings backed up by a later meta analysis.

So, while heavy loads are best for increasing strength, they’re probably not better at building size. If you’re working out for functional reasons, heavy weights might work best. If you’re working out more with aesthetics in mind, there’s no real need to go super heavy.

What really matters is that you are lifting weights, no matter how heavy, or for how many reps. As well as helping control body fat levels, people who do muscle-strengthening workouts are less likely to die prematurely than those who don’t. The same study shows that just 30 to 60 minutes of weight lifting per week gives a 10 to 20 percent lower risk of dying from cancer and heart disease.

And really, that’s a lot more important than the size of your guns.

Takeaways

The above is a lot to remember next time you’re on the gym floor. Here, our PTs break down their key tips to help you stay focused, and injury free, whatever your weight-lifting goals.

• Prioritise proper form and technique when lifting heavy weights to minimise the risk of injury and ensure optimal performance.
• Tailor your training approach to align with specific goals and objectives, like improving endurance, building strength, or enhancing overall athletic performance.
• If you are looking to build strength, use a weight which is heavy enough, but not too heavy so you can manage at least 3 - 6 reps.
• If you’re looking to build muscle, you need to be lifting heavy enough that you can manage 8 - 12 reps.
• If you’re using weights to build your muscular endurance, you need to use a weight of which you can do 15 - 25 reps.
• It’s more beneficial to do a short 20-30 minute session and really focus on the weight and number of reps to see a significant improvement quickly.
• Experiment with different rep ranges and training methods to keep workouts varied and engaging.
• Consistency and patience are key to long-term progress. Understand that fitness is a journey and don’t worry if you don’t see immediate results.
• Stick to a programme for 12 weeks, evaluate and monitor your progress, and change the programme when necessary.
• Whatever your goal, don’t skip ahead to weights that are too heavy for your abilities, as this will increase your risk of injury.

Words: Tom Ward