If you’re looking to build strength but find yourself gazing forlornly at a pair of light dumbbells, wondering how they can help, I have good news. Research suggests that it doesn’t matter how light or heavy you lift, so long as you lift to the point of near failure.
That’s the lesson recently shared by certified trainer, Technogym ambassador and friend of the show James Stirling, also known as London Fitness Guy to his 1.4 million followers on Instagram.
Pointing to one small 2015 study on 18 well-trained young men, Stirling wrote that lifting light weights for 25-35 reps or heavy weights for 8-12 reps produced a similar muscle growth response so long as “the set was taken to the point where only 1-2 reps were left in the tank”.
“Most people say heavy [weights build more muscle] but the research says both work, as long as you’re pushing close to failure,” he added, while pictured wielding a heavy and light dumbbell in the accompanying video.
The study, published in The Journal of Strength and Conditioning Research, did however, find high-load resistance training to be superior for maximizing strength adaptations.
Stirling’s assertion neatly aligns with another more recent preprint by the same lead author that was published last year.
Brad J Schoenfeld and his fellow authors found that lifting weights within two reps of the point of failure, known as two reps in reserve (RiR), was the winning formula to build muscular endurance and strength.
Better still, the researchers, led by author Tom Hermann, found just two 30-minute sessions of resistance training a week is plenty to build size and strength.
How do you know when you’re close to failure?
Lifting close to failure taps into the principle of progressive overload, in which you consistently challenge yourself to lift near your maximum.
Repeating this process week upon week forces your muscles to adapt and become stronger. Muscle fibres grow, ligaments and tendons become more resilient, and strength increases.
But how do you know for sure when you’re close to failure?
Stirling has two telltale signs:
- The weight starts slowing down when you’re lifting it.
- It feels like your muscles are on fire.
“Think of it like your car’s fuel warning light,” he writes. “Stop just before you’re empty, not when you’re cruising.”
Use Stirling’s light weights workout to build full-body muscle
To illustrate this point, I asked Stirling for one of his favorite full-body workouts that can be practised with whatever weights you have at your disposal.
His session includes seven exercises, four of them combined into two supersets to keep muscles under increased tension if you’re making the most of light dumbbells.
“Perform three sets of each exercise, working close to failure on each,” Stirling tells Fit&Well. Rest for one minute between sets.
For the supersets, perform one set of exercise A, then move straight onto exercise B. After you finish the set of exercise B, rest for one minute, then return to exercise A and continue that pattern until you’ve completed three sets of each exercise.
Here are the moves, with either a link to our exercise guide, or a guide on our former sister site Coach.
Just remember that you should take each set close to failure.
“That will ensure enough load to build muscle, regardless of rep range, making this workout convenient if you want to try it at home or if equipment is limited,” says Stirling.
“Ensure you follow the principle of progressive overload,” he adds. “When it feels comfortable, increase the weights. Aim for small progressions in reps or the weights you lift.
“Or add more volume each week by increasing the number of sets you complete.”
