Anyone who hits the weight room regularly will inevitably face the question: Should you add more weight and do less repetitions or use a lighter weight and do more reps?
The debate has raged on for as long as people have argued over cake versus pie (the answer is pie, obviously), but it’s not quite that simple.
The truth behind weight versus reps lies somewhere in between, but to paint a clearer picture, you have to understand why we ask this question in the first place.
A Worthy Villain: The Fitness Plateau
Once you’ve been following a fitness program for a while, you’ll eventually hit a fitness plateau—that dreaded no-man’s land where your body adapts to your routine, and you no longer make progress. It sucks, but it’s normal, and it happens to everyone.
One way to bust through the plateau is simply to change things up. This is where lifting heavier weights, adding more reps, or doing both (called a double progression) can shake up sleepy progress.
The Case for Heavier Weights
When you pile on the pounds, you typically lift on the lower end of reps (as few as 1-5 for some people). That doesn’t sound like much, but by doing so, you’re increasing your overall maximum strength and greatly improving your ability to lift heavier weights.
Most of that newfound superhero strength is because you’re improving your efficiency at a given exercise. Think of how your bank account grows when you minimize unnecessary spending. It's like that, and the more you practice restraint with a budget, the easier it is to save.
Lifting heavy weights feels awesome, but it’s easy to get sucked into chasing the numbers and running into a wall. Eventually, you’ll reach a point where you simply can’t add any more weight, and if you push it, you could compromise your form and put yourself at risk for injury.
“If you've increased your weight and now your form is breaking down, it’s best to drop the weight and then increase the number of reps you're performing,” says Tanner Baze, a certified personal trainer.
Which brings us to...
The Case for More Reps
When you lift lighter weights for more reps, you are still getting stronger, just in a different way. You’re developing “muscular endurance,” or your ability to exert a certain amount of effort before you fatigue. Sure enough, doing more work (more sets and reps, more workouts, more overall bad-assery), will help you get stronger in the long run. Busting out more reps is also a challenging workout at a high-intensity level, which burns major calories and has a greater afterburn effect.
Plus, when you hit a plateau, adding reps instead of heaving more weight allows you to focus on proper technique and form and still leaves room for additional changes to your program, if necessary.
The upside of maintaining tip-top form is you end up really working the muscle as intended, not relying on a bunch of compensatory patterns (for example, letting your quads do all the work when your glutes are too weak) or potentially hurting yourself. One downside to this technique is that it may make your workouts slightly longer, as you’ll spend more time doing more reps.
Why Not Just Do Both?
Confusion about lifting heavier weights or doing more reps still lingers in the weight room because weightlifting and its effects on our bodies are often misunderstood, Baze says. Hint: It involves a lot more than lifting super-heavy weight or banging out more reps in isolation.
You need a combination of muscle damage (that hurts-so-good soreness after a great workout), mechanical tension (the sheer strain of lifting something heavy), and metabolic stress (that “burn” you feel from your muscle really working). Both heavy-weight and high-rep training check those three boxes and will ultimately build strength. Plus, both methods require proper form, because without good technique, it doesn't matter how much weight or how many reps you do, you could be risking injury.
“If your goal is just to generally get stronger and more fit, choose one or the other,” says Nathan Jones, a doctor of physical therapy student and strongman competitor.
For long-term progress and to keep things interesting, you can incorporate both heavy-weight, low-rep training and light-weight, high-rep training by switching up the sets and reps on different days or weeks (a technique known as periodization). “If you’ve been doing 5 sets of 5 squats and can’t add weight or get an extra rep, drop the weight and go to 5 sets of 8, or add weight and go to 3 sets of 5,” Jones says. Basically, imagine your sets and reps as a wavelength continuously going up and down.
There’s nothing inherently magical about changing things up this way. “Personally, I think it's more psychological than anything,” Jones says. “Doing the same rep range every single time you lift gets boring. So doing something different helps you maintain motivation, and subsequently, keeps your effort high.”
“There is no wrong decision here,” Jones says. When you lift more weight, add more reps, or do both appropriately with good form while keeping effort high, you’re nudging your body toward continually improved fitness and strength.
That said, when you add weight or make changes, do so in small increments. Your goal is to squeeze big results from little changes. It also helps to include a proper warm-up and cool-down.
“The single most important factor in your progress is your willingness to work hard and exert high effort,” Jones says. “So long as you’re doing more of something over time, you will get stronger.”
Mixing it up just a teeny bit to keep yourself motivated and to see progress—whatever your goal—will go a long way.