Browse evidence-based analysis of health-related claims and assertions
Doing more sets of weightlifting each week helps you build more muscle, but after a certain point, adding even more sets gives you less extra benefit.
Correlational
When trained guys do lots of reps, they feel more tired, weaker longer, and more stressed than when they do fewer heavy reps — even though their muscles are damaged about the same.
Causal
Even after a tough workout, your body doesn’t show signs of widespread inflammation in the next few days.
One workout, whether heavy or high-rep, doesn’t change your testosterone levels in the hours after.
Your muscles don’t get bigger or smaller right after a single workout, no matter how hard or how many reps you do.
Pulling or squatting as hard as you can from a static position doesn’t get weaker after either type of heavy lifting session.
Lifting heavy weights just a few times doesn’t stress your body as much right after as doing lots of lighter reps.
More reps don’t break your muscles more than heavy lifts — but they do make you more stressed and tired right after.
Doing many reps triggers a bigger stress and inflammation response in the body right after exercise than doing fewer heavy reps.
Both heavy lifting with few reps and light lifting with many reps cause muscle damage, but neither does it more than the other.
Doing lots of reps leaves your muscles weak for days, but doing fewer heavy reps doesn’t make you weak for long.
Doing a lot of reps with lighter weights right after each other makes your legs feel way more tired right after than doing fewer reps with heavier weights.
Just because changing your shoulder angle makes your biceps work harder during one workout doesn’t mean it will make your muscles bigger over time — this study didn’t test that.
Descriptive
When measuring muscle activity with electrodes during bicep curls, the results can be affected by how the muscle stretches and where the electrode sits — so the numbers aren’t always a perfect measure of effort.
Mechanistic
After a tough bicep workout, your muscles swell and show stress signs, but they bounce back fully by the next day — so these signs don’t tell you much about long-term growth.
Doing bicep curls with your arm stretched behind you makes the lower part of your bicep feel more strained right after the workout than doing them with your arm at your side.
Switching up your shoulder position during bicep curls makes your muscles fire more, even if you're lifting the same total weight.
Whether you change your shoulder angle or not during bicep curls, your muscles recover at the same speed over the next three days.
The middle part of your bicep gets a little more 'hazy' on ultrasound after a workout, but it clears up by the next day — and it doesn’t matter if you changed your shoulder angle.
When you do bicep curls with your shoulder stretched back, the lower part of your bicep shows more signs of stress on ultrasound right after the workout than when you keep your shoulder neutral.
After a tough bicep workout, your arm gets a little swollen, but it goes back to normal by the next day — and it doesn’t matter if you changed your shoulder angle during the workout.
Even when you change your shoulder position during bicep curls, you still lift the same total amount of weight — your total workout effort doesn’t go up or down.
Changing the angle of your shoulder while doing bicep curls makes your biceps work harder during the workout, even if you're lifting the same total weight.
Doing 14 sets vs. 21 sets doesn’t make your muscles look any different on ultrasound—even though you lifted more total weight in the 21-set version.