Browse evidence-based analysis of health-related claims and assertions
For young women, doing resistance training with lighter weights for 10 weeks can build leg strength just as well as training with heavier weights, with strength gains around 10-16%.
Causal
For young women, doing lighter weightlifting for 10 weeks can build leg muscle just as well as heavier lifting, with muscle growth between 3% and 12%.
Different ways of lifting weights, like using machines or free weights, or changing how you do your sets, don't always make you stronger or bigger than basic training, according to big reviews of studies.
Descriptive
Lifting weights or doing strength exercises helps healthy adults walk faster, stay balanced, get up from a chair more easily, and move around better compared to not exercising at all.
Correlational
For healthy adults, certain types of weight training—like lifting moderate weights quickly or doing Olympic lifts—can help improve how fast and powerful your muscles work, according to research reviews.
When healthy adults lift weights, doing more sets each week and focusing on slowly lowering the weight helps build bigger muscles.
Lifting heavy weights at least twice a week, doing full movements for a few sets each time, and doing it early in your workout can help healthy adults get stronger compared to not exercising or doing other types of training.
Lifting heavy weights puts stress on your muscles, which is thought to be a main reason they get bigger and stronger.
Lighter weight lifting with more reps might be safer and easier to stick with than pushing yourself to the max every time.
Lifting heavy weights and lifting lighter weights can both build muscle just as well for different people, as long as you do the same total amount of work. It suggests that how hard you push might not be the main thing that matters for muscle growth.
This claim says that light weight training doesn't really help older adults get bigger muscles, move faster, or get up and go quicker after doing it twice a week for 12 weeks.
Light weight training helps older people move better by making it easier to stand up from a chair and walk faster after doing it twice a week for three months.
Older adults doing light weight lifting twice a week for 12 weeks can get about 20% stronger, even if they don't push themselves to their absolute limit every time.
For older adults doing light weight training, pushing muscles to complete exhaustion doesn't give extra benefits like more strength or muscle growth compared to stopping before exhaustion, since both ways work about the same after 12 weeks.
For young active men, doing lighter weights with more reps three times a week for a month might cause less muscle damage than lifting heavy weights with fewer reps, based on a blood test that measures muscle stress.
Lifting heavy weights fewer times, three days a week for a month, helps young active men build more muscle and get stronger than lifting lighter weights many times.
Different workout styles for building muscle didn't show big differences in how the nerves responded in trained men over 6 weeks, meaning nerve changes might not be the main reason some workouts make you stronger than others.
When guys who work out regularly do high-volume weight training, they feel it's much harder than doing shorter sets with more breaks—even if both ways build similar strength.
When trained men lift heavy weights using certain training styles, they spend more time under tension and generate more force per rep than with other styles, which might help them get stronger.
When trained men do certain types of weightlifting workouts, their bodies produce more lactic acid compared to other workout styles, which means their muscles are working harder and under more stress.
Quantitative
When trained men take longer breaks between weightlifting sets, they can lift heavier weights and still get just as strong as with shorter breaks, even if they do more total work over 6 weeks.
Lifting heavy weights with longer breaks between sets helps build muscle strength better than lifting lighter weights with shorter breaks, especially for guys who already work out.
When lifting lighter weights, pushing until you can't lift anymore helps build bigger muscles, but this doesn't happen with heavier weights. Heavier weights always build more strength than lighter ones, no matter how hard you push.
For people who already lift weights, pushing to muscle failure with either light or heavy weights gives the same muscle growth and strength improvements after 12 weeks.