Strength training studies, tips and resources
Every tip and study on this site, each in one line you can pass on. Tap Copy and it goes in a message with its link.
Tips to pass on
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If you can, build muscle the natural way first: lifting, protein from ordinary food at every meal, and seven hours of sleep. Supplements come last.
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Two full-body sessions a week, two or three days apart, is enough to start building muscle at any age.
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Make every set hard. Stop with one to three good reps left. Going all the way to failure added nothing in 15 studies.
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Once every set hits the top of its rep range, add the smallest weight step you have. The weight going up is what keeps the muscle changing.
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Train every big muscle, front and back. Every muscle in the mirror has a partner on the back of the body that pulls the other way.
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Reps matter less than you think. Muscle grew about the same from 30% to 100% of your max, as long as the sets were just as hard.
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Typical protein for building muscle is 1.2 to 1.6 g per kg of bodyweight a day, about 100 to 130 g at 180 pounds.
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One night without sleep cut muscle building after a meal the next day by 18%. Muscle grows between sessions.
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You get stronger within a couple of weeks of starting, long before it shows. That first gain is mostly your nerves learning to use the muscle.
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Nursing home residents aged about 90 got 174% stronger after eight weeks of heavy leg training. It's never too late to start.
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Your triceps are about two and a half times the size of your biceps, so presses do more for your upper arm than curls.
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Test yourself at home in ten minutes with push-ups, a dead hang and getting up off the floor, then again in eight weeks.
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If you have heart disease or high blood pressure, ask your doctor before you add heavy lifting.
The studies
How much lifting, and how hard
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2026. Muscle grew most with 10 or more hard sets per muscle a week, flattening around 18 to 20, and planned cycles and equipment type made no consistent difference.
Currier and others, the American College of Sports Medicine, 137 reviews of more than 30,000 people
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2017. Each extra hard set a week went with a little more muscle growth, about 0.37% a set.
Schoenfeld, Ogborn and Krieger, 15 studies
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2021. Heavy sets built the most one-rep max strength, but muscle grew across a wide range of loads, with "no ideal hypertrophy zone".
Schoenfeld and three colleagues, a review
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2022. Taking sets all the way to failure added nothing for strength or muscle over stopping short of it.
Grgic and others, 15 studies
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2018. With the total number of sets matched, lifting one, two, three or four days a week made no difference to strength.
Grgic and others, 22 studies
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2016. Three minutes of rest between sets built more squat and bench strength and more thigh muscle than one minute.
Schoenfeld and others, 21 trained men, 8 weeks
How muscle grows
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1979. Nerve factors explained most of the strength gained in the first weeks of lifting, and muscle growth took over after about three to five weeks.
Moritani and deVries
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2007. Strength rose 39% in 35 days of heavy training, and the thigh muscle was measurably bigger by day 20.
Seynnes and others, 7 young adults, 35 days
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2012. An army doctor, Thomas DeLorme, built progressive resistance exercise in 1945 to get injured servicemen back on their feet.
Todd and others, a history
Food, supplements and sleep
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2018. Extra protein added muscle and strength on top of lifting, and the gains stopped rising past about 1.6 g per kg a day.
Morton and others, 49 trials, 1,863 people
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2007. Men who drank fat-free milk after lifting gained more lean mass than men who drank a matched soy drink or a carbohydrate drink.
Hartman and others, 56 young men, 12 weeks
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2023. Eating 15% over maintenance built no more muscle than 5% over, and the people who gained the most weight gained the most fat.
Helms and others, trained lifters, 8 weeks
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2013. Once total daily protein was counted, protein timing made no difference to muscle or strength.
Schoenfeld, Aragon and Krieger, 23 trials
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2015. Creatine added a small extra gain in leg strength on top of training, whatever people's age, sex or dose.
Lanhers and others, 60 placebo trials
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2017. The body uses 1 to 3 g of creatine a day, gets about half of it from food and makes the rest in the liver and kidneys.
Kreider and others, International Society of Sports Nutrition
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2020. 90% claimed to raise testosterone, only about a quarter had data behind that, and 13 went over a safe upper limit for a vitamin or mineral.
Clemesha, Thaker and Samplaski, 50 testosterone boosters
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1996. Men given high-dose testosterone gained more arm and leg muscle than men on a placebo, even without lifting.
Bhasin and others, 43 healthy men, 10 weeks
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2021. One night without sleep cut muscle building after a meal the next day by 18%.
Lamon and others, 13 young adults
Age, women and teens
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1990. The nine who finished heavy leg training got 174% stronger, and their thigh muscle grew 9%.
Fiatarone and others, 10 nursing home residents aged about 90, 8 weeks
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1994. Strength rose 113% in the people who lifted, against 3% in those who didn't, and a nutrition drink on its own did nothing.
Fiatarone and others, 100 frail residents, average age 87, 10 weeks
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2012. Muscle falls about half a percent a year in midlife and closer to 1% a year by 75, and strength falls two to five times faster.
Mitchell and others, a review
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2018. Eight months of supervised heavy lifting raised spine bone density 2.9%, while it fell 1.2% in a light home program.
Watson and others, LIFTMOR, 101 women past menopause with low bone mass
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2010. Resistance training caused 0.7% of school sports injuries, against 19% for American football.
Faigenbaum and Myer, a review
Strength and a long life
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2015. Grip strength predicted death better than systolic blood pressure did.
Leong and others, 139,691 adults in 17 countries
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2026. Lifting 90 to 119 minutes a week went with 13% lower risk of death, and more than two hours added nothing.
Zhang and others, 147,374 US health professionals, up to 30 years
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2022. The lowest risk of death came at about 40 minutes of muscle-strengthening a week.
Momma and others, 16 studies
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2025. The lower people scored on getting down to the floor and back up, the larger the share who died.
Araujo and others, 4,282 adults aged 46 to 75, about 12 years
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2019. Men who could do more push-ups had fewer heart events, though only one comparison stood clear of chance after adjusting.
Yang and others, 1,104 male firefighters, about 10 years
Muscle by muscle
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2007. The triceps averaged 372 cubic centimeters, against 144 for the biceps.
Holzbaur and others, MRI of 10 young adults
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2023. Triceps extensions done overhead grew the triceps about 1.4 times more than extensions with the arm at the side.
Maeo and others, 21 adults, 12 weeks
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2019. Programs that added Nordic curls had about half as many hamstring injuries.
van Dyk, Behan and Whiteley, 15 studies of 8,459 athletes
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2015. People with weak quads had about 65% higher odds of developing painful knee arthritis.
Oiestad and others, 5 studies of 5,707 adults
Resources
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Adult Activity: An Overview Adults need muscle-strengthening activity on at least 2 days a week, working the legs, hips, back, belly, chest, shoulders and arms.
CDC, December 2023
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Physical Activity Guidelines for Americans, 2nd edition The US guideline, in a short executive summary.
US Department of Health and Human Services, 2018
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Resistance training prescription for muscle function, hypertrophy, and physical performance The review behind most of the numbers on this site, free to read.
American College of Sports Medicine position stand, 2026
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Adults who do enough muscle-strengthening activity (PA-04) How many US adults lift twice a week, tracked year by year.
Healthy People 2030
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Caution: Bodybuilding Products Can Be Risky Why some products sold as supplements contain hidden steroids, and what they can do to your liver and heart.
US Food and Drug Administration, September 2024
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Strength Training (for Teens) For teens: learn each move with no weight first, with a coach or teacher nearby.
Nemours TeensHealth, March 2022
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Strength Training The pediatricians' handout for young athletes and their parents.
American Academy of Pediatrics, HealthyChildren.org
