What Is Hypertrophy? How To Train To Sculpt Your Muscles, According To Trainers

But hypertrophy training isn’t just beneficial for sculpting your muscles. “Having muscle is the baseline of health; it keeps you moving and protects you from injury,” Miranda says. It can also decrease body fat, stave off diabetes, and improve strength, she says.

Ahead, learn how to add hypertrophy training to your routine—and what kind of factors outside of the gym can also affect your gains, according to fitness pros.

How To Train For Hypertrophy

In general, there are three categories of resistance training styles—strength (heavy weight/low reps), muscular endurance (low weight/high reps), and hypertrophy. While there’s crossover (meaning you’ll still build strength when working on hypertrophy and vice versa), you can maximize actual muscle growth gains by staying within a certain window of weight, reps, sets, and recovery time.

Volume

Focus on four- to six-week training cycles to really see results, Miranda recommends—progressing in weight, reps, or sets as you move through each week. In general, hypertrophy training focuses on moderate weight—like 65 to 85 percent of your one-rep max, or the most weight you could lift in a certain move for a single time. You’ll lift that weight for 6 to 12 reps for three to six sets.

Exercise physiologist Rachelle A. Reed, PhD, ACSM-EP, recommends training for hypertrophy at least two days a week. However, focusing on your weekly training volume (reps and sets) is actually more important than the number of days you lift, per 2021 Sports Medicine research. (The research recommends performing 6 to 15 reps for a minimum of four weekly sets per muscle group if you’re short on time.) So make sure to hit those rep/sets recommendations—and go for the higher end or the reps/sets range if you’re working out fewer days a week.

If you’re new to lifting, you may not know your one-rep max. So, Miranda suggests starting with bodyweight exercises and nailing down the movement patterns. That could be a squat, bicep curl, deadlift, or skull crusher, depending on the body part you want to build. Then, slowly ramp up the weight each week, so you can test what that one-rep max would feel like.

You’re using the correct weights if you feel the burn—and start to feel fatigued—by the end of your reps during each set.

Rest Time

Another way to increase your gains is by reducing rest time between sets to 30 to 90 seconds. Shorter rest times allow your blood to keep flowing and force you to recover faster, which will help grow your muscle size, says Tyneka Pack, CPT, a certified personal trainer. But when you minimize that window of recovery, you *might* not be able to lift the same heavy load, Reed adds. When in doubt, experiment with rest periods and find what works for your body where you’re challenged, but still able to complete those last reps.

Your Body During Hypertrophy Training

In the short-term, hypertrophy training causes microtrauma to the muscle, making it break down and leading to tiny tears. Over time, your body repairs and rebuilds those tears, Miranda says. “When you rest, the muscles grow in size,” she adds, noting that you need proper recovery, protein, and hormone balance for that effect to actually take place.

When you’re training for hypertrophy, lactate is being metabolized and used as an energy source. Towards the end of your set when you feel a burning sensation, you’re nearing fatigue—those are hydrogen ions working, Reed adds. “The water that gets pulled into the muscle cell, which creates the growth, also causes an immediate swelling,” Miranda says. (That’s why you might feel like your muscles are extra plump right after working out.)

There are three types of hypertrophy:

• Sarcoplasmic hypertrophy pumps up the muscles, making your muscles appear bigger and fuller, Pack says.
• Myofibrillar hypertrophy is “the growth of the actual muscle fibers,” says Pack. It makes the muscles denser, harder, and stronger, in addition to bigger.
• Transient hypertrophy is the temporary “muscle pump effect” that you get after strength training from fluid accumulation, which lasts for an hour or two, says Reed. (This is different from long-term hypertrophy that you get after months of strength training.)

Factors That Affect Hypertrophy

This principle is the “gradual increase in the demand on your muscles,” says Pack. The more you challenge your muscles over time, the more the fibers will tear, grow, and repair. You can up the demand on your body through lifting heavier weights, increasing reps or sets, slowing down your reps, and reducing your rest time to make your muscles work harder, she adds.

Metabolic Stress

Exercise is “activating metabolic pathways to create the energy needed for skeletal muscle contraction,” says Reed, because you’re moving and contracting these muscles. When you feel fatigued at the end of a set, that’s those metabolic pathways working. Recovery (both during and in between workouts) is so important so the pathways can reset, then, you can go crush your next workout.

Hormones

Hormones can also play a role in hypertrophy. When you don’t get enough sleep or you’re super stressed out, your cortisol levels increase, and this hormone holds on to body fat, Miranda explains. “So you may not see as many benefits as someone who’s sleeping more and less stressed,” she says.

Of course, testosterone also plays a role: When your muscle fibers tear during workouts, growth hormones—like testosterone—also increase, which grow your muscles, Pack says.

Plus, you experience tons of hormonal changes as you get older, including during menopause, which also plays into how well you build muscle. “We can build muscle better in our younger years,” Pack says, adding that hypertrophy is usually easier to achieve when you’re in your 30s and younger. But it’s still very possible—and important—to build muscle in your 40s and beyond.

Nutrition

To build muscle, it’s crucial to eat enough protein. The recommended daily allowance (RDA) is 0.8 grams per kilogram of your bodyweight per day, but for hypertrophy, you might want to increase your intake to 1.2 grams for every kilogram, Reed says.

And don’t skimp on carbohydrates: “Carbs are also needed to build and repair those muscles just as much as protein is,” Pack says. She recommends eating two grams of carbs for every one gram of protein per meal, especially for every post-workout meal.

Recovery

Work hard, rest hard: Shoot for at least seven to eight hours of zzz’s per night and make sure you’re staying hydrated throughout the day, Reed says. Always monitor how your body feels, and if you need to space out your training days or take more rest days than normal, go for it, Reed says. (You can always make it an active rest day by taking a walk and still getting your movement in.)

Genes

Even if you’re doing all of the above, it’s important to remember that there are certain factors around building muscle that are out of your control. Your genes, for example, play a role in how much body fat you have—and therefore, how noticeable your muscles are from the outside. That said, “everyone can build muscles,” Miranda says—they might just not be as visible depending on your ratio of body fat to lean muscle mass.

Overall, the biggest influence on building muscle is consistency. “Watch the amount you lift, week after week, sleep enough, and eat enough to actually gain that muscle,” Miranda says. “It takes patience and an adherence to a plan.” Seeing results is about to feel so dang good.

Mallory Creveling is an ACE-certified personal trainer and RRCA-certified run coach, who also holds certifications in kettlebell training, sports performance, and more. She has more than a decade of experience covering fitness, health, and nutrition for a wide range of publications, and nearly 10 years of experience as a trainer and fitness instructor. Mallory stays on top of her continuing education in fitness, as well as the latest science in wellness. She has worked with some of the best experts in their medical fields, and regularly interviews researchers, trainers, athletes, and more to find the best advice for readers looking to improve their performance and well-being. As a freelance writer, Mallory’s work appeared in Women’s Health, Self, Men’s Journal, Reader’s Digest, and more. She has also held staff editorial positions at Family Circle and Shape magazines, as well as DailyBurn.com. A former New Yorker/Brooklynite, she’s now based in Easton, Pennsylvania.

Addison Aloian is the associate health & fitness editor at Women’s Health, where she writes and edits across the health, weight loss, and fitness verticals. She’s also a certified personal trainer through the National Academy of Sports Medicine (NASM). In her free time, you can find her lifting weights at the gym, running on the West Side Highway in New York City—she recently completed her first half-marathon—and watching (and critiquing!) the latest movies that have garnered Oscars buzz. In addition to Women’s Health, her work has also appeared in Allure, StyleCaster, L’Officiel USA, V Magazine, VMAN, and more.