How Fast Can I Build Bigger Legs?

If you're ready to start doing serious leg workouts, mark your calendar for three months from now. That's about when you can expect to start seeing serious gains — although each body responds differently to stimulus, and you might see intermediate gains before then.

Can you build bigger legs instantly? No — and you probably won't see squat results in a week either, aside from the neural adaptations that Len Kravitz, Ph.D., an exercise physiologist with the University of New Mexico, explains are one of your body's first responses to strength-training stimulus. (And even those "early gains" usually show up in the first two to eight weeks of training.)

If you train consistently and at the appropriate level of intensity, though, you can expect to start seeing measurable, significant results within a couple of months. The typical minimum period for studies meant to measure strength, hypertrophy and other muscle adaptations at clinically significant levels is eight weeks, or two months. And as ExRx.net explains, the average person can expect to build about 3 pounds of muscle after two months of consistent strength training.

The way the body responds to the strength-training stimulus is a little different for everyone. As the American Council on Exercise explains, many of the factors that determine your body's response are entirely out of your control. These include your age, gender, hormonal balance and ratio of fast-twitch to slow-twitch muscles.

If you have all of those out-of-your-control factors in your favor — for example, if you're a 20-year-old man with lots of fast-twitch muscle fibers and high genetic potential for muscle growth — ACE estimates your potential gain of lean muscle mass at 2 pounds per month. That would work out to about 6 pounds in three months, or twice the "average" rate.

So if you suspect that some of the other folks you see at the squat rack are bulking up notably faster or slower than you are, you're probably right. If that's not proof enough, consider a small but notable study of 20 subjects that was published in the April 2019 issue of the ​Journal of Strength and Conditioning Research​. It showed that individual responses in terms of strength and hypertrophy can vary greatly, even when exercisers are working out under the exact same conditions.

Happily, there are quite a few things that you can control to help you get the best leg gains in three months — or ideally longer, as your leg muscles will continue to grow as long as you eat properly, practice appropriate self-care and subject them to the right stimuli. Those factors that are in your power include choosing the right exercises, eating properly for muscle growth, balancing appropriate training and rest intervals, staying hydrated and getting plenty of sleep.

​Read more:​ How to Gain Muscle Mass at Home Fast

You do need to work hard if you want to build big leg muscles — after all, those weights aren't going to lift themselves. But that doesn't mean you should be resistance-training your legs every day. Contrary to popular belief, your muscles get bigger and stronger during the recovery period between workouts, not during the workouts themselves — so if you short yourself on recovery time between workouts, you're actually shorting yourself on those leg gains.

That means that you can, at most, work your legs three times during a typical week (alternating leg-exercise days with rest days, plus one overall rest day during the week). But so far, there is no convincing scientific evidence to show that training your legs three times a week will offer more benefits than training them twice a week.

There is, however, strong evidence that training twice a week is better than just once a week, and it's the training frequency recommended by the Department of Health and Human Services to maintain a healthy body. If that's not convincing enough, a systematic review and meta-analysis published in the November 2016 issue of the New Zealand journal ​Sports Medicine​ showed that twice-weekly resistance training offered significantly better muscle growth than once-weekly training.

​Read more:​ How Long Does It Take for Muscles to Recover After a Workout?

Once you've hit the weight room, how many sets and repetitions should you do? Start with what you're able to manage safely, using proper form — one to three sets of eight to 12 repetitions for each exercise is a good initial goal. As you get stronger, gradually increase the amount of resistance so that completing the last repetition of each set is a proper challenge.

If you need to decrease weight to complete subsequent sets safely, that's totally okay. Just make sure you're challenging yourself instead of coasting, because as the American Council on Exercise points out, there are two known (if not fully understood) ways to stimulate the protein synthesis process that rebuilds your leg muscles between workouts.

Those are either creating a sufficient amount of mechanical damage inside the muscle (by lifting heavy weights) or working your muscles to metabolic fatigue, the point when they've momentarily exhausted their supply of ATP, the "fuel" that drives muscle contractions.

Finally, if you hit the point where you can add more sets into your leg workouts, doing so can increase the speed and magnitude of your results. As shown in a systematic review published in the July 2016 issue of the ​Journal of Sports Sciences​, the more weightlifting sets you do, the more muscular hypertrophy you can look forward to. Or to boil the concept down to its simplest expression: The more time your muscles spend under tension, the bigger and stronger they'll get in response.

There's a saying that abs are made in the kitchen, but the same holds true for your leg muscles. If you're not eating the right types of foods, your body won't have the nutrients it needs to build your muscles. The most critical macronutrient to keep an eye on is protein, and a position statement from the International Society of Sports Nutrition, published in the June 2017 issue of its publication, the ​Journal of the International Society of Sports Nutrition​​,​ gives you a good place to start.

The Society's position: For most exercisers looking to build more muscle, a daily protein intake of 1.4 to 2.0 grams of protein per kilogram of body weight is enough. That falls easily into the macronutrient balance recommended by the Department of Health and Human Services for general health.

However, if you're at a calorie deficit (burning more calories than you take in), whether to lose weight or cut fat for bodybuilding purposes, you might need an increased daily protein intake of 2.3 to 3.1 grams per kilogram of body weight to maintain and build lean muscle mass.