In this Spartan Fit franchise, we ID the most interesting newly-published research, and talk to an expert about how the findings apply to you, Spartans, specifically.

It’s not just in your head: Some athletes really do build muscle faster than others do. 

In fact, in a new study published in Cell Reports, researchers examined just how genetically gifted some lifters are. Over the course of 10 weeks, exercisers performed the same strength routine training just one of their legs; the other one served as a non-exercise control. Then, for the last two weeks of the study, the researchers immobilized the non-exercising legs with braces designed to keep them from bearing any weight or doing any work.

The results: In 10 weeks, the lifters boosted their working legs’ muscle mass anywhere from 1% all of the way up to 15%. The average lifter increased muscle mass by 8%. And when the exercisers kept their opposite leg immobile, their muscle loss ranged from 1% to 18%. 

Related: Spartan Notes: What is Muscle Power & How Does it Affect Performance?

Why so much variation from one person to another? Well, the work-one-leg approach wasn’t only meant to be a scientific control. It also enabled researchers to better pinpoint the genes that drive muscle growth, aka hypertrophy. In the end, researchers ID’ed 141 individual genes that influence just how fast (or slow) people gain muscle. 

Fortunately, maximizing your muscles isn’t just about your DNA, says Sam Stauffer, Spartan Director of Training. Your DNA determines what’s possible, and your actions determine what becomes reality. 

How to Build Muscle (Safely & Efficiently)

Here’s how to achieve your genetic potential and build more muscle, faster.  

1. Progressively Overload Your Body 

“An athlete who follows a detailed hypertrophy program will see more success than somebody who just goes into the gym and wings it,” Stauffer says.

Stay consistent with your workouts, and each week strive to do just a little bit more in terms of weights, reps, or tempo. Every four to six weeks, try integrating some small progressions and changes to your rep and set schemes to keep pushing yourself on anything that starts to feel “easy.” 

2. Be Intentional About Rest

“Rest days and taper weeks are so overlooked, yet so crucial,” Stauffer says. “Your body needs time to recover and build muscle in response to the stresses placed upon it. If you don't take the time to rest and recover, you can end up drastically slowing your body's natural healing process. In other words, you take two steps forward, one step back.”

When planning your weekly workout routine, include at least one or two recovery days. These can include both passive rest days, in which you take the day completely “off” from your workouts as well as active recovery days, in which you engage in restorative exercises such as yoga, mobility drills, and light cardio. 

If you still feel like your progress is stalling or that you’re just burnt out, track your workouts and recovery to best understand how you may need to integrate longer recovery periods, such as de-load or “taper” weeks, throughout the seasons or year. 

3. Dial In Your Nutrition 

Nutrition provides your body not just the energy to go hard during your workouts, but your muscles the building blocks to grow back bigger and stronger after those workouts are over, he says. 

Focus on nutrient-rich foods, with an emphasis on carbs for energy and protein for muscle recovery. A review published in the Journal of the International Society of Sports Nutrition suggests that, for maximal muscle growth in response to exercise, athletes should eat between 0.4 and 0.55 grams of protein per kilogram of their body mass four times per day. Try these meal ideas from our post-workout nutrition guide. 

4. Be Honest On Form

“Reality check: Half and quarter reps don't really do much for you, even if you can 'squat' 400 pounds,” Stauffer says. When you perform an exercise through only a small part of your available range of motion or, worse yet, cheat an exercise by using momentum, you’re really just cheating your muscles. 

Working them under tension through a full range of motion allows you to stimulate growth in the most muscle fibers possible. With a greater focus on form and quality of movement, you’ll get more muscle benefits—even if you end up lifting lower weights or total volume.

5. Get Serious About Sleep

Sleeping for five hours, as opposed to eight hours, per night for just one week cuts muscle-building testosterone levels by 10 to 15 percent, according to one study published in the Journal of the American Medical Association.

“It’s not just length, it's also sleep quality that matters,” Stauffer adds. To get more info on how you’re sleeping through the night—and make more informed changes to your sleep habits—he recommends investing in a sleep-monitoring fitness tracker like WHOOP or the Oura ring. 

Related: Power Down: The Optimal Bedtime Routine for High-Performance Athletes

6. Play It Smart with Supplements

“I’m not a big advocate of supplements, but there are some out there that can play a huge role in one’s rate of muscle growth,” Stauffer says.  

His number-one pick: protein powder. It’s an easy add-in for anyone who’s having trouble hitting their protein goals through food alone.  

To make sure that your powder contains everything it says it does—and nothing else—always buy brands that are third-party verified. They will say so on the label, and you can also check out NSF International and USP to see a complete list of verified products.