From Frail to Fit: The Science of Building Muscle

As we grow older, our bodies become weaker and are at risk of age-related diseases such as sarcopenia (muscle loss). While that doesn’t sound like much, the effects really add up. Loss of muscle mass results in significant declines in muscle size, strength, and the ability to perform daily tasks without assistance. Within an average human lifespan, a person can lose up to 30% of their muscle mass by their 70s.

We’ve known for decades that resistance training is the single most powerful tool for slowing the negative effects of sarcopenia. But how much training is necessary to prevent muscle loss? How many sets and reps should one perform to optimize muscle growth? And should we lift heavier or lighter weights? In this article, we’ll take a look at both the science-based ideal and the minimum amount of exercise you need to preserve (and even build) muscle mass as you age.

Many Roads Lead to “Gainz”

If you’ve spent any time in a gym, you’ve probably heard that “low rep, heavy weight” training is best for strength, “medium rep, moderate weight” training is best for building muscle size, and “high rep, light weight” training is best for endurance.

But it turns out that this guideline isn’t really supported by the literature.

When it comes to resistance training, many variables can stimulate muscle growth. Everything from low reps and high weights to high reps and low weights can build muscle — as long as you maintain training intensity.

In research reviewed by Brad Schoenfeld and colleagues, trained men and women completed resistance training programs using low (5 reps per set), moderate (10 reps), and high (15 reps) rep ranges. Not surprisingly, all groups got stronger and built muscle. But what’s interesting is that all groups built roughly the same amount of muscle, despite using very different training volumes and weights. When you keep training intensity constant, how much weight you lift doesn’t matter as much. As long as you’re doing the same number of “hard” sets (i.e., sets that bring you close to failure), you’ll get similar results.

This is great news if you’re looking to gain muscle. Simply pick a weight heavy enough that you can only perform about 5-15 reps per set with good form, and lift away. If you prefer lifting lighter weights, only have light weights available, or can’t lift heavy due to injury, you can still gain muscle. Lifting heavy weights for low reps works too. But heavy weights may allow you to lift more overall (which is better for building strength), and might also have other benefits, like increasing bone density.

The Minimal Effective Dose for Hypertrophy

Now that we know there are many ways to build muscle, it’s important to differentiate between an optimal training program and a minimum effective dose. An optimal training routine (what a competitive bodybuilder might do to prepare for a stage show) is very different from the one we would recommend to just about anyone to prevent age-related muscle loss. According to research, an optimal muscle-building routine would involve about 10-20 challenging sets per muscle group per week. This can be done all at once or spread out over several sessions. A minimally effective amount of training to stimulate muscle growth requires about 4 sets per muscle group per week.

Whoa. Just 4 workouts per week? If you only train 4 times per week, how will you reach 10-20 sets per muscle group? The trick is that each major muscle group can be trained multiple times per week. For example, you might train your chest 2 times a week, your back 2 times, your legs 2 times, your shoulders 2 times, your arms 2 times, and maybe even your abs twice.

That’s 12 total workout sessions for just your upper body muscles alone. That’s without even touching your legs, which a lot of guys don’t do anyway.

As you can see, even if you’re only training each body part once per week, you have the opportunity to greatly exceed the “minimum effective dose” of training.

Short on time? Don’t worry about the gym. Even as few as 4 strenuous sets per week are sufficient to build muscle. Each set should take you only a few minutes, so you can preserve muscle mass in just 15-20 minutes per week.

How Much “Failure” is Necessary? 

Earlier, we stated that, given equal training volume, the number of reps you perform doesn’t matter as much. But how intense do your sets need to be? Do you need to push every set to absolute failure? Luckily, the answer to that is no. Going to “failure” means lifting until you can’t complete another rep with good form. While lifting to failure can be a great way to challenge your muscles, you don’t need to collapse on the ground after each set. Instead, aim to have no more than 3-4 reps remaining in the tank when you finish your set. If you can do more than that, you’re not training hard enough.

Bottom Line

As long as you’re lifting intensely enough, there are plenty of ways to build muscle. You can go heavy, go light, or do a mix of both. The key is consistency. If you have the time and ability to perform several sets per muscle group per week, you will build muscle. As you get better at lifting weights, your muscles will adapt to the challenge, and you will need to continue to increase your training intensity to see gains. But that’s a problem for future you to deal with.

If you’re new to weight training, don’t worry about finding the perfect routine. The most important thing is that you find something you enjoy and will continue to do. Any exercise is better than none, but regular exercise over a lifetime yields the best results.

You May Also Enjoy

4 Essential Gym Tips for Beginners
Everything You Need to Know About Sleep
3 Secrets All Good Diets Share

References

Keller, K., & Engelhardt, M. (2013). Strength and muscle mass loss with aging process. Age and strength loss. Muscles, ligaments and tendons journal, 3(4), 346.

Schoenfeld, B.J.; Grgic, J.; Ogborn, D.; Krieger, J.W. Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis. J Strength Cond Res 2017, 31, 3508–3523.

Schoenfeld, B.J.; Peterson, M.D.; Ogborn, D.; Contreras, B.; Sonmez, G.T. Effects of Low- vs. High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men. J Strength Cond Res 2015, 29, 2954–2963.

Iversen, V. M., Norum, M., Schoenfeld, B. J., & Fimland, M. S. (2021). No time to lift? Designing time-efficient training programs for strength and hypertrophy: a narrative review. Sports Medicine, 51(10), 2079-2095.

Helms E.R., Byrnes R.K., Cooke D.M., Haischer M.H., Carzoli J.P., Johnson T.K., Cross M.R., Cronin J.B., Storey A.G., Zourdos M.C. RPE vs. Percentage 1RM Loading in Periodized Programs Matched for Sets and Repetitions. Front. Physiol. 2018;9:247. doi: 10.3389/fphys.2018.00247.