Is it Necessary to Lift Very Heavy to Build Muscle?

So often we’re told that the “only” way to build muscle is to lift heavy weights for low reps and eat a lot of food.

And while that certainly is one way to go about building muscle, it by no means is the only way to build muscle.

You see, the truth is that there are many ways to stimulate muscle growth.

In reality, to build muscle you really only need to focus on five things:

• Consume a surplus of calories each day
• Consume enough dietary protein and carbohydrates to support recovery and growth.
• Perform resistance-training following the principles of progressive overload.
• Get enough sleep each night
• Supplement to support recovery and  growth

In case you missed it, there’s nothing in those five points that says you “have” to lift heavy. Now, don’t get us wrong, muscles do need to be challenged and fatigued in order to grow, but you can accomplish that several different ways.

Lifting “heavy” is but one way, albeit an effective way at that.

What Qualifies as “Heavy”, Anyway?

Lifting “heavy” in the world of strength training generally refers to weights that can be lifted between one to five reps per set, which generally consists of loads that are greater than 80% of your 1-rep max in a given exercise.

Now, research has clearly shown that hypertrophy can occur across a wide spectrum of rep ranges. Research by Doctors, Brad Schoenfeld (the “hypertrophy doc”), Stu Phillips, and several others have shown that lifters can achieve significant muscle growth utilizing by low-rep, higher weight (intensity) protocols (3-5 reps per set) as well as higher-rep, lower weight (intensity) training programs equally.[1,2,3,4,5]

In fact, some studies show that significant muscle building can be achieved even when training with weights that are as low as 30% of 1-RM, which is a weight that you can do 30+ reps with.

Researchers have identified this 30% 1-RM as the bottom end “threshold” below which the load is not challenging enough to your muscles muscle to significantly disrupt homeostasis and stimulate muscle growth.

But, there’s a catch when training with a light load -- you have to take the muscle to failure, or pretty dang close. Otherwise, you’re just wasting your time and performing “junk volume”.

This brings up another issue when discussing the practicality and utility of ultra-high rep protocols in a training program -- the average fitness enthusiast may not have the pain tolerance or patience to push themselves to the point of true muscular failure.

Quite often when training with light loads, a lifter will end the set short just because they are starting to “feel the burn”, but in actuality, they are nowhere near failure and thus have not created enough homeostatic disruption to spark muscle growth.

They may also stop the set early due to boredom from having to perform 25-30 reps.

This is why many of the most popular muscle building programs have gym-goers perform the majority of their work in the “hypertrophy range” of 6-15 reps.

This allows for a challenging enough weight to stimulate the fast-twitch muscle fibers and cause you to approach failure relatively soon so that you don’t lose focus during your set and bail early.

At the same time, training in this rep range is also not so heavy that it beats up your joints and overly taxes the CNS the way that training with very heavy loads (>80% 1-RM) does.

For practicality purposes, your average person looking to get in shape and build muscle would benefit from incorporating a variety of rep ranges in their training programs.

Perform a few working sets in the 6-8 rep range, some in the 8-12 rep range, and some in the 15+ rep range. Doing so allows you to fully stimulate all types of muscle fibers (slow and fast-twitch) allowing for better muscle growth and more complete physique development.

Besides, some movements just lend themselves better to lower rep ranges (squats and deadlifts) than higher rep protocols (curls, pushdown, etc.).

Takeaway

You can build just as much muscle lifting heavy weights as you can lifting lighter weights (so long as you go to failure). If you are training with lighter loads, the lowest intensity you will want to use is ~30% 1-RM.

Which rep range you choose to use ultimately depends on several factors including:

• pre-existing joint issues
• training history
• the specific exercise you’re performing, and
• personal preference (some people just love training with low reps while others love high reps).

In the end, the best results come from using a mix of exercises and different rep ranges so that you hit the muscle from multiple angles and fully stimulate the various types of muscle fibers in the muscle.

However, for those looking for the most time-efficient way to build muscle and seeing as most people don’t want to perform 25-35+ reps per set to build muscle, the average gym rat would be best served by working in moderate rep ranges (6-20 per set) with a total weekly volume of 10-20 hard working sets per muscle group.

References

1. Schoenfeld, B. J., Ratamess, N. A., Peterson, M. D., Contreras, B., Sonmez, G. T., & Alvar, B. A. (2014). Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men. Journal of Strength and Conditioning Research, 28(10), 2909–2918. https://doi.org/10.1519/JSC.0000000000000480
2. Mitchell CJ, Churchward-Venne TA, West DW, et al. Resistance exercise load does not determine training-mediated hypertrophic gains in young men. J Appl Physiol (1985). 2012;113(1):71-7.
3. Fink J, Kikuchi N, Yoshida S, Terada K, Nakazato K. Impact of high versus low fixed loads and non-linear training loads on muscle hypertrophy, strength and force development. Springerplus. 2016;5(1):698. Published 2016 May 20. doi:10.1186/s40064-016-2333-z
4. Schoenfeld, B. J., Grgic, J., Ogborn, D., & Krieger, J. W. (2017). Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis. Journal of Strength and Conditioning Research, 31(12), 3508–3523. https://doi.org/10.1519/JSC.0000000000002200
5. Schoenfeld, B. J., Peterson, M. D., Ogborn, D., Contreras, B., & Sonmez, G. T. (2015). Effects of Low- vs. High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men. Journal of Strength and Conditioning Research, 29(10), 2954–2963. https://doi.org/10.1519/JSC.0000000000000958
6. Clarkson, P. M., Nosaka, K., & Braun, B. (1992). Muscle function after exercise-induced muscle damage and rapid adaptation. Medicine and Science in Sports and Exercise, 24(5), 512–520.
7. Brandenburg, J. P., & Docherty, D. (2002). The effects of accentuated eccentric loading on strength, muscle hypertrophy, and neural adaptations in trained individuals. Journal of Strength and Conditioning Research, 16(1), 25–32.
8. Schoenfeld, B. J., Ratamess, N. A., Peterson, M. D., Contreras, B., Sonmez, G. T., & Alvar, B. A. (2014). Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men. Journal of Strength and Conditioning Research, 28(10), 2909–2918. https://doi.org/10.1519/JSC.0000000000000480