Can high-volume, low-intensity weight training build lean body mass? To build strength and lean body mass you need to progressively overload your muscles. The conventional way bodybuilders use to build strength is to use a heavy resistance, 80 to 90% of one-rep max and do a lower number of reps, between 1 and 5. If the focus is muscle hypertrophy, 6 to 12 reps using a resistance that’s 60 to 80% of one-rep max is considered to be ideal.
With the growing popularity of circuit training and boot camp workouts, you see more people doing workouts using lighter resistance, a weight that’s 30 to 40% of their one-rep max) and doing a high number of reps. This type of workout builds muscle endurance and has conditioning benefits, but ask most bodybuilders and they’ll tell you it’s not an effective way to build muscle. You need more resistance to do that. On the other hand, some research suggests that higher volume workouts with low-resistance reps and can also cause muscles to hypertrophy. Is there any truth to this?
High-Rep, Low-Intensity Weight Training: Does It Build Lean Body Mass?
Can you really build muscle doing high volume, low-resistance workouts? An interesting study published in PLOS One looked at this issue and came to some surprising conclusions. A small study involving only 15 young, healthy males compared the effects of high-load, low-volume resistance exercise (90% of one-rep max to failure) to low-load, high volume resistance exercise (30% of one-rep max to failure) on muscle protein synthesis. The participants did unilateral leg extensions to failure using different training protocols. Surprisingly, muscle protein synthesis was the same in the low-load, high-volume resistance group as in the high-load group BUT it was more sustained in the low-load, high-volume group.
This study found high-volume, low-load training to be MORE beneficial for inducing muscle protein synthesis and growth. Of course, this was a small study that looked at the effects of high-volume, low-load training on muscle protein synthesis, not hypertrophy, although the two are correlated. The participants did unilateral leg extensions to volitional failure. The average person that does a circuit training workout using light weights doesn’t do a high enough number of reps to reach muscle failure.
Not all studies support the benefits of high-volume, low-resistance weight training for muscle hypertrophy. A study published in Strength Conditioning Research measured the degree of muscle activation experienced when doing a high volume of Bulgarian split squats to failure (eight sets). They discovered that muscle activation dropped off after about three sets due to fatigue. Plus, the participant’s form became sloppy after three sets. Bad form and muscle fatigue would likely limit their gains. This points out how hard it is to maintain good form when doing a high-volume workout.
Differences between Low-Resistance and High-Resistance Training
When you use a heavy resistance, you’re activating mostly type 2 fibers. These fibers are built for exerting lots of force but they also fatigue quickly. When you train using lighter weight and do a higher number of reps (15 or more), you’re activating mostly type 1 or slow-twitch fibers, fibers that can’t exert as much force but are more resistant to fatigue. That’s why you can do 15 or more reps. Type 2 muscle fibers that you activate with heavy resistance training are believed to be the primary “growth” fibers, but research also shows type 1 fibers have the ability to grow in response to resistance training and these fibers are best targeted using low resistance, high-volume training.
One study published in the Journal of Applied Physiology in 2012 showed three sets at 30% one-rep max resulted in a similar degree of muscle hypertrophy as three sets at 80% of one-rep max when participants lifted to failure. Based on some studies, high-volume, low-resistance training can be effective for muscle hypertrophy as long as you lift to failure. Of course, you’ll have to do considerably more reps to reach failure using a lighter weight. Therefore, high-volume workouts are more time-consuming.
Strike a Balance
High-volume, low-intensity or low-volume, high-intensity? Why focus exclusively on one or the other? Your muscles will benefit from different types of workouts. You can even periodize your training so you emphasize high-volume, low-resistance during some workouts and low-volume, high-resistance training during others. Varying the stimulus you expose your muscles too will help you avoid plateaus. Plus, building muscle endurance using lighter weight and higher reps will help you perform better when you train with more resistance since your muscles won’t fatigue as quickly. Lifting lighter weights during some of your workouts can also help you avoid overtraining.
Here’s another point to keep in mind. Nutrition is just as important as training for building lean body mass. Make sure you’re eating a clean diet and getting enough lean protein and aren’t shortchanging yourself from a calorie standpoint. It’s hard to build lean body mass when you’re training with a calorie deficit.
The Bottom Line?
If your primary goal is to build lean body mass, using a weight that’s 60 to 80% of your one-rep max, one you can lift no more than 8 to 12 times, is a tried and true way to get results. If you had to choose only one training method for building lean muscle, this would be it. On the other hand, training to failure using a lower resistance may also help you build lean body mass too and it’s a way to challenge your muscles differently. Why not do both? Vary your workout with higher rep training and give your type 2 fibers a different kind of workout. It’s a way to add variety to your fitness routine.
References:
PLOS One. “Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men” (2010)
The Journal of Strength and Conditioning Research (Impact Factor: 1.8). 05/2014; 28(5):1226-34. DOI:10.1097/JSC.0000000000000226.
J. Appl. Physiol. 113, 71-77 (2012)
The Mystery of Skeletal Muscle Hypertrophy. Richard Joshua Hernandez, B.S. and Len Kravitz, Ph.D.
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