Heavy Weight Vs. Light Weight. Which is better?

You’ve heard of the saying, “Go heavy or go home,” implying that, the only way to get any results is to lift the heaviest weights possible and lighter weights are often just a waste of time. Going to the gym, you’ll definitely see those guys that are lifting weights well beyond their capabilities. It seems that people definitely believe in “go heavy or go home” or they forgot to leave their ego at the door. In any case, it leaves us with one question: Does lifting lighter weights have a place in your program?

 To answer that, we of course will have to look into the research. Fortunately for us, there has been a solid amount of such research recently published. The one that will allow us to best understand this is a 2016 meta-analysis coming out of the lab of the well-renowned muscle hypertrophy specialist, Dr. Brad Schoenfeld. This meta-analysis looked at studies comparing a “high-load” group employing a training load of 65% or greater 1RM, versus a “low-load” group employing a training load of 60% or less 1RM. 1RM, short for one rep max, the amount of weight one can maximally lift just once. Ten studies met their criteria, giving them an… OKAY amount of information to work with, but better than others. What’s important is what they found. To a mild surprise to the researchers, in terms of hypertrophy, aka muscle growth, although the findings somewhat suggest a level of superiority using a heavier load with fewer reps, lighter loads with higher reps also had a very similar positive effect. And it wasn’t just moderately high reps. Some of the studies reached upwards 30 or more, with some reaching as high as 100 reps per set. It looks like you can build muscle using a wide variety of rep schemes and weight variations. According to the research, the more important factor seems to be the total work volume, reps times sets times weight. As long as volume is similar, both heavy and light weights worked.

However, all of the studies used untrained subjects. As we know, untrained subjects can respond to typically any resistance training program since they inherently have a greater potential for growth. Knowing this, Schoenfeld and his colleagues ran their own study using a similar protocol but with trained subjects. What they found… virtually, the same thing. But, again, they did find that lifting heavier does have a slightly greater hypertrophic effect. If you want to simply maximize growth, why not just focus on lifting heavier? Even though lighter and heavier weights can effectively build muscle, they might be building predominantly different fiber types. Type 2 and Type 2x are your stronger, more fatigue-prone muscle fibers which is fully stimulated when lifting heavy weights for a very short amount of time. They also grow roughly 50% more than their type 1 fiber counterpart. Type 1 are your not-as-strong, fatigue-RESISTANT muscle fibers. These characteristics allow you to lift a lighter weight with many more reps. Although these fibers don’t grow as much as type 2 fibers, they indeed still grow. Hypothetically, this means that training with heavier weights are better at building type 2 fibers and lighter weights are better at building type 1. We do have some study showing this.

In a 2012 study, when comparing 80% 1rm to 30% 1RM training, the light group increased type 1 fiber growth by 23% versus 16% in the high load group. Conversely, the high-load group had a slightly greater type 2 fiber growth (15 vs 12). But... we haven’t yet discussed… strength. In all cases measuring strength improvements, using heavier weights of roughly 85% or more of your 1RM always beat out anything less. And it makes sense when you apply the SAID principle, aka..

Specific

Adaptations to

Imposed

Demands.

If you want to adapt and become specifically stronger, you need to create the demand by lifting heavier. Doing so maximizes mechanical tension, stimulating your stronger type 2 fibers and also improves neuromuscular adaptations. But the same SAID principle also applies with light weights in terms of muscular endurance. If you want to lift for more reps, you’ll have to do more high rep training, which also increases metabolic adaptation and lactate threshold, combating muscle fatigue. This also explains the so-called “hypertrophy range” of 6 to 12 reps you might have heard of. It taps directly into the center of the metabolic-mechanical spectrum, giving you a solid balance for growth. Along with that, it capitalizes other potential growth factors such as time under tension, quality technique, and avoiding excessive burnout. So, let’s ask the question again: Do lighter weights have a place in your program? Clearly now, the answer is “yes” in terms of muscle growth. You should spend time in the whole gamut of rep ranges without ignoring one too much. However, it still somewhat depends. In this case, it depends on your goals. If you want to become stronger, it’s very clear that you should swing your program towards heavier lifting with sporadic time in light weight training. If you’re pure muscle building, training throughout all rep ranges evenly is perhaps the best approach. If you’re going for endurance, then you should primarily lift lighter weights with more reps with a moderate amount of time training in the other ranges.

The main takeaway is that everyone should do a little bit of everything. Light weights, heavy weights, and everything in between. They all have benefits to your overall fitness. Share your thoughts on rep ranges as well. Do you believe there is a benefit to training with lighter weights? Let me know. As always, thank you for reading.