Most people grow muscles well with both heavy and light weights, but a few might grow better with one than the other — it’s rare and not predictable.
Scientific Claim
While the majority of individuals exhibit similar hypertrophic responsiveness across high- and low-load resistance training, a subset may demonstrate load-specific responsiveness, though such responses are inconsistent and not reliably predictable.
Original Statement
“Finally, we know that on average growth was similar between higher and lighter loads. But could some people grow more with one over the other? Well, aggregating the hypertrophy measures, the researchers ranked responsiveness with the different loads, we generally see that those that grew well with the high loads also tended to grow well with the lighter loads. However, we do see some data points that would seem to suggest certain individuals may experience better growth with lighter loads and others higher loads.”
Context Details
Domain
exercise
Population
human
Subject
Individual hypertrophic responses
Action
are generally similar across load ranges
Target
with a subset exhibiting inconsistent, non-predictable load-specific responsiveness
Intervention Details
Evidence from Studies
Supporting (5)
Higher- and lower-load resistance exercise training induce load-specific local muscle endurance changes in young women: a randomised trial.
Some people’s muscles get stronger in a way that matches the weight they trained with—light weights help more with light tasks, heavy weights help more with heavy tasks—but this doesn’t happen the same way in every part of the body, so you can’t always predict it.
Individual muscle hypertrophy in high-load resistance training with and without blood flow restriction: A near-infrared spectroscopy approach
Some people grew more muscle with regular heavy lifting, others grew more with heavy lifting while restricting blood flow — and there was no clear way to tell who would respond better to which method.
Resistance training load does not determine resistance training-induced hypertrophy across upper and lower limbs in healthy young males.
People’s muscles grow differently no matter if they lift heavy or light weights — some grow a lot, some grow little, but it’s not because of the weight; it’s because of their body’s natural differences, and you can’t reliably predict who will respond better to heavy vs. light lifting.
Potential Moderators of the Effects of Blood Flow Restriction Training on Muscle Strength and Hypertrophy: A Meta-analysis Based on a Comparison with High-Load Resistance Training
Some people build muscle the same way no matter if they lift heavy or light weights, but others—especially those who already train a lot—build more muscle with light weights and restricted blood flow, showing that not everyone reacts the same way.
The Effect of Low-Load Resistance Training on Skeletal Muscle Hypertrophy in Trained Men: A Critically Appraised Topic.
Most people gain muscle just as well with light or heavy weights if they train hard to exhaustion, but a few might respond better to one over the other—though we can’t reliably tell who those people are.