According to a recent study conducted at the State University of Campinas (UNICAMP) in São Paulo, Brazil, there’s no significant difference in muscle growth between low load, high repetition and high load, low repetition resistance training.
Study Details
The research spanned eight weeks and involved 18 volunteers split into two groups.
The high-load (HL) group exercised with heavier weights but fewer repetitions, while the low-load (LL) group trained with lighter weights but with more repetitions.
Measures of muscle mass at the beginning and end of the experiment showed no significant difference between the two groups, nor were there differences in metabolic stress, gauged by analysis of substances released into the bloodstream during exercise.
In the HL group, participants lifted up to 80% of their own weight. In the LL group, the limit was 30%, but they performed more repetitions until muscle fatigue.
The study’s findings were published in the journal Metabolites.
Implications
“Resistance training is known to promote muscle growth, but it’s still not completely clear whether the key to muscle hypertrophy is the load or the number of repetitions.
Our study supports the theory that both types have the same effect.
We also showed that muscle activation occurs in a different manner in each type, although metabolic stress is the same and the effect on hypertrophy is therefore also the same,” stated Renato Barroso, a professor at UNICAMP’s School of Physical Education.
Surprisingly, the expected higher metabolic stress response in the LL group was not observed. Though the level of muscle activation was higher in the HL group, metabolic stress was similar for both.
According to Barroso, the similarity in metabolic responses suggests both training types may act on the same pathways to stimulate hypertrophy.
Metabolic Variations
The metabolomic analysis detected changes in 50 metabolites in the blood in response to muscle activation during both types of training.
However, only a few of these metabolites differed between the two groups.
Though the overall metabolic response did not differ between the groups, some metabolites correlated with muscle hypertrophy in both.
These correlations could be linked to the characteristics of the muscle fibers activated by exercise and the metabolic demands of the training protocols.
Closing Thoughts
This study brings a fresh perspective to resistance training practices, suggesting that muscle growth can be achieved with both high and low-load training, challenging the popular notion that heavier weights always yield greater muscle growth.
Whether you prefer to lift heavier weights for fewer reps or lighter weights for more reps, the end result may be more similar than previously thought.
If you care about wellness, please read studies that vitamin E can prevent muscle damage after a heart attack, and these vitamins could help reduce bone fracture risk.
For more information about wellness, please see recent studies that Krill oil could improve muscle health in older people, and why beetroot juice can strongly boost muscle force in exercise.
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