Light weights also stimulate muscle growth
This article is verified by 2 studies/publications.
“Go hard or go home” is a well-known saying in the bodybuilding world. Many beginners associate it with lifting heavy weights until they can’t lift anymore. But is it really necessary, or does it just sound cool?
A meta-study from the US tackled this question, investigating whether heavy weights are essential for muscle growth[1], or if lighter weights can also help build muscle.
Too long; didn’t read (Summary)
- A meta-analysis investigated the effects of using light and heavy training weights on muscle growth and strength.
- The study compared low loads (<60% 1 RM) with high loads (>65% 1 RM).
- Results showed that heavy weightlifting is more effective in increasing strength and promoting muscle growth.
- However, lifting a lower weight with the same volume still has a positive impact on muscle growth, although it may not have as much effect on maximum strength.
- Combining light and heavy weights could be advantageous for targeting both type 1 and type 2 muscle fibers.
What was analyzed
The analysis started with 846 studies in the screening process, but only 10 studies met the researchers’ inclusion criteria.
The effects of low-load strength training (less than 60 percent of the repetition weight of maximum strength [1 RM]) were compared to high-load training (more than 65 percent of the repetition weight of maximum strength) in untrained subjects.
The focus was on two parameters: strength and muscle hypertrophy (muscle growth). The strength analysis included 251 subjects in 20 groups from 9 studies, while the muscle-building analysis had 191 subjects in 17 groups from 8 studies.
Light vs. heavy weights
The results were similar for both analyses: heavy weight lifting offers advantages in increasing strength and tends to stimulate muscle growth more effectively. However, the meta-analysis also revealed that working out with low weights can lead to increased strength and muscle hypertrophy.
For strength gains, the analysis showed a clearer advantage for heavy weights, meaning heavy resistance training is more effective in increasing maximum strength.
When it came to muscle hypertrophy, the picture was less clear. Although heavier weights tended to promote stronger muscle growth, the effect was also significant with lighter weights. In this context, the researchers questioned if muscle growth was influenced by the type of muscle fiber.
Findings for practical use
Citing another study, it’s suggested that low loads tend to activate type 1 fibers and high loads tend to activate type 2 fibers to a greater extent[2]. However, this distribution couldn’t be reproduced in other studies.
Generally, high training weights do show advantages in strength increase and muscle building, but lower weights can also help build muscle.
For practical everyday training, the study authors recommend a possible combination of heavy and light weight training to achieve an optimal response of type 1 and type 2 muscle fibers.
Lastly, it’s important to note that light training weights don’t mean you don’t have to put in any effort. To stimulate muscle growth, the training volume (resulting from: training weight x repetitions x number of sets) must still be sufficiently high. This means that low weights need to be moved more often, and you should train just before muscle failure to achieve a positive effect on muscle growth. So, while heavy weights have their place in strength training, don’t discount the benefits of lighter weights as part of a well-rounded workout routine. Combining both heavy and light weight training can help you achieve the best results and optimize the growth of different muscle fibers.
Sources
- Muscular adaptations in low- versus high-load resistance training: A meta-analysis. Schoenfeld BJ, Wilson JM, Lowery RP, Krieger JW. Eur J Sport Sci. 2016;16(1):1-10. doi: 10.1080/17461391.2014.989922. Epub 2014 Dec 20. PMID: 25530577.
- Resistance exercise load does not determine training-mediated hypertrophic gains in young men. Mitchell CJ, Churchward-Venne TA, West DW, et al. J Appl Physiol (1985). 2012;113(1):71-77. doi:10.1152/japplphysiol.00307.2012