Both moderate and light weight groups had similar effects on body composition and strength; an athlete can add both phases to a training cycle to periodize the stimulus and avoid training monotony, at least in the general population. More research needs to be done in a well-trained population to replicate these findings.
A NEW STUDY FINDS LIGHT WEIGHTS, HIGH REP WORKOUTS RESULT IN MORE FAT LOSS AND SIMILAR MUSCLE GAIN AS HEAVIER WEIGHT WORKOUTS SUMMARY
- Moderate and light weight groups (i.e., high rep workouts) gained similar amounts of muscle, but the light weight group lost slightly more fat.
- The moderate weight group gained more muscle earlier (<6 weeks), whereas the light weight group gained more muscle (>6 weeks).
An Introduction to High Rep Workouts
If you have been following the research, muscle growth is similar with both heavy and light weight training taken to failure. (1,2) Check out the Reddit bodybuilding section for the discussions, and you will see many people find that heavier weights work best, whereas others find light weights work better for gaining muscle.
Many have suggested using a combination of heavy and light weights in the training cycle to give the joints and soft tissues a break from excessively heavy weights for a prolonged period.(3) The research also suggests that heavier weights do not need to be taken to failure, with similar increases in muscle growth occurring between going to failure and not going to failure. Many studies have examined the impacts of different loading routines short term (<6 weeks), but few have examined the different effects long terms (>12 weeks).
Researchers examined two different routines using either a moderate weight program (70% of a 1RM) or a light weight routine (30% of a 1RM) for 12 weeks. The subjects were untrained and performed a circuit training routine with 30 seconds of rest in between sets. The subjects were instructed to perform as many reps as possible in the 30 seconds of each exercise.
Volume (weight x sets x number of repetitions) was equal in the two groups. The subjects performed 24–28 repetitions for the light weight resistance exercise protocol (30% 1-RM) and 8–12 repetitions for the moderate-weight protocol (70% 1-RM). The training protocol comprised five different exercises (bench press, squat, bent-over row, deadlift, and dumbbell shoulder press) performed in a circuit. They alternated the order between upper and lower body exercises. Body composition was assessed at weeks 6 and week 12.
> 20 REP SETS FOR HYPERTROPHY? HIGHER REP WORKOUTS RESULTS IN MORE FAT LOSS
In a comparative study between light and moderate weight training, both groups managed to reduce body fat by the end. However, the light weight group had a slightly more significant reduction in body fat, losing -3.19 kg compared to the -1.64 kg lost by the moderate weight group. The training volume remained consistent between the two groups.
When it came to muscle mass gains:
- Both groups saw similar overall increases over the 12-week period: 1.25 kg for the moderate weight group and 1.11 kg for the light weight group.
- The rate of muscle gain varied between the two groups:
Moderate Weight Group: Gained 1.05 kg in the first six weeks and only 0.2 kg in the subsequent six weeks.
Light Weight Group: Gained 0.45 kg in the first six weeks but saw a more significant increase of 0.66 kg in the last six weeks.
In summary, the moderate weight group experienced more rapid muscle growth in the initial six weeks. In contrast, the light weight group saw a more substantial increase in muscle mass during the latter half of the study period.(4) This suggests that while both training methods can be effective, the timing and rate of muscle gains might differ based on the weight intensity used.
HIGHER REP WORKOUTS FOR MUSCLE GROWTH MAY TAKE LONGER
In a study comparing the effects of light weight versus moderate weight training on muscle growth, the light weight group performed as many reps as possible within 30 seconds. However, referencing prior studies, sets with 30% of a 1RM taken to failure typically averaged around 40 seconds per set.(5,6) This indicates that the light weight group might not have been training as close to failure as the moderate-weight group. Despite this, both groups experienced similar gains in muscle mass.
However, there are some caveats to consider:
- The study did not utilize DEXA, a gold standard for measuring body composition, so the results might not be as accurate.
- There was no mention of standardizing the dietary protocols for the participants, which could influence muscle growth and recovery.
- The study’s conclusion was that both light and moderate weight training had comparable effects on body composition and strength. This suggests that athletes could incorporate both training methods into their routines, alternating between them to provide varied stimuli and prevent training monotony. This approach might be particularly beneficial for the general population.
However, it’s essential to note that more research is needed, especially with well-trained individuals, to validate these findings further.
1. Schoenfeld, B.J.; Grgic, J.; Van Every, D.W.; Plotkin, D.L. Loading recommendations for muscle strength, hypertrophy, and local endurance: A re-examination of the repetition continuum. Sports 2021, 9, 32.
2. Schoenfeld, B.J.; Contreras, B.; Vigotsky, A.D.; Ogborn, D.; Fontana, F.; Tiryaki-Sonmez, G. Upper body muscle activation during low-versus high-load resistance exercise in the bench press. Isokinet. Exerc. Sci. 2016, 24, 217–224.
3. Schoenfeld, B.J.; Peterson, M.D.; Ogborn, D.; Contreras, B.; Sonmez, G.T. Effects of low- vs. High-load resistance training on muscle strength and hypertrophy in well-trained men. J. Strength Cond. Res. 2015, 29, 2954–2963.
4. Kapsis, D.P.; Tsoukos, A.; Psarraki, M.P.; Douda, H.T.; Smilios, I.; Bogdanis, G.C. Changes in Body Composition and Strength after 12 Weeks of High-Intensity Functional Training with Two Different Loads in Physically Active Men and Women: A Randomized Controlled Study. Sports 2022, 10, 7.
5. Burd, N. A., West, D. W., Moore, D. R., Atherton, P. J., Staples, A. W., Prior, T., Tang, J. E., Rennie, M. J., Baker, S. K., & Phillips, S. M. (2011). Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men. The Journal of nutrition, 141(4), 568–573. https://doi.org/10.3945/jn.110.135038
6. Burd NA, Andrews RJ, West DW, et al. Muscle time under tension during resistance exercise stimulates differential muscle protein sub-fractional synthetic responses in men. J Physiol. 2012;590(2):351-362. doi:10.1113/jphysiol.2011.221200