by Eric Helms, Ph.D.

Study Reviewed: Higher Resistance Training Volume Offsets Muscle Hypertrophy Nonresponsiveness in Older Individuals. Lixandrão et al. (2024)

If you’re a high responder to resistance training, you likely already know it. You probably grow more than others generally, and may do quite well with low volume training. The huge diversity in the response to resistance training has been observed empirically, where some people respond so poorly to a given training program that changes aren’t measurable over the course of a study.

Lixandrão and colleagues set out to determine if non-responders to a low volume, twice weekly, single-set (two weekly sets) resistance training program would experience better hypertrophy following a twice weekly, four-set (eight weekly sets) program in a sample of untrained older male and females.

After initial 1RM testing, MRI-derived quadriceps muscle cross sectional area assessment, and dietary recalls, each participant had one of their legs randomly assigned to a twice weekly, single set leg extension protocol (two sets per week total) and their other leg assigned to a twice weekly, four set leg extension protocol (eight sets per week total). During the first two weeks, participants performed 12-15RM sets to momentary muscular failure, and then for the remaining eight weeks they performed 8-12RM sets to momentary muscular failure, with 60-90 seconds rest between all sets. 60% of participants were responders, while 40% were non-responders. participants were classified as responders and non-responders based on the change in quadriceps cross sectional area of their leg assigned to the single-set protocol. Participants were classified as responders if their leg performing the single-set protocol increased quadriceps cross sectional area by greater than two times the typical error (>3.27%). Likewise, participants were classified as non-responders if their leg performing the single-set protocol increased quadriceps cross sectional area less than or equal to two times the typical error (≤3.27%).

There were no significant differences in nutritional intakes, age, body mass, body mass index or training adherence. The responders experienced a significant increase in both 1RM and cross sectional area in both legs following the 10-week training interventions, with no significant differences between the legs performing the single-set protocol, or the multi-set protocol. However, non-responders did not experience a significant increase in cross sectional area in their leg following the single-set protocol. Only the non-responders’ leg performing the multi-set protocol increased cross sectional area. Further, while 1RM increased in non-responders’ legs following the single-set protocol, 1RM increased to a significantly greater degree in their legs following the multi-set protocol.

To summarize the findings succinctly, responders grew in response to both protocols, with some indication they responded slightly better on average from the four-set regimen compared to the single-set regimen. On the other hand, non-responders (by definition) did not grow in response to the single-set regimen, but grew substantially more from the four-set regimen. Interestingly, the percentage increase in cross sectional area in the non-responders’ legs following the four-set, twice weekly protocol was the same as the responders’ legs following the single-set, twice weekly protocol (5.5%).

What we can take from this study is, that on average, those who respond well to resistance training benefit a great deal from relatively low volumes and may get an additional small benefit from increasing volume. However, those who respond poorly to low volume, might respond much better to higher volumes. A limitation of these data, however, is that this study was on untrained individuals aged 60 and older. When we think about the generalizability of these findings, this context is important. While I’m comfortable with my speculation that poor responders to resistance training might benefit from higher volume training, and that high responders don’t need or benefit as much from higher volume training, ideally I’d like to see more research to increase our confidence and the precision of our understanding. Specifically, I’d love to see the present study repeated in younger individuals, trained individuals, using other muscle groups, and with a wider variety of volumes.

If you’re a high responder to resistance training, you likely already know it. You probably grow more than others generally, and may do quite well with low volume training. My first piece of advice to you, is if you do plateau, look to turn over other stones than volume first. Consider evaluating your nutrition, exercise technique, selection, proximity to failure, and sleep before simply doing more. If you’re someone who struggles to make gains, however, and you’ve generally done low to moderate volume training, it might be worth considering a higher volume approach (and of course the other factors I mentioned above as well).

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