What Drives Your Gains?
If you've ever asked yourself whether lifting heavier weights or doing more reps gets better results in the gym, you're not alone. It’s a question that’s been debated on gym floors, in sports science journals, and, of course, all over social media.
As a sports chiropractor and performance specialist, I often get asked:
“Should I be training heavier to get stronger?”
“Does lifting heavier really help me grow muscle?”
“How many days a week should I be training?”
Or especially from women who have not done any strength training- “Aren’t I going to get bulky if I start lifting heavy?”
So let’s break it down, using real data, and separate bro science from actual science.
Strength Gains: Intensity Leads the Way
If your goal is to increase maximal strength, your priority should be lifting heavier loads. The research consistently shows that training at higher intensities (like 80–90% of your 1-rep max, but even as low as 60%) leads to greater improvements in strength.
One standout study by Lasevicius et al. (2018) found that when total training volume was matched, higher loads produced significantly more strength gains than lighter loads. That means two people doing the same number of total reps and weight (overall volume) still got very different results based on how heavy they lifted per rep.
This is echoed in an umbrella review by McLeod et al. (2024), which concluded that intensity and weekly volume (number of sets) were the biggest drivers of strength. Frequency (or how many days per week you train) didn’t seem to matter much, so long as total work was the same.
Ralston et al. (2017) took it a step further. They showed that weekly set volume, not frequency, was a key predictor of strength gains. So whether you lift three days or six, what matters is how many quality sets you're putting in each week.
Hypertrophy: Volume Is King
Now let’s talk about muscle size. For hypertrophy, the research points to one consistent conclusion:
More weekly volume = more muscle growth.
Again, frequency and intensity play a role, but they're not as important as how much total work you're doing.
The Schoenfeld et al. (2017) meta-analysis found that doing 10+ sets per muscle group per week led to nearly double the muscle gains compared to those doing fewer than five sets. That’s a pretty big difference.
In the same lane, McLeod (2024) and Ralston (2017) confirm that weekly volume, not frequency, is the better predictor of hypertrophy. You can spread those sets over 2, 3, or 6 days, but the total number of hard sets per week is what really matters.
Interestingly, studies like Lasevicius et al. (2018) show that light and heavy weights both build muscle, as long as the set is taken close to failure and the weekly volume is high enough. That means hypertrophy can be achieved across a wide range of rep schemes, giving you flexibility in your programming.
So... What Should You Actually Do?
Here’s how I guide my athletes and clients:
For Strength:
Use loads around 80–90% of your 1RM
Aim for 3–5 sets per lift, and get in 10–15 hard sets per muscle group weekly
If you are just starting training, doing 8-10 sets per week has plenty of efficacy to increasing strength!
Don’t worry too much about training every day. Focus on progressing load and tracking total sets.
For Hypertrophy:
Hit 10–20 hard sets per muscle group per week
Intensity can vary- use 40–80% 1RM and push sets near failure
Mix rep ranges to manage fatigue and joint stress
Training frequency gets a lot of hype, but what really moves the needle are volume and intensity. Whether you're chasing PRs or biceps, it's not about how often you train- it's about how smartly you train.
If you’re programming your training, or working with athletes in the gym or your clinic, take a look at the weekly set volume and relative intensity. That’s where the real gains are made.
Have questions? Want help dialing in your training volume for strength or hypertrophy? I’d love to help. Drop a comment, send a message, or come find me at Delta S Performance in Golden, CO.
References
Colquhoun, R. J., Gai, C. M., Aguilar, D., Bove, D., Dolan, J., Vargas, A., Couvillion, K., Jenkins, N. D. M., & Campbell, B. I. (2018). Training volume, not frequency, indicative of maximal strength adaptations to resistance training. Journal of Strength and Conditioning Research, 32(5), 1207–1213. https://doi.org/10.1519/JSC.0000000000002487
Lasevicius, T., Ugrinowitsch, C., Schoenfeld, B. J., Roschel, H., Tavares, L. D., De Souza, E. O., Laurentino, G., & Tricoli, V. (2018). Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy. European Journal of Sport Science. https://doi.org/10.1080/17461391.2018.1450898
McLeod, J. C., Currier, B. S., Lowisz, C. V., & Phillips, S. M. (2024). The influence of resistance exercise training prescription variables on skeletal muscle mass, strength, and physical function in healthy adults: An umbrella review. Journal of Sport and Health Science, 13, 47–60. https://doi.org/10.1016/j.jshs.2023.06.005
Ralston, G. W., Kilgore, L., Wyatt, F. B., & Baker, J. S. (2017). The effect of weekly set volume on strength gain: A meta-analysis. Sports Medicine, 47(12), 2585–2601. https://doi.org/10.1007/s40279-017-0762-7
Schoenfeld, B. J., Ogborn, D., & Krieger, J. W. (2017). Dose-response relationship between weekly resistance training volume and increases in muscle mass: A systematic review and meta-analysis. Journal of Sports Sciences, 35(11), 1073–1082. https://doi.org/10.1080/02640414.2016.1210197