Everywhere you look on the Internet people are suggesting on how often you should train. But rarely are these opinions backed by science. However, scientific literature says that you should train a muscle group between 2-3 times a week. Strength gains increase as you approach 3 workouts a week. Most people should perform between 4-8 sets per muscle group per week as well. Once you pass these levels, you experience diminishing returns.
A group (Mark Peterson, Matt Rhea, and Brent Alvar) out of Arizona State University (at the time) wrote a paper in 2005 outlining how to optimally design training volume and frequency for strength gains (link to paper).
**All figures in this article come from the paper by Peterson, Rhea and Alvar. The figures are used purely to highlight the findings from the paper and to help inform the reader of the main findings of the paper.
The authors used a meta-analysis, similar to what the one I summarized in a recent article about the importance of exercise order in strength gains and muscle hypertrophy.
Meta-analyses are when authors review all of the literature on a subject and pool the studies’ results to get an overarching idea of the outcome of similar studies.
The group did a great job of outlining the above variables (volume, frequency, intensity) for people of different training histories (training ages), which I’ll outline below.
Read More: How to add variety to your workouts to keep things interesting
TL;DR
Below is a TL;DR summary. Based on your training status, you can determine how often you should train a muscle group, how many sets you should do per muscle group and what intensity to train at to maximize strength gains.
| Training Status | Frequency (Per Week) | Number of Sets (Per Muscle Group) | Intensity (%1RM) |
| Untrained | 2-3 | 4 | 60 |
| Trained | 2 | 4-5 | 80 |
| Athlete | 3 | 8 | 85 |
How frequently should you strength train
Some people suggest training 1 day a week vs. training 3 days a week. But most of these arguments are based on bro-science.
However, when looking at the real science, there’s a clear picture. There is clear evidence of a “quantifiable, functional framework whereby the human musculoskeletal system adapts to strength training.” There is a science to strength training. The body responds in predictable and measurable ways to the stresses placed upon it.
This is a dose-dependent relationship. Strength-gain results are related to the number of training sessions for a muscle group in a week, as shown in the figure below.
The above figure shows strength gain [effect size] (y-axis) is dependent on the frequency that you train a muscle per week and the level of training you have.
The authors of the meta-analysis suggest that progressive training is needed to elicit, and continue eliciting, a strength adaptation.
A person new to strength training is capable of getting strength gains at low volume (1 set per muscle group per week). This will only result in general muscular fitness though.
As training history/experience increases, the frequency of strength training must also progress. The above figure highlights this relationship.
“Newbie-gains” are real and the science shows it. We’ve all heard about the person that starts training seriously for the first time and adds 50lbs to a squat in a couple of months. The majority of this is via neural adaptations – mostly increased motor unit recruitment in the muscles.
On the other hand, people with greater training history will make smaller gains in strength, and those gains will take a long to materialize.
Athletes require 2-3 sets per muscle group per week to get similar gains to what untrained subjects can get in about 1 set per muscle group per week.
In general:
The rate of improvement in muscular strength, after initiation of a given training prescription, decreases with increased training experience and current level of muscle conditioning.
Peterson et al. 2005
What is the right amount of volume when strength training?
Training volume is a product of the sets and reps.
If you’re interested, check out my article here on the sets and reps you should use in your programs and why (it opens in a new tab so you can keep reading this article too).
In the Peterson et al. article, the authors only refer to volume in regard to the number of sets. So, that is what we’ll talk about here.
The key is to remember that you are considering the total number of sets for a muscle group within the workout. So, if you did 5 sets of squats and 3 sets of knee extensions on a machine that totals 8 sets.
Looking at volume in this manner gives a better overall impression of the load that is placed on specific muscle groups.
As the above figure indicates, there is a continuum along which strength is developed for a given volume. This is also dependent on the training status of the individual doing the training.
For most people reading this article, the authors’ figure shows that somewhere in the neighbourhood of 4-8 sets is necessary to get maximum strength gains (peak of the lines).
The discrepancy in the amount of volume needed to get results between untrained/recreational people and elite athletes is intriguing to me. Elite athletes need somewhere around 10 sets to START seeing noticeable training effects. However, 2-4 sets for untrained and minimally trained individuals is more than enough.
The figure also shows the huge difference in the amount of strength gains possible for people at different levels of training status.
I recently wrote about how exercise order in training influences strength gains. You can check it out here.
Is 1 set of an exercise enough?
This is a huge debate in the fitness world. Should you only do one set for each exercise in your workout? Or are more sets better for you?
The results of the meta-analysis by Peterson and colleagues from 2005 suggests that one set is NOT enough to get full strength benefits.
As shown in the figure above, untrained and trained subjects showed virtually the same amount of strength gain for each set performed per muscle group. Approximately 50% of strength gain potential was realized after 1 set (per muscle group, per workout).
Just over 80% of strength-gain potential was achieved when these groups reached the 3rd set. And finally, at a 4th set, a maximum strength gain was realized.
Only 26% of potential strength-gain is achieved with athletes by doing 1 set per body part. Even bumping an athlete up to 4 sets per body part only leads to 75% of the potential strength gains. For athletes, the scientific literature says you need to hit 8 sets per muscle group (3 times per week) to get full strength gains.
Read more: The sure–fire signs that you need a deload week.
What intensity should you train at for strength
Intensity is probably the most important training variable when it comes to strength training. You need to be lifting enough load to cause mechanical stress in the muscles. This will lead to a super-compensation by the body, leading to increased muscle mass and strength.
The intensity of training is usually described as a percentage of one-rep max (%1RM). And intensity is what determines the number of reps.
Obviously, you won’t be able to do 7 reps of an exercise at 98% of your 1RM. Therefore, intensity dictates repetitions.
As the above figure shows, untrained lifters can get significant strength gains at relatively low intensity. Untrained subjects maximize strength gains by lifting at intensities of 60% of 1RM.
However, people experienced in strength training need to lift at about 80% of 1RM.
When looking at volume we saw that with increased training history, volume had to be increased to see continuing strength gains. Similarly, here we see that the intensity of lifting has to increase with increased training history to get strength gains.
And finally, athletes need to work at or above 85% of 1RM to get maximal strength gains
Training at high intensity might lead to muscle soreness. Click here to check out my article on why you get sore after working out and how to combat that
The Take Home: training frequency, volume, and intensity for strength gain
Based on this meta-analysis (which takes into account all of the relevant research published in the field), it’s pretty clear that training variables need to be manipulated based on your training status. The SAID Principle reigns supreme, like in all parts of training – your body responds to the demands placed on it. And you need to make sure those demands match your goals and training status.
- Untrained individuals should perform 4 sets at about 65% of 1RM, 2-3 times per week for each muscle group.
- Trained individuals should perform 4-5 sets at 80% of 1RM, 2 times per week per muscle group.
- Athletes need to perform 8 or more sets at 85% of 1RM, 3 times per week per muscle group.
Read More: Is the post-workout gain window real?