Training volume refers to the total number of repetitions performed, typically per week. This can be calculated by multiplying the number of repetitions by the number of sets completed across a given training week in order to quantify such stimulus/stress and therefore assist in planning an effective periodised training programme.
Personally, I take this one step further by multiplying the total number of repetitions by the load (kg) lifted, again, over a period of a week or microcycle. Although I measure this variable with every client, I tend to only consider such measure with my strength athletes as those who train for changes in body composition will have numerous training methodologies incorporated into their programme such as bodyweight exercises and those using resistance machines therefore making volume x load an inaccurate measure in comparison to those training with barbells and dumbells only.
As with any topic in this industry, optimal training volume for both strength and hypertrophy has been debated for some time. Arthur Jones (Nautilus) for example, argued that only a single set per exercise is required to stimulate muscular hypertrophy as long as that set is performed to failure. Although this training method is still prescribed by a number of coaches today (especially to individuals with limited time), you only have to glimpse at most programmes designed by trainers, bodybuilders, athletes and coaches to understand that multiple set protocols appear to be more popular.
But how many sets of an exercise will maximise strength and hypertrophy?
A fairly recent article published in the Journal of Strength & Conditioning Research reviewed 14 separate studies analysing the effects of single or multiple sets on strength (Krieger, 2009). Multiple sets were associated with significantly greater improvements in strength in comparison to single set protocols. In fact, 2-3 sets were found to lead to 46% greater gains than 1 set per exercise whether the individual had training experience or not.
A more recent meta-analysis, published in the same journal, reviewed 8 studies and compared the effects of single and multiple sets per exercise on muscle hypertrophy (Krieger, 2010). Changes in lean body mass, regional lean mass, muscle cross sectional area, muscle circumference and thickness were all assessed in studies involving training programmes for adults that lasted for a minimum of 4 weeks. It was concluded that multiple sets of an exercise induced 40% greater gains in muscle hypertrophy compared with those performed for a single set. Again this was true in both trained and non-trained individuals. It was also suggested that 4-6 sets may give an even better response, however only a small number of studies reviewed the effect of this volume in comparison to those analysing the effects of 2-3 sets.
Looking deeper, this time at the physiological mechanisms of muscle hypertrophy and the connection with training volume, there is evidence that multiple set protocols elicit greater response in Growth Hormone and Testosterone levels, however not until 4 sets of an exercise are performed (Schoenfeld, 2010). Both Testosterone and Growth Hormone are seen to have anabolic effects on muscle tissue.
Although single set protocols were found to produce improvements in both strength and size, the research suggests that 3 sets per exercise is the best starting point. Sessions incorporating 4 or more sets per exercise may bring greater improvements, particularly where hormones are concerned, however there does not appear to be a great deal of research analysing the effects of such volume.
As with any training variable, volume should be manipulated throughout the training year to allow for a greater stimulus and therefore avoid a plateauing effect, as well as ensure sufficient recovery (especially if the athlete is near or within a competition phase).
It is recommended that a minimum of 3 sets per exercise are performed throughout the entire programme, potentially increasing to 4-6 sets per exercise over time in order to induce a greater hypertrophic response. Of course, just like intensity, a period of high volume must be followed by a period of reduced volume to allow for recovery and recuperation.
As an example, you may want to perform 3 sets per exercise in the first 2-4 weeks phase of a programme, 4 sets in the second phase, 5-6 sets in the third followed by a return to 2-3 sets to allow the body to adapt to what could be seen as a planned overreach.
If time is limited, then single set protocols may be used however improvements in strength and hypertrophy are expected to be 46% and 40% less, respectively, in comparison to sessions incorporating greater volume.
Author: Karl Page
Krieger, J. W., 2009. Single Versus Multiple Sets of Resistance Exercise: A Meta-Regression. Journal of Strength & Conditioning Research. 23(6), pp.1890-1901.
Krieger, J. W., 2010. Single Vs. Multiple Sets of Resistance Exercise For Muscle Hypertrophy: A Meta-Analysis. Journal of Strength & Conditioning Research. 24(4), pp.1150-1159.
Schoenfeld, B. J., 2010. The Mechanisms of Muscle Hypertrophy and Their Application to Resistance Training. Journal of Strength & Conditioning Research. 24(10), pp. 2857-2872.