More or Harder?

Although the concept of training volume has been discussed for a long time, it continues to be a contentious topic. It is clear that volume plays some role in resistance training adaptations- one set will get you more gains than no sets, after all. But after that, it can be surprisingly hard to find consensus between individuals on what is the right amount of training volume for a given individual. Devotees of Mike Mentzer and Dorian Yates will claim that one hard set taken close to failure is all anyone needs. Others, perhaps inspired by the epic videos of Arnold’s arduous training in his Golds’ Gym heyday, insist that high volumes are essential to achieve best results. So, who is right? As we will see, a definitive answer might not be so simple, but nowadays we do have some good evidence to help guide our decisions.

Although training volume has been discussed for decades in sport science circles, the literature on the topic was surprisingly sparse until recent years. In general, training volume was discussed for sports performance in track and field, Olympic weightlifting, and other sports dependent on maximal output. In running nomenclature, volume might refer to total mileage, or the number of runs at a given temp or percentage of maximal heart rate. This concept of intensity was inherently tied to any discussion around volume. Intensity refers to the effort of a given performance relative to an individual’s maximum ability. In powerlifting or weightlifting intensity generally refers to a weight that is a percentage of an individual’s one-repetition maximum for a given exercise. There is an inherent interaction between volume and intensity; as the intensity of an athlete’s training increases, they will generally need to reduce the amount of work they do, the volume. 

Given that bodybuilding is a relatively niche sport- depending  on how you define ‘sport’- research which addresses how the above factors influence muscle growth has been extremely limited until the last two decades or so. Fortunately, that is starting to change.

Recall that intensity is relative to maximal performance, and varies between individuals. Some people can tolerate more hard training than others, but the general principle still holds that volume and intensity should be adjusted in relation to one another. Advocates of the Mentzer approach take the view that intensity, not volume, is the primary driver of muscle growth. This High Intensity Training (HIT) approach promotes simply taking one heavy set to failure once every 7-10 days, rather than performing multiple sets per session. Note that this definition of intensity is different to that of powerlifting, where intensity is expressed as a percentage of one-repetition maximum (%1RM). In a bodybuilding context intensity is often framed as how close to failure you are getting to during a set with any given weight.

On the other end of the spectrum is a training method like German Volume Training (GVT) which prescribes 10 sets of 10 reps. This approach embraces volume, sheer workload, as the main driver of muscle gain. This approach considers volume as a function of weight multiplied by sets multiplied by repetitions completed, which is known as Volume Load. 

While some very big and strong individuals have had great success with both of these approaches, and many other variations on the same theme, both sides are probably guilty of misunderstanding one another. As outlined above, HIT is actually referring to how difficult a set is, not necessarily the weight on the bar. As such, intensity in this context can better be described as Proximity to Failure, where the goal is to achieve failure on each working set. 

Although volume load can be a valid way of measuring the overall work completed during a training session, or over a training block, it does not tell the whole story. 

If we were to use the example of GVT, for an individual to be able to complete 10 sets of 10 reps with a given weight, they will have to be much further from failure during the first few sets than the last few. 

To put this in perspective, let’s say a given athlete can perform a Barbell Bench Press with 135lb/60kg for 18 reps before hitting failure. If we were to express proximity to failure as Repetitions in Reserve (RIR), then an individual using this weight for 10 x 10 might look something like this:

Set 1: 10 x 135lb (RIR 8)

Set 2: 10 x 135lb (RIR 7)

Set 3: 10 x 135lb (RIR 7)

Set 4: 10 x 135lb (RIR 5)

Set 5: 10 x 135lb (RIR 4)

Set 6: 10 x 135lb (RIR 3)

Set 7: 10 x 135lb (RIR 3)

Set 8: 10 x 135lb (RIR 2)

Set 9: 10 x 135lb (RIR 1)

Set 10: 10 x 135lb (RIR 1)

In this example, this individual is training pretty comfortably for the first 4-5 sets of this exercise, before really exerting themselves for the last 3 sets. Although they would have accumulated a significant volume load, a HIT advocate could pretty reasonably make the claim that this trainee is only really exerting themselves on the last two of those ten sets. If the trainee were to use longer rest intervals of 3-5 minutes, they may be able to recover enough where they are still at RIR 5 for the last sets. 

One of the reasons that proximity to failure is considered so important for hypertrophy is that getting closer to failure will recruit a greater proportion of muscle fibers in a given muscle. Recruiting more muscle fibers during a set will expose more of these fibers to Mechanical Tension, and it is probably mechanical tension which we should be focused on. In this framing, intensity and proximity to failure are simply a proxy measure of the mechanical tension of any given set. Volume, or the number of sets, is another metric for measuring the dose of this mechanical tension.

In perhaps the most comprehensive meta-analysis on the relationship between volume and muscle growth and strength, Pelland and colleagues (2026) found a positive relationship between weekly training volume and changes in muscle size. When viewed graphically, however, there is an incremental flattening of this line as training volumes increase. The authors observed that just 4 weekly sets per week was enough to elicit meaningful hypertrophy.