Strength in Numbers

How do we optimise muscle gain? This week in strength notes, we delve deeper into the relationship between intensity and volume.


Torsa Studios


Like many training methods, there is rich debate about which is the most effective for muscle and strength gain. Today we’re breaking down the debate about training volume vs training intensity. Those in the volume camp claim that the total number of reps and sets you do is what drives muscle growth, whilst the intensity camp contends that using heavier weight for lower reps ultimately puts more tension on the muscle, leading to greater strength and muscle gain.



What is volume?

Simply put, volume refers to the total amount of work an athlete is doing over a period of time. One popular method of measuring volume in weightlifting is something referred to as volume load. For example, if you do 3 sets of 5 reps of squats with 100 KG, your volume load would be 1,500 KG (3 x 5 x 100). The issue with measuring volume is it can be seen as a vanity metric. For example, if you performed 3 sets of 12 reps at 80KG, your volume load would equate to 2,880 (3 x 12 x 80), far greater than the 3 x 5 set. However, studies suggest this doesn’t subsequently lead to more muscle gain. In fact, research shows that any weightlifting set taken close to failure in the 6-to-20 rep range will produce the same amount of muscle gain. That is, a set of 6 reps taken close to failure will produce a similar result as a set of 20 reps taken to failure. That means wildly different volume loads can produce more or less the same amount of muscle gain.

So, what’s the best way to quantify volume for the purposes of workout programming? Most research shows the answer is ‘hard sets’ which are sets taken within 1-to-3 reps of muscle failure. 


What is intensity?

Intensity refers to how hard an athlete trains, and can be measured in a number of ways. One popular method is known as reps in reserve (RIR), which is how many more reps the athlete could have done before failure. Failure is the point at which you can’t complete another rep with good form, and you can think of it as the limit of your ability.

Once you estimate roughly how many reps it would take to reach failure with a particular weight, you can measure your weightlifting intensity in terms of how many reps you could have done, but didn’t. In other words, how many reps you had “in reserve” at the end of your set. 

Your RIR figure can be used to ensure you’re training intensely enough to maximise muscle growth. As a general rule of thumb, research suggests that you should end most of your sets with 1-to-3 reps shy of failure.

If you’re a more advanced lifter, you can also measure intensity with methods such as % of 1-rep max and RPE (rate of perceived exertion) – essentially, how hard an exercise or workout feels on a scale of 1-10.



Which is better for building muscle?

Essentially, neither. In reality, you need a combination of both to build muscle efficiently and effectively. If we break down how muscles are built, we can get a better understanding of why we need both for effective muscle gain. Dr Eric Helms, one of the most highly respected and regarded trainers and coaches in the industry put it simply, “Muscle growth occurs due to cumulative tension stimulus over time.” In other words, you build muscle by contracting your muscles at a sufficient intensity for a sufficient duration over time. The process of increasing the amount of tension your muscles are exposed to over time is known as progressive overload, something we touch on regularly.


The two ways you can increase tension stimulus are;

  1. Increase the amount of tension produced in each rep by lifting heavier weight.
  2. Extend the amount of time your muscles are exposed to tension by doing more sets or reps. 


With option 1, you use heavy weights for relatively few reps, forcing your muscles to contract very hard for a brief period of time. With the second option, you use lighter (though not necessarily “easy”) weights for more sets or reps, forcing your muscles to contract moderately hard for a longer period of time. This often leads to similar tension using both approaches, and therefore the same ‘absolute’ strength. That’s why research suggests that 6-20 reps take close to failure will produce the same amount of muscle growth, they produce the same amount of cumulative tension by the end of the set.


When it comes to muscle growth, although both approaches build muscle, it’s volume that’s the primary driver. Why is this? Well, it’s the volume of tension over time that makes your muscles bigger. You can’t expect your muscles to grow if you’re only performing 3 reps of heavy weights, because you don’t have the tension over a sufficient amount of time to grow the muscle.


This, however, relies on a few different factors.


Firstly, that you’re taking sets relatively close to failure (1-3 RIR is a good target). If you’re not pushing yourself close to failure, you won’t generate enough tension to stimulate muscle growth. Secondly, you should aim for the 6-20 rep range that we touched on before, and we recommend 8-12 reps for optimal muscle growth. Anything past 20 reps, you’re likely using too light a weight to stimulate sufficient tension in each set. Anything fewer than this range, you’ll significantly reduce the amount of time your muscles are forced to produce tension, thus short-changing your gains.


 Too much intensity?

There’s a tendency to think that the more weight you lift, the more muscle you’ll build. This approach is interesting to many people as it’s to track weight on the bar as a precursor to muscle gain. However, as Dr Helms points out, getting stronger isn’t what causes muscle gain. In fact, muscle growth causes strength gain.


“But don’t get so hung up on strength to the point that you think putting weight on the bar is the only thing that matters, or that doing so is what causes hypertrophy. It’s actually the other way around, increased strength is a sign that you are providing an adequate overload for hypertrophy. You not only have to apply a tension stimulus (performing at an adequate RPE) for muscles to grow, but also ensure you have provided enough of that tension (volume; number of sets).”

If you’re strength is going up and you’re able to lift more weight at the same RIR (reps in reserve), the same weight for more reps, or for the same reps with more RIR, then it’s a sign that you’ve provided adequate progressive overload to build muscle.


The main reasons to add weight to the bar are as follows;


  1. Ensure you taking sets close to failure, and therefore maximising sufficient tension on the muscle to stimulate growth.
  2. Improve your ability to move heavy loads, which allows you to rack up more tension in your workouts over time.
  3. Determine whether your programme is working. If you’re an experienced lifter, continually adhering to progressive overload is far more challenging than a new lifter. If you’re strength hasn’t gone up in a while (plateaued), then it’s maybe a sign your programme isn’t providing enough tension, might be providing too much, or that you may not be recovering enough. For many, there comes a point where strength and muscle gain isn’t the main objective, but if you are looking to get stronger and have hit a ceiling, recruit a highly experienced strength and conditioning coach that could help you break through that ceiling with proper programming.



Too much volume?

On the other side of the coin, focusing too much on volume also has its drawbacks. From the previous points we’ve made, it may seem that higher volume, (more sets, more reps) lead to more tension on the muscle, and therefore maximising muscle growth. There are a number of issues with this approach and thinking.


Firstly, there is a qualitative aspect to tension. If the weights you are using are too light, it won’t provide enough tension to stimulate substantial amount of muscle growth, irrespective of how many reps you are performing.


The degree of tension that you illicit in each rep is an important factor. There are of course other issues performing high rep training, namely the increased time spent on each set, cardiovascular fatigue, and recovery time.


Also, performing 30 reps of a compound lift like bench press or squat can be dangerous. Form begins to break down because of fatigue, and it’s just simply not the optimal way to build muscle.



The best approach

Of course, there is an overwhelming amount of research on the most optimal way to build muscle. The bulk of the research points to balancing volume and intensity, using the following guidelines.


  • Do 10-to-20 sets per muscle group per week.
  • Use 60-to-90% of your one-rep max (between 2-to-15 reps) for most of your sets
  • Take all sets 1-to-3 sets shy to failure


Mixing lighter and heavier training is important. Our suggestion is that for heavier compound lifts, like the squat or bench press, at least once a week you should focus on heavier weight, lower reps. That’s not to say that you shouldn’t also be doing 6-12 reps of a bench press, you should, but combining both within a week is an efficient way to adhere to progressive overload.


Dr Helms recommends 2/3 or ¾ of your total sets should be within the 6-to-12 rep range, whilst the remaining sets either in the 1-to-6 or 12-15 re ranges.