Quantifying resistance training variables is something that many trainers and trainees practice, in order to establish some tangible numbers that they can use for current and future decision-making. Different methods of quantifying volume will be discussed in a separate article, but for the purpose of this article, we will simplify resistance training volume as the number of sets performed for a given muscle group, with the assumption that those sets are performed close to the point of failure (~0-3 reps in reserve). However, tracking indirect training volume is a bit tricky. For the purpose of this article, our goal is to answer the following question:
Indirect Training Volume
You may be wondering, what exactly “indirect training volume” is. Well, it is probably easier to illustrate this with an example:
Let’s say you do 3 sets of a barbell row. Classically, people would consider this to be an exercise that targets the back muscles (the latissimus dorsi, or lats for short). Therefore, when tracking training volume, we would just say:
3 sets of barbell rows = 3 sets of volume for the latissimus dorsi.
However, with something like a barbell row, there are many, many muscles involved in the exercise. Do we also count those barbell rows as trapezius and rhomboid volume? Posterior deltoids? Teres major? Teres minor? How about infraspinatus? Spinal erectors? The glutes, hamstrings and adductors? Biceps?
You may think this is just a minor thing and doesn’t deserve much attention, however, it is something we must account for when planning our training and assessing the results we get. It is especially important when we consider that different people react differently to different exercises, with a big reason for this being differences in their overall anatomy and biomechanics. So, while we will continue to use rows as our illustrative example, do realise that this does apply to all exercises. However, it is important to note that most people tend to focus on this primarily around upper body training, however, the issue is still important when discussing lower body training (especially when you consider the low back can be an area that gets excess training volume from both upper and lower body training, and can limit progress as a result). Many individuals wonder if they should count rows and pulldowns toward their bicep volume, or pressing variations toward their tricep volume. So, with that said, let’s take on the following question:
For one to provide an answer to this question, one would have to assume the following:
- We can equate the stimulus applied to one muscle with that applied to another (e.g. the bicep stimulus during a set of rows has a 1:1 ratio with 1) the bicep stimulus applied during an “isolated” elbow flexion exercise, or 2) the stimulus to the latissimus dorsi or any other muscle we might be counting), OR, if we can’t equate them, we can predict the difference (e.g. 1 set of rows = 0.5 units of volume for biceps, giving us a 2:1 ratio of sets to units of volume for that muscle).
- This stimulus can be assumed to be the same between individuals. While this is less important for individual decision-making, it’s certainly very important if we are going to try and create generalisable rules for quantifying resistance training volume, especially in the context of exercise science research.
- Counting this will allow us to make more effective training decisions that will enhance training outcomes. If it does not enhance our ability to actually make decisions, then making such calculations and delivering that information to a client (or just taking the time to track it yourself) may not be the most efficient use of resources.
With that said, our concern is now with figuring out whether or not we can really make those assumptions. Personally, I don’t think we can, but rather than just giving you my opinion, I will lay out the most pertinent points to consider, which will then allow you to form your own opinion on this matter.
The Stimulus
Trying to pinpoint the stimulus applied to any given muscle during an exercise is a very complex task. This is especially the case when we try and transfer that measurement between different subtypes of a given exercise category.
For example, is a bent-over barbell row just the same as a chest-supported machine row?
There are gross similarities, in that we may be able to pinpoint the prime movers in a given exercise, but getting more specific than that is very difficult and certainly not generalisable. There are many moving parts that could potentially affect the training stimulus:
Grip Width: Generally, when one adopts a wider grip, shoulder position tends to be modified in accordance with the next point.
Shoulder Ab/Adduction: The amount of shoulder abduction one maintains during a rowing exercise is going to modify the relative contribution of the involved muscles. For example, where the shoulder is adducted (humerus close to the side of the body), the latissimus dorsi is going to be in a better position to produce force than it otherwise would [during a row]. This is influenced by both grip width and radio-ulnar joint position.
Radio-Ulnar Position: Not only will radio-ulnar joint position modify which of the elbow flexors are likely to contribute to the elbow flexion moment (e.g. biceps brachii, brachialis, brachioradialis), but it will also influence the position of the shoulder joint and hence the contributions of the shoulder musculature. For example, where one is in a “neutral” position at the RUJ (90 degrees anti-clockwise from supination and clockwise from pronation), the shoulder is typically going to be in an adducted position, whereas a pronated (palms down) grip is typically going to lead to more shoulder abduction as the RUJ moves away from pronation. This may vary depending on the individual’s available range and their intent during the exercise.
Support/Bracing: In the case of a chest-supported row variation, the individual has anterior restraint in the form of the chest support, allowing for efficient transfer of force. As they pull/row, the body is going to want to move forward, which is then restrained by the chest pad. Where this is not the case (e.g. bent over barbell row), individuals typically exhibit more extraneous bodily movement and increased movement velocity.
Row Handle Endpoint: Where one pulls the handle/dumbbell/bar to is also going to modify the distribution of forces. For example, if one rows high toward the sternum, we would typically expect the elbow joint to be moving through a much larger range of motion than if they were to row low toward the hip. Along with changes in the range through which different joints are moving, this also modifies the moments at each respective joint. For example, where one pulls low, there will be a larger shoulder extension moment than if one was to pull toward the sternum, and vice versa for the elbow joint.
Fatigue: This is another variable often forgotten, despite the fact that it is so frequently cited as a complaint by trainees. For example, many individuals cite their lower back as being a limiting factor to performance during unsupported row variations (e.g. bent over barbell row). Therefore, this limiting factor is detracting from your ability to train the shoulder extensors (if that is the goal).
Resistance Profile: The point at which the resistance is greatest can vary greatly between different exercises that look the same. Some rowing machines will be designed in such a way that the load is greatest when the shoulders are flexed between 70-90 degrees and the elbows are in extension, with the load reducing as one rows toward the body. However, for the vast majority of free-weight rowing exercises, the opposite is true. As is the case with all of the above variables, this modifies the stimulus.
There are more points that could be discussed, but this hopefully gives you some insight into some of the “moving parts”.
As a simple qualitative example that likely makes sense to most of you, if we have two trainees who perform a set of bench press to failure, one of whom reaches failure and reports “my shoulders are burning, but I didn’t feel anything in my chest”, while the other reports “my chest is on fire”, can we consider that stimulus to be equal? I’m not so sure…
Devil’s Advocate
At this point, you may be thinking…
If you are thinking along these lines, then you have identified that we are probably not at a point where we can generalise the applied stimuli between individuals, but you may be thinking that there is still some value in quantifying the stimulus for a given individual. And I do believe there is some merit to that thought, but it’s still not so simple…
You see, as alluded to above regarding Rowing Exercise Variables, this is not just about the differences between individuals. It’s also about the differences between the stimulus for a given individual across different exercises, during different sets, at different times in the workout, and so on. If I, a single individual, “feel” my biceps working a lot during a particular rowing exercise, maybe I should count that as being closer to 1 unit of volume? But, maybe that’s only for certain rowing variations? If I then perform a rowing variation with different variables (e.g. RUJ position, shoulder abduction, restraint, resistance profile, etc.) and feel it all in my shoulder extensors, should I then count that as a unit of volume closer to 0 for the biceps? Maybe 0.5, or is that too much?
Reflect on the example touched on previously…
Practical Implications For Tracking Indirect Training Volume
What I am getting at here is that we do not currently have a reliable way of trying to quantify a training stimulus based on simply counting. In a recent paper, Brad Schoenfeld, Jozo Grgic, Cody Haun, Takahiro Itagaki and Eric Helms provided some insightful discussion on this topic, with three primary areas of focus; (1) biomechanical and physiological factors; (2) acute research; and (3) longitudinal research (Schoenfeld et al. 2019). For further insights into the research on this topic, I recommend checking out the full paper, which is open-access. In their conclusion, they recommend the following:
In terms of application, we don’t want to just throw the baby out with the bathwater. Just because we don’t have a perfect means of quantifying the training stimulus does not mean you shouldn’t bother at all, but I’d ask you to consider how you might actually use that information and to maintain some humility in the accuracy of your assessment. My general rule of thumb is that if measuring something will not actually modify your course of action, you needn’t bother with it.
In this case, the integration of qualitative (e.g. how did that feel? any soreness in the days to follow?) and somewhat quantitative (e.g. number of “hard” sets, perceived proximity to failure/reps in reserve) information can be informative, provided one has the necessary background knowledge to integrate this information. An example of where background knowledge might come into play would be in the case of squats and leg press for hamstring development. One may have a very loose understanding of anatomy and biomechanics, recalling that the hamstrings extend the hip, and so the squat and leg press exercises should be just fine for hamstring development, right? However, in reality, the bi-articular nature of the hamstring muscles implies that the hamstrings are not lengthening as they would during hip flexion when the knee is maintained in extension, since the knee is also flexing simultaneously. As a result, the hamstrings are certainly playing a role, but they are not going to be very effectively trained during these exercises. Therefore, if one was to assume a 1:1 ratio of stimulus between the quads and hamstrings based solely on muscle actions listed in the textbook, this may lead to poor application of this information.
If we get back to the example of the biceps, personally, if a client of mine is doing lots of rows and pulldowns, I acknowledge that they are getting some bicep training in there, but if someone is trying to really develop their biceps, I’m far more concerned about the number of additional elbow flexion exercises they are doing, since it’s likely that their row/pulldown volume is somewhat of a constant variable. If it’s not constant and they’ve just started doing far more chin-ups, or they are doing no rowing/pulling exercises due to a shoulder injury, for example, then that might influence my decision-making and lead me to add in more or less elbow flexion exercises to account for the change in baseline stimulus applied through those multi-joint movements*. If you can maintain flexibility in your thought process and recognise that you can’t expect to quantify everything, decision-making will be less stressful and potentially more effective.
This may not seem important to you right now, but it is worth considering when you think about what exercises are challenging certain joints.
Indirect Training Volume Conclusion
I’m summary, be sceptical of anyone who has a hard stance on these topics. The more specific one gets in their analysis, the more one needs to zoom out and be self-critical. Oftentimes, we think we can quantify everything and make training planning out to be a far more scientific endeavour than it really is. You have to maintain humility and recognise that there are many unknowns, or at least variables that are not practically quantifiable. If you acknowledge these limitations, you can still make effective decisions, so as alluded to above, you needn’t just give up and count nothing either.
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