This is yet another republication of an old series of articles I did. It originally appeared in the now defunct newsletter and was later re-run on the site. If I’m very motivated, I might add a section on power training methods (I had some requests for such when it originally ran) but I’m not sure how relevant that is to most readers of the site. I’m running it here again as a lead up to a (somewhat late) look at a recent study comparing rep ranges and hypertrophy that has a lot of people talking.
What I want to look at over these articles is various “categories” or “types” of weight training, focusing on those of the most relevance to folks wanting to change body composition. That is, I’m not going to talk about things like power training or things aimed more at performance.
The three primary types of weight training I want to talk about are
- Metabolic/depletion training
- Hypertrophy training
- Maximum strength training
I’d note that while I’m going to discuss each type of weight training as a distinct entity, it’s better to think of them as overlapping zones (some call this the rep continuum). For example, the low end of what is typically considered the hypertrophy range (perhaps 5 reps) is often considered the top of the maximum strength range.
As usual, rather than arguing for the inherent superiority of one or the other, I would rather look at the pros and cons of each as they might pertain to such things as fat loss, muscle growth, performance, etc. That is to say, depending on the goal of the trainee, their training age, etc. each type of training can have relative more or less relevance or importance or benefit (or drawback). You get the idea.
Defining the Training Categories
Each of the different types of training is usually defined by what are often called acute training variables (acute here refers to the individual set or workout). There are a number of different variables that coaches and trainers usually use to define training, including repetitions per set, the number of sets, the rest interval between sets and the load (intensity), to name just a few. Many coaches add tempo (lifting speed) and/or time under tension (total set time) and many others can be added until people’s brains explode with confusion and over-complication.
I’d note that a lot of arguments erupt over the definition of training intensity; some use percentage of 1 repetition max to define intensity, others use repetition maximum load and others still use subjective intensity (failure or not, some version of rating of perceived exertion). I discuss this topic in some detail in What is Training Intensity?
I should mention that exercise selection is relevant here here as well due to the fact that certain exercises tend to lend themselves to certain types of loading of one kind or another. For example, 3 sets of high rep deadlifts with a short rest is a good way to cripple yourself, heavy sets of three in the lateral raise tend not to work so well. There are always exceptions to this, mind you, but there are some generalities in terms of what types of exercises tend to go best with certain types of training.
Of course, each type of training generally has an explicit goal in terms of what the trainee is trying to accomplish. As above, note that each category of training has some overlap with the others in terms of the goal or adaptation seen with that kind of training. It might be more helpful to think of the training types as falling on a continuum. This will make more sense as I detail the different loading parameters for each type of training over the next few articles.
And with that out of the way, I want to look at the first type of training, which is metabolic or depletion training.
Metabolic or depletion training generally describes any type of training built around relatively higher reps (typically 15-20 or sometimes higher, with sets typically lasting perhaps 45-60 seconds) and short rest periods (typically 30-60 seconds).
As you’d expect, the loads used are generally relatively low in terms of percentage of 1 repetition maximum (60% or often less). As far as total sets, typically 3-4 sets of any given exercise are done, depending on the goal (e.g. in The Ultimate Diet 2.0, a total of 10-12 sets per body part is needed to deplete muscle glycogen).
So for any given exercise, 4 sets of 15-20 reps with 60″ (1 minute) rest might be done. Alternately, two different exercises might be alternated with a very short rest period with a slightly longer rest interval between each exercise pairing.
So you might move from exercise 1 to exercise 2 with only 15-30 seconds rest and then rest 90 seconds after exercise two before returning to the next pairing. This tends to make the workout harder in general while still allowing sufficient recovery between similar exercises. This might be done for 3-4 exercise pairings or whatever. So a total of 6-8 exercises per workout for 4 sets apiece might be a typical workout.
As far as exercise selection, in my experience, less technical exercises are better (or at least safer) for this type of training. Trying to do 3 sets of 15-20 reps of squats or deadlifts on a short rest interval is simply a recipe for disaster: invariably, form breaks down and even with light loads, the risk of injury becomes too high. Can it be done? Yes. Do I think most should do it? No.
In The Ultimate Diet 2.0 I recommended primarily machines for this reason for the depletion workouts. Not only do I feel that they’re safer, they allow for faster movement through the workout since you don’t have to worry about loading bars or finding dumbbells; just set the pin and go.
Many who are advocating this type of training (usually for fat loss) tend to use a lot of body weight exercises. At least unloaded, this makes more sense from an injury standpoint although I question whether the average unfit or extremely overweight individual would be able to do those types of movements in the first place (a topic I discussed in detail in the Training the Obese Beginner series). Which is odd given that many are heavily promoting this type of training for fat loss. I guess I simply question the likelihood of an individual carrying 50-100 pounds of excess body fat doing a T-push up or burpee or what have you properly or effectively.
Things such as kettlebell exercises (and the simpler movements) can readily be done in this format are often included in this and some groups even use high rep Olympic lifts for metabolic conditioning. I question the latter highly. Without years under the bar, technical breakdown is almost guaranteed with high repetition Olympic lifting; even with light loads, I think the risk of injury is simply too high.
Of course, none of the above are mutually exclusive. A combination of kettlebell, body weight and weight (free weight or machine) exercises can all be put together in a circuit fashion as long as the loading parameters described above are adhered too.
Metabolic/Depletion Work and Fat Loss
In recent years, the metabolic/depletion type of training has been heavily promoted for fat loss based on the idea that it burns more calories than traditional heavy training (probably true) and that it generates a large post-workout calorie burn. I’ve discussed the issue of EPOC in the research review Effects of Exercise Intensity and Duration on Excess Post-Exercise Oxygen Consumption as well as other articles on the site.
This type of training does tend to deplete muscle glycogen (my primary reason for using it in The Ultimate Diet 2.0) and generates a hormonal response similar to that of interval training in terms of catecholamine release. In The Stubborn Fat Solution, I suggested a variant using metabolic type work in lieu of traditional intervals as well.
While this type of training can certainly have its pros for fat loss (esp. via glycogen depletion/hormone levels), I don’t consider it sufficient as the only type of training to be done on a diet (except for rank beginners) as it’s not terribly effective for maintaining muscle mass or strength levels.
And while a common idea in bodybuilding training has been to use this type of training (or something akin to it) during contest preparation, this idea came from a time when anabolic steroids were used heavily, which limited muscle mass loss. For natural lifters to use this type of training exclusively for fat loss is a mistake. I discuss this in detail in Weight Training for Fat Loss Part 1 and Weight Training for Fat Loss Part 2.
Other Uses of Metabolic/Depletion Work
Another use for this type of training is for general physical endurance or local muscular endurance. I know I said I wouldn’t really talk about performance in this series but, well, there ya’ go. Muscular acid levels and fatigue tend to be very high during this type of training and some athletes will train in this fashion at some point in the year to improve local muscular endurance or fatigue resistance. Again, while this can certainly work, you can only build muscular endurance on a base of strength, so I don’t think this type of training can be used exclusively.
I’d note that this type of training can be used to improve work capacity (essentially, how well you can tolerate increasing volumes or frequency of training) and focusing on increasing work capacity (which can also improve the ability to recover both during and between workouts) is not a bad thing for most people during at least some part of the training year. Even a couple of weeks of higher repetition lifting can improve overall tolerance to heavier work down the road. It can also be good for the joints (important for older trainees).
I’d also note that I don’t think this kind of training is appropriate for rank beginners. Few would have the tolerance to fatigue that this type of training requires initially and none would have the technical ability to maintain proper form in the face of fatigue; tolerance can certainly be built up over the first few weeks of training.
So I really question the folks advocating that to relative beginner trainees as an effective way of losing fat. Perhaps it can be made workable under the eye of a trainer who will correct improper form or stop the individual when form starts to break down, along with building up the volume gradually. Even then, I think there are better ways to get beginners into training without murdering them with this type of training. Again, see the Training the Obese Beginner series for more on this.
In terms of gaining muscle mass, this type of training might have some small benefit and, as noted above, a lot of bodybuilders train (or used to train) in a fashion similar to this; this type of training is also sometimes referred to as pump training. This type of training can cause increased visible muscular size by increasing the amount of glycogen, water, minerals, etc. in the muscle. At least one recent study found that low-load high repetition training could stimulate protein synthesis as well.
For the majority of trainees, I’d consider this type of training fairly inferior for growth. However, in conjunction with other types of (usually heavier) training, a small volume of metabolic work can sometimes be useful. Glycogen depletion and such improves nutrient uptake and insulin sensitivity in skeletal muscle and doing a handful of sets as a ‘finishing’ movement might have some benefits in this regard. This type of training also seems to benefit connective tissue and joint health; whether this is a direct effect via blood flow or lactate is debatable, it may simply be an issue of giving the joints a break from endless heavy training.
Specifically for advanced bodybuilding (specialization cycles, something I’ll write about eventually), I’ve used a couple of very high rep sets in specialization cycles for that (and other reasons). So a trainee (and this would usually be a more advanced bodybuilder) might do something for say, legs, along the lines of
- Squat: 5 sets of 5 with 3 minutes+ rest
- Leg press: 2-3 sets of 12 with 1.5-2 minutes rest
- Leg extension: 2 sets of 15-20 with 30-45 seconds rest
Again, this is usually only for advanced bodybuilders in a specialization cycle; others seeking hypertrophy are usually better suited by sticking with more traditional hypertrophy methods. And that’s where I’ll stop for today.