For decades now, we've heard basic rep prescriptions that go something like this:
- Strength: 1-5 reps, 85-100% 1RM
- Power: 3 reps, 70-80% 1RM
- Hypertrophy: 8-12 reps, 60-75% 1RM
- Muscle endurance: 50-60% 1RM
This isn't an exact chart (the recommended protocols vary a fair bit), but that's the idea: heavy maximal effort for strength, heavy submaximal effort for power, moderate loads for hypertrophy, and light loads for muscle endurance and conditioning.
The problem is that anecdotally, examples abound of people breaking these rules. Robert Forstemann (mentioned in the previous post), a German Olympic sprint cyclist, can squat over 600 pounds in a high bar position, going below parallel. But his training consists of lots of reps, continuous tension, and high-intensity interval work. Mike O'Hearn, self-proclaimed natural bodybuilder, has an exceptionally muscular physique but trains with low reps more common to powerlifting. Classic bodybuilders like Serge Nubret and Paul Dillett built massive physiques using very high repetitions. And no one is going to accuse strongmen like Brian Shaw and Hafthor Bjornsson of lacking muscle despite their low-repetition training.
What's going on here? I'm going to suggest something that's against the popular mold: the number of reps is far less important than how they're performed.
Let's take Olympic lifters. These men and women are remarkably strong. Even amateur lifters are able to launch hundreds of pounds overhead in incredible fast, dynamic movements. But looking at most Olympic lifters, their physiques aren't renown for being particularly impressive — at least, not to the degree of muscularity one would expect from a bodybuilder. My hypothesis — and I have to emphasize that this is somewhat speculative — is that this is not necessarily due to training in low rep ranges (as is usually what's attributed to their lack of muscularity), but because Olympic lifts are almost entirely concentric efforts:
Of course these trainees are muscular and highly, highly athletic; but compared to someone who does more time under tension and controlled concentric work, they don't exude much of a bodybuilding aesthetic. Contrast the above physiques with that of the aforementioned Robert Forstemann:
Notice the difference not just in repetition volume, but the manner in which Forstemann performs the reps: controlled eccentric descents and minimal intra-set rest. Reps are done continually, with tension remaining on the working muscle until the set is finished.
Powerlifters are likewise generally regarding as muscular, but not to the degree of bodybuilders despite the fact that powerlifters move extraordinary amounts of weight. But in the powerlifters' case, it's a matter of technique: The powerlifter is aiming for maximum leverage, and isn't concerned with targeting this or that muscle group.
This is my somewhat speculative hypothesis: rep ranges are of secondary importance to time under tension (TUT). TUT is generally correlated with repetitions, but the cadence of repetitions is a better indication of TUT than the number alone. TUT also entails eliminating leverage as much as possible (bands and chains help greatly) so that tension remains as constant as possible through each repetition, and it entails the elimination of intra-set rest such as pauses in the lock-out position.
Since tension and time are inversely proportional (more tension = less time, and vice-versa), I'm not skeptical of research which suggests that x number of seconds is an 'optimal' TUT. I think what's important is that the tension remains as constant and consistent as possible, and whether you're doing 3 reps or 30 that small change can make a dramatic difference in the productivity of training.