Well, that’s actually. very complex question.
And sadly it really depends on what you are trying to accomplish.
First, we do need to differentiate hypertrophy and strength training.
While there is some cross-over effects, i.e. if you get bigger you will also likely gain some strength and if you get significantly stronger you will also likely have built some muscle in the process; the reality is that both a different. And if you want maximum results in one, you can’t train the same way as if you want to maximize the other, and trying to get the best of both worlds at the same time might prove inefficient.
This can be confusing to many because:
Both, training for strength and hypertrophy use the same tool (resistance training) in a seemingly similar way.
A bigger muscle is biomechanically a stronger muscle.
However, to someone who truly understands how to program for specific adaptions, there will be some slight, but very significant, differences in how you apply resistance training (loading schemes, exercise selection, methods, repetition style, etc).
Knowledgeable people also understand that while muscle’s strength potential is correlated to its size BUT other factors are involved in actualizing that strength potential. The most important being the various neurological efficacy elements (muscle fiber recruitment, muscle fibers firing rate, intramuscular coordination, intermuscular coordination, antagonist contraction/relaxation at the proper times, etc). But other like the Golgi tendon sensitivity, tendon resiliency, joint stability, lifting technique, etc. play a role.
If we look at it from a VERY general perspective we can establish several large training zones based on which element is emphasized the most.
1-3 reps (92-100%): Develop mostly the neuromuscular factors with a much less impact on tissue growth. We could say that this zone develops your capacity to demonstrate strenght the most.
4-6 reps (82.5-90%): Is the zone where you can gain the most strength. That’s because it’s heavy enough to get near-maximal neuromuscular adaptations but will also get you some muscular/tissue adaptations and also get you psychologically used to handeling fairly heavy weights.
7-10 reps (70-80%): Is the zone that stimulates the most tissue growth per set (provided that you use the right effort level). It causes a fairly low central fatigue effect, has a much smaller impact on neuromuscular factors and begins to have some effect on metabolic conditioning (glycolitic system efficiency)
11-20 reps (50-70%): Still provides good tissue growth stimulation per set at the proper effort level (1 rep in reserve or even to failure) but comes with a higher central fatigue cost (which reduces the number of effective sets you can do), has an even smaller effect on neuromuscular factors and starts to have a significant impact on improving the efficacy of the glycolitic patha=way,
20-30 reps (30-50%): Can still promote good tissue growth per set at the right effort level. But because you have to do so much work in a set to get to those effective reps (last 5 reps before failure) each set causes a lot of central fatigue. This means that, unless you take VERY long rest periods, you can’t do a lot of total sets in your workout as the cumulative central fatigue will make the later sets inefficient by reducing the nervous system’s capacity to recruit the growth-prone fast-twitch fibers. On the plus side, the effect on the glycolitic pathway and upregulating your muscle’s capacity to store glucose is significantly increased.
More than 30 reps (less than 30%): This is a very poor zone to train for hypertrophy because even if you do reach muscle failure, it will happen without having recruited and trained the growth-prone fast-twitch fibers (failure in this case happening for different reasons than full fiber fatigue, likely central fatigue reducing the strength of the excitatory drive to the muscles). However it can be useful to develop tendons and improve muscle capilarization, the later possibly improving work capacity and recovery capacity over time.
If you stay within a zone you can change the loading schemes and still get the desired adaptations but if you wave through different zones you might not be training what you actually desire to improve.
You must understand exactly what you are trying to accomplish and stay in the zones that will have the greatest impact for what you want to develop.
For example, if you goal is hypertrophy, a case could be made for using the following zones:
- 7-10 reps/set
- 11-15 reps/set
These would be your main “development zones”. That doesn’t mean that you cannot use other zones, but you should use them for very specific purposes.
- 4-6 zone for hypertrophy: useful to improve neuromuscular factors, making the future work in the pure hypertrophy zones more effective.
*20-30 reps for hypertrophy: can be used to improve glycogen storage/surcompensation or to create a large muscular pump which can be followed by loaded stretch work. Stretching a pumped up muscle being an effective secondary growth stimulus
However in both cases these zones wou represent a small portion of the mesocycle. For example you could do a 4 weeks period in the 4-6 reps zone at the beginning of a 16 weeks mesocycle to prime the body for the hypertrophy work.
Or could can end your workouts with one exercise per muscle for 2-3 sets in the 20-30 reps range, followed by 90-120 seconds of loaded stretching for that muscle. The bulk of the workout still being in the two “ideal” hypertrophy zones.
If your goal is maximum strength, then your two key zones become:
*4-6 reps/set to develop the greatest amount of strength
- 1-3 reps/set to develop your capacity to actualize your muscle strength potential during a maximal effort.
Again other zones can be useful.
If you train for strength, the 7-10 reps/set zone can be useful to increase muscle mass, if that is your limiting factor in increasing you strength. This can either be done as a 4-6 weeks phase at the beginning of a 16 weeks mesocycle in which the last 10-12 weeks would be mostly done in the two strength zones, OR you could do about half of your assistance volume in that zone (the other half of your assistance being in the 4-6 range, never in the 1-3 range since assistance work’s purpose is to build strength).
I would NOT personally recommend the 11-20 and 20-30 zones for strength development (although I am aware that some guys, notably some of the Westside guys, use that zone on minor movements). I feel that it provided no added muscle growth benefits over the 7-10 range and will cause a lot more central fatigue, which could hurt recovery and performance.
HOWEVER, the super high reps zone, at a very low number of sets, can be interesting early in the training cycle to develop tendons and reduce the risk of injuries during the heavy work. Although I much prefer slow eccentrics and stato-dynamic sets to accomplish that.
NOW, one thing I want to mention is that you do need to spend some time in a zone to get a significant level of the adaptations provided by that zone. Don’t get me wrong: each workout does stimulate adaptations/gains (provided the proper effort level and recovery/nutrition) but it takes several such bouts to amount of significant changes. If you change training zone every week, you are shooting yourself in the foot as you don’t give your body enough time to build-up certain adaptations.
FULL DISCLOSURE: I did the mistake of recommending alternating intensity zone weekly at one point in my career, but that was because my knowledge was not up to the level that it is now and it FELT like a smart concept.
“Yeah but Thib, don’t you recommend changing repetition style weekly in some of your plans?”
Not as often as I once did. BUT keep in mind that even though the repetition style of execution changes from week to week (e.g. slow eccentrics / stato-dynamic / regular reps…) the intensity zone stays the same, which is the key thing here as that’s what influences the type of adaptations you get.
Changing the repetition style while staying in the same intensity zone can work because you are still targeting the same category of gains, the change in repetition style simply changing the neurological command which can adapt within 1-2 weeks.
I guess my point is that changing loading scheme every week CAN be done IF the loading schemes stay in the same intensity zone. But still, if you only change the loading schemes (not the repetition style of execution) the main effect is mostly psychological, not physiological. But it still matters because if you are more motivated, you will train harder.
But I would not change the intensity zone more frequently then every 3-4 weeks.