Range of motion (ROM) is a very hot topic amongst sport scientists right now. Apart from the rare loon, it’s well accepted that full ROM is better than partials at short muscle lengths (think ATG squat vs quarter squat) for muscle growth. Recently, however, partials at long muscle lengths have gained a lot of attention. It’s conceivable that long-muscle-length partials (LPs) might be better than short-muscle-length partials (SPs), but the emerging research is suggesting that LPs are, at the least, as good as, and may even be slightly better than, full ROM for muscle growth.
How did we arrive here?
A few very cool studies have pointed towards the idea that, despite going through an equal ROM, a bigger stretch on a muscle while lifting leads to more growth. One study even looked at stretching without lifting, and that, in and of itself, also caused growth. So there really seems to be something to this “stretch-mediated hypertrophy”.
How does stretch-mediated hypertrophy work?
That’s still being figured out. There are probably a few different mechanisms at play, but we don’t really have the evidence to say. A couple of the suggested mechanisms are increased intramuscular hypoxia and increased passive tension. Whatever it is at play may also look slightly different in different muscles with different exercises. But let’s ground ourselves for a moment. It doesn’t really matter. All that matters is that it gets me more jacked.
So, how do you go from stretch-mediated hypertrophy to only using LPs?
It seems reasonable that spending more time in a stretched position would be a more efficient use of adaptational and recovery capacity than wasting it on the less effective shortened position. Indeed, a recent meta-analysis on ROM gives us that first nail. It looked at the effects of full and partial ROM and found full ROM to be better for growth than partial ROM. However, when you separate out SPs and LPs, LPs seem to do better than full ROM. It should be noted that the effects are “trivial to small”, which means you’re not going to gain an inch on your arms overnight. But if you want to maximise your training effectiveness, this looks like a promising road.
What’s the takeaway? How can you apply this to your training? Does this justify not hitting squat depth?
No. Absolutely not. In fact, it does the opposite. This justifies only hitting squat depth. In all seriousness, squats might not be the best exercise to do LPs with. But something like a dumbbell bench press that easily allows you to drop the weights from the bottom position if things do go wrong is ideal. So, with exercises that it is safe to do so, maximise the stretch at the bottom and lift through one to two-thirds of the ROM. Don’t expect to be able to lift the same weights as you would doing full ROM – treat it as a separate exercise. Of course, more data is needed (and more is on the way, as it happens) before any strong conclusions can be made. If you remain unconvinced that LPs are worth it, at the very least, you can make the effort to use slow eccentrics with a pause in the deep, painful stretch at the bottom position.
How about strength?
Strength is a slightly different story. Strength is highly specific, and specificity, as we’ve talked about before, is a fundamental pillar of training. When training for strength, you need to be training in the range of motion that you want to be strong in. LPs, however, might be useful for accessory work and hypertrophy blocks.
Goto et al., 2019. Partial range of motion exercise is effective for facilitating muscle hypertrophy and function through sustained intramuscular hypoxia in young trained men. Journal of Strength and Conditioning Research, 33(5), p1286-1294.
Kassiano et al., 2023. Greater gastrocnemius muscle hypertrophy after partial range of motion training performed at long muscle lengths. Journal of Strength and Conditioning Research.
Maeo et al., 2021. Greater hamstrings muscle hypertrophy but similar damage protection after training at long versus short muscle lengths. Medicine and Science in Sports and Exercise, 53(4), p825-837.
McMahon et al., Muscular adaptations and insulin-like growth factor-1 responses to resistance training are stretch-mediated. Muscle & Nerve, 49(1), p108-119.
Pedrosa et al., 2022. Partial range of motion training elicits favorable improvements in muscular adaptations when carried out at long muscle lengths. European Journal of Sport Science, 22(8), p1250-1260.
Rhea et al., 2016. Joint-angle specific strength adaptations influence improvements in power in highly trained athletes. Human Movement, 17(1), p43-49.
Schoenfeld et al., 2020. Effects of range of motion on muscle development during resistance training interventions: a systematic review. SAGE Open Medicine, 8.
Warnere et al., 2023. Comparison of the effects of long-lasting static stretching and hypertrophy training on maximal strength, muscle thickness and flexibility in the plantar flexors. European Journal of Applied Physiology.
Wolf et al., 2023. Partial vs. full range of motion resistance training: a systematic review and meta-analysis. International Journal of Strength and Conditioning, 3(1).