A study just came out by Goto and colleagues on partial range of motion exercises for muscle hypertrophy. Full study here: https://journals.lww.com/nsca-jscr/Abstract/2019/05000/Partial_Range_of_Motion_Exercise_Is_Effective_for.16.aspx
For a long time, bodybuilders have looked to find ways to obtain more hypertrophy beyond your traditional rep and set schemes. They have used drop sets, supersets, forced reps, etc.. all with the idea of doing more to elicit more growth. As a strength athlete, we look to do the same thing with our accessories so we can add more muscle which in turn will become a stronger muscle or at least make us look better in a singlet.
In this study, they took a look at a partial range of motion compared to a full range of motion movements in the lying elbow extension exercise. This is important to note that this is only tested in an upper-body movement and may not be applicable to the lower body. The did this test on 44 resisted trained men (members of a resistance-weight training club). Inclusion criteria consisted of at least 1 year of resistance training experience and performing at least 3 training sessions a week with at least one session performing a triceps brachii movement. So a pretty standard criterion for trained subjects but probably not what we would consider trained.
They performed a lying elbow triceps extension with a barbell for 3 sets of 8 reps 3 times a week for 8 weeks. Full range group went to 90 degrees flexion of the shoulder and took the exercise through a full range of motion while the partial range kept with 90 degrees shoulder flexion but only went from 45 degrees to 90 degrees elbow flexion. They increased the intensity by adding 2.5kg on the first day of every week.
The results of this study showed that the partial range group improved their Oxy-Hb curve, blood lactate concentration, and greater motor unit activation acutely and long term the partial range group improved muscle size and isometric strength. These improvements were greater than the full range group.
This is a cool study in terms of ways to improve muscle hypertrophy without increasing the risk of injury. It shows that keeping constant tension on a muscle is a great way to elicit growth and that maybe full range is not always as important. For me, the take away is the option of a partial range is there so if I had to choose between forced or cheat reps it will be a far better idea just to do a partial range of motion reps. One it is safer and two by not compromising technique you can make sure the load and stimulus are still paced on the intended muscle. The second thing that a lot of people don't think about is instead of stopping and breathing a few seconds and doing a rep and repeating that it may be better just to start doing partials so that you can keep tension on the muscle and increase the hypoxia which can enhance a glycolytic pathway.
