In the world of bodybuilding full ROM is often mentioned as a method superior to others when the purpose of training is muscle growth. The intention with this article is not to confirm nor deny the theory of its effectiveness. However, me personally would rather just say that one definition of truth not necessarily needs to outrule the other.
Full ROM stands for “full range of motion” and means that you are allowing the muscle to work in its outer position as you properly complete the movement, instead of interrupting it somewhere in between point A and point B.
This has been shown to catalyze muscle hypertrophy at the same time as strength development.
Many studies have been conducted in which the subjects saw obvious increases in both muscle mass and actual strength, although they used significantly lower weights than those who were parallelly challenged in other groups where the weights were 30-40% heavier.
A few hits on Google pretty fast summarize that documented results often find that heavier weights and low number of reps generally are not as effective as the opposite when the goal is strength and muscle gain.
With this in mind, is it necessary to use full ROM in each exercise?
As always things are not completely black or white. In order to know (or at least theorize around) what training method is the most optimal for the given individual it is important to weigh in factors such as training experience, physical status in general and specific goals in particular. Not every person is built for this type of training since uncompromising full ROM training may expose the individual to increased risk for injuries. Some of us are probably better off with partial reps instead, even though this approach as well as the other has its own downside.
The upside, on the other hand, when it comes to partial reps is that you can handle considerably higher weights than in the case with full motion lifts. The muscle is at its strongest position in mid-range and although the movement through these partial reps has been shortened you are still lifting weights heavy enough to achieve desired muscle activation.
I would like to claim that the best effect is obtained through exercises where the tension is constant, whether you force the muscle to its outer position or choose to limit its range. To just work around the muscle’s strongest position (partial reps) will inevitably lead to the use of weights that are far too heavy and this type of overload will probably in the next stage cause injuries of different severity.
Variation is always an important ingredient.