Should I perform exercises in full range of motion if my goal is to build muscle

Question

I'm quite experienced in fitness and bodybuilding by that I mean I have been lifting weights for about 5 years, I'm not professional nor fitness "guru" or expert in anyway but I'm still always asking myself if I should go full range of motion when doing exercises for every muscle group.

There are so many different opinions some say full range of motion is better than partial range and vice versa.

When I perform exercise with partial range it helps me to get constant tension on muscle I'm working on, and I can train with heaver weights and I definitely get better pumps than going "Full". I'm not sure, for example, why many personal trainers recommend doing, let's say, dumbbell press exercise really carefully I mean they would say: don't go lower than your eye or ear level. I always feel that I can go lower and not hurt myself and the same thing is with other exercises. Wouldn't going lower engage more muscles to work harder and wouldn't it help to build muscle faster in the long run? It seems that if your primary goal is health when doing partials is more suitable and of course I believe that doing "full range" puts you at higher risk of injury.

Personally, I like both ways and it looks like they both do work but would you suggest me doing full range of motion all the time or switch sometimes between "full" and "partials" when my main goal is to build muscle.

Any explanations why one is better than other would really help and why do you think one particular way is better than other, I mean give me a a proof to back up your opinion.

Answer 1

I answered a similar question pertaining specifically to the biceps muscle. I'll reiterate that answer.

In a nutshell, yes, whenever you can you should try to exercise at full range of motion. While it's not a strict requirement to go full range each and every time you train, in the long run, you're more likely to reach your training goals as evidenced by the study I referenced in my original answer. The study found that...

What they found was that during resistance training (RT), the group that exercised with full range of motion (LR) actually outperformed the other test group that used shorter range of motion (SR). There was even some discussion that ROM could also provide a reduction in fat stores.

The study findings indicated...

The practical implications for this body of work follow that LR should be observed in RT where increased muscle strength and size are the objective...

LR = Longer range movement. SR= Shorter range movement. RT = Resistance training.

Answer 2

Should I perform exercises in full range of motion if ...

Yes ... most of the time

While it is true that using a partial range of motion is useful; in that it allows you to use more weight, work around sticking points, strengthen parts of a movement pattern, etc. (ie it's a useful tool in the lifter's toolbox); it should not replace using a full range of motion as the primary method for lifting.

Muscle Imbalances can be one of the biggest consequences of partial ranges of motion. For instance, lets take a look at the squat. When performed to at least parallel, the entire leg is hit. However when a partial squat is performed, generally only the quads will be hit, leaving out the hamstrings and glutes. Over time, this sets the lifter up for injury.

A full range of motion not only loads the primary muscle groups, but it also places a load on the antagonistic muscles in order to stabilize the load. A partial range of motion may engage these muscles as well, but to a much smaller degree.

However, a full range of motion isn't always better. Sometimes a full range of motion causes too much of a stretch in a muscle group (could be a side effect of warming up incorrectly / not at all) which can lead to injury. In the example you gave of dumbbell benching, some people are more likely to experience an injury if they use too full of a range of motion. It is very easy to injury the shoulder girdle, and depending on arm lengths (upper, lower), the dumbbell bench press (and variations) can potentially lead to injury when a full range of motion is used. This can be avoided with a warm up set or two to gauge how much range of motion the lifter can use without experiencing too much of a stretch in the muscle.

Ultimately, a full range of motion is superior in that it takes fewer reps to achieve time under tension (since each rep is longer), it properly loads muscle groups and their antagonists, avoids muscle imbalances, and prevents the lifter from using more weight than they can / should use.