Anyone who has ever asked me a question related to strength training has certainly heard my mantra, “work through a full range of motion.” Let’s take a little closer look at that phrase, what it means, and its implications.
In practical terms, range of motion (ROM) refers to the path that muscles take to move a joint. “Full range of motion” would obviously refer to the total path, while “partial range of motion” would refer to only some portion of that path. ROM is determined by several factors: joint flexibility, muscle and connective tissue elasticity, injury, and any other genetic or structural issues. Also, development of strength is specific to the ROM utilized during exercise. If you are only strength training through some partial ROM, you are only getting stronger in that range.
Utilizing only a partial ROM allows you to work with more weight than would be possible through a full ROM. So if you load too much weight, it shortens your ROM. If this cycle is repeated, a portion of the muscle group will become stronger and the portion you have neglected will become weaker. This makes it more likely that you will be injured at some. Muscle strength, flexibility, and resistance to injury are greater when strength training is undertaken through a greater ROM.
A good example is someone trying to get up from a low, soft couch. Difficulty in this situation is typically the result of weakness in the lower body muscles at the hip and knee angles, generated by the seated position. This means the individual simply cannot generate enough power to stand up.
The photos of the squat exercise demonstrate this situation. Image A represents a standing position: hips forward, chest and head held high. Image B represents a descending position: knees beginning to flex and traveling out over the toes, hips beginning to travel to the rear, the head and chest still held high. Unfortunately, too many individuals stop at this level when they descend into a squat, leg press, or lunge. Image C shows what should be the true midpoint of a squat (or leg press, lunge, etc.). The head is still held high, keeping the back straight, hips have shifted behind the heels, which are still on the ground, and (most importantly) the tops of the thighs are parallel to the floor. The photos can be viewed in reverse order to bring you back to a standing position.
Lower body strength was given in our example, but avoiding weakness through a certain ROM should be the objective of your entire strength-training program. Work through a full range of motion in everything you do so you’ll be strong in any position you find yourself!