Monday, October 4, 2010
by Alex Chaple
Using partial range movements can have huge advantage when aiming to break through plateaus or perform advanced exercise protocols. However, to the average exerciser, partial range movements (or movements that do not use a full range of motion) can present a number of problems. A few of which shall be explained here!
First of all let's put the problem in to context. We shall take a chin up as our exercise to examine, 1- because everyone knows what they look like and 2- because it is a common exercise performed incorrectly in this manner. The typical example is a male performing chin ups where they either do not clear their chin above the bar on the ascent, or do not fully extend the arms at the end of the descent. The reason for this style of chin up is simple, chin ups are far easier to perform if you only do half a repetition!
For many people the first phase of a chin up is the hardest part (due to weak elbow flexors). So in order to make it easier for themselves (and impress whoever might be looking) they will only lower themselves to where the movement becomes too challenging for them to continue. Similarly, for many people the final phase of the chin up (when the chin clears the bar) is the hardest part due to weakness in the muscles of the upper/mid back. For this reason, many will skip this part in order to perform more reps for whoever is watching.
One problem with this method is that by avoiding an area of weakness, that area will never improve! By never training your weakest range you are setting a limit on your performance on that lift and your strength or endurance. You will never become stronger or able to perform more full repetitions with an ignored weakness in the range. The concept is the same as being poor at putting and strong at driving. Never working on your putting ability and constantly practicing driving is not going to improve your golf game.
The second problem is that of injury. When a muscle is designed to move from one range to another but you only work it half way or two thirds of the way to that point, you experience what is known as adaptive shortening. Put simply, the muscle realises that it has no need to stretch as far as it was intended and therefore tightens enough to only accommodate the new, shorter range. You have now tightened your muscle. Excessive tightness along with deficits in the strength curve (as mentioned in the previous paragraph) can and very often do lead to injury!
The moral of the story is, when first beginning an exercise program try to use a full range of motion on all exercises.
The next article in this series will explore the use of resistance machines vs free weights!