amplitude of movement in bodybuilding

Posted on: 06/29/2017

In bodybuilding, there are a number of parameters to be taken into account during a training session. Each of these parameters will have an impact on the quality of the session, the quality of stimulation of the muscle being worked, and therefore on the quality of the result.

These parameters include the load used, the length of sets, the speed of execution and the amplitude of movements, to name but a few. In this article, we'll take a look at range of motion.

what is amplitude of movement in bodybuilding?

the amplitude of a movement is the distance covered in a given movement by the load from the starting point of the movement to the furthest point and back to the starting point. the full amplitude of a movement means that the load will have covered the greatest distance between the starting point of the movement and the return to this point at the end of the movement.

If we look at the muscle as a whole, it's a collection of muscle fibers, contained in a "sac" (sheath of connective tissue) and attached at each end to a joint by a tendon. the muscle's amplitude is complete when the two insertion points are at their farthest apart during the stretching phase, and the muscle is shortened to its maximum during contraction.

What influence does amplitude have?

We often talk about controlling the load to increase the tension applied to a muscle, and in particular the eccentric phase of the movement, which is just as important, if not more so, than the concentric phase. The amplitude of the movement is just as important as control, as both influence muscle stimulation.

Indeed, when a muscle is worked at full amplitude, this results in maximum stretching and therefore maximum distance between the two extremities of the muscle. This distance between the insertion points will activate the muscle fibers along their entire length. The more the fibers are activated, the more the muscle is stimulated. The greater the stimulation and the more muscle fibers recruited, the greater the impact on muscle hypertrophy.

What's more, full amplitude training has a major impact on joint flexibility. Indeed, the more a joint is exercised to its full amplitude, the more supple it will be or remain, which will help protect it from injury.

Of course, this only applies if the joint is not put into hyper-extension - i.e. beyond its maximum stretch!

When should partial amplitude be used in bodybuilding?

There are several cases in which using a reduced "partial" amplitude can be beneficial.

Case number 1: Motor-related problems

It's not uncommon to encounter difficulties in executing a movement at a specific point. For example, during a bench press, the transition or bulk of the work shifts from the pectoral muscles to the triceps (the last third of the movement). This is because the arms can't stretch because the triceps aren't strong enough. In this situation, partial amplitude work will focus solely on this transition point. In other words, the bar will not go below this first third of the movement, which will enable the triceps to be put to maximum use and strengthened.

In this situation, the partial amplitude serves to pass a hot spot in your execution.

Case 2: Targeting a muscle area

This can be useful when you want to stimulate a very specific area of a muscle. By performing the movement only over the amplitude in which the targeted zone is involved, it's possible to over-stimulate that zone and thus induce hypertrophy. For example, if the lower part of the biceps lacks volume, it's possible to work the biceps by not exceeding the 90° angle between the arm and forearm during a curl. This amplitude enables you to stay focused on the beginning of the movement.

Another circumstance that may lead the athlete to reduce amplitude is joint preservation. For example, during squats, if you go down to full amplitude, you're going to put maximum strain on your quadriceps, hamstrings, lumbar vertebrae, etc... but your knee joints are also going to be put under a lot of strain. To avoid traumatizing them, the athlete will reduce his or her range of motion by descending less far. In general, we stop when the quadriceps are parallel to the ground.

To increase the intensity of a set and continue it beyond what we would be able to do with full amplitude, it is possible to continue it in partial amplitude for a few repetitions, with the help of a partner.

For example, during a bench press set in which you've been able to do 10 complete repetitions, but the eleventh is not, you'll do a few repetitions, not going all the way down to the chest and only coming back up two-thirds of the way. This keeps the pectoral muscle under tension without the shoulders getting too involved (they participate in the lower part of the movement) and without overtaxing the triceps, which come into play at the end of the movement.

Coach's advice and recommendations

As you can see, the amplitude with which we execute a movement has just as much impact on the muscle and its development as the load used or the speed of execution. A muscle stretched to its full length will recruit more fibres during contraction than one that is only partially stretched, and will therefore have a better chance of developing. However, it may be worthwhile temporarily to reduce the amplitude in order to reach a milestone, or to increase the intensity of an exercise.