March 20, 2011

Everything You Need To Know About Stretching To Increase Results, And Avoid Decreasing Performance

Contorting your body and cranking your muscles through extreme ranges of motion, also known as ‘stretching’, can be used to improve performance if done correctly, but unfortunately the majority of those who attempt to use various stretches to improve performance do so incorrectly and actually end up decreasing performance.

Before explaining how stretching can be used advantageously, it’s worth explaining the different kinds of stretches, and the downstream effects they have. The different types of stretching and types of flexibility are:

1. Ballistic – Using momentum to propel your body or limbs into extreme ranges of motion that would be considered beyond normal. This type of stretching is perceived by the brain as dangerous to which it responds by increasing the firing rate to the stretched muscle group, making it beneficial for those looking to improve performance (assuming performance consists of generating more power/force).

2. Dynamic – The difference between dynamic stretches and ballistic is that with a dynamic stretch you don’t try to explosively force your body or limbs beyond its normal range, you rather gradually increase speed, intensity, and range of motion. These are best suited at the beginning of a training session to prepare the body for the movements to come (AKA, movement preparation).

3. Active – An active stretch is an unassisted stretch, meaning there is no external factor affecting the stretch like leaning on a wall or bench, or using bands to increase the range of motion to create leverage. When a muscle contracts, the opposite muscle, or antagonist, is forced to relax, in almost all cases (one exception being a sit up in which both the abs and spinal erectors contract simultaneously). Anyone can take advantage of this to enhance almost any stretch. For example, to enhance the stretch of the biceps, you could ‘actively’ flex your triceps as hard as you can while extending the elbow. The same can be said for the quads in that, by flexing as hard as you can, you can really maximize the stretch in the hamstrings, and vice versa. This phenomenon is called reciprocal inhibition and can be used to instantly improve performance, as by rapidly contracting the antagonist, you in turn rapidly stretch the agonist, to which the nervous system responds by increasing the amount of motor units sent to the working muscles to prevent what it perceives could be potentially dangerous. This ‘trick’ is best suited for those looking to build more strength or muscle mass and is especially effective for the muscles responsible for flexing and extending the knee and elbow joint.

4. Passive – A passive stretch is an assisted stretch, meaning there is some sort of external factor used to create leverage and increase the range of motion. Having a partner pull your arms back with your hands resting on your head is an example of a passive stretch for the pecs, and this type of stretching is best suited at the end of a training session to help clear away any metabolic waste that may have accumulated during the workout and not been cleared, and assist with recovery. Also, stretching a pumped muscle can facilitate growth as the cells could perceive the stretch as a threat to their integrity, to which they respond by increasing the sensitivity of their IGF-1 receptors which increases protein synthesis, and also by stretching the surrounding connective tissue (fascia) which essentially makes room for the cells to grow larger.

5. Static/isometric – The difference between a static stretch and a passive stretch is that a passive stretch is ‘relaxed’, and no attempt is made to resist the stretch, whereas a static stretch is one in which you attempt to resist the muscles from being lengthened by contracting them eccentrically. The benefit to this type of stretching is that some of the muscle fibers that would normally remain inactive, or at rest, are actually stretched as the fibers close to them contract and pull on them.

6. PNF – Which stands for PROPRIOCEPTIVE NEUROMUSCULAR FASCILITATION, is a combination of passive and static/isometric stretches. There are a few different types of PNF techniques, but to explain all in great detail goes beyond the scope of this article as the purpose is to shine light on why certain types of stretching during your workout can either increase, or decrease performance.

Now that the different types of stretches are out of the way, here’s a brief rundown of the physiology of stretching to help one better understand what happens to muscles when they are stretched, so you can use them to your advantage, and avoid using them disadvantageously.

The body is made up of bones, and muscles that attach to them which provide movement.

A joint refers to an intersecting area where bones connect via ligaments.

Muscles are connected to bones via tendons, and located around all of this is connective tissue which envelopes not only muscles, bones, tendons, and ligaments, but also each and every muscle fiber.

Proprioceptors are the nerve endings which relay all information about the musculoskeletal system to the nervous system, and are responsible for detecting any change of movement or tension within the body.

When a muscle is stretched, a proprioceptor called a muscle spindle, records the change in length, and how fast it occurred, and sends signals to the brain that convey this information. This activates the stretch reflex (AKA myotatic reflex), which attempts to resist the change in length by forcing the muscle to shorten by forcefully contracting.

The harder and faster your muscles are stretched, the harder they will be instructed to resist being lengthened by being forced to contract by the stretch reflex, which is basically a built in self defence system.

The proprioceptors habituate to new lengths and ranges of motion the longer a stretch is held, and reduce their firing rate (basically they shut off), enabling you to achieve a greater stretch.

When a muscle contracts, it produces tension at a point where the muscle is connected to the tendon called the Golgi Tendon Organ (GTO). The GTO also records the change in tension, and the rate at which it occurs.

When the tension exceeds a certain threshold it activates the lengthening reaction which disables a muscle from contracting. The purpose of the GTO is to prevent the muscles, tendons and ligaments from getting injured (although it may not seem that way based on the fact that it temporarily disables the muscles ability to produce force). The lengthening reaction takes place when the GTO overpowers the proprioceptors that are telling the muscle to contract.

Where a lot of people go wrong is they use the wrong stretches at the wrong times. Stretches are time dependent, meaning the longer they are held, the greater habituation that occurs, yet so many people hold stretches for prolonged periods of time for the muscle they are training between sets, not realizing that they are basically shutting off the muscles they are training (which is as counterproductive as it gets).

While it is possible to recruit dormant muscle fibers by cranking and contorting your body and holding stretches for a sustained period of time, the pay off of possibly recruiting a few more muscle fibers at the expense of possibly shutting most of them off simply isn’t worth it. A more logical approach may be to hold stretches for the antagonistic muscle groups so there is a greater level of net motor unit recruitment to the agonist, but even still you risk losing stability which negatively affects force production.

The stretches, or rather types of stretches, are presented in order from those which are held for the shortest periods of time, and also have the greatest potentiating effect, to those which are held for the greatest periods of time, but have the greatest habituating effect, and should be used in that order in relation to the beginning and end of a workout.

If you have any questions about stretching as far as when, and what types of stretching you should be doing, feel free to contact me at I'm available for online consulting and personalized program design, as well as one on one training if you are located in the Greater Toronto Area (GTA).

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