How Stretching Works

Surely everyone has tried stretching before. But what exactly does stretching do and how does it do it? And how should you be stretching, when should you be stretching and should you be stretching? This post should clear up some of the confusion about what stretching does and how you should do it.

Stretching has a few different effects, and depending on what effect/s you’re going for the particular stretch, the time you hold the stretch and how often you perform the stretch may vary.

The effects of stretching are:

• Pain relief
• Increased blood flow
• Increasing muscle length
• Reducing perceived muscle tightness
• Improving ROM and posture
• Reducing neural spasticity

Let’s go through these effects one by one

Pain Relief

Stretching can relieve pain, largely through the other effects it has. Sometimes stretches can relieve pain by taking you out of a painful position. For example, if your back hurts because you’ve been on your feet all day (lumbar extension) then a stretch that takes your back into flexion will help to relieve your pain.

Increased Blood Flow

When muscles are being stretched, the blood vessels supplying the muscle are more open, allowing more blood to flow through. A good deal of the benefit of stretching before exercise comes from the increased blood flow to muscles a stretch held for 10-15 seconds provides.

Lengthening

Muscles are made up of small units called sarcomeres. Holding a stretch for 30-45 seconds at a time or longer actually results in lengthening the muscle by causing a small amount of lengthening to each of the sarcomeres which make up the muscle or portion of the muscle being stretched.

Reduced Tightness

“Tightness” as a sensation can be seperate to an actual lack of muscle length. Other than lengthening the muscle, stretching can help reduce a sensation of muscle tightness by increasing blood flow, and also by resetting the nervous system to no longer feel like that muscle is tight and reduce the resting tone in the muscle.

ROM and Posture

Tight or shortened muscles can impede how far a joint can move and can pull you into suboptimal postures. Your hamstrings, for example, when tight can reduce how easily you can straighten your knee, and they can also make you more prone to slouching when sitting. Overactivity in your upper trapezius muscles can pull you into a ‘poking chin’ posture and elevate your shoulders towards your ears.

Spasticity

This is an issue for people with injuries to the central nervous system such as cerebral palsy, head injuries, spinal cord injuries or strokes. These injuries can lead to significantly increased resting tone in certain muscles, such that they are resistant to being lengthened. Your 10-45 second stretches won’t have much impact on spasticity and sustained positions that stretch the affected muscle/s are required.

There are certain times when you shouldn’t be holding a muscle in a passive stretch. This is when you have an injury for which the tight muscle is not the main issue. For example, if you’ve torn a muscle you don’t want to be stretching that muscle for usually 2-3 weeks. This is because the primary issue is the tear in the fibres that make up the muscle. Stretching will weaken the tissue repairing the tear.

Another time when you should avoid stretching is when you have an injury which is irritated by being held in the stretch position. For example, if you have an acute back sprain which is irritated by bending your back, stretching your lower back muscles or glute max will irritate the back injury until the acute, inflammatory process has settled down

If you think tight or short muscles are a problem for you, we would be happy to set you up with some stretches, as well as provide any other treatments you may require based on a thorough assessment.