The physiology of stretching
Posted March 08, 2011
As I am a student of Osteopathy and as this is my first proper article for Daily Cycle, I thought I would go with my instincts and do something science/health related. By coincidence, I was stretching the other day and I found out I could put my head on my legs. I have no doubt that my flexibility has been directly affected by yoga which I have been doing for the last 4 months.
The problems caused by cycling
Cycling is very good for building strength and endurance in certain muscles and muscle groups, however the pedalling action doesn’t put all of them through their full range of motion. This can lead to hypertonic (shortened and tight) hip flexors, quadriceps, calves and hamstrings. Regular cyclists who don’t stretch will have permanently hypertonic leg muscles; this can lead to all sorts of other problems. For example:
- Sciatica – the sciatic nerve runs around or sometimes even through the piriformis muscle, which is one of the hip rotators. Although it is not directly used in cycling, it is often tight on cyclists due to the other hypertonic muscles around the hip. So, a tight piriformis can impinge on the sciatic nerve and cause pins and needles, shooting pains and numbness down the leg. A piriformis stretch is shown in the diagram below.
- Rotated pelvis – If you think about the structures involved in cycling then it becomes easy to see how problems can develop. For example, rectus femoris (one of the quadriceps) attaches onto the side of the pelvis (the ilium).
This is one of the most frequently used muscles in cycling and therefore if this is hypertonic and contracted, it will pull the ilium forwards and cause a rotation. - As you can see from the diagram, the ilium is rotated 50 degrees instead of 30 degrees. This means that when you walk or when the leg is extended, increased curvature of the spine is a result and this can lead to back pain, scoliosis (lateral curvature of the spine) and postural problems. The intervertebral discs can be affected and nerves can also become impinged.
I could go on, but I won’t...
Instead lets have a look at what stretching actually does to the muscles and structures.
The benefits of stretching
Firstly, when a muscle contracts, it does so by filaments within each muscle cell gliding and overlapping one another, pulling the muscle fibres centrally. When the muscle relaxes, the filaments glide back to their original position, occupying more space than when they were overlapping.
When you stretch the muscle, the fibres are stretched to their full capacity and the rest of the stretch is taken up by the connective tissues. Imagine a web like structure around the bundles of muscle fibres in each muscle. This web is actually made up of collagen fibres that realign themselves in the direction of tension when you stretch. The more you stretch, the more this web will expand and allow you to be more flexible. If you don’t stretch for long enough, however, the web will just spring back to its original position and no lasting flexibility will be achieved.
Flexibility
Flexibility means that your muscles will easily be able to go through their full range of motion, less stress will be put on the other structures in your body that have to adapt to the hypertonic muscles and your body will be in alignment and function well (providing there are no other pathological or neuro-musculoskeletal problems). This all relates back to the Osteopathic belief that structure governs function and that the body is a unit!
From the point of view of a cyclist and an Osteopath, I think the point I am trying to get at is that you have to think about what your muscles are doing and look after them. As I previously mentioned, I find yoga has been a massive help to my flexibility and the classes are the perfect place to take some time out for yourself and relax. If yoga isn’t your thing then just try and make sure you do a good 10-15 minutes of stretching after a ride or as often as you can. You’ll reap the benefits when you’re 80!
Main photo via mikebaird
Diagrams via athleticadvisor.com and massagetoday.com
