This is the time of year when everyone dives into a fitness regime with enthusiasm. Unfortunately, many people are stopped in their tracks when injury occurs and lose their intial enthusiasm. When I treat patients who exercise, I always ask what their stretching routine consists of. A couple of years ago I was quite stunned when a patient, an avid badminton player, told me that he had read an article stating that stretching for exercise was bad for you, so therefore he had stopped all stretching!! When I pointed out that there could be a link between his low back pain and lack of stretching, he conceded that there could have been a flaw in that argument. Unfortunately, at the time I did not find out which article he was referring to, however, I have managed to track down an article which was probably the original source of the misinformation, which I will refer back to later.
Most of us understand that we should stretch with exercise, however, most do not realise why. This article will go some way to explaining why, but first I want to look at the make up of muscles. All muscles are made up of 3 main types of fibres, slow twitch or Type I and fast twitch Type IIA and IIB. These muscle fibres are intermingled in every muscle but there is usually a predominance of one or the other depending on the main action of the muscle.
Type I muscles are red, rich in oxygen and can undergo repetitive contraction without fatigue. In comparison, the Type II A&B are white in appearance and have low levels of oxygen. They contract much quicker but also fatigue rapidly. In general Type II fibres are dominant in non-postural limb muscles, i.e. the bicep, which generates a powerful force over a short period, whereas Type I form a higher proportion is postural muscles, i.e. muscles which support the middle of our spine and deep calf muscle
During exercise, Type I muscles are recruited with endurance types of exercise and produce energy aerobically. The bi-product of aerobic energy production is carbon dioxide, which we breathe out. However, the Type II muscles, which are used for burst of speed or strength produce energy anaerobically and the bi-product of this form of energy release is lactic acid.
So, why stretch?
Lets start with the ‘warm up’ stretches. Warm up stretches, do exactly what it says on the box. Gently increasing blood flow, especially to the Type II fibres, and gradually stretching the muscle fibres before embarking on a full work out. This ensures the muscle is supple and has sufficient oxygen for energy production, thereby preventing injury and increasing performance.
Now we come on to the ‘cool down’ stretches. This is the one part most people forget to do or cannot be bothered with, however, these stretches are just as vital as the warm up exercises. In the past it was believed that the reason why we have pain after exercise was due to the accumulation of lactic acid during exercise, which became locked in the tight muscles that had not been stretched out. It has now been shown that lactic acid is metabolised by the body and cleared out of the muscle within an hour. Therefore the affects of lactic acid are felt during and immediately after working out.
So, what is the pain we feel the next day and how does stretching help? The pain we feel one or two days after exercise is know as Delayed Onset Muscle Soreness (DOMS). It occurs when a person is new to exercise, has changed their exercise intensity or routine. The theory is that the pain is due to micro tears in the muscle, which heal over the course of a few days. Stretching immediately after is not shown conclusively to reduce DOMS, however, it is important to the muscle’s overall health. During exercise, muscles contract and can stay shortened for a period of time, hence, why competitive body builders work out immediately before going on stage, to maximise the bulk of their muscle. If this muscle is not lengthened, it becomes habitually shortened, which then leads to lack of flexibility and increased injury rate.
Cooling down stretches lengthen the contracted muscle, increases blood flow into the area to flush out lactic acid and lengthens the muscle fibres to pre-work out state. If you have done a particularly intense session, you will still feel the affects DOMS, however, the muscle maintains its flexibility, so less prone to injury or spasm.
Getting back to the original statement that my patient made about the article he had read. A study by the University of Nevada, Las Vegas was published in the Sept 2008 issue of the Journal of Strength and Conditioning Research. They looked at the typical static stretches that we do, i.e. holding a position for 10 seconds This study found that static stretching may reduce performance by decreasing leg power. The research investigated how 2 typical stretching techniques for the hamstrings and quadriceps affected measurements of strength and power in a group of male and female athletes.
Contrary to what my patient had read, the basic conclusion of the research was not that stretching is bad for you, but that static pre-game stretching in competitive athletes should be replaced with dynamic or sport specific stretching. It seems that the article was subjected to a journalistic version of Chinese whispers! It also maintained that developing flexibility is important for reducing sports injury, post work-out stretching being a vital part of that.
So, remember, when working out you must stretch all the muscles. This includes, neck, shoulders, low back and arms and legs. It wont take long, 5 mins at most but will prevent injury, joint pain and increase your endurance.Share