To stretch or not to stretch – The science behind the question which has plagued athletes for centuries.
We’ve all heard it “you don’t stretch? That’s going to cause an injury!”. But how true is this? Stretching is a topic which has actually been hotly debated in science, as to whether it is effective, and how necessary it actually is for the casual athlete. Many sportsmen and women make time in their schedule for it and never miss a stretching session, swearing that is the key to performance and injury prevention. While others never stretch, and yet never get injured either, seemingly disproving the rule. So what is the actual science behind stretching?
Firstly, let’s explore what stretching actually is. There are many types and methods for stretching, and all have their place, depending on your sport and what you want to get out of it.
- Passive stretching is where someone applies a stretch to you, whilst you maintain a relaxed posture. This is most typically seen in the physiotherapist or sport’s therapist’s treatment room. A passive stretch can sometimes give a little extra range.
- Active stretching is a broad term applied to any stretch you do yourself. There are different types of active stretching, the most common being static stretching. This is where you hold a stretch for a period of time without moving. Active stretching also includes dynamic stretching, where you repeatedly move into and out of a stretched position, and ballistic stretching, similar to dynamic stretching except you use momentum to force the limb into a deeper stretch. Whilst static stretching is probably the most commonly used post workout stretch, dynamic stretching is rapidly gaining popularity for warm ups.
- PNF (Proprioceptive Neuromuscular Facilitation) or MET (Muscle Energy Technique) are a slightly more technical method of stretching, but one which I often teach my clients. It involves contracting a muscle group for 10 seconds prior to stretching. It is a way of “tricking” the muscle into yielding more length.
So, as you can see there are many different types of stretching, all having purported benefits. These include improved flexibility, increased blood flow leading to faster recovery, and improved performance. Stretching is easy to do, can be done by anyone and without the requirement of any specialist equipment.
Sounds good, right? So where’s the debate?
Some scientific studies into the effects of stretching have reported that static stretching in particular, prior to exercise, can hinder the muscle’s ability to generate force. I’m going to get all scienc-ey for a second to explain this concept. Muscles are made up of various types of cells. Among them are cells called muscle spindles and golgi tendon organs, whose job it is to detect the length of a muscle. These cells trigger muscle contraction if they feel that a muscle is stretching too far, and that the muscle is at risk of over-lengthening or tearing. Another type of cell is a motor unit, which is responsible for muscle fibre recruitment. Recent studies have shown that static stretching actually decreases the activity of these cells. A decrease in activity means that the motor units are recruited less, thus less power is generated, leading to a reduction in force generation, and the muscle is less likely to sense the potential for over-lengthening, leading to an increased risk of injury.
These effects, however, are extremely short term, only lasting perhaps several minutes, up to an hour, following a static stretch. So while static stretching might not be the best thing to do just before you exercise, a regular stretching routine can actually increase muscle hypertrophy in the long term, thus leading to increased performance and strength.
So what does this mean for you?
Our recommendation is to perform an activity specific warm up, prior to exercise, which can include some gentle dynamic stretching if you wish. Increasing blood flow to the areas specific to your sport, is a much more effective way of preparing to train or compete. A warm up is important to ensure that not only the body is ready for action, but it will also put you in the right frame of mind, giving you time to focus on the task ahead. Foam rolling is also a useful tool for warming up the muscles and increasing blood flow.
After exercise, then running through some static or MET stretches of all of the major muscle groups will see long term benefits, and allow the body to cool down and recover from the session. Whilst the muscle fibres are warm, you will find you can stretch further without risking injury.
Whilst performing any kind of static stretching, it’s important to listen to the body. Always stretch to the point of mild resistance, not pain. Holding a less extreme stretch, for 30-60 seconds, relaxing into it and increasing the stretch in small increments as the muscle fibres relax, will give a better overall benefit, than a short sharp stretch.
If you would like to receive one of our free PDF guides to Dynamic Warm Up for Runners, or Static Stretches to Enhance Recovery, then please drop us an email to info@personalbesttherapy.co.uk or message us via our Facebook Page or Website.