Physical therapists (chiropractors, osteos, physios), sports practitioners, trainers and coaches have for decades routinely prescribed stretching in pursuit of various fitness goals for recreational and elite athletes alike. Generally stretching is prescribed to achieve one or more of these 5 common goals:
- Most commonly, to increase muscle length
- To reduce the risk of injury
- To enhance prospects of healing for injured tissues
- To enhance performance
- To reduce pain associated with muscle and joint stiffness
The fact that there are so many applications of stretching makes it difficult for research to completely analyse its effectiveness, but first it is important to understand what stretching physically does to the muscle and its attachments.
Muscles have properties of elasticity, plasticity and viscosity, strength training (weights/high intensity exercise) over time generally bulks up and shortens the muscle; stretching lengthens it. The ‘stiffness’ of a muscle-tendon complex describes how readily it stretches when a given force is applied: a stiff muscle moves less than a compliant one, which means it is less flexible, but on the other hand has greater potential elastic recoil and therefore stored power. The speed of movement also matters: the slower the loading, the more pliable and less resistant the quality of movement. Within muscles we have spindle cells which govern the stretch reflex; when a muscle is taken to a length near the edge of its ‘safe zone’ the reflex will contract the muscle shortening it saving it from physiological damage.
Stretching for flexibility uses various slow, static and end-of-range movement techniques to overcome the stretch reflex and encourage a gradual lengthening of the muscle and tendon fibres and/or greater nervous system tolerance of the stretch at the end of range.
To increase muscle length through stretching, research shows both static stretching (holding a stretch for 15-30 seconds) and PNF (cycling between a stretch and muscular contraction) are very effective in both increasing the musculo-tendon elasticity and overcoming the stretch reflex. Research suggests that long-term isometric stretching programmes should produce changes in less than six weeks if stretches are done daily after a five-minute warm-up, held for 30 seconds and performed four to five times. This can be helpful in chronic injury conditions especially injuries involving the joint, as the more compliant a muscle is the less unnecessary force it places upon the joint it controls.
In terms of stretching to reduce the risk of injury research has suggested that:
- It is proven that static stretches have a short-term beneficial effect on muscle stiffness and that muscle tone and flexibility can affect the movement of a joint.
- An overall static stretching regime can help prevent muscle-related injuries, but not necessarily because it promotes increased muscle flexibility.
- It is not necessary to perform static stretching before or after exercise to prevent injury.
The aim of stretching during rehabilitation is to aid the speed and quality of healing at the site of injury and return normal muscle length as early as possible. Research has found that in some muscle groups most notably the hamstring group, when comparing recovery times the group which carried out a more intensive stretching program,was found to have a statistically significant shorter time of regaining normal ROM and shorter time spent in the rehabilitation stage. Research is still unclear on whether damaged tissues (muscles, tendons) should be stretched in the same way as normal muscular tissue which leads into the importance of a practitioner controlled stretch program to ensure no further damage is done to the injured tissues.
In terms of stretching for performance gain research has shown that static stretching can decrease performance! Especially in those skills involving explosive movement and relying upon the stretch reflex to be activated in order to achieve higher peak forces.
In summary, although there is range of ‘best practice’ protocols in terms of stretching we know that:
- For long-term changes, stretches should be held for 30 seconds and also repeated four to five times. Long-term results should take six to seven weeks at most before the changes start to plateau. This is generally what we prescribe to our patients in order to reduce excessive forces through musculo-tendon structures and also the joint structures they act upon, which for a patient suffering from musculoskeletal pain is a very handy tool to reduce pain levels in between visits and help to improve function overall.
- PNF can achieve range of movement changes, and is often more effective than static stretching, but is also more difficult for athletes to perform on their own, which is where we come in to play! PNF has been shown to be more effective in achieving the desired changes and with a practitioner assessing the muscle during the stretch results are generally better than an at home stretching program.
For any further information or a stretching program don’t hesitate to contact Synergy Healthcare either via email clinic@synergyhealth.com.au or phone 02 9522 2125.