The role and effects of stretching and injury prevention

Static vs Dynamic Stretching

Both types of stretches have advantages and disadvantages depending on your aim and purpose.

Benefits of Dynamic Stretching – it is now thought that dynamic stretching may be better prior to exercise or sporting activity than static stretching (1) particularly if the stretch is prolonged (2).

Benefits of Static Stretching – is considered to help, promote and maintain range of movement and flexibility in general for better performance opposed to dynamic stretching (1,4).

The research of Static and Dynamic stretching

A meta-analysis study in 2012 reviewed all the research available and found that strength power and performance (vital for most sports) may be compromised and reduced. Therefore the study concluded, static stretching should be avoided as a ‘sole’ warm up prior to exercise or sporting activity. However the key phrase ‘sole’ has been appropriately misinterpreted and potentially overlooked by anti-static stretching advocates. Although the study reported a decrease in strength power and explosive performance the results were minimal but significantly different between 5.4% - 1.9%. The study suggests that unless you are an elite professional athlete the adverse effects would be very small barely visible and short lived (5-10 minutes post stretch) providing the stretch is kept approximately under 45 seconds.  It concluded that short intervals of static stretching are recommended for slower eccentric contractions or sports that involve increased range of movement (e.g. martial arts and gymnastics). All of the tests that were studied did not actually measure sports performance instead they simply just measured general performance (1).    

A systematic study in 2011 reviewed the effects of static and dynamic stretching on performance. The research found that dynamic stretching either offered no effect or ‘may’ even supplement later performance particularly if dynamic stretching is prolonged (2). This has also been misinterpreted by anti-static stretching advocates as they consider that dynamic stretching should always be performed prior to activity or sporting event.

In summary the study concluded, generally warm ups minimise impairments, promotes performance. However this is provided that they are constructed of a submaximal intensity of aerobic activity followed with a degree of large amplitude dynamic activities and then finished with sport specific dynamic activities (2). It recommended that sports that utilise higher degrees of static flexibility should implement short intervals of static stretches with reduced intensity stretches in a trained population to reduce the risks of potential impairments.     

Which stretch is best Static or Dynamic?

The research suggests that both ‘Static and Dynamic’ stretching should be utilised and combined in most general sports and therefore be guided by the chosen activity or specific sporting event.       

Which stretch reduces injury risk Static or Dynamic?

This is a very good question but from reviewing the evidence available for both static and dynamic stretching this is still inconsistent. Studies that reviewed the role of stretching in injury prevention and performance, showed mixed results of pre-participation stretching on injury prevention with variable qualities (3,4). Put simply, this would imply that we don’t yet know!

What is the best exercise routine?

Firstly you need to understand the effects of stretching which will assist your performance. Ultimately preparation is ‘key’ preparing your body for the optimisation stages specific to a sport or exercise activity clearly creates the individual fully prepared which is often a good intervention.  Therefore as each sport or exercise activity is different each warm-up should be different (i.e. the intensity and type of stretch specific to each individual requirement). Thus the research is recommending that we should predominantly spend time performing dynamic stretches and reduced intensity of aerobic activity specific to our chosen sport or exercise activity. However if the sport or exercise activity is going to involve large amplitude movements then it is advised to add short duration static stretches as well!   

Examples:

A sprinter often runs in intervals and in straight lines, therefore the athlete is more likely to perform a progressive warm-up such as running drills and possibly a small degree of plyometric warm-ups in a few directional planes. This would also combine a large degree of dynamic stretches such as hip flexor and hamstring movements.

Rugby and basketball players would potentially incorporate in their warm-ups, multi-directional drills which would not only involve the legs but other anatomical locations such as their necks and shoulders specific to their sport.  

What is the ideal warm-up duration?

Currently the research is still inconsistent. However working with fellow professionals and coaches we often recommend at least 25% to 30% or in some cases even up to 50% depending on your aim and purpose of pre-exercise or pre-sporting activity (i.e. intensity). For example if you are planning on a simple low intensity jog for around 40 minutes, I would advise a warm-up for approximately 30% (at least 10 minutes). However if you were going to perform a 40 minute high intensity sporting activity which involved a mixture of brief periods of exercise i.e. multiple sprints (football, rugby etc) then I would advise a 50% warm-up (at least 20 minutes). Although these times are approximated, endurance activities such as marathons, the athlete may only require less than 15-20 minutes warm-up session as potentially they are more likely to be optimised and prepared through training.  

Final thoughts on Static and Dynamic Stretches

After reviewing the literature, it is apparent that we should predominantly perform a large degree of dynamic stretching in our warm-up sessions prior to exercise or sporting activity. However it is also important to understand that static stretching may also have an important role and therefore can be included into the warm-up session as there are barely any adverse side effects as first claimed. However if you already combine both forms of stretching in your warm up sessions without any adverse effects and feel it helps then continue. If you already don’t then that’s fine too and finally I would probably leave most of the static stretching either between your exercise sessions or in the treatment room. It is simply just trial and error and what method(s) best suits you.