I only have to bring up the word ‘stretching’ with some of my colleagues in the therapeutic and fitness industry to generate lively debate. Something that we have all thought was a good thing to do is now in question. Truth be told, there is a lot of contradictory research out there and no solid
proof of the advantages and disadvantages so it’s no wonder there is confusion. What is clear is that we have many joints and muscles in our bodies and even more confusingly, many many different stretching protocols each with a number of pros and cons, so where does one start when considering a regular stretch routine?
What does the research say? The good and the bad.
Good? Studies have shown that static stretching of the calves can increase the dynamic passive and length of the muscle, tendon unit. R1
Good? Another study again showed that static stretching increased the flexibility in plantar flexors of the leg but that ballistic stretching did not, yet did improve tendon stiffness levels. R5
Good? It has been shown that a static stretching routine can increase the range of motion in a joint. Multiple Sources including R5
Bad? Over stretching can lead to unstable ranges of motion which in turn may cause injury.
Bad? Studies have shown that Dynamic stretching is not as effective as Static stretching in increasing flexibility. R7
Good? Hamstring stretching has been shown to improve hamstring performance in closed chain activities. R4.
Bad? Passive static stretching to fatigued muscles has been shown to reduce the power (maximum force generating power). R2
Good? Foam rolling can increase range of motion without decreasing power. R6
Confused? I know I was, as believe me the lists of conflicting research goes on and on.
It is clear that people benefit from stretching in its various forms but the problem and cause for debate is that there is actually very little evidence on exactly ‘how’ it works. Take the following piece of research by KonradR8 in 2014 which found that although static stretching did increase Range of Motion the increased range of motion could not be explained by the structural changes in the muscle-tendon unit, and was likely due to increased stretch tolerance possibly due to adaptations of nociceptive nerve endings. So we know it can help us achieve increases in range but the how is still a mystery. Add to this lack of evidence, a large number of people stretching muscles that don’t need stretching, people using foam rollers to elicit all sorts of pain, bruising and damage and another bunch of people ballistic stretching themselves a hernia. Clearly some caution and guidance is needed.
The Stretch Factor
First things first, you need to understand what you are trying to achieve in order to know ‘what’and ‘if’ you need to stretch. If something hurts, that doesn’t automatically mean you should stretch it, we seem to have picked up this jerk reaction to muscular pain. First you need to understand why you have pain as often pain is felt in the long, weak inhibited muscles so stretching will make the problem worse. It’s not all bad news though as studies show stretching the right muscles can improve range of motion so if your pain is due to a muscle being weakened or even overloaded then restoring normal range of motion in the joint in which it plays a role may help to relieve the pain. Its just knowing what muscles you need to stretch. Again my belief is 2-3 key stretches, along with some strengthening work that is right for your body may be all that is required to restore your balance. Too many of us try to stretch everything, get bored, declare it pointless and stretch nothing.
Secondly, once you know what you want to stretch you need to know what you are trying to achieve so that you can select the right type of stretching for the right occasion. Are you trying to prevent injury pre event/pre exercise/ pre match? Then it is important to keep your power levels high so long sustained static stretches are out the window. Increasing flexibility while firing up the key muscles is critical here so dynamic stretching fits the bill. I love this RAMP warm from Exercise Lab, take it modify it and get it to fit with your sport or activity:
To increase range of motion post exercise or even as part of a daily flexibility plan then static stretching is going to be useful as it is focused and to the point once managed within normal ranges of motion. To ensure that the connective tissue is also being stretched to allow the muscles to hold their length then a Foam Roller, used correctly I may add (that needs a blog in its own right!), is a really useful addition. We know that fascial health is vital but again, little is known on the how in terms of stretching but foam rolling seems most likely to impact this tissue.
R1 – A stretching program increases the dynamic passive length and passive resistive properties of the calf muscle-tendon unit of unconditioned younger women. (2006 Gajdosik RL1, Allred JD, Gabbert HL, Sonsteng BA.)
R2 – Acute passive stretching in a previously fatigued muscle: Electrical and mechanical response during tetanic stimulation. (2009 Esposito F1, Ce E, Rampichini S, Veicsteinas) A.http://www.ncbi.nlm.nih.gov/pubmed/19816836?itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum&ordinalpos=1
R4 – Effect of hamstring stretching on hamstring muscle performance. (1994, Worrell TW1, Smith TL, Winegardner J.) http://www.ncbi.nlm.nih.gov/pubmed/7951292?dopt=Abstract
R5 – Effect of static and ballistic stretching on the muscle-tendon tissue properties. (2007, Mahieu NN1, McNair P, De Muynck M, Stevens V, Blanckaert I, Smits N, Witvrouw E.) http://www.ncbi.nlm.nih.gov/pubmed?Db=pubmed&Cmd=ShowDetailView&TermToSearch=17473776&ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_Res
R6 – MacDonald, G. Z.; Penney, M. D. H.; Mullaley, M. E.; Cuconato, A. L.; Drake, C. D. J.; Behm, D. G.; Button, D. C., An acute bout of self-myofascial release increases range of motion without a subsequent decrease in muscle activation or force. Journal of Strength and Conditioning Research 2013, 27 (3), 812-82
R7 – The effect of static stretch and dynamic range of motion training on the flexibility of the hamstring muscles. (1998, Bandy WD1, Irion JM, Briggler M.) http://www.ncbi.nlm.nih.gov/pubmed/9549713
R8 – Increased range of motion after static stretching is not due to changes in muscle and tendon structures. (2014, Konrad A1, Tilp M2.) http://www.ncbi.nlm.nih.gov/pubmed/24856792