When growing up as a kid playing copious amounts of sport, stretching was a normal part of the training and match day formalities. It was great, it was part of the sporting routine. I remember sitting down in a circle on the damp grass, steam radiating from everyone’s bodies after the warm up shuttle runs. We were all stretching in sync, together as a team, focussing on the play ahead, it wasn’t questioned.
That was until I felt some knee pains and got taken to a tired looking physio with bags under his eyes. He gave me a shiny light blue stretching strap and told me to stretch my hamstrings daily… yeah right! Why would I do such a boring thing? I’m sure many of you have wondered what stretching actually achieves. How would this help my knee? Well, this week I delved deep into the research to clear up this contentious topic.
To put it simply, the research is highly conflicting and quite complicated.
To translate my findings, let us first get comfortable with the terminology (you’ll be able to discuss these concepts with your physio or PT).
Term 1: Muscle length
Muscle length refers to how long your muscles can be stretched, which one would often refer to as “flexibility”.
So how flexible do we need to be? It all depends on the demands of your sport. Being able to bend yourself into a pretzel may not be particularly helpful for a soccer player, but maybe essential for a gymnast or acrobat. A research group recently found that for static stretching to be most effective in increasing muscle length, it needs to be at a high intensity (ie. very painful!), held for more than 60 secs and repeated 3-5 times per day (Freitas et al. 2014, Walters et al. 1996).
Did my physio intend on me becoming more flexible? There may have been an element of this, however, I was a soccer player and relied on strength and explosive speed, there must’ve been more to it. Moving on.
Term 2: Tendon hysteresis
Hmm, how do I start to explain this … okay firstly, what is a tendon? A tendon is tough, slightly elastic tissue that connects a muscle (or group of muscles) to bone (muscles don’t attach to bone).
It works like this… feel your calf muscle. At the top it is connected by a couple of tendons to the back of the knee, and at the bottom it is connected to the heel via the achilles tendon. To stand on your tippy toes (for example) your calf muscle will contract (thus shorten in length) and pulling up on your achilles tendon. Your tendon wont stretch much and as a result your heel lifts up and you’re on your toes.
If you wanted to repeatedly perform this movement powerfully and rapidly (ie. skipping), your calf muscle will need to work well, yes, but it must relies heavily on your achilles tendon being able coordinate the force from the calf to the heel, over and over again without relaxing. Make sense? This is what we mean by tendon hysteresis.
It has been found that regular stretching can increase the tendon’s ability to continually respond with efficiency (Kubo et al. 2003), or in sporty terms, long term stretching can improve tendon quality and also sporting performance.
Okay, so was this what the physio was aiming for me to improve? Quite possibly, but I was 14 so shouldn’t my tendons have been healthy and efficient? Let’s move on.
Term 3: Passive muscle torque
Another complicated concept, but put simply relates to how tense or relaxed your muscle is when it isn’t being contracted. “Passive muscle torque” has been well studied in relation to injury prevention and performance.
Let’s continue with the skipping example to explain this. Our calf muscles have sprung us up into the air, then they get a chance to relax before landing. But when landing your calf muscle will contract to cushion the landing, but not as much as it did to jump. Try it out. Your calf needs to take the impact of your body weight landing otherwise your knees will jar. Your calf muscle cannot completely let go otherwise your heel will crunch on the floor. Naturally you have learnt to contract your calf in a controlled and cushioned manner to lower the heel down to a point at which it is ready again for the jumping stage.
Still following? My point is almost made.
The less tense your calf muscle is at rest, the more it is able to store energy when landing and cushioning, and therefore is at less risk of muscle strain or tear. And conversely, the more tense the muscle, the higher risk it is at.
It has been found that high intensity stretching for 90 secs, repeated at least 3 times can effectively reduce this muscle tension (Freitas et al. 2014).
Clear as mud? On reflection I can see that this is what my physio was on about. I think…
What does this mean practically? 90 secs, 3 reps per muscle group, that’s getting close to 5 minutes per muscle. We’ve got a lot of muscles! This would equate to between 40-60 minutes of stretching a day depending on the individual.
Wait a minute, I remember being told by a Dad at soccer that stretching before activity reduces muscle performance? Come to think of it, when I’ve watched Adelaide United warm up they don’t seem to use static stretches!?
Yes this has some merit. Looking back through the books, it was found that static stretching of relaxed muscle was shown to lead to a reduction in muscle strength immediately after. Just to complicate things, only one side was stretched but both sides were affected. Strange huh! Yep this implicates the central nervous system as playing a part, however we will not get into this right now.
What is important is that these experiments were done in a lab, are not relevant to complex movements which sports require and has not been shown to translate to game-day where there are other activities in the warm up. Further, a recent review of the literature suggests that stretching for less than 60secs per muscle within a warm-up (that includes additional dynamic activity afterwards) is recommended for reducing muscle injuries and increasing muscle length with no negative effects on performance (Behm et al. 2015).
Hmm… to stretch or not to stretch. Essentially this really relates to your sport and your goals, and something that your physio should be discussing with you.
- If you want to be able to contort your body into a pretzel, I’d suggest high intensity stretches daily, for at least 60 secs repeated more than 3 times.
- If you want to reduce risk of injuries and potentially improve performance on game day, I’d suggest a warm-up including 45 second stretches targeting muscle groups known to be at risk for your particular sport (eg. hamstrings, groins, hip flexors for soccer and AFL), followed by dynamic, submaximal warm-up exercises.
- If you want to improve your tendon health, muscle length, performance and reduce risk of injuries long-term, regular high intensity, 60-90sec, 3-5 rep stretching routines are suggested.
Now that I understand what my physio was getting at with daily stretches, I still wouldn’t have done them at home and won’t in the future. But recently I stumbled upon the 75 minute Yin classes at Power Living Yoga. It comprises a high intensity group stretching session that targets all your inflexible areas with a relaxing and almost meditative component and more importantly it coaches you to understand your body better. Add this to strength and balance work in the Vinyasa flow classes and you’ve got yourself a rockin’ pre-season conditioning program ready for next winter! Take that Mr tired physio!
Jamie Wetherell
My passion for physiotherapy has evolved to become my life’s work because I was inspired while working for some of the worlds leading chronic pain researchers. Since then I have been living and breathing physiotherapy, applying all of its aspects to my own life and those around me. Through surfing and travelling I have come to understand the individuality in everyone and embrace their stories as part of their injury or pain.
Individualised physiotherapy is a transformative way to actively generate change in your life and maintain and stoke the inner fire.
