We’re often told to stretch after a run to reduce the risk of soreness afterwards. But we may be doing ourselves more harm than good. Running Injury & Performance Specialist Matt Phillips explains.

Most runners now realise that there is little point to performing static stretches before a run, i.e. holding a calf or hamstring stretch for 20 seconds or so. Research confirms common sense; some kind of dynamic movement like some leg swings or lunges is more likely to prepare you for the demands of running than standing on the spot with one leg up on a wall. But what about after our run? That’s when we should be dedicating five minutes or so to static stretching, no? It turns out maybe not…

Why do runners stretch after a run?

There is a common belief that stretching post run will help ‘return muscles to their normal length’ and in doing so reduce soreness over the next few days (known as DOMS, delayed onset of muscle soreness) and most importantly reduce the risk of an injury. There is actually very little research that supports either of these beliefs. Let’s look at each in turn.

Post run soreness

Although it is true that some runners feel they experience more muscle soreness if they fail to stretch, others are surprised to discover that if they skip it, they are actually less sore. The reason for this may lie in the physiology. After a demanding run, it is normal for muscles that have been worked hard to have micro-tears in them. It is the healing of these micro tears that is thought to actually make us stronger and able to perform better next time, hence the importance of adequate recovery. Trying to forcefully stretch a muscle with these micro-tears could potentially increase the size of the tear and lead to more soreness.

How can you avoid post-run soreness?

The most likely reason for post run soreness is that you have pushed your body harder than it was prepared to work at. By the time you get to the end of your run, how sore you will feel has already been decided. Soreness after a hard session should really be expected, as that’s how you get faster and stronger, but if you are sore the whole time then you may well need to take a look at your training plan. You may well also benefit from a longer dynamic warm up before your run to reduce the shock factor of suddenly launching into what is essentially 1600+ hops a mile.

Reducing injury risk

The other reason that runners typically stretch post-run is the belief that being flexible is a way of reducing injury risk. This makes sense if you are talking about the range of movement required to run and trying to force the muscles into a length that we will never actually need or use, while running doesn’t do this. The degree of hip extension (leg reaching back underneath your body) needed for running is actually about the same as that of walking (10-15˚). Running simply doesn’t require the same level of flexibility as a dancer or martial artist. Stop and think for a second…. why as a runner do you feel the need to be able to touch your toes? When will you ever need that amount of flexibility in your hamstrings?

Let’s use Paula Radcliffe as an example. In 2003, she set a new women’s world marathon record time of 2:15:25. As part of her training, Paula actually reduced her hamstring flexibility by 4cm. This decrease was most probably a by-product of a specialised weight-training programme that saw Paula’s maximum vertical jump increase by 10cm, producing the powerful stride and heightened efficiency that saw her set a new world record. One study of collegiate runners published in the Journal of Strength & Conditioning Research in 2009 (Trehearn TL1, Buresh RJ) has since shown that those who were 20cm less flexible during a sit-and-reach test ran 27 per cent more efficiently with elite athletes having less flexibility than runners who they beat.

Strengthening not stretching

During running, muscles and tendons act like springs. When you land, they absorb and store energy from the ground and then use it to propel you forwards (referred to as the Stretch-Shortening Cycle). Imagine a spring that is loose with very little tension: on impact with the ground it would absorb and release very little energy. However, picture now a spring that is stiff and tense: it will store much more energy on impact and in doing so release more energy for each stride. It is strengthening work that helped Paula achieve greatness, not stretching.

In 2004, a review by Thacker et al. (Impact of Stretching on Sports Injury Risk) concluded that stretching was not significantly associated with a reduction in total injuries. A 2010 study following nearly 3000 runners over three months showed that risk of injury was the same (16 per cent) regardless of whether the runners had done a specified pre-run stretching routine or not. Faced with such data, we really need to ask ourselves why we feel the need to hold static stretches after a run. If it’s just to relax and feel better, then fine, but if we believe that it will significantly reduce soreness, prevent injury or improve performance then we need to think again. As for what we should be doing after a run? We’ll leave that for another article….        

More information

Matt Phillips is a Running Injury & Performance Specialist at StrideUK and hosts the podcast RunchatLive. Visit his website at www.runchatlive.com