As you get older, you may notice that everything takes a little longer to get better. If you have a drink or two in the evening, you no longer leap salmon-like from your bed the next morning with a head like a limpid pool, but suffer for the whole day and sometimes the next. If you do anything crazy such as go for a run or play a game of football, your body no longer recovers in time for another one 24 hours later, but aches and twinges and grumbles for days.
That’s what I find, anyway. As I write this, my ankle is sore and my quadriceps are twanging from a short, not especially speedy run I went on two days ago. When I told someone who’s fitter and more exercise-y than me, he asked: did you warm up and down properly? When I admitted that I didn’t, nothing more was said, but his expression made it clear that I had no one to blame but myself. So I thought, is that true? Any of us who have done gym inductions, or those brutal British Military Fitness things in parks, or even school PE lessons, will know the drill: stretches and steady exercise to warm you up and afterwards, to let you cool down gently. But does this make you less sore in the days afterwards, or less injury prone? What’s the evidence? The importance of the warm-up and warm-down is taken for granted, but no one has ever told me of any evidence that they do any good.
In one sense, it wouldn’t be surprising if the evidence was patchy — blind trials are impossible. But trials have been carried out. One, published in the Australian Journal of Physiotherapy in 2007, looked at 52 adults, divided into four groups: warm-up, warm-down, warm-up and warm-down, and neither. They each carried out half an hour’s exercise, bookended with 10-minute warm-ups and/or -downs.
Our bodies ache and twinge after exercise because of ‘delayed onset muscle soreness’ (DOMS), and this is most painful between 24 and 72 hours after exercise, especially ‘eccentric’ exercise — lengthening a muscle while keeping it tensed, such as the downward part of a bicep curl. Exactly what causes it is not clear, but it is believed to be ‘microtrauma’, tiny tears in the muscles at cellular level. Stuff that’s usually stored in the cells then leaks into the tissues, causing an inflammation reaction.
The hypothesis with warm-ups, then, is that by making the muscle warmer before exercise, the bundles of muscle cells, myofibrils, will move more easily and suffer less damage during exercise. The hypothesis with cool-downs is that they interfere with the cascade of damage caused by microtraumas, reducing inflammation. That’s the theory. But as we all know, plausible biomedical hypotheses don’t mean anything if the empirical evidence isn’t there. So what did the Australian Journal of Physiotherapy research find? Not much. There was some evidence of a very minor reduction in pain for people who did warm-ups and none for those who did cool-downs.
An earlier survey, in the Research Quarterly for Exercise and Sport in 1989, found ‘static stretching and/or warm-up does not prevent DOMS resulting from exhaustive exercise’; and, most damning, a Cochrane Library review of the literature, from 2007, looked at 10 studies of warm-ups and found that there was ‘minimal or no effect on the muscle soreness experienced between half a day and three days after the physical activity’.
You will also be told that warming up prevents injury, but again the evidence is inconclusive. A systematic review in the Research into Sports Medicine journal (2008) found that static stretching ‘does not reduce overall injury rates’. A review of five studies, published in the Journal of Science and Medicine in Sport in 2006, was similarly uncertain; three found some improvement, two found none.
If you are a warmer-upper, continue. It won’t do any harm, and there’s a chance you might be at slightly less risk of some injuries. But if you struggle to find time to exercise, it might be encouraging to know you don’t have to waste half an hour warming up and cooling down each time you play squash.
As a lifelong non-warmer-upper, I find all this stuff vindicating; the back twinges and thigh pains and the difficulty getting on my bike in the days after exercise are not my fault for being lazy, they’re unavoidable, the price of my half-hearted attempts to keep fit. Now if you’ll excuse me, I’m going to find some ibuprofen.