Stretching: negligible effect on muscle soreness |
STRETCHING BEFORE and after exercise to try to warm up and help prevent injury has little or no effect, according to new research from Australia, reported in the British Medical Journal. The almost religious dedication shown by athletes and keep-fit enthusiasts to their warm-up routines may have negligible effect on their physical well-being.
The researchers, at the University of Sydney, reviewed five studies, involving 77 subjects, on the effect of stretching on muscle soreness. Measurements of the extent of muscle soreness after exercise showed stretching reduced it by less than one percent (0.9mm on a 100mm visual analogue scale).
“Most athletes will consider effects of this magnitude too small to make stretching to prevent later muscle soreness worthwhile,” said Dr Rob Herbert of the School of Physiotherapy, one of the report’s authors. The studies also revealed no useful reductions in injury levels. Data from two studies of army recruits in basic training, whose risk of injury is high, showed that muscle stretching prevents on average one injury every 23 years. Most athletes are exposed to lower risks of injury, so the absolute risk reduction from stretching is likely to be smaller still.
Much of sport and exercise medicine, and the management of musculoskeletal injuries, has developed empirically with little research evidence. The study is likely to make a valuable contribution to an emerging science-based sports culture.
Don’t forget to breathe
If stretching falls out of fashion, athletes may want to devote the time they save to developing muscles they may have neglected in their training. Researchers at Loughborough are developing new technologies to train breathing the muscles that draw air into our lungs are crucial to ensure efficient oxygenation, yet are largely ignored in training programmes.
The research leader, Dr Mike Caine, of Loughborough University, said: “Athletes preparing for big performances currently cannot train their breathing muscles as best they might. If the breathing muscles start to fatigue, this has a knock-on effect on the muscles of the legs or arms.”
The main muscles responsible for drawing air into the lungs are the diaphragm and the intercostal muscles between the ribs. To make these more powerful they need to be loaded in some way. One technique is an adaptation of a method used for patients who have breathing problems. The user breathes through a hand-held device with a mouthpiece and valve, which provides resistance upon inhalation.
“While it is possible to increase the strength of the inspiratory muscles by 30 or 40 percent in this way, it is not ideal for training an athlete,” added Dr Caine. “It is important that the loading on the breathing muscles is applied while the actual exercise swimming, or running or rowing, for example is taking place. For this reason a hand-held device cannot be used.”
The Loughborough team has taken two approaches to the problem. The first is to directly load the chest muscles. The team has invented what they are calling a 'RespiVest': a garment that the athlete wears around the chest. The vest has a number of elasticated arms, which squeeze the chest, restricting its expansion.
The second device fits over the athlete’s mouth and has an automatically controllable valve to apply variable resistance upon inhalation, depending on the strength of the breath. This is more finely tailored to the user’s own breathing patterns than the vest, and the researchers are looking at ways to package it to make it easy for the training athlete to wear. |
