Stretching is always an interesting topic and one that is clouded by conflicting opinions, not only in how we stretch, but in why we stretch. Some people stretch to reduce risk of injury, others stretch to provide relief of soreness and stiffness, and other stretch because it gives them a sense of well-being.
My focus for this posting pertains to the first two points. Does stretching pre-and/or post exercise reduce the risk of injury? Does stretching provide relief of soreness?
I did a little digging, and found some interesting research conducted out of the University of Tampa back in 2002 that addressed whether pre and post-exercise stretching affected muscle soreness and the risk of injury.
This research was a compilation of 5 studies, with the focus being on military recruits. The data on stretching and muscle soreness indicated that, on average, individuals will observe a reduction in soreness of less than 2 mm on a 100-mm scale during the 72 hours after exercise.
With respect to risk of injury, the combined risk reduction of 5% indicates that the stretching protocols used in these studies do not meaningfully reduce lower extremity injury risk of army recruits undergoing military training.
Most of the physical benefits of a warm up (increased blood flow to the muscles, enhanced metabolic reactions, reduced muscle viscosity, increased extensibility of connective tissue, improved conduction velocity of action potentials, etc.) are obtained during the first few repetitions of an exercise.
2007 research conducted out of Sydney, Australia concluded that stretching before exercise reduced soreness on the day after by just half a point on a 100-point scale, and stretching after a workout reduced soreness by one point, and neither measure was statistically significant.
The 2007 study by Robert Herbert, Ph.D., and Marcos de Noronha, Ph.D. of the University of Sydney, conducted a systematic review and meta-analysis of 10 previously published studies of stretching either before or after athletic activity. They concluded that stretching before exercise doesn't prevent post-exercise muscle soreness. They also found little support for the theory that stretching immediately before exercise can prevent either overuse or acute sports injuries.
Much of this confusion comes from a misinterpretation of research on warm-up. These studies found that warming by itself has no effect on range of motion, but that when the warm-up is followed by stretching there is an increase in range of motion. Many people misinterpreted this finding to mean that stretching before exercise prevents injuries, even though the clinical research suggests otherwise. A better interpretation is that warm-up prevents injury, whereas stretching has no effect on injury.
If injury prevention is the primary objective the evidence suggests that athletes should limit the stretching before exercise and increase the warm-up time.
It is important to note that there are a multitude of studies that support the use of 30-second stretches for increasing range of motion and as such, it makes sense to add stretching as part of a general fitness program.
I choose to stretch independent of my workout (usually at night while watching the news). For my warm-ups I usually focus on a few of the core exercises I’ll be performing. For example, a typical warm-up may include: