Static stretching (holding for 20–30 seconds) used to be the recommended limbering method to use before workouts. The thought was that it would prepare the muscle and reduce the risk of muscle injury. Research has recently confirmed that this not only does little to reduce injury, but it also actually decreases muscle strength. However, a type of stretching called dynamic stretching, in which you don’t hold the stretches but do them as quick reps, may actually increase strength and flexibility, as a new study reports.
Researchers from the University of North Carolina at Chapel Hill had male and female soccer players perform one of three warmups before they were tested for leg strength and flexibility. Each group first warmed up on a stationary cycle for five minutes. One group performed static stretching for the legs, holding each position for 20 seconds. A second group performed dynamic stretching, such as butt kicks, walking lunges, and carioca (the sport step/drill, not karaoke, where you grab a mic and pretend to be on American Idol). A third group did no stretching after the cycling warmup.
They found that the group doing the dynamic stretching increased leg strength by 12% and flexibility by more than 35%. The groups doing the static stretching and the group doing no stretching had no positive changes in leg strength or flexibility.
Dynamic stretching at the start of a workout may increase muscle strength and flexibility, while static stretching before workouts offers no benefit.
Consider doing dynamic stretches specific to the muscle groups being trained at the start of each workout. Doing so can help increase muscle strength and enhance flexibility. Good upper-body dynamic movements include arm circles, arm swings, and side bends. Good lower-body dynamic movements include butt kicks, walking lunges, and carioca. But don’t completely give up on static stretching. Use that at the end of the workout as a cooldown and to stretch out the muscles that were trained.
Reference: A.J. Aguilar et al., J Strength Cond Res., 26(4):1130–41, 2012.