Stretches that work several muscle groups at once are great for upper-body warm-ups before a workout, an Australian study finds.
Getting the blood flowing
Although athletes and coaches often swear by stretching, many common pre-workout routines may not actually enhance performance, said lead author Matt McCrary, a master's degree candidate at the University of Sydney.
Higher load dynamic warm-ups are "the best bet" in most situations, said McCrary. For the upper body, these include pushups, dumbbell back flys, and resisted lateral raises, he told Reuters Health by email.
Dynamic stretches focus on getting the blood flowing and increasing range of motion by using multiple muscle groups simultaneously. Unlike static stretches, which generally involve holding a single pose for a minute or two, dynamic stretches use a series of controlled movements.
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To analyse the effect of upper body warm-ups, McCrary and colleagues reviewed findings from 31 past studies.
The review, published in the British Journal of Sports Medicine, included 628 people playing sports at many levels, from youth leagues to college athletics and adults in recreational activities. Most studies involved sports where upper body strength is essential, such as baseball, football, tennis, golf, kayaking and shot put.
The review found that high-intensity dynamic stretching improved strength and flexibility while delaying muscle soreness.
Low-intensity stretching has little effect
But low-intensity stretching had little effect on performance, which agrees with previous research on upper body warm-ups, McCrary said.
"Flexibility increases are generally unrelated to any type of performance improvements," he noted.
Heating and cooling during a warm-up also does little to improve performance, the study found. While applying heat to specific muscles before strenuous activity may minimise the loss of flexibility in the days following the workout, this practice didn't show other benefits.
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And for baseball players, batting warm-ups didn't work as well when bats were much lighter or heavier than those used during games.
"This runs somewhat contradictory to the prevailing narrative that higher load warm-up is better than lower load warm-up," McCrary said.
"The two theories here are that warm-up swings with a heavier weight bat significantly and sub-optimally alter swing mechanics and/or that a resisted movement longer in duration than a baseball bat swing is necessary to produce a warm-up effect."
Fatigue by warm-up exercise
While high intensity dynamic stretching can help elite and professional athletes, the same warm-ups may not be a good idea for more casual exercisers, said Dr. Kazuki Takizawa, an associate professor of sports training science and exercise physiology at Hokkaido University in Japan.
"Warm-up exercises may reduce injury by improving performance for serious athletes," Takizawa said in an email. "But recreational athletes and weekend warriors are at a lower physical fitness level, especially in aerobic capacity, and they may fatigue by warm-up exercise and reduce performance."
Takizawa also made a distinction between endurance sports like long-distance running or cycling and more intense activities done for shorter periods.
"Short-term, high intensity exercises need vigorous warm-up," Takizawa said. "But long-term endurance exercises do not."
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Because the study didn't look specifically at injury prevention, it's impossible to say for sure how intense dynamic stretching or other warm-ups might affect the risk for injuries, McCrary said.
"We haven't really zeroed in on what kinds of warm-ups best prevent injuries," he said. "Anecdotally, I feel like warm-ups definitely do play a role in injury prevention, however, further study is required before I'd be able to confidently make any recommendations or explain how or why this is the case."
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Image: Man Stretching from Shutterstock