The Importance of Stretching

December 8, 2015

If you have ever exercised or played sports you have most likely been told about the benefits of stretching. However, you wouldn’t be alone if you didn’t know exactly when or how to stretch to best prepare your muscles for activity and prevent injuries. In a new study published in Applied Physiology, Nutrition, and Metabolism, David Behm and his co-authors reviewed hundreds of studies to determine the best way to stretch. Their findings? You’ve probably been doing it wrong all along. 

By David Behm

We don’t really know when stretching was first incorporated as a warm-up activity for humans. Although predators such as cats, wolves, dogs and other animals have been observed stretching upon waking or after being stationary for prolonged periods, we don’t know if historically, humans systematically stretched prior to hunting, fighting, or early competition like jousting.

We do know that systematic stretching was incorporated during the training of soldiers during the world wars and scientific investigations of optimal resistance training routines were sought out by Colonel DeLorme of the United States Armed Forces. Soon thereafter, Dr. Orban, a Canadian researcher, in conjunction with the Royal Canadian Air Force developed the 5BX (5 Basic Exercises) program, which involved ballistic type activities. Ballistic exercises involve stretching the muscle with rapid bouncing or explosive movements like bounding, jumping and hopping activities. These ballistic activities for stretching and muscle endurance became quite popular and were used not only for military personnel but also as training in physical education classes and athletic pursuits. 

However, after many years this type of dynamic stretching lost popularity when it was cautioned that dynamic or ballistic activities that elicited reflex muscle contractions while elongating the muscles and tendons could result in injury. This resulted in static stretching becoming the dominant activity within a warm-up to increase range of motion (ROM). Static stretching was recommended since the slow movement into the stretch position and maintenance of a static stretch over a prolonged period would minimize the reflex firing of the muscle. Static stretching has been demonstrated as an effective means to increase ROM resulting in improved performance, a decrease in subsequent muscle soreness and a reduction of the incidence of activity-related injuries.

Since the 1960s static stretching has been considered an essential component of a warm-up but is it really the best way to stretch? 

Recently, a substantial body of research has been published showing that sustained static stretching could impair subsequent performance. This has resulted in a shift once again from static stretching back to dynamic stretching, however there remains much confusion and disagreement regarding the benefits and risks of static vs. dynamic stretching within the stretch literature. 

So what is the best way to stretch? 

Our new review paper shows that static stretching can be used in your warm-up to increase ROM and help prevent injuries if the following procedures are followed:

  1. At least 5 minutes of aerobic activity that increases your core temperature by 1-2 degrees Celsius (you should start to sweat lightly) before stretching.
  2. Static stretching of each muscle should not exceed 60 seconds. For example, you can stretch your hamstrings for 3 repetitions of 20 seconds or 4 repetitions of 15 seconds and do the same for other muscle groups like the quadriceps and calves.
  3. Follow static stretching with 5 to 15 minutes of dynamic stretching and sport or activity-specific dynamic activities (e.g. tennis players move and hit a variety of different shots, basketball and hockey players practice shots, passes and movement).
  4. Do not use prolonged (>60 seconds per muscle group) static stretching within 5 minutes of an activity without subsequent dynamic activity.
Integrating new research findings into your warm-up, workout or lifestyle

With so many new studies being published each year it is essential that you critically assess the research before fully integrating the findings into your warm-up, workout or lifestyle. When reading these studies pay attention to the duration of the stretching, whether there was a prior aerobic warm-up or subsequent dynamic activities. Is the duration of stretching valid or realistic or is it much longer than what the typical athlete would do? Did the researcher just study stretching in isolation without dynamic activities before and after the stretching, as you would find in typical athletic situations? Was the subject group used in the experiment applicable to you? Was the study conducted on humans or animals? If you are a 65-year-old, a study that examined 18-year-old Olympic athletes is not going to apply to you. Consider if the findings are of significance to you personally. For example, if static stretching can reduce the incidence of muscle strain injuries but causes a 5% reduction in performance, is that small impairment important to you when you play your weekly golf game with your buddies? Remember that not everything that is statistically significant is personally significant!

Watch Dr. Behm's TedX Talk: Stretching the way we think about athletes

"Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review" by David G. Behm, Anthony J. Blazevich, Anthony D. Kay, and Malachy McHugh is now available for free in Applied Physiology, Nutrition, and Metabolism.

David G. Behm PhD, School of Human Kinetics and Recreation, Memorial University of Newfoundland: Dr. Behm was drafted in the Canadian Football League (CFL) by the Ottawa RoughRiders, worked as a hockey and football coach at Bishop's University, managed an athletic club in Dartmouth, NS, and lectured at the University of Regina. Dr. Behm completed his master's degree from McMaster University under the supervision of Dr. Digby Sale and completed his doctorate in rehabilitation science from McGill University (advisor: Dr. Diane St-Pierre) while working full-time as a physical education teacher at Dawson College. He has published over 180 articles in peer-reviewed scientific and professional publications, provided invited presentations to audiences in North and South America, Europe and Australia and has appeared on national and local television and radio.

Filed Under: NRC Research Press Science News Applied Physiology Nutrition and Metabolism

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