New research puts an interesting twist on the age-old “we must stretch” mantra most of us have been hearing since we started Physical Education class as children. Researchers at Nebraska Wesleyan University looked at runners’ flexibility and their “running economy”, or how much oxygen they used when running. Running economy is considered one of the most important factors in distinguishing great runners from good ones.
When the research physiologists compared the runners’ sit-and-reach scores to their running economy scores, they got a surprising result. The least flexible runners had the highest running economy. This was true across the board, and within each gender. That is, the tightest men had better economy than the women, and for both genders, the least flexible had the best economy and the fastest 10-kilometre race times. The researchers hypothesise that tighter muscles allow for more efficient energy storage and use during each stride.
This result goes counter to what much of us have considered the cornerstone of fitness for decades. While there’s been some debate as to how much stretching should be done before exercise, when your muscles are not warm, we’ve always been taught that flexibility is a critical component of fitness. “It’s been drummed into people that they should stretch, stretch, stretch — that they have to be flexible,” says Dr. Duane Knudson, professor of biomechanics at Texas State University in San Marcos, who has extensively studied flexibility and muscle response. “But there’s not much scientific support for that.”
It is thought by some that when we stretch before we work out, we lengthen our muscles and increase our range of motion. Apparently recent science indicates that although we stretch regularly, the actual length of our muscles and tendons doesn’t change that much. According to Dr. Malachy McHugh, the director of research for the Nicholas Institute of Sports Medicine and Athletic Trauma at Lenox Hill Hospital in New York, what increases as you stretch is your tolerance for the stretch. “You’ll start to develop a tolerance for the discomfort of the stretch,” Dr. McHugh says. “Your brain will allow you to hold the stretch longer. But the muscles and tendons themselves will not have changed much. You will feel less tight. But even this sensation of elasticity is short-lived.”
A new review article on the effects of stretching in the Scandinavian Journal of Medicine and Science in Sports, Dr. McHugh looked at the effects of several stretching regimens. He found that when people stretched their hamstrings for four, 90-second periods, they felt much looser, and their “passive resistance” to the stretch decreased by 18 percent. However, the effect went away within an hour. He contends that you only see actual, physical changes in the muscles with months of daily stretching, for hours at a time, such as that done by gymnasts and dancers – something most of us clearly aren’t going to do.
Which brings us to the main point of flexibility: functionality. You need enough range of motion in the joints to complete daily tasks and avoid injury. While most of us would agree we don’t need the flexibility of a ballerina in daily life, a certain degree of flexibility is very useful and should be consistently maintained. All of us need to be able to reach a high shelf, tie our shoes, and dodge out of the way of the kid on the bike at short notice. This level of flexibility requires some basic daily stretches, most of which can be completed in about 15 minutes and without pain. Ask your personal trainer or fitness class instructor about the best stretches for your daily needs.
This new research shows that runners may benefit from a degree of inflexibility, so extra efforts at stretching probably won’t help your running time. The message seems to be to evaluate your daily activity and injury prevention needs, and design your stretching program accordingly. If you are a dancer, you’ll need to spend those hours working on your splits. If you are a yoga instructor, flexibility is a key component of your work. But if you are the type who works out at the gym or on the track or bike, you need not feel guilty for not spending as much time on the flexibility as they do.