Warm up More Productive Than Stretching-

I’ve read studies on the topic of stretching for several decades and the consistent evidence is as Dr. Mirkin presents it (below).

Every opportunity I get to work with competitive dogs is an opportunity to reeducate the human clients about sport training and competition. People in the pet competition world often promote ball stretching as an acceptable form of pre-competition warm up or exercise.

Ball stretching before an event is more destructive than helpful. Coming out of a crate and trotting around just a short bit is not enough of a warm up prior to competition. Dogs should do better in events with at least a quarter-mile slow jog warm up and then a few sprints. This would also be beneficial prior to training drills as well. Just the basics…

The article below comes from Dr. Gabe Mirkin’s Fitness and Health e-Zine
April 7, 2013

Stretching Before Exercising Provides Only Flexibility

Whenever I see someone stretching before running, cycling, tennis, swimming, or any other sport, I worry that the person doesn’t know much about training.

Stretching Before Exercise Only Weakens Muscles:

Two recent studies show that stretching before competition and training weakens muscles. Stretching prevents you from lifting your heaviest weights or running your fastest miles. It limits how high you can jump, and how fast you can run (The Journal of Strength and Conditioning Research. April, 2013; The Scandinavian Journal of Medicine and Science in Sports, April, 2013).

Stretching weakens muscles by almost 5.5 percent. The longer you hold the stretch, the more strength you lose. Holding a stretch for more than 90 seconds markedly reduces strength in that muscle. Stretching reduces power: how hard you can hit a baseball or tennis ball, how fast you can swim, run or pedal, Stretching also does not prevent next-day muscle soreness, and it does not prevent injuries. On the other hand, warming up helps to prevent injuries and helps you to run faster and lift heavier.

How Muscles Move Your Body:

Every muscle in your body is made up of thousands of individual fibers. Each fiber is composed of sarcomeres, repeated similar blocks, lined end-to-end to form the rope-like fibers. Each sarcomere touches the sarcomere next to it at the Z line. Muscles move your body by contracting, a shortening of each muscle fiber. Muscles do not shorten (contract) equally throughout their lengths. Muscles contract only at each of thousands of Z lines. It is the cumulative shortening of thousands of Z lines that shorten fibers to make muscles contract and move your body.

How Stretching Saps Strength:

When you stretch a muscle, you pull on the muscle fibers and stretch apart each fiber at the thousands of Z lines. This damage occurs only at the Z lines throughout the length of the muscle fiber, to weaken the entire muscle.

Prolonged Stretching Limits the Ability of Muscles to Store Energy:

Muscles are like rubber bands. They stretch and contract with each muscle movement. This constant stretching and contracting stores energy. For example, when you run, you land on your foot and the muscle stops contracting suddenly.

The force of your foot striking the ground is stored in your muscles and tendons and this energy is released immediately to drive you forward. Your foot hits the ground with a force equal to three times your body weight when you run at a pace of six minutes per mile. Up to 70 percent of the force of your foot strike is stored in your Achilles and other tendons. This energy is released by your muscles and tendons to drive you forward for your next step.

Stretching decreases the amount of energy you can store in muscles and tendons and therefore weakens you and you have less stored energy to drive you forward, so you have to slow down.

Stretching Saps Speed and Endurance:

Elite college sprinters were timed in 20 meter sprints, with and without prior multiple 30-second stretches of their leg muscles. Both active and passive stretching slowed them down (Journal of Sports Science, May 2005).

Stretching Does Not Prevent Next Day Muscle Soreness:

A review of 12 studies published over the last 25 years shows that stretching does not prevent muscle soreness that occurs 8 to 24 hours after you exercise vigorously (The British Journal of Sports Medicine, December 2011; 45:15 1249-1250). Researchers in Australia reviewed five studies, involving 77 subjects, to show that stretching does not prevent next-day muscle soreness. (British Medical Journal. December 2007; 325:468-70 and 451-2).

Stretching Does Not Prevent Injuries:

A review of the scientific literature shows that there is no good evidence that stretching prevents sports injuries (Clinical Journal of Sports Medicine. March 2005). Muscles and tendons tear when the force applied to them is greater than their inherent strength, so anything that makes a muscle stronger helps to prevent injuries. Strengthening muscles helps prevent muscle and tendon tears, but stretching does not make muscles stronger. This review showed that stretching does not prevent shin splints, bone stress fractures, sprains, strains or other arm and leg injuries.

Original Post August 3, 2014. Updated February 19, 2018