Dr. Stewart McGill, possibly the most regarded expert of spine biomechanics, and professor at the University of Waterloo in Canada, has stated that “static stretching deadens the muscle from a neural perspective – diminishing the stretch reflex and reducing peak strength and power.“ He goes on to state that active warm-ups actually facilitate muscle contraction, and have a positive effect on muscle function. This line of thinking isn’t shocking to anyone who has followed studies published in the Journal of Strength and Conditioning Research, the Journal of Orthopedic and Sports Physical Therapy, Strength and Conditioning Journal, The New England Journal of Medicine, just to name a few, over the past 20 years. Those studies have shown stretching to decrease vertical jump eight, increase 40 yard dash time, decreased single leg stance stability, and have no benefit on decreasing injury rate. One study done by the US military showed that recruits who entered boot camp with the most flexibility for the most likely to get injured and not finished boot camp.
The question is, what should someone do with this information? First, it helps to understand what muscle is, what it does, and why it gets “tight.“
- Muscle is a contractile tissue.
- When it contracts, it either stabilizes a joint or causes motion at a joint.
- When muscles provide stability (like the muscles in your neck or as you read this), there should be equal contraction on all sides of the joint. When muscle contracts to cause motion (like bending your elbow to put food in your mouth), one group of muscles contract concentrically as the opposing muscles contract eccentrically. Notice, none of the muscles RELAX. If the muscle on either side relaxed, or misfired, joint mechanics would suffer, performance would decrease, an injury (acute or chronic) could also occur.
- Muscles get “tight“ when they don’t to give/receive a normal input with the nervous system. Nerves regulate muscle tension. If a muscle is in a shortened position, and doesn’t have normal regulation from nerve, it will contract and get “tight.“ Things like fatigue, swelling, dehydration, malnutrition, and stretching can cause the nerve/muscle relationship to be impaired.
Second, stop stretching, and know what to do instead.
- Isometrics help to engage muscle and “reset“ the nervous system input. When you watch a dog or cat wake up and “stretch“, they’re actually doing isometrics to get their muscles firing. Isometrics are easy to do, just think of flexing muscle that feel weak or tight, just like when you wake up.
- Use an active/dynamic warm-up prior to exercise. This could include a light jog, high knees, lunges, skips, push-ups, crunches, band or dumbbell work, etc. Anything that involves movement in and out of different positions would fall into this category.
- What about post workout cool downs? Just re-do your warm-up routine.
The take-home message here is that movements that engage muscle will increase range of motion, maximize athletic ability and decrease the risk of injury. This is a much better option than increasing range of motion by forcing muscles to relax, become weak and no longer function normally. So, get moving and leave stretching behind.