We all know we should be stretching. But when is the best time? How long? How often? Does it matter what kind? So many questions!
As we age, we should all be stretching more. As freshly hatched youngsters we are flexible and as we grow the muscles start to tighten and tone increases, supporting the bones and joints. As we get older our tendons become less elastic, our cartilage starts to thin, ligaments become shorter, and the lubricating fluid inside the joints decrease. This causes decreased mobility and increased tightness in muscles, joints, and tendons.
There are three kinds of stretching. The first is a gentle prolonged stretch. This is known as static stretching. Each position is eased into gently and held for a certain time—30 seconds to 2 minutes. This is generally the best stretching for recovery and post-workouts. And this is often the classic kind of yoga style stretching, though yoga itself I split into sub-categories for different techniques and styles. Static stretching after a workout also helps prevent and relieve sore muscles.
There is also ballistic stretching which is characterized by “bouncing” into the stretch quickly, not maintaining for more than a few seconds at a time. Due to the sudden speed and intensity, something called the “stretch reflex” starts. This causes the muscle group to then tighten after each stretch. For example, someone squatting down quickly and returning to standing over and over will get a stretch in their quads/hamstrings on the way down, followed by a contraction when they stand up. This kind of stretching is best done in preparation for explosive movements. An example is a cross-fitter who will be doing a very fast compound lift for their one-rep max. They can actually use this reflex to their advantage to increase the recoil through the movement, whereas static stretching prior to this kind of lift would actually cause them to lose power and would not be beneficial.
Dynamic stretching is a bit of a mix. It’s usually specific to the muscle groups prepared for a certain activity. An example would be running or swimming. Runners will use dynamic stretching such as walking kicks for hamstring and hip flexor stretches, side to side kicks for the hips, and vaulting up onto the toes for quads, and butt kicks for quads. A swimmer will require more upper body dominant stretches for the shoulders, arms, and neck. Those funny flapping motions done by Michael Phelps before jumping in the pool are very dynamic and specific!
PNF stretching stands for proprioceptive neuromuscular facilitation. It’s a more advanced form of stretching often used in rehab. Unlike the stretch reflex that causes a contraction, PNF stretching starts by initiating a contraction and then relaxing into a stretch. The brain receives a signal following a contraction to relax the muscle fibers even further after a muscle contraction. They’re opposites! There is a couple of different techniques. On involves contracting a muscle group for 5-10 seconds, and then stretching that same muscle group. This is called contract/relax. The other is contracting one muscle group while stretching the opposite at the same time. This is contract/relax antagonist and is also referred to as reciprocal inhibition. These techniques can often be very beneficial for PT when pain is high and the muscles tend to be guarding during stretching, especially if a patient is anxious for a painful stimulus after a surgery when pain is already high. General consensus from one article in the Journal of Medicine & Sports in Science shows PNF stretching is better for tendon stiffness but both PNF/static are good for sore muscle stiffness. They also found PNF stretching to cause the most deficits for power movements due to fatigue in agreement to our crossfitting example as it’s more fatiguing than other stretching techniques. It also appears that increased range of motion is directly affected by the length held of static stretches, with more hold leading to more range of motion. However, it’s important to ease into longer holds as being too aggressive can cause some soreness (Konrad, Stafilidis, Tilp, 2016).
The general recommendations according to the American College of Sports Medicine:
- Warmup prior to stretching so the muscle is warm
- Stretch 2-3 days a week, stretching to the point of mild tightness but not pain
- Hold the stretch 10-30 seconds (individuals older than 65 benefit from a longer held static stretch and it is recommended to hold 30-60 seconds to better maintain flexibility)
- Repeat 2-4 times per muscle group
- Complete 2-3 days a week, with greater gains if done daily
Konrad, A., Stafilidis, S., & Tilp, M. (2016). Effects of acute static, ballistic, and PNF stretching exercise on the muscle and tendon tissue properties. Scandinavian Journal Of Medicine & Science In Sports, 27(10), 1070-1080. doi: 10.1111/sms.12725
American College of Sports Medicine,, In Riebe, D., In Ehrman, J. K., In Liguori, G., & In Magal, M. (2018). ACSM’s guidelines for exercise testing and prescription