Stretching Basics

WHEN TO STRETCH? BEFORE EXERCISE, AFTER, OR BOTH?

Even though this really isn’t a shoulder specific post, this is a question it seems like I address every day. It has been an accepted dogma that you must stretch before exercise, although no research proves that it’s necessary for injury prevention. A review by Witvrouw et al showed that there is an obscure relationship between stretching and injury prevention. Thacker et al found in a systematic review of literature that there is no evidence to endorse or discontinue stretching before or after exercise to prevent injury. Intuitively, it would seem that it can’t be true, but the research has not shown otherwise. I imagine the reason that it’s always been assumed that we should stretch before exercise because the perception is that if you go into an exercise or competitive session “tight” you are at risk for injury. Clinical experience and the literature reveal that this argument is partly true.

First of all, it’s important to understand the different types of stretching. Static stretching is what we’re most familiar with – placing a muscle or joint on stretch and holding the stretch position. For example, placing your foot on a chair to stretch your hamstring. Now, static stretches can be active or passive. Active is when you do it yourself and determine amount of stretch, or passive when someone does it for you. Dynamic stretching is basically stretching while moving. An example of dynamic stretching is doing lunges with exaggerated steps, doing “high knees” while running, etc. The next type of stretch is ballistic. Ballistic stretching, depending on who you talk to, can be thought of in two ways. One method is to hold a static stretch and then move back/forth to increase range, or “bounce” back and forth. The other and more common way is to perform jumping and hopping maneuvers. For example, jumping up/down from a box. The theory behind this is that by increasing activity of the muscle spindle (stretch of this determines the speed of contraction), it increases acute power. Some people argue that ballistic stretching is actually a bad idea because it may actually shorten the muscle through the muscle spindle. Regardless, it’s important to know about ballistic stretching. Finally, PNF (proprioceptive neuromuscular facilitation) is the last type. Here, a muscle is stretched by contracting the opposing muscle. PNF is used both for flexibility, strengthening, and for rehab. It is an excellent treatment tool.

Static stretching (place and hold) has been shown to actually decrease acute strength and power. Winchester and others have found that it impairs sprint performance and Robbins et al found that it adversely affected vertical jump performance. Other studies have substantiated these conclusions. The proposed reason that this occurs is basically due to muscle’s length-tension relationship. Essentially, muscle physiology principle says that the muscles contractile proteins (actin and myosin) are supposed to have an optimal position so maximize muscle function. It is believed that acute bouts of stretching increases that length and subsequently decreases the ability of the muscle to contract at its best. Hopefully, that makes sense.

All that being said, evidence is mounting that performing dynamic stretching before exercise is the best way to “stretch” before exercise. Ce et al and Manoel et al are just two groups of researchers that have recently found that dynamic stretching is the optimal way to increase power prior to sport performance. I tend to agree that dynamic stretching is the way to go the more I practice. First of all, because it’s dynamic, you are moving and you’re likely to work up a sweat. If you are sweating, there is increased blood flow which has been shown to increase tissue extensibility. Further, it is believed to increase joint mobility as well because it’s multi-directional. The problem with static stretching is that in order to get benefit, you can’t be “cold”. Basically, it’s better to do some squats, lunges, and push ups for example when you hop out of bed for a jog as opposed to just putting your leg on a chair and stretching. Hopefully, that makes sense.

So, what’s the best way to stretch? In my opinion, I prefer a general warm up first. A bike, a short jog, an elliptical trainer, or stair stepper is just a way to get the heart rate up and work up a sweat. After a 5-10 minute warm up, the athlete or patient performs a specific or dynamic warm up. Here, they’ll perform a series of movements in the upper and lower extremities. Lunges, mountain climbers, and arm circles are just a few examples that would follow for another 5-10 minutes. I encourage athletes to continue moving and take no rest between these movements to keep the heart rate up. After this is done, I would then move into the rehab or conditioning session.

Once the session is done, a brief stint on a bike or a short jog is a good way to “flush” the body of waste products created during exercise to help minimize delayed onset muscle soreness (DOMS). I assure you’ve had DOMS if you woke up the morning after an intense workout and could barely walk! After the cool down period, I then have the athlete perform static stretching. In theory, static stretching should be more productive at this point because the tissues are much warmer and more extensible at this time as opposed to being “cold” prior to any exercise.

Hopefully, that makes sense. I’d love to hear what you think…

Witvrouw et al, Sports Med, 2004; Robbins et al, J Strength Cond Res, 2008; Winchester et al, J Strength Cond Res, 2008; Ce et al, J Strength Cond Res, 2008; Manoel et al, J Strength Cond Res, 2008

WHEN I STRETCH, HOW LONG SHOULD I HOLD IT FOR?

Again, a common question that gets asked on a regular basis. Two studies by Bandy and others have shown that holding stretches for 30 seconds is the optimum time frame to hold a stretch for acute increases in flexibility. The “rub” here is that you aren’t going to sustain the new length unless you consistently stretch.

It is worth clearing up some misconceptions about stretching. If someone stretches your hamstring and you have greater range of motion or can bring your leg higher, that is not an actual increase in muscle length. You have many soft tissues that compose and attach to muscles that are increasing in length that result in an acute increase in flexibility. To actually increase muscle length, you have to stretch consistently over a few weeks. You haven’t actually increased length of individual muscles, you have added muscle “sarcomere’s, which is a fancy term for muscle cells. It is beyond the scope of this blog to go into extreme detail on sarcomeres. Please just understand that there is a difference.

Bandy WD et al, Phys Ther 1997; Bandy WD and Irion JM, Phys Ther 1994