To Stretch or Not to Stretch?

I invite you to explore the science of stretching so you understand how to use stretching properly in order to increase range of motion and flexibility without negatively affecting muscle strength and force generation.

When I ran cross country in high school, the whole team would meet on the upper field and usually start our practice with some static stretching. You have seen and probably done these stretches; standing, sitting, lying down, bend at the waist, touch your toes, hold a particular pose that focuses on a particular muscle or set of muscles. Hold it for 30 seconds or so, switch to the next pose. Hamstrings, quads, calf muscles, shin muscles, lats, stretch your core, roll out your neck, bend to the side. We stretched them all. Then we would head off into the woods to run for the rest of practice. What did all that stretching do for our running? Well, as it turns out, not a heck of a lot.

  1. Physiology of a stretch

It is thanks to our Golgi tendon reflex that we can stretch a muscle (within reason) without causing injury. The Golgi Tendon Organ (GTO) is a nerve receptor located at the junction of a muscle and tendon (tendons connect muscle to bone).  When we stretch, the GTO senses the tension in the muscle/tendon unit and sends a message to the spinal cord. The spinal cord receives that message and then sends a message back to the muscle to relax. This is the Golgi tendon reflex. Without it we would pull muscles all the time in everyday use as well as in sports and stretching.

Muscle spindles also play a role in the physiology of a stretch. Muscle spindles are stretch receptors located deep within a muscle that work to protect the body from injury due to over stretching. They sense how much and how fast a muscle is lengthened or shortened and send a signal to the spine which triggers the stretch reflex. The stretch reflex resists an increase in muscle length by causing a muscle to contract. The more rapidly muscle length increases, the stronger the stretch reflex is. The goal of stretching is to minimize the stretch reflex so a muscle can be lengthened thus increasing flexibility and range of motion. When holding a stretch for a long time (greater than 40 seconds) the muscle spindles get used to the increase in length and reduce the signals sent to the spinal cord to tell muscles to contract. 

2. Strong muscles are tight muscles?

Muscles are like springs – they store and return energy.  Think back to high school physics and you might recall that the stiffer the spring, the greater the energy stored.  You know the metal springs you find in cheap plastic pens? The ones that pop out and go flying when your pen breaks?  The spring goes flying because there is energy stored in compressed or tightly wound coils. Once the spring is stretched out though, it no longer has the potential to sproing across the room.  And like a stretched out spring, a stretched out muscle stores less energy and is able to produce less force. Scientists now theorize that pre-stretching a muscle before exercise decreases the force production of a muscle while running. 

3. Static vs. Dynamic stretching

Static stretches are the old school ones – where you hold a single stretch for 30-60 seconds without movement; think of your classic quad stretch – while standing, bend one knee and grab your foot behind you, hold for 30-60 seconds. Static stretches are great for increasing range of motion. They are an important component of recovery after your run, when you want to loosen up tight muscles but as it turns out, not the best pre-exercise.

Dynamic stretches are controlled active movements where joints and muscles go through a full range of motion like walking lunges or straight leg kicks. Dynamic stretches can be functional and mimic the movement of the sport you are preparing for, in this case running. They are a great way to warm up before exercise. Because dynamic stretches are not held, rather they are a movement through range of motion, they don’t have the same impact on the muscle spring that a static stretch can. Dynamic stretches are an important part of your warm up pre-run.

4. Do I still need to warm up?

Regardless of what sort of exercise workout you have planned, a warm up is always important. A warm up allows your body to ease into exercise. Just like you don’t start you car and drive away in 5th gear, you don’t want to start your workout at a full-tilt boogie! A good warmup will prime your cardiovascular system for hard work, raise your body temperature, and increase blood flow to your muscles ensuring that your muscles are well-supplied with oxygen. It will also help minimize the chance of injury. A warm up for running doesn’t need to be complicated – just ease into it. Start with 15-20 minutes of easy jogging or even walking before diving into the meat of your workout. Add some functional dynamic stretches after your warm up and your body should be ready to go. For added injury prevention, specifically target any tight or injury prone areas of your body with your choice of dynamic stretches. Tight hamstrings? Try a hamstring sweep. Trouble with plantar fasciitis, shin splints, or tight Achilles? Try ankle and calf mobilizations. Need to wake up your glutes before you run or struggle with IT Band issues? Try glute and piriformis activation.

With proper use of stretching and warm up you can prime your body for an injury-free workout without compromising the force production capacity of your muscles.

Next running workout, start out with a 15-20 minute easy jog followed by a couple minutes of dynamic stretching. Try one of the following dynamic stretches:

Hamstring Sweep:

Take a short step forward keeping the heel firmly on the ground. Keep the front leg straight and bend the back knee (allow the toes of your straight leg to come off the ground) sinking your bottom towards the ground as though you’re about to sit in a chair. Keeping your front leg straight, sweep down with your hands towards the ground creating a dynamic stretch on your hamstring muscle group. Don’t hold the stretch, rather move to the next leg! Each movement should take only 2-3 seconds on alternating legs over a 20 meter distance at a slow walking pace. Repeat for 3 x set.

Ankle and Calf Mobilizations:

Place the foot on the ground, toe and ball of the foot first. Then lower your weight through the foot eventually allowing the heel to return to the ground. Each movement should take 1-2 seconds per foot. Aim for 15-20 seconds but pick up the pace to a brisk walking speed. Repeat for 3 x set with a recovery walk back in between.

Glute and Piriformis Activation:

Stand up straight with good posture and balance. Bring one ankle up across the other knee, use your hand to invert the foot toward the knee and then up towards the waist. Hold onto a railing or a friend for balance. Feel the stretch in the glute and lateral quad area. Each movement should take 2-3 seconds on alternating legs over a 20 meter distance at a slow walking pace. Do 3 full sets with a walk-back recovery.

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