What Happens When We Stretch

Relate and Review: 

Our muscles are stretched by elongating the sarcomeres, increasing and decreasing the area of overlap between the myofilaments. When the muscle is enlongated to its full extent, the sarcomeres are fully stretched and collagen fibers in the connective tissue align themselves along the tension. When a muscle is stretched, some fibers elongate, but others do not move and stay at rest. Proprioceptors give us the ability to sense our body's position and movement, detecting changes to our physical movement. When our muscle contracts, tension is transferred to the golgi tendon organ. It is important to stretch for long periods of time because the muscle "habituates" to the new length, allowing your muscles to gradually increase in length over time. When I stretch for color guard, each muscle stretch us held for around 30 seconds to 1 minute, sometimes even longer. We also stretch the muscles in different ways: for example, when we stretch our legs we'll bend over with our feet pointed and stretch over with our feet flexed to stretch different muscles. The reason we become more flexible is through the persistent stretching of the same muscles consistently, giving more elasticity to the fibers and habituating our muscles to the new length. It is more difficult to stretch a contracted muscle, therefore stretching for a prolonged period of time helps the muscle relax when being stretched. 

Quotes: 

"One of the reasons for holding a stretch for a prolonged period of time is that as you hold the muscle in a stretched position, the muscle spindle habituates (becomes accustomed to the new length) and reduces its signaling."

• When we stretch in color guard, the goal is to become more flexible and warm up our muscles for the physical activity ahead. We often push the stretches a little further, and this will eventually accustom the fibers to be longer. This results in a longer muscle and more flexibility. We usually hold our splits for at least 2 minutes, in order to get effective stretching and truly elongate those muscle fibers, resulting in a larger and more elastic muscle. 

"Just as the total strength of a contracting muscle is a result of the number of fibers contracting, the total length of a stretched muscle is a result of the number of fibers stretched -- the more fibers stretched, the more length developed by the muscle for a given stretch."

• Both contraction and stretching is controlled by muscle fibers creating a parallel reactions in our muscle, increasing the contracting fibers and increasing the stretch fibers help our body adjust to the physical activity we assert onto it. I understood that stretching your muscles overtime makes you more flexible, but I was not aware of the individual fibers that are extended. 

"The muscle spindle records the change in length (and how fast) and sends signals to the spine which convey this information."

• Our nervous system plays a role in remembering the changed length of our muscles when we stretch by sending a signal to the spinal cord, which then sends it to the brain. This recorded measurement plays a role when our muscles habituate and keep that new stretched length. This signal also triggers the stretch reflex to resist the change and cause the muscle to contract; this function prevents the body from injury and maintain the tone of the muscles.