What Happens When You Stretch

• "When you stretch, the muscle fiber is pulled out to its full length sarcomere by sarcomere, and then the connective tissue takes up the remaining slack. When this occurs, it helps to realign any disorganized fibers in the direction of the tension. This realignment is what helps rehabilitate scarred tissue back to health." This was interesting, and raised several questions for me. I would like to know what about scar tissue makes fibers disorganized and how it happens, as well as if there is any benefit from stretching out the connective tissue, which 'takes up the extra slack.'
• "This triggers the stretch reflex (also called the myotatic reflex) which attempts to resist the muscle length by causing the stretched muscle to contract. The more sudden the change in muscle length, the stronger the muscle contractions will be (plyometric, or 'jump,' training is based on this fact). This basic function of the muscle spindle helps to maintain muscle tone and to protect the body from injury." This caught my attention both because it could be relevant to my more effective joint project and because it sounded like an ingenious method of preventing injury, one I never even knew existed.
• "Some sources suggest that with extensive training, the stretch reflex of certain muscles can be controlled so that there is little or no reflex contraction in response to a sudden stretch. While this type of control provides the opportunity for greatest gains in flexibility, it also provides the greatest risk of injury if used improperly." This is interesting because it seems like the stretch reflex should be automatic, which leaves me wondering how one learns to control it, and if it takes a conscious effort to do so.

Relate and Review
    The article "What Happens When You Stretch" discusses what happens in your body when you stretch out a muscle- it's a surprisingly complicated process. The sarcomeres begin to lengthen as each overlapping pair of muscle fibers is pulled apart, although depending on the intensity of the stretch, some fibers will stay in place instead of stretching like all the other fibers. However, when you stretch, intrafusal fibers, more commonly known as muscle spindles, send signals to the brain and cause the stretch reflex, which makes the muscle contract. This reaction is particularly strong if the stretch is sudden. When the tension becomes too high, though, it causes a lengthening reaction, allowing the muscles to stretch in order to prevent injury.
    This article helped me to understand more about the physiology of muscles. It supplemented the lessons we have been learning on muscle contraction by teaching me more about the opposite function of muscles- stretching. I enjoyed learning about stretching, because I have always wondered how it works, but I still have many more questions. Why is it that, as a young child, I was more flexible than I am now? If you stretch too far, could you damage your connective tissues? How does stretching prevent injury?