What is posture? “Posture may be defined as, ‘the position of one or many body segments in relation to one another and their orientation in space’ (Ham et al, p.26).” It is the position in which one holds the body while standing, sitting or lying down. Traditionally these three positions are the main ones adapted by the body, however there are multitude of intermediary postures to assume these three final positions. Postures can also be classified as static or dynamic based on whether you are moving or relatively in a still position.
Posture can be impacted by several factors, most basic of which are joint position, muscle tone and gravity.
Nowadays a lot of attention is being given to good posture since, with all the technology available, we are doing less walking and upright activities and more sitting. Heard of the popular phrase, “Sitting is the new smoking?” This phrase was coined by Dr. James Levine, director of Mayo-Clinic at the Arizona State University. This is not literally true. In fact, “sitting” is being compared to “smoking” to bring home the point that the side effects of sitting for more than 6 hours a day are equivalent to the health hazards caused by smoking. For example, their study reveals prolonged sitting can predispose to heart disease, and even certain types of cancer. In that context, standing desks may be a blessing.
From a physiological point of view, our body has different types of muscle fibers. And since prolonged sitting calls for holding a posture, it employs what are the slow-twitch (type I) muscle fibers, or the red fibers, which have a profuse blood supply to permit aerobic metabolism. The other type of muscle fiber, the fast-twitch (type II), or white muscle fiber, (so called due to fewer blood vessels and anaerobic metabolism), is employed for power activities needing greater force and speed like sprinting. The good news is that with endurance training, human skeletal muscle fibers can show increased blood supply. Studies on fish’s white muscle fibers show these fast twitch muscle fibers, when subject to slow low frequency stimulation, behave like slow red fibers with increased blood supply. This is where training comes in and thus, listen to your physical therapist when they say practice for “x” repetitions and do “y” number of sets. With early intervention, the process, if followed diligently, can reverse effect on the muscle fibers! That is why it gets easier to sit, or the achiness and soreness experienced in muscles decreases with postural exercises. Extrapolating this, sitting may actually be a boon- ever wonder why meditation (in other words maintaining a posture for prolonged periods) is found to have beneficial effects? The body never ceases to amaze us, does it? Anyway, the point I want to make is don’t get hung up on what the body does, go beyond.
Ami Gandhi is a licensed physical therapist in the state of California. She is the owner of StableMovement Physical Therapy, a small boutique practice in San Jose that offers patient centered, one-on-one, hands-on physical therapy.