atp

Rigor

Last week I returned to my massage alma mater in Bend, Oregon to take a continuing ed class on deep tissue sports massage with a focus on injury treatment and prevention. My instructor was Bill Musser, a former NCAA College Division All-American swimmer, an orthopedic nurse, and a university instructor, coach, and administrator, with 40 years of manual therapy under his belt. We've all heard the term rigor mortis, the postmortem state of muscular contraction; but it was Bill who first coined the terms rigor livis, and explained that the same thing happens in the muscles of the living. 

Muscles need a type of fuel called ATP to contract. In individual muscle fibers, myosin heads lock onto actin and then ratchet the fiber tight, like an oar pulling a boat forward through water. What most folks don't realize is that muscle fibers don't just use ATP to contract; they also need ATP to relax, for the myosin to let go of the actin. If we exhaust all available fuel during the contracting phase, muscles will remain in a locked, shortened state. This is rigor. 

Deep tissue massage is the physical act of breaking myosin heads away from the actin they are locked onto, returning the muscle fibers to their original, resting state. How can we prevent our muscles from forming rigor? The two easiest ways are with sufficient hydration and a proper warm up. 

Water is the catalyst for ATP fuel production in muscle cells. We loose 8oz of water for every 15 minutes of physical exertion, or two pounds an hour, so we need to make sure muscles can continue to make the ATP they need to avoid rigor from forming due to dehydration. Seventeen gulps of water two hours before exercise gives the body time to turn this water into blood and to keep tight bands of rigor from forming. 

At rest, 80% of our bodies blood supply is in our trunk, close to our internal organs. It takes 8-12 minutes of gentle aerobic activity to open up the capillaries in our extremities like the arms and legs. We all take time to warm up before working out or going for a run, yet we rarely do so before we do a deep clean of our homes, move a piece of furniture, or take the trash to the dump. Our muscles don't discriminate between exercise and non-exercise exertion. If they are asked to perform work without the necessary blood available, then tight bands of rigor will form, leading to decreased range of motion and muscle weakness. 

We need to understand that exercise happens throughout the day, not just in the gym. Especially with the summer months ahead, drinking enough water and adding a warm-up, like ten minutes of walking, to our morning routine will have us -- and our muscles -- ready for whatever adventures come our way!