By, Sean Light CSCS
Pick up a dumbbell, start with your arms fully extended and attempt a bicep curl. Now, instead of starting with your arms extended, start the arm at a ninety degree angle. The curl is certainly easier when starting with the modified start position. This is because at the end of any given range of motion, the muscle is at its weakest.
In order for a muscle to contract, myofilaments called actin and myosin must connect using cross-bridges within the part of the muscle called the sarcomere. When the muscle is fully contracted, the actin and myosin are too close together to get a maximal amount of connections. Conversely, at the end range of motion, the myofilaments are too far apart to achieve maximal connections. Thus, somewhere in between end range of motion and full contraction is the range for the most cross-bridge connections.
One of the most common ranges for injury to occur is at the end range of motion. In order to better prevent athletes from finding themselves on the disabled list, it’s important to increase strength and the end range of motion.
Traditional weight lifting, assuming proper form is used, strengthens throughout an entire range of motion. Isometric exercises pinpoint one area of the range of motion to strengthen.
Isometric exercises are holds. The athlete locks into one position and holds the position for a given amount of time. Examples are pushup holds, wall sits and pull up holds.
If the strength and conditioning coach properly selects the isometric exercises, he or she can increase the athlete’s strength at the end range of motion and decrease the athlete’s risk of injury at that particular range.
Yoga revolves around “poses,” or positions held for a given period of time. Sound familiar? These poses are isometric exercises. Instituting yoga poses into strength and conditioning program is a great way to help athletes avoid the disabled list.