Topics: Range of motion, isolation exercises vs. multi-joint/muscle exercise, and functional fitness vs. health-related fitness.
The triceps are a muscle group in the back of the arm responsible for straightening (extending) the elbow. It works in conjunction with the biceps muscle on the front of the arm, which bends (flexes) the elbow joint. One of the most popular exercises for the triceps is elbow extension, often called triceps extension or “cable triceps push-downs” (picture). Consequently, this is an exercise I often see performed with poor form.
In general, we gain or maintain strength and flexibility within the range of motion through which we exercise the specific muscle(s). The elbow joint has nearly 160 degrees of motion. But I often observe exercisers starting the elbow extension at 90 degrees (elbow bent; see photograph with SRPMIC Council Member Tom Largo demonstrating). This shortens the range of motion at the elbow, and could limit Council Member Largo’s strength gains because he is not moving his elbow through the full range of motion. So he will become stronger when he straightens his arm from the bent starting point to the fully extended elbow, but potentially not as strong if he tries to straighten his arm from the fully bent position or when he resists the bending of his arm greater than 90 degrees. Unless there is a compelling reason, such as an injury, Council Member Largo should work this exercise using his full “pain-free” range of motion. This way he can build and maintain strength through the normal motion of his elbow joint during day-to-day activities.
Isolation Exercise vs. Multi-Joint Exercise
The triceps extension is an “isolation exercise,” which means it uses a very limited muscle or muscle group. In normal activity, we use our triceps muscle along with other muscles to cause motion in multiple joints. For example, if we push something away from our body, we have motion at our elbow and shoulder joint. So we use the triceps as the prime mover of the elbow joint, but we also use our chest muscles (pectoralis major and minor) and our shoulder muscles (anterior deltoid) to move the arm at the shoulder joint. The combination of the movement at the elbow and shoulder joints caused by these muscles is what allows us to shove something away from us.
Strengthening the triceps muscle group with an isolation exercise will help Largo more effectively generate force for shoving, but not as well as the “multi-joint” approach of “functional” exercise. The bench press (photo) is a multi-joint exercise that uses the joints and muscles mentioned involved in shoving. So this exercise improves the strength and flexibility of the muscles in the range of motion used during the bench press.
In the bench press exercise, the elbow is not typically worked through the full range of motion. So using the bench press (multi-joint) exercise may be more efficient, since it strengthens more muscles and uses more joints at one time, but it isn’t as effective as the triceps extension at improving flexibility of the elbow joint or strengthening the triceps through the full range of motion. The bench press is more functional because it uses a motion very similar to shoving, which we may do in normal day-to-day activities. Functional exercises are exercises that generate increases in strength and flexibility in a way that transfers best to day-to-day activity.
Functional exercises are good for working efficiently because they tend to use multiple joints, muscles and exercise speeds that mimic real life. They help us function better. The normal course of aging is associated with a loss of flexibility, muscle mass and bone mass. Resistance training has been demonstrated to not only avoid this loss, but actually reverse it. Largo is an excellent example of how muscle mass, flexibility and function can be maintained and improved throughout the lifespan, as he has the muscle mass and function of a typical man in his 20s or 30s.