What Is the Strength Curve?

The strength curve is a graphical representation of how the human body generates and applies force in a specific direction. Strength curves are especially useful in understanding athletic movements, and athletes can maximize their performance by studying their body's kinetics. Physical therapists also use strength curves to measure and evaluate the progress of their patients.

Phases of Motion

Jumping in the air or tossing a football both produce a similar strength curve. The shape resembles a check mark, with a curved rather than a pointed bottom. During the first phase, as the line travels downward, the body is preparing for action. Muscles tense in anticipation of a vertical leap or quick swing of the arm. The bottom of the curve takes only a fraction of a second, as the body pauses before springing to life. The ascending portion of the curve represents the hard and steady application of muscular force.

More About Motion

A strength curve graphs muscle force on the vertical axis against time on the horizontal axis. Sports scientists typically measure athletic movements in milliseconds. The angle of the ascending portion of the strength curve conveys information about the athlete's conditioning. A steep, constant line indicates fast and powerful engagement of the muscle fibers. A curve that wobbles or trails off may indicate an injury or an area where an athlete needs more dedication and training.

Athletic Considerations

The highest point of the strength curve indicates the most powerful muscle involvement. However, people typically never maximize the full potential of their muscles. The goal of elite athletes, however, is to do exactly that. By combining good nutrition, training and dedication, competitive athletes can bring the top of their strength curve closer to their ultimate strength threshold. Another goal of athletes is to reduce the amount of time spent gearing up and pausing before the muscles engage. In sports, even fractions of a second can make the difference between winning and losing.

Clinical Applications

Doctors and physical therapists rely on precise measurements of a patient's physical strength to gauge progress during a rehabilitation period. A comparison of strength curves over a span of weeks may indicate when a patient needs extra encouragement or perhaps an alteration in exercises. A loss of strength at certain positions points to an injury or weakness. For nonathletes, the objective is to achieve a smooth strength curve and a full range of motion.

About the Author

Josh Patrick has several years of teaching and training experience, both in the academy and the private sector. He presented original work at the 20th Century Literature Conference in Louisville, Kentucky. Patrick worked for three years on the editorial board for "Inscape," his alma mater's literary magazine. He holds a Master of Library and Information Science.