Power in Performance:
Development of Functional Power in Fast-Twitch Athletic Events
In the United States, track & field describes a variety of competitive events on or near an 8-lane, 400-meter track. To the rest of the world, “athletics” is the more commonly accepted name for track & field, because the sport covers such a wide range of feats that test the boundaries of human performance. Typically, the athletic community recognizes the athlete who achieves the highest score in the heptathlon (women) or the decathlon (men) as the World’s Greatest Athlete. The athlete with best time in the 100-meter dash is considered fastest man or fastest woman in the world. The best athletes embody the pinnacle of human performance for their respective event. It should come as no surprise that elite athletes in the same event often appear similarly to one another due to the unique muscular demands for the event. In other words, jumpers look like jumpers and distance runners look like distance runners. Shot putters do not look like pole vaulters because their fitness demands are different. Adolescent athletes don’t usually demonstrate the same degree of similarity because their bodies are not fully developed and they have less years focused on event-specific fitness as the elites.
Although all athletes vary by a wealth of genetic factors (weight, height, limb proportions, ratio of fast- to slow-twitch muscle fibers, etc.), event-specific fitness will focus muscular development to reflect the performance demands of the respective event. With fitness and technique held mostly constant, muscular variation between athletes in separate events should increase with age.
An athlete’s performance is the product of their genetics, technique and fitness. Barring performance-enhancing drugs, or physical debilitation, this principle should not change throughout the course of an athlete’s lifetime. If one accepts that an athlete cannot modify their genetics, then fitness and technique remain the only malleable aspects in their performance. However, a good coach recognizes that genetics can influence their athletes’ fitness and technical adjustments. Genetics, technique and fitness do not operate exclusively from one another, but each factor has its respective limit. When an athlete reaches their technical limits, they must improve their fitness. A good coach assesses their athletes’ limits and then creates individualized training plans for based on these assessments. Strength, velocity, acceleration, endurance, coordination and flexibility are just a few possible measures of assessment. For sprints, jumps and throws, an athlete at their technical limit must increase their strength and velocity to improve their performances. This does not assume an athlete has reached a technical or genetic limit, but when an athlete achieves such limits (wow, good job!) the only option is to get stronger and get faster. (Note: Coaches should devote adequate time to technique and fitness concurrently.)
For fans, the combined limit of genetics, fitness and technique is probably the most exciting part of competition. In the 100-meter dash, eight athletes crouch shoulder to shoulder on the start line waiting for the gun to sound. When the race begins, it’s apparent that each athlete has invested an astounding amount of time on developing incredible strength in each stride and an extremely high-frequency of stride turnover. Lane 5 was born tall, lean and broad on top. Lane 7 is short, big-boned and muscular. Lane 2 has an averagely proportioned frame, but a greater proportion of fast- to slow-twitch muscle fibers. Lane 4 has a long torso, short legs and a high stride frequency. Lane 5 wins. Not because Lane 5 was born with the best body for sprinting, but rather, because Lane 5 has the best combination of genetics and fitness and technique. Or, Lane 5 won because Lane 2 just had a bad race. There are a lot of possibilities when it finally comes down to the day of competition. The result of this imaginary race and the genetic variation of our imaginary athletes may seem contrary to the claim that event-specific fitness creates similar looking athletes, but this is not an absolute. Genetics, fitness and technique do not operate exclusively from one another because effective coaching incorporates genetics and technique into an athlete’s training.
Success in explosive events like sprints, jumps and throws requires an athlete to generate power, the product of muscular force and velocity. More powerful athletes have an objective advantage over less powerful athletes because they are more efficient. Each stride forces them farther forward and each stride occurs more frequently. Power is energy per unit time. If an athlete trains their muscles to increase power, then, with proper technique, they will sprint faster, jump higher and throw farther.
In general, each one of imaginary athletes has developed a similar musculature through the unique fitness demands of the 100-meter dash. Their muscles have been trained to execute maximal strength at the greatest velocity possible. Each stride represents the force applied by the athlete to move them forward. Each repetition of the athlete’s stride represents the velocity at which the leg moves before it applies that same force. To clarify, this velocity is the concentric and eccentric contraction of the muscle, and not the velocity of the athlete as they move down the track. They are related, but for the purposes of understanding the development of power, the individual muscle, or muscle group, deserves isolation. And finally, technique will determine how the athlete manifests the velocity of their muscle’s contraction into raw speed on the track. The force applied multiplied by the velocity of muscular contraction equals power output for that muscle group.
Understanding the relationship between force and velocity (Figure 1) provides the first step toward its application in training. In 1935, Fenn and Marsh presented the relationship for the first time as a model for muscular performance. Either end of the curve represents the muscular ability to accomplish different tasks. The relationship demonstrates that as the velocity of motion increases, the force, or load, must decrease to accommodate the higher velocity. An athlete exerts their greatest force in a one-repetition maximum (1RM) for a given muscle group. The other end of the curve, the velocity extreme, characterizes how fast that same muscle group can move without resistance. Baker et al. (2001) determined that muscle groups in explosive motion achieve their maximum power at approximately 50-60% of an athlete’s 1RM. The power curve can be seen overlaid on the force-velocity graph in Figure 2. Strangely, the location on the force-velocity curve directly below peak power may not prescribe the most appropriate adaptation for an athlete’s training.