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The Science of Performance |
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Part 2: Power I explained in part 1 of this series that muscles limit your ability to run. With that fact firmly established, we must examine the particular characteristics of muscles that cause them to limit running. We will then be able to use this information to design an effective training program that will maximize performance and minimize risk of injury and overtraining. Running is all about one thing – force production. Your running muscles generate the force required for you to move. This force is used to start, stop, accelerate, decelerate, and change your direction of movement. Without this force, there is no movement. To increase your running pace your muscles must generate more force. When you slow down, your muscles generate less force. The pace at which you run is determined by the amount of force you produce. More force equals a faster running pace and less force equals a slower running pace. Unfortunately, our muscles have a definite upper limit to the amount of force they can generate, how quickly they can generate it, and how long they can sustain it. These three characteristics – maximum force production, contraction speed, and time limit for force production – are described by the term “muscle contractility”. When I talk about muscle contractility, I am referring to the combination of these three muscle characteristics. This discussion of force production may seem too elementary, but it is absolutely critical to understanding how to maximize your performance. If you want to improve your performance, you must train your muscles to produce more force for a longer period of time. It is as simple and straightforward as that. All of your training should be focused on increasing the amount of force you are capable of producing and the length of time you are capable of sustaining it. Any other goal is secondary. Physiologists have several ways of expressing force production. The two most common terms are strength and endurance. Before proceeding, we need working definitions of both terms. Strength: a measure of the amount of force a muscle is producing. Notice that the term strength is simply a measure of force generation with no regard to time. This makes it difficult to use as a measure of running performance. Unlike weight trainers, runners can’t easily manipulate the amount of resistance they are working against, plus there is most definitely a time factor in running. Also, due to limitations in muscle contraction speed, an increase in strength does not necessarily result in an increase in the maximum pace you can attain. Endurance: the time limit during which a set amount of force can be maintained. An increase in endurance results in being able to run at a set pace for a further distance than you could previously. An example would be improving your endurance so you can maintain your 3k race pace for 4k. These definitions are fine as far as they go, but they don’t really address the goals of the competitive runner. Competitive runners are most often seeking to improve their performance at a distance they have run before. It seems we are all looking to set a PR at some distance. The term that best addresses this goal is power. Power: the amount of force generated during a set interval; the product of force production and velocity; the derivative of work with respect to time. Power is a measure of the amount of force being generated and the length of time it is generated. An increase in power results in running a set distance, such as 5k, in a shorter amount of time. The terms strength, endurance, and power are all different ways of expressing the concept of force production. All three terms are useful to runners, but the term power is the most important. When I say you have to increase your ability to produce force, I mean that you have to increase your power. Power is what you should focus like a laser beam on improving. Each time your power increases, you running performance will improve. Power is what it’s all about, hence the name of this series and my running program – Power Running. The Power Formula So, how do you increase power? Our running formula for power is: Power = muscle contractility + metabolic fitness Any increase in muscle contractility or metabolic fitness will result in an increase in power (we will discuss metabolic fitness in part 4). Seems pretty simple doesn’t it? Remember, muscle contractility is composed of three physiological characteristics. Muscle contractility = strength + contraction speed + time limit for force production (resistance to fatigue) Plugging our muscle contractility formula into our power formula results in: Power = strength + contraction speed + muscular fatigue resistance + metabolic fitness Power is the result of the combination of these four factors, of which three are muscle characteristics. Any increase in any of these four will cause an increase in power. An increase in power results in improved performance. Again, this may seem elementary, but it is truly at the heart of improving running performance. We will cover the specifics of maximizing these four factors in the remainder of this series. For now, the important thing for you to understand is that running performance is determined by force production. Muscles limit running performance because they are limited in how much force they can produce. Force production, as measured by power output, is the end all, be all, of running. If you want to improve your performance you must increase the amount of force you are producing, which means you must increase your power output. Each time you increase your power, you will run faster. Till next time keep on running.
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