Okay, so let's now discuss movement time and rate of force development and why this is an important consideration when selecting assistant exercises. I'm going to put up a curve here and this curve shows the athlete's maximum force development. Now the thing that you have to realize is that it takes 0.3 to 0.4 seconds for the athlete to apply their maximum strength. Zatsiorsky calls this the athlete's maximum strength or their Fmm, which he refers to as their force maximum maximorum. So it's an interesting term that I'll use. I'm going to come back and talk more about the athlete's maximum strength or their force maximum maximorum in a minute. Now the time available to produce force in many sport movements is usually between 0.08 to 0.18 seconds. The athlete cannot summon their maximum strength in that particular time frame and this is an important consideration when selecting assistance exercises. In most sports, the athlete who can tap into more of their maximum strength in the shortest amount of time usually has the upper hand. And this depends on the maximum delivery force that I've got labeled here as Fm. Now the maximum delivery force is the time it takes the athlete to reach their maximum possible delivery force during their performance and this is called the rate of force development. High delivery force and very fast rate of force development in the lower body is highly correlated with faster sprint speeds and greater jumping heights. Neural activation and the firing frequency of the muscle fibers is also a key to the athlete's rate of force development. Okay, so on this slide then you have a couple of important points, the maximum delivery force, which is Fm. And you have the maximum force the athlete is capable of producing, and that's their Fmm, or their force maximum maximorum. Okay now, you can appreciate the importance of delivery force by examining this table. Throwing type movements, such as javelin and shot put throwing takes around 0.15 to 0.18 to complete. And pushing type movements, such as sprinting, permit only 0.08 to 0.10 seconds to produce a force. And long jumpers have 0.11 to 0.12 seconds and high jumpers have 0.18 seconds. These are all very, very short times. In all these cases the movement is completed before the athlete can apply their maximum force. Zatsiorsky, remember, refers to the athlete's maximum force as the force maximum maximorum, or their Fmm. And the maximum force, remember that an athlete can produce in the time permitted to complete the movement is denoted here as Fm. And this is the athlete's maximum delivery force and it's always much lower than their maximum force production. The difference between their maximum delivery force, which is their Fm when they reach when completing a given sport movement, that is their delivery force, remember. And the maximum force the athlete can produce without considering the time constraints, that is their Fmm. That is their force maximum maximorum. This difference between those two different types of forces is termed the explosive strength deficit. In equation form the explosive strength deficit as a percentage is equal to 100 times the Fmm minus the delivery force, the Fm, and that's divided by the Fmm. Now according to Zatsiorsky, only half the athlete's strength potential is used when performing explosive movements. For example, elite shot putters throw the shot around 21 meters and when delivering these shots they apply a peak force, a delivery force of Fm of 50 to 60 kilograms. Now their highest arm extension force that they can produce as measured by a one rep max bench press is typically 220 to 240 kilograms. That is, it's about 110 to 120 kilograms per arm. That's their Fmm. Therefore, the elite shot putters are using about 50% of their potential maximum arm extension force, their Fmm, while they are throwing the shot. And this is about as close as any athlete can come. The value of improving an athlete's maximal force, or their force maximum maximorum, to improve their performance then, depends on where they are on the experience scale. When an inexperienced shot putter increases their arm extension strength, they're throwing performance typically improves. Advanced shot putters, on the other hand, who already have superior arm extension strength, do not benefit much by increasing their arm strength further. It's better that they look at their rate of forced development during the delivery phase for throwing and improve that ability, so that they can use their maximum arm force in a better way. The athlete's maximum explosive strength, or rate of force development by putting the shot, is a much more critical factor than their total maximum strength. And we're going to return to rate of force development and I'll show you how to estimate it for each athlete.
