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Power Development

July 22, 2015

 

Power is at the FOREFRONT of high level sports performance. Power and its derivatives all contribute to how successful an athlete will be on the field or court of play. Without developing it, a dynamic sport athlete may never truly see his or her athletic potential. Now keep in mind the adjective; dynamic. If you look at the definition of dynamic it says “characterized by constant change, activity, or progress.” Simply put,  it is a state of unpredictability and the ability to react to it without hesitation. With that in mind, the way you develop power for dynamic sports is very unique. We will also look at sport specific power application. Power development is not and cannot be the same for all dynamic power sports (DPS). In a similar comparison, individual human performance cannot be a one size fits all. How we train a tennis player for power is very different to how we train a football player. Power is specific in nature and specific to imposed loads. Before we jump into the guts, lets take a brief look into what power is, its pieces, and their relationships.

 

 

WHAT IS POWER and HOW IS IT DIFFERENT THAN STRENGTH

Here are some basic concepts that need to be understood to begin to have a deeper understanding of power development.
A formula we have probably all seen Power = Force x Velocity. Thus Power and Strength have a unique difference. Power has many variables and if you break down this formula you find that a unique characteristic to these variables is time. Time is a variable in both acceleration and velocity and is the most important variable. Whichever athlete has the ability to display the most force at the highest rate of speed wins. Period.

Force = mass of object x acceleration

Acceleration = change in speed of object divided by time it takes for the change to take place (rate of change of velocity per unit of time)

Velocity = denotes speed of an object as it moves over a specified distance, dividing the distance an object travels by the total time it takes to cover that distance ^Distance/^Time
Strength is the ability to produce maximal force against an object or resistance independent of time, distance, or velocity. Although there may be range of motion requirements in some feats of strength such as powerlifting, or set tempos where strength is the goal, it is unique to the individual. Same with olympic lifting. This is not intended to depreciate the value of strength training, as we will see, it is very important, but POWER IS KING. Rate of force development. How fast and efficiently can you take your strength and transfer it to power. How fast can you accelerate and how much force can you generate. Athletes that can run a 4.4 40yd dash can accelerate up to 22mph in less than 2.5 seconds covering upwards of 20 yds and produce over 1200 N of force in less than .10s off the start. As Cal Dietz put it: “Strength is not what sport is about. Sport is about force production at high velocities and high rates of speed. Sport is about being powerful.” Again, strength is a component of force so an increase of strength will give us an increased “opportunity” for power.

 

SPECIFIC APPLICATION OF POWER

“Virtually all human movements are aimed at achieving something in the environment. In any case, each and every movement takes place in an environment. Mechanically, the environment influences movements through the forces from the environment that act on the body” -Gerrit Jan van Ingen Schenau (a Dutch Biomechanist)
In my opinion this quote speaks volumes to specific power application. As some might call it Functional Power Development. In essence this is appropriately designing training protocols and power development to the demands of the sport or even specific positions of a sport. Considerations for power have to be sport specific to maximize carryover and cannot be one dimensional, uni-planar, or non-reactive. Some athletes produce power against an opposing or outside force equal to or greater than their body weight (football, rugby, wrestling, MMA) where as other sports do not have to produce power against such an opposing force and are more ballistic in nature (baseball, volleyball, tennis, golf). Power production CANNOT BE GENERIC or potential will NOT be reached. One example and commonly used tool for sport specific power application or training power over several unique domains is the Force Velocity Curve.
Simple concept here – 2 dependent variables that share an inverse relationship. One variable increases and one variable decreases. As force goes up velocity goes down and as force goes down velocity goes up. With this concept there are two main variables to be changed to increase power. Either the velocity at which you lift a load or the amount of load you lift. This does have some implication to training and will give you a solid base if you cover multiple modalities along the curve. However it also states that they are inverse, meaning one has to give. Although in theory this makes sense, the application of it may not be as accurate when applied to training means, especially for instances where athletes must be able to generate high speeds with high forces or loads. Thus the Force Velocity Curve may not give coaches the optimal training percentages for training all athletes. One thing Dr. A.V. Hill did not take into consideration when developing his FV Curve was the stretch-shortening cycle involved in dynamic muscle contractions. This is interesting because this means there is more mechanical energy available to produce more power. If you are unfamiliar with the Stretch Shortening Cycle it is the change from dynamic muscle lengthening (eccentric phase) to dynamic muscle shortening (concentric phase). This mechanical model states that energy is created and stored in the musculotendinous junctions when a rapid stretch is induced. If it is then followed by a rapid shortening then the stored energy is released and adds to the total force production. This also infers that there is potential for athletes to produce maximal amounts of power at loads heavier than the FV Curve might insinuate. This obviously requires the ability to monitor power production via Tendo Units, Force Plates, Keiser equipment or other calculations and is not the end all be all. Overall the point is that developing power, although can be general at times according to athletes and timelines, needs to be specific in nature to the activities one will be participating in as a part of their goals, needs, or environment to maximize power expression on the court or field. As Verkhoshansky put it: The characteristics of the power produced by muscle contractions are determined by the specific working regime typical of every sports discipline: the typology of the sports discipline determines whether it is important to be able to express power in the shortest period of time or maintain a high level of average power over a set period of time. Both are determined by the muscular capacity to produce the greatest quantity of mechanical energy per unit of time. Better known is motor potential. (Rationally choosing when to exert force and power or producing max power at every opportunity) Which takes us to our next point of emphasis.

 

POWER FOR DYNAMIC SPORTS vs POWER FOR FITNESS

 The following statements are not meant to takeaway from the accomplishments of those who have participated in fitness sports. They are merely observations and scientific facts meant to clarify the difference between a variety of training methodologies including the uniqueness of dynamic power sports and bring to light some things that may not have been discussed previously.

Sports such as; Powerlifting, Body Building, Olympic Lifting, and Crossfit do not fit into the dynamic sports category and thus an athlete wishing to optimize his performance should not use one of these methods as theirprimary means of training. They are played in controlled environments, are very one-dimensional,  and mostly sagittal plane dominant. Therefore, the route of power development and the goals are very different. Powerlifting and Olympic lifting have set exercises to accomplish and they do not change. Crossfit, although you may not know what you are doing until right before an event or a workout, has a set of exercises, and once they are revealed there is no dynamic variability to affect the need for the central nervous system to react or generate instant power or force production. Now before I get into this, I want to clarify that I am not taking away from crossfits contribution to fitness and what it has done for so many people physically and psychologically nor takeaway what some of the people at the games are able to accomplish. I have also participated in crossfit for upwards of 16 weeks with the University of Texas Rugby team in preparation for our Collegiate Rugby Championships. So I do feel capable of speaking on the subject and I do want to justify and clarify that for any athlete wanting to play a DPS, and be successful, crossfit is not the best route for them and can in fact create a performance deficit on the field.

 

CrossFit itself is defined as that which optimizes fitness (constantly varied functional movements performed at relatively high intensity).
*First fault in crossfit for a DPS athlete is that of relatively high intensity. We need maximal recruitment of motor neurons and muscle fibers in a reactive manner at any given moment.

 

Directly below is off of crossfit.com and the crossfit journal. I encourage you to read the whole article.

 

“Health can now be concisely and precisely defined as increased work capacity across broad time, modal, and age domains. Work capacity is the ability to perform real physical work as measured by force x distance / time “Velocity” (which is average power).
“In other words, cutting your Fran and Helen times, increasing your max deadlift and getting more rounds of Cindy or Mary is really all you need to know about power.” “

 

Excuse me, what!?

 

http://journal.crossfit.com/2010/02/the-importance-of-power-and-the-irrelevance-of-measuring-power.tpl

 

The definition of power here is not technically wrong. That being said, there are distinct differences that must be addressed. The biggest distinction is that power should be considered in very short time frames or rapid movements. As quoted above, completing a “Fran” faster, with all other variables the same moving a heavier weight in a “Helen” would elicit an increase in power. This would better be described as rate of work production. As Mark Rippetoe states however, “this could be effected by simply resting less between the components of the work without increasing the rate of force production on the movements themselves. Increase in frequency with no increase in amplitude of individual components. Thus rate of force production and rate of work production requiredifferent metabolic adaptations.”

 

 

There is way more to know about power. In fact, all the Russian and Bulgarian coaches that many crossfit programs have based exercise selection off of would think so too. Is this a bad thing? Yes and No. If you are a dynamic athlete trying to play a dynamic sport, then yes, very bad. If you are a person trying to be fit by competing in the Crossfit games, then no not necessarily.

Again, power is a measurement where the main variables are time and load with more emphasis placed on time because we see it in each variable. Crossfits broad definition of power is measured in foot pounds per minute. In other words how much energy is needed to move 1 pound of load 1 foot per unit of time (minutes). A dynamic athletes power is measured in Newtons or Watts per second, tenth, or even hundredth of a second. Big difference again for a DPS vs a crossfit athlete.

If you were training for the NFL which methodology would you prefer? If you were having to react to someone throwing a punch or kick at your face and return a counter which methodology would you prefer. How many times you can do it in a minute or if you can do it in tenths of a second. Pretty clear to me, not a lot of discussion necessary. The goal of DPS athletes is not to survive, it is to dominate the opponents. Why wait until the fourth quarter to bring it when you can take their will to win in three? You need dynamic plays to win dynamic sports, not simply to sustain a “fairly high intensity” well. Obviously we believe in diverse energy systems development and it is a defining pillar in our athletes success. It is a foundational component of our systems, a basis for work capacity, and NOT power development. Once it is developed to a certain level, all we need to do is maintain it.

Last point would be the differences in stretch shortening cycle development as touched on briefly before. Now hold onto your britches this is definitely not me talking but I think its good to hear the research.

 

The amplitude of the stretch reflex component and the subsequent force enhancement may vary according to the increased stretch-load but also to the level of fatigue. While moderate SSC fatigue may result in slight potentiation, the exhaustive SSC fatigue can dramatically reduce the same reflex contribution. ; All these parameters and their reduction during SSC fatigue changes stiffness regulation through direct influences on muscle spindle (disfacilitation), and by activating III and IV afferent nerve endings (proprioseptic inhibition). The resulting reduced stretch reflex sensitivity and muscle stiffness deteriorate the force potentiation mechanisms. Recovery of these processes is long lasting and follows the bimodal trend of recovery. Direct mechanical disturbances in the sarcomere structural proteins, such as titin, may also occur as a result of an exhaustive SSC exercise bout.

 

So, that means that doing “power exercises” in an endurance format programs your body to never hit max power, with the high risk of severe damage to the muscle spindle that could in fact be irreversible over time.  In the event that you need maximum power your joints and muscles are incapable of handling it do to the adaptation to the endurance focus, therefore, your injury risk while playing sport sky rockets.
Projects are currently in progress to investigate this concept and preliminary results suggest that the structural integrity of titin (holds thick filaments in place and helps them spring back into shape after being stretched) may be compromised as the result of an exhaustive SSC exercise bout (McBride et al., work in progress). If titin break down occurs in intrafusal fibers as a result of SSC exercise performed until exhaustion it could have a direct mechanical consequence in reducing Ia afferent (neurons that send info the the CNS) responsiveness. In addition, this mechanism may operate independently of the presynaptic inhibition induced by activation of the III and IV afferent nerve endings.
This says a lot. Exhaustive plyometrics, distance running, and rep max olympic lifting do nothing but change overall work capacity and potentially body composition, at a high and risky cost. For performance however, exhaustive plyos do the opposite of everything that a DPS athlete is trying to accomplish. In fact, it has the potential to inhibit the CNS’s ability to relay information from the muscle to the brain and back thus decreasing an athletes reaction time. Not a good thing. This is a formula for an athlete to move at a very average pace for extended periods of time. Not only is there a disconnect from reactivity, but also a decrease in the ability of the musculotendinous junction to develop the stiffness or rigidity needed to carry out a mechanically productive SSC. Delayed proprioceptive feedback also increases the likelihood of injury exponentially. An argument may be a crossfit athlete uses olympic lifts for RFD (Rate of Force Development) or power. Yes they are producing high amounts of power only if done well rested, well coached, and well executed, but again very one dimensional uni-planar and very finite. Crossfit does Olympic lifting during workouts that are for time, meaning they do not get rest and only get the calorie burn and not the power production. Not what a DPS athlete needs to solely depend on for performance goals.

 

HOW TO TRAIN POWE