First Step – Context
The more I have thought about the whole first step scenario the more I come back to context. The first step is only one part of a bigger picture. What is the purpose of the first step? The purpose of the first step is to displace the center of gravity in the intended direction and create a positive shin angle to be effectively apply force back against the ground. I break movement down into the following components:
1) Stance or starting position
2) Start
3) First Step
a) Position
b) Direction
4) Getaway Step (Second Step)
5) Acceleration to Optimum Speed
6) Deceleration
7) Possible Reacceleration
8) Stopping
This whole scenario takes place in about two to three seconds, possibly four seconds at the maximum. The ultimate goal is to keep each of the segments in the context of the ultimate objective which is to stop effectively and make the play. It is also important to recognize that in the majority of sports starts are moving, not stationary. This does not minimize the importance of first step and in many ways in accentuates the necessity of creating a good shin angle on the first step.
posted by Vern Gambetta @ 12/22/2006 08:03:00 AM
4 comments
4 Comments:
Here it is vern. I would love to talk more on this topic- it is really interesting to me.
Journal of Biomechanics 34 (2001) 211}215
Starting from standing; why step backwards?
G.A. Kraan!,*, J. van Veen", C.J. Snijders!, J. Storm!
That is another important point you made. I teach my athletes to accelerate out of many different athletic stances. Active and stationary with each of these having different foot positions. It still comes down to the random reaction in most cases. Unless the athelete is already aligned with a positive shin angle ie; track sprinter or wide reciever, they must quickly create it so the first second and third steps are powerful and in line. taking a positive forward step the first step and sometimes the second step is outside the vertical line of optimal force. If you draw a line down the center of the body and then tilt it forward to show acceleration- the positive step is too wide and doesn't allow for optimal force application. The plyo step immediately aligns the legs for optimal power.
In terms of the active athletic stance, like a tennis player recovering back to the center after hitting a wide forehand and then a drop shot is hit by the opponent- the player will immediately perform a plyo step to align and accelerate all in one movement.
I agree with the active and stationary training to maximize the varied positions an athlete will encounter during their sport. Another study (Is stepping back really counterproductive) in the Strength and Conditioning Journal (2004, Vol. 26 No. 1 p 42-44) analyed the false step in regards start time, mean power and velocity and displacement. The study concluded that the false step to be more effective.
One questions - biomechanically, with a false step, do the hips move forward at all or does the center of gravity lower preparing for greater force production on the second and third steps???
The center of mass becomes the pivot point during the plyo step. because the knees are bent during active or stationary stances the plyo step is simply a rotation of the shoulders forward and the force application foot back. The hips do not lower much at all (only is the athlete is high on the balls of the feet with mostly extended legs), certainly not intentionally. The lead leg prepares to accept drive down and back. in a straight line. All this occurs so quickly it basically is a smooth summation of parts leading to an explosive start and acceleration.
When a player reacts quickly and performs the plyo step, there is a quick change of position of the feet due to a quick small flexion of the lead leg hip and small quick flexion of the plyo step leg followed by an aggressive hip extension of the plyo step leg. This flexion of the plyo step leg is not easily detectible (I broke have broken in down via super slow video). There is not a lifting of the center of mass in order to perform the plyo step, remember it is a quick reaction, much like taking your hand off a hot stove, you simply react and move.
Another point that I always try to emphasis in ragards to why I feel the positive step is too slow biomechanically and due to laws of physics not effecient is; If you have an athlete get in an athletic stance, lets say a basketball player playing defense, and you have extended a straight vertical line from the point of push off which is the balls of the feet up through the body you will notice how much of the body, including the center of mass, is behind the push off point. The athlete must actually pull the center of mass forward of the push off point to create a down and back action into the ground. So actually if the athlete was forced to react and take off, the natural occurance of the body is to drive a foot down and back behind the center of mass on an appropriate angle to accelerate the body forward (plyo step). If the athlete is coached not to take a plyo step the body must find a way to roll the center of mass forward so the push off is down and back behind the center of mass. Otherwise the athlete will lift the center of mass vertically due to the vertical arrangement of the center of mass over the feet (and in most cases behind the feet).
Lee
Many good comments being brought up in my opinion. Two thoughts I am pondering now are might the plyo step be most effective on occassion IF the player is not in the preloaded/ready position? Allowing the plyo step would still not be proper - teaching the athlete to get in a proper position would be.
I often wonder about the role of anticipation of the upcoming playing. Imagining the probable upcoming play helps set the neural system and completely eliminate the need for a plyo step. Teaching the athlete how to help anticipate the upcoming play by evaluating their oppenent's posture and tendincies is invaluable.
Mark Day D.C., CSCS, DACBSP
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