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Hi Everyone -
Interesting points here. The main thing I've discovered in researching and teaching the strokes is that there are infinite ways a player can ultimately get the racquet to the ball. Even at a very high level we see a variety of ways so these discussions often go to this one or that produces big shots this way so it must be ok or even better.
My approach has always been to look at the full array of options and assess the biomechanical attributes in such a way that I feel comfortable teaching it to my young players because I know this will provide a sound (and safe) foundation. That foundation may morph to individual expansion into areas that work for them - but I still would not have taught it to them initially - I teach the base by which I know they can build their own interpretations - which I encourage.
The reason I start with this pedological explanation is that the points discussed are by and large individual interpretations. The racquet facing forward around the hesitation point is a case in point. In moving the racquet into a hesitation point type position obviously the racquet facing forward reduces the moment of interia of the racquet during the elevation (depending on the windup type and especially for continuous transitions). And this advantage can continue between the hesitation point and the initial instants of descent - however as the racquet begins the descent a diagonal swing plane of the type desired (by me) is not possible unless the racquet is more or less squared to the side fence - this is the case for many of the examples given. Keeping it facing forward creates the mechanical problems I already described. Do some some players pull it off - yes. Would I build a serve that way - never in a million years.
The method by which the body attains the hesitation point is an interesting discussion but I'll leave it to you guys and for the most part my players.
nickw - thanks and great questions - a 20 degree drop is the most I'll allow because anymore tends to change the backswing plane unless it is re-elevated first which a waste of motion in my book. Also, if you accept that the ESR in the backswing is a function of the leg drive then the rotational effect on the arm/racquet due to the force applied to the arm by the torso accelerating (from the leg drive) up would be optimized if the axis of ESR (roughly the humerus) is at a 90 degree angle to the line of the force (ESR axis in line with the shoulders). 20 degrees below is less efficient and more than 20 unacceptable to me.
The cartwheel is a torso event and independent of that arm orientations though many try to get past the coaches eye by manipulating the arms rather than using the torso lol. The left arm (stretched and timed) is an important factor in leveraging (term used loosely) the cartwheel of the TORSO through distributing load on the back leg and I suppose attaining the tilted position of the torso but I've yet to see that explained in a mechanically correct way and it is beyond the scope here.
By to the right of the player I assume you refer to an internally rotated humerus. I proposed a 20-30 degree internal rotation. The rotational consequence of the leg drive to the hitting arm structure doesn't occur functionally until that structure is moving vertically down. The 20-30 ISR is to provide a muscular boost in acquiring acquiring ESR before the leg drive takes over. I've found that that enhancement becomes counter productive if the ISR goes much past 30 as the lower to upper body synchronization becomes too complicated for most. Despite recent popularity of the idea (up to 90) I would NEVER teach it. 20-30 does about the same job without the sychronization baggage. And I realize Roddick pulls it off beautifully - personal interpretation.
Thanks all for considering my presentation. I've enjoyed the discussion and applaud the extent to which other mechanics junkies have thought about these issues.
Interesting points here. The main thing I've discovered in researching and teaching the strokes is that there are infinite ways a player can ultimately get the racquet to the ball. Even at a very high level we see a variety of ways so these discussions often go to this one or that produces big shots this way so it must be ok or even better.
My approach has always been to look at the full array of options and assess the biomechanical attributes in such a way that I feel comfortable teaching it to my young players because I know this will provide a sound (and safe) foundation. That foundation may morph to individual expansion into areas that work for them - but I still would not have taught it to them initially - I teach the base by which I know they can build their own interpretations - which I encourage.
The reason I start with this pedological explanation is that the points discussed are by and large individual interpretations. The racquet facing forward around the hesitation point is a case in point. In moving the racquet into a hesitation point type position obviously the racquet facing forward reduces the moment of interia of the racquet during the elevation (depending on the windup type and especially for continuous transitions). And this advantage can continue between the hesitation point and the initial instants of descent - however as the racquet begins the descent a diagonal swing plane of the type desired (by me) is not possible unless the racquet is more or less squared to the side fence - this is the case for many of the examples given. Keeping it facing forward creates the mechanical problems I already described. Do some some players pull it off - yes. Would I build a serve that way - never in a million years.
The method by which the body attains the hesitation point is an interesting discussion but I'll leave it to you guys and for the most part my players.
nickw - thanks and great questions - a 20 degree drop is the most I'll allow because anymore tends to change the backswing plane unless it is re-elevated first which a waste of motion in my book. Also, if you accept that the ESR in the backswing is a function of the leg drive then the rotational effect on the arm/racquet due to the force applied to the arm by the torso accelerating (from the leg drive) up would be optimized if the axis of ESR (roughly the humerus) is at a 90 degree angle to the line of the force (ESR axis in line with the shoulders). 20 degrees below is less efficient and more than 20 unacceptable to me.
The cartwheel is a torso event and independent of that arm orientations though many try to get past the coaches eye by manipulating the arms rather than using the torso lol. The left arm (stretched and timed) is an important factor in leveraging (term used loosely) the cartwheel of the TORSO through distributing load on the back leg and I suppose attaining the tilted position of the torso but I've yet to see that explained in a mechanically correct way and it is beyond the scope here.
By to the right of the player I assume you refer to an internally rotated humerus. I proposed a 20-30 degree internal rotation. The rotational consequence of the leg drive to the hitting arm structure doesn't occur functionally until that structure is moving vertically down. The 20-30 ISR is to provide a muscular boost in acquiring acquiring ESR before the leg drive takes over. I've found that that enhancement becomes counter productive if the ISR goes much past 30 as the lower to upper body synchronization becomes too complicated for most. Despite recent popularity of the idea (up to 90) I would NEVER teach it. 20-30 does about the same job without the sychronization baggage. And I realize Roddick pulls it off beautifully - personal interpretation.
Thanks all for considering my presentation. I've enjoyed the discussion and applaud the extent to which other mechanics junkies have thought about these issues.
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