Very nice discussion guys. Sorry I've been out of it for a while and I hope my quick read of the posts didn't overlook anything. Here's my thoughts / responses to some of the questions……
[i]Originally posted by todd[/i]
Data shows that U.S. athletes
1) arrive at board w/ horizon vel close to average Oly finalist
2) lost less horizontal velocity during takeoff than avg finalist
3) took off w/ horizontal velocities above average, vertical velocities and angles of take off below average.
This would clearly indicate two problems. The first one is that we are not directing enough of our top-level, sprint-speed athletes to the long jump. The first point supports this because we have the most dominant women???s sprint group in the world (and arguably the best and largest pool of fast athletes) yet our horizontal jumpers are actually AVERAGE speed! The second issue is that that the athletes that we are funneling into the event either A) are not setting up takeoff correctly, or B) do not have the physical capacity (specifically high-load, high-velocity eccentric strength) to withstand the impact forces that the takeoff leg receives when an athlete is running at maximal or near maximal velocities and attempting to get a sudden vertical impulse. The third point clearly supports this because if their horizontal velocities are above average (which is actually THE most important thing) and they are still not performing as well as the other athletes, it indicates that their vertical velocities and projection angles are so far deviated from the optimum range that it doesn???t permit them to perform at the medalist level. In addition, we must take note of the fact that vertical and horizontal velocities and projection angles are not independent of one another. That is, the lower the projection angle, the greater the conservation of horizontal velocity from the approach and the lesser the vertical velocity. This very point, combined with the fact that our athletes arrive at the board with slower horizontal velocity, makes the seemingly beneficial point of our athletes having higher horizontal takeoff velocities seem like less of a good thing and more a consequence of their inability to setup takeoff and create higher takeoff angles. This could be a result of either of the two points I indicated above.
[i]Originally posted by todd[/i]
Thoughts and questions without looking at what other research shows::::
1) When I watch- European jumpers on the runway seem to be more vertical in running and striking the track than do Americans. Am I correct in what I see?
I???ve seen this too. This would almost certainly cost them in approach speed but perhaps their bounciness and more vertical running positions are beneficial for setting up a takeoff and maybe this benefit outweighs or negates the disadvantageous decreased horizontal approach velocity.
2) If this is not true, than are we in the U.S. lacking the 1) strength to convert the horizontal components into vertical components (DaveK???) as seen in poor ability to lower CoG? 2) too fast on the runway to convert? 3) a combination of the two?
I would think it is probably either that our athletes don???t have the capacity to lower correctly and setup takeoff or that our coaches are cueing athletes to ???run off the board??? way too much without any regard to the vertical forces necessary for jumping 7.0m.
3) Does a true hitch kick as many U.S. jumpers use, allow for 1) greater horizontal velocity, but lower vertical? 2) is this greater horizontal occuring because of less of a lowering of CoG??
I don???t think flight style would have any effect on horizontal velocity at takeoff unless the athlete is prematurely attempting to prepare for flight mechanics prior to takeoff.