should the planting foot on the takeoff be forced inorder to produce force or should i just run off the board. i’ve noticed a slight dragging effect when i plant hard and when i run off the board i feel kinda effortless with a lot of floating time. I wonder which should be more efficient.
Sprinter984, the forces on foot plant are determined in large by knee angles. During take off lower the hips slightly by bending the knee. This will increase the time interval for force production. I=Fxt
Its important not to allow your takeoff leg to sag or elastic energy stores will be wasted( transfered to heat energy).
The lowering of the hips should precede the take-off (i.e. as part of the penultimate stride). This second-to-last stride should be slightly longer (to effect the lowering of the hips) than the take-off stride. I wouldn’t encourage athletes to plant hard. In fact, I would encourage them to drive the free leg faster through (which could also have the effect of establishing a more rigid plant).
I would suspect that telling someone to plant hard would result in them either reaching for the plant (not good) and/or pushing too much off the plant (longer ground contact time and possibly a pronounced over-rotation during the flight phase - a la Marion Jones). This can be practiced in short-approach jumps (4-8 stride jumps).
Athletes generally arrive at the penultimate rhythm intuitively - you see this when you watch an athlete dunk or perform a lay-up in basketball with a single-leg jump. This is why I suspect Marion’s best long jumps occurred in the late-1990’s (closer to her b-ball career) and has fallen off considerably in recent years. In effect, she lost her rhythm and long jumping moved from the rearbrain to the forebrain (as perhaps Charlie would describe it) particularly as she felt more pressure to do well in the long jump (i.e. Sydney 2000). You can see from her jumps that she was reaching for the board more, and tended to foul at the board quite a bit.
Originally posted by NumberTwo I would suspect that telling someone to plant hard would result in them either reaching for the plant (not good) and/or pushing too much off the plant (longer ground contact time and possibly a pronounced over-rotation during the flight phase - a la Marion Jones).
The problem with over-rotation is almost always because of the arms. The action that your arms take upon take-off, will dictate how much rotation you have. And it sets up the landing. Marion is a great example because her arms play such a little part in her jump. Especially at the take-off. And as you have probably noticed her landing isn’t exactly text book either.
Ivan Pedroso is a great technician.
Originally posted by Sprrinter984
should the planting foot on the takeoff be forced inorder to produce force or should i just run off the board. i’ve noticed a slight dragging effect when i plant hard and when i run off the board i feel kinda effortless with a lot of floating time. I wonder which should be more efficient.
Nope. Sometimes a coach will see something on tv and try to explain it to the athlete based on what it looks like the pros are doing. What may look like Carl Lewis forcing his foot down is just the visual effects of the penultimate step.
Number 2 brought up a great example, of how basketball players will do the penultimate step before they take off to dunk. It’s a natural occurance that happens to load the take off leg for the jump. If your foot upon take-off is too close to your center of mass you won’t get any lift. You’ll just be running.
To add to what sharmer said, the knee angles vary depending on how fast the jumper is. The more speed you have when your about to take-off, the smaller the knee angles have to be. The slower you are at take-off, the bigger the knee angle has to be. But this isn’t something that you can control conciously. It usually happens on it’s own.
You answered your own question. Go with the (kinda) effortless version.
Did any of the great dunkers in B-Ball ever look like they stamped down w/ their foot when they dunked? I haven’t seen one.
Try this: Skip around the house/track for height and/or length and try one series w/ stamping your foot and one series without it. Which one feels like your wasting energy and not getting anything in return? Which one made you reach out too far in front of your C of G?
Both Treble and #2 made some good points. I hope that helps a little.
-Balance
Originally posted by Treble
The problem with over-rotation is almost always because of the arms. The action that your arms take upon take-off, will dictate how much rotation you have. And it sets up the landing. Marion is a great example because her arms play such a little part in her jump. Especially at the take-off. And as you have probably noticed her landing isn’t exactly text book either.
The lack of arm motion is not necessarily the cause of the over-rotation, but it can helpt to counter the over-rotation created by planting at the board. However, if the rhythm in the approach run is way off (as it is in MJ’s case - I’ve watched hundreds of hours of video in this case, so trust me) her arms will not bail her out.
The common rhythm in LJing is slightly longer penultimate and slightly shorter take-off stride. In MJ’s case, she shortens her penultimate and reaches for the board on her take-off stride (I have the stats to show this trend in her approach run). What further complicates the issue is that both arms are forward at take-off (rather than opposite to her leg position). The hips drop because of the long stride and the arm position. Also, she is anticipating throwing both arms back and around for her landing (much like you would see a triple jumper do on their final jump phase - a la Willie Banks). This is not an intuitive method of Long Jumping.
From my analysis of her jumping over the last 6 years, it appears that someone had directed her to change what was natural (i.e. doing a layup or dunking the basketball) into something that is not so natural. The sad part about it is that everyone (including bright Dwight Stones) always comments on the apparent fact that Marion needs to correct her landing. In fact, she needs to correct her approach run and take-off mechanics.