Wayne, Ignoring all the physics (which don't exactly appeal to me and don't really address the question of differing wind conditions), two related pieces stand out as begging comment:
> Since the runner will have the best time the earlier he reaches maximum > speed, he will have the best time the sooner he becomes erect. If all your formulas reach such a conclusion, then I suppose an upright standing start would be ideal? > I watched the Seoul men's 100 with a sprinter that I coached, > taping the race. My athlete commented "Look, Ben stood straight > up at the start. Why do you always want me to stay lower?" We > played the tape back and my athlete was right, the drug-aided Ben > Johnson did indeed become nearly erect in two steps. Did you point out to your athlete that no one else in history has ever been able to duplicate Ben's start (that I'm aware of)? Most people would fall flat on their face if they tried setting their blocks like him, too. What worked for Ben would work for very few others, so I'm afraid that isn't a very relevant example. Dan --- "Wayne T. Armbrust" <[EMAIL PROTECTED]> wrote: > I wanted to reply to this post a long time ago, but was rather busy last > week. Everyone is trying to get their track striped this time of year! > > The runner really can't nor does he want to extend length of his drive > phase. The drive phase continues only as long as the runner continues > to > accelerate, and the angle that his center of mass makes with the ground > depends on his rate of acceleration. If the runner is to remain in > balance - > the only way he can continue to apply force - the angle that the > runner's cm > makes with the track for a particular step is given by A = arctan(g/a), > where > a is the average acceleration during that step and g is the acceleration > due > to gravity. This neglects air resistance which will require a slight > forward > lean at maximum speed. Note that the angle with respect to the ground > is a > minimum at the start, where acceleration is a maximum, and zero at > maximum > speed (neglecting air resistance) where by definition acceleration in > zero. > Since the runner will have the best time the earlier he reaches maximum > speed, he will have the best time the sooner he becomes erect. > > An example: I watched the Seoul men's 100 with a sprinter that I > coached, > taping the race. My athlete commented "Look, Ben stood straight up at > the > start. Why do you always want me to stay lower?" We played the tape > back > and my athlete was right, the drug-aided Ben Johnson did indeed become > nearly > erect in two steps. However, I pointed out that on his first step he > was > nearly horizontal with the ground! He was following the relationship > given > above but his acceleration was so great on his first step, as indicated > by > his flat angle with the ground, that he was virtually at top speed after > two > steps and hence was running erect from that point. > > Dan Kaplan wrote: > > > --- Jonas Mureika <[EMAIL PROTECTED]> wrote: > > > I never said my figures are absolute. If you read any of my papers, > > > you'd see that I am willing to admit limitations. > > > > Fair enough. > > > > > Since we're discussing pulling figures out of the air, I > > > would be interested in hearing how the effects you propose > > > will account for 40% of the race. > > > > Easy. Athletes typically train for a drive phase of around 30m, and > with > > different resistance training techniques could push that anywhere from > > 20-40m, which means a lower cross sectional wind resistance can be > > obtained for up to 40% of the race (100m). If you do harness > resistance > > work, you quickly see that you can hold perfect driving form for as > long > > as your energy holds up and there is enough resisting you. > > > > > That's what I keep hearing when people say "Wind affects different > > > people differently", as if they can train to overcome drag forces. > > > > I don't think you can train to overcome wind effects, other than > mental > > training to not be thrown off by it and to maintain maximum effort. > Maybe > > a little bit in terms of increasing leg strength for better balance to > > handle cross winds and what not... But I know of no one has put on a > > speed suit or body suit for a race and not felt it made them faster. > > > > Dan ===== http://AccountBiller.com - MyCalendar, D-Man, ReSearch, etc. http://Run-Down.com - 10,000 Running Links, Fantasy T&F ------------------------------------------------------------ @ o Dan Kaplan - [EMAIL PROTECTED] <|\/ <^- ( [EMAIL PROTECTED] or [EMAIL PROTECTED] ) _/ \ \/\ (503)370-9969 phone/fax / / __________________________________________________ Do you Yahoo!? New DSL Internet Access from SBC & Yahoo! http://sbc.yahoo.com
