In Reply To:
In Reply To:
Sure, that's easy to figure out. High-Tech Cycling has a study of 17 riders at 350w at 90rpm. Average *PEAK* normal (perpendicular to the pedal) force is 400N. That's the equivalent of 90lbf. That's the MAX force that is applied to the pedal (so for like 1deg).
The average force during the peak 90deg of power application at 350w is ABOUT 300N or so, or maybe 65lbf (67.XX if you want to be super particular). The distance traveled during 90deg, assuming 175mm cranks, is 175mm*pi*1/2 = 274mm.
Or, put another way, each pedal stroke at 350w @ 90rpm, you are moving a 65lb weight about 12inches.
Time, of course, is essential, for power calculations, so you really need to move a 65lb weight 12inches in
0.167seconds.
And, of course, there is momentum involved in both cycling and weight lifting, which makes it even harder to really say "X is like Y." Because what most people will equate that force with is how hard it is to start the weight moving - accelerating it - not keeping it moving.
However, as Jack said, all a child needs to do is to lean their body weight on a pedal and it'd be as much force as an elite cyclist generates during the peak 1/4 of a pedal stroke.
Rappstar, thank you very much for the informative response. So, it's difficult to be exact because of acceleration/inertia but basically we are talking about moving a 60lb weight 12 inches.
Jack said
'think of it this way, a small child, with a single hand, can put as much force on a pedal for a few reps as lance does with each pedal stroke in a 40k TT' I think this would imply that the child is not 'leaning' in the pedal but turning it while holding it. I don't know any, maybe Jack does, small children who can handle what is probably about their body weight that easily. In fact i wonder how my single arm curls with a 60lb weight most adult male triathletes can manage.
Sorry to be obtuse, my point is some people on the board seem to grossly underestimate the power requirement of cycling. Not that it isn't easily overstated but a dose of reality would be better.
Kind Regards
As others have pointed out, there are some terminological issues here, but more to the point, peak power (along with other things) has been studied in children, somewhat carefully, so we don't need to speculate here.
First, 'leaning against the pedal' won't produce even close to 400W. Or rather, it depends a lot on what one means by 'leaning'. For example (just to make it extreme), a child certainly
can produce 400W by being dropped onto the pedal from a great height ('leaning hard'). Gently resting against the pedal will likely not produce 400W.
Second, yes 'medium sized' children can produce 400W on a bike for a very short time (a few seconds). There is obviously a huge age-dependence (among other things), but for example
this study shows 13-year olds with peak power (over 1s on an ergometer) of around 450W. (In that study, there was a big difference between 12yo and 13yo children. It isn't totally clear why, but definitely the relationship between age and power is not linear. One more example:
this study shows 9-year olds producing around 300W PP.)
Or, if you want to be even more impressed by children's athletic prowess, you can have them do a vertical jump test. You don't have to get very far off the ground to be producing a whole lot of watts, albeit for an extremely short time.
In general, I'd say that the numbers really do support the contention that pretty much anyone can do for a few seconds what pro cyclists can do for hours. I won't 'weigh in' on the strength training part.
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Michael