Neuromuscular power question--for A. Coggan (or anyone else) - Page 3

Having read "the" book and looked at the power profiling I did some sprints today and reached for 900 watts (5 seconds).

In the power profiling this gives me a rating of untrained ? Do I miss something or am I really that bad in sprinting

treshold 288 watts
75 kg for 1m82

You're not a natural sprinter. That is what it tells you. But it can be trained to acceptable levels.

Practice sprinting for a month and then see what it is. Maybe two times a week, do a few 10-12" sprints out of the saddle in something like 53x19, from various starting speeds, mostly on the flat but occasionally on a slight rise. Just 3-4 in a session, with about 4-5' minutes between sprints.

Try sprinting from a dead-stop in a 39x15, then post your file here.

(PS: What sort of power/mass do you suppose it takes to cover 250 m in ~15.5 s from a standing start?)

I'm thinking around 25 W/kg, or at least that's what my code spits out. Low ball estimate of 18.4 W/kg is no good (P/m=acc_avg*vel_avg+Fdrag*vel_avg/m, vel_avg^2=2*acc_avg*s). I'm in no jeopardy of hitting either value for 15.5 s.

Sorry, try it w/ an air density commensurate with ~1850 m.

How about a heavier rider (200# rider+bike), 25 inHg, a rather pleasant day at altitude (60 F), a VERY good CdA for sprint position (0.33), and some lower rolling resistance (.004) which needs a whopping 2200 W for the effort?

Does the rider get out of the saddle for the standing start? For how long?

Are you sure about those calculations? I was coming up with a really high power/mass, but not that high.

To accelerate from a dead stop with constant power? Yes. I compared my results to http://www.analyticcycling.com/DiffE...ions_Page.html and they are pretty much dead nuts on. Since the analyticcycling site and my code both solve the diff. eq., I have confidence the 2 independent models are getting the correct value.

You can get a VERY SIMPLE estimate by basic physics

1) assume constant acceleration - distance=.5*acceleration*time^2
2) solve 1) for acceleration (a=2.08)
3) accounting for only acceleration (i.e., no rolling resistance or drag), P=F*v=m*a*v
4) use v=v_average=distance/time for an estimate, so v=16.12 m/s
5) P/m=a*v=33.56 W/kg

Admittedly, 33.56 W/kg is a bit high since you wouldn't have constant acceleration. Nonetheless, I'll stick by my numbers.

My bad: I was recalling the half-lap split for somebody doing a 500 m on a 333.3 m track, not the half-distance split.

Have been watching discussion with interest.

Glad the 15.5 sec 250 was pulled up - I'd sure want those legs and a bloody strong bike! Sub 18 is world class.

I have now set 5 sec all-time PBs from 3 different scenarios in last 10 months:

1st was in a crit - jumping hard with 1k to go to grab an attack by one of the strongest Masters riders in the country. (Strong motivation)

2nd was a standing start on the track with fixed gear some 4-5 months later during peak period around track championships in March this year. (Good form)

3rd was rolling accelerations on track with fixed gear this past weekend following a world masters track champion. (motivation again). In fact I broke my PB, then I broke it again on the next effort by a considerable margin. If you ever needed one more example of how NMP is impacting by freshness - this was after 3 weeks off the bike due to bad case of flu. (Bad news of course is my FTP & VO2 are down the toilet after illness. )

I have never tried the incline / minimal cadence change method to get a 5sec number. But that never happens much in the races I do. Actually I never specifically try to get a 5 sec number, I just track it from the efforts I do.

Your having too much fun. Wipe the smile off your face.

...which, of course, meant that your TSB was sky high.

"Form equals fitness plus freshness" - A. Coggan

my 2 cents... i find that with a downhill start it is easier to get into the ball park of my highest 5s power... with a standing, up hill start i can get slightly higher power but not as repeatably... think the uphill standing start does depend much more an technique so if you haven't mastered it you are not going to get very good numbers doing it that way... guess the opposite might be true too if you have terrible leg speed?

up hill standing start.. torque is huge...160N.m, rpms lower...
http://www.cyclingforums.com/attachm...tid=6311&stc=1

down hill rolling start... lower torque 85N.m peak with higher rpms 140 or so..
http://www.cyclingforums.com/attachm...tid=6312&stc=1

oh... and i'm 5'7" and weigh about 56.5-57 kilos

for top end.. work on leg speed (i.e. rolling starts.. longer sprints)... acceleration do standing starts.. imho.. the former.. rolling starts give the most benefits... i devote one day a week to this (2x uphill standing followed by 4-5 rolling start) and on my endurance days slow down and line it up and do 2 or 3 all out sprints..

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