bike fit, hamstring "weakness"

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Decided to get pictures up, as today, before nationals i went out and did a 20min interval. held back starting up and held 294w comfortable for about 8 minutes, at around the 8min-9min mark, like usual, i get this weak/tight feeling in my hamstrings. i cant keep the power up and it slowly drops, im not out of breath or breathing that hard. so it leads me to believe its my muscles. ive noticed this almost 100% of the time after i broke my toe (~10 weeks ago, took the first 3.5weeks almost off). but i have felt it alot during the winter months when i ride a trainer.

ive thought of bike fit, as i have a ton of setback, way more than anyone else, and have thought of moving a bit forward. also, an idea being that i do a more 12 minute intervals than 20, i can still hold 320w for 12 minutes if my legs dont get that feeling, but my 20min has dropped to ~285-290w. from my earlier this season i could do ~335w for 12min, and ~315w for 20min.

my 5 min power is still good, ~370-380w. and i remember reading that difference between 4k pursuit power and 1hour power wasnt all that much different, is there any correlation between my 5min power and what i should be able to do for 12-20+ minutes?

enough blabbering by me. here are the pictures.

http://img412.imageshack.us/img412/7875/spinjg2.th.jpg (http://img412.imageshack.us/my.php?image=spinjg2.jpg)

http://img242.imageshack.us/img242/7352/img3364ub2.th.jpg (http://img242.imageshack.us/my.php?image=img3364ub2.jpg)

http://img174.imageshack.us/img174/1808/img3361ry7.th.jpg (http://img174.imageshack.us/my.php?image=img3361ry7.jpg)

Check these out:
http://www.cyclefitcentre.com/further%20reading.htm

Dave

i remember reading that difference between 4k pursuit power and 1hour power wasnt all that much different, Ooooh, that doesn't sound right. For an average cyclist 4k pursuit power may be 120-140% of functional threshold power (FTP - 1hr power), for a pursuit specialist that percentage might be greater. Just my estimation.

is there any correlation between my 5min power and what i should be able to do for 12-20+ minutes?

There's always some corellation, but it depends on one's particular talent. This is all helpful stuff, but look up the part on power profiling:

http://www.cyclingpeakssoftware.com/power411/