Fast twitch, Slow twitch fibres

[mikesbytes]

Having done a little research on fast twitch and slow twitch and found there to be a lot more to it than initially meets the eye.

Have a read of the following and discuss

http://en.wikipedia.org/wiki/Skeletal_muscle

[sogood]

You need both and fortunately have both types.

[mikesbytes]

However I understand you can change the quantities thru selective training

[sogood]

I also understand that there's conflicting studies showing either the shift in % in very limited or no change at all. The genetic determinant is overwhelming. At the end of the day, we train to go faster and/or further, the biological adaptation will just happen in the background.

[Alex Simmons/RST]

Doing nothing (i.e. being exceptionally sedentary) and resulting atrophy will result in the proportion of fast twitch fibres increasing. But it's not a performance improvement methodology!

There can be some conversion of faster to slower twitch, at least faster twitch fibres taking on some properties of slower twitch fibre, but as sogood says, it's not a big percentage and fibre type proportions are basically genetically determined (IOW - you have to be born a sprinter). It is however something that does happen with large volumes of endurance training and is speculated that it is one way that gross metabolic efficiency might be improved over the course of an elite athlete's career.

IOW, train lots and improve.

[Alex Simmons/RST]

single speeding makes use of both muscle fibre types.

pretty much all cycling does.

[toolonglegs]

For example...sprint training.
Say I have a 1250w 5 sec...train hard for a year doing sprint efforts etc and get to 1400w...I will never get higher than that,have to be happy with a small % increase...in an actual race scenario the % will probably be even smaller anyway.I am not going to knock a 5% increase of course.But I was not born a sprinter so I am better off improving the things that I really can increase right?.
Not that I am riding...but what are the areas of biggest gains usually?....ftp then descending I suppose?.

[Alex Simmons/RST]

For example...sprint training.
Say I have a 1250w 5 sec...train hard for a year doing sprint efforts etc and get to 1400w...I will never get higher than that,have to be happy with a small % increase...in an actual race scenario the % will probably be even smaller anyway.I am not going to knock a 5% increase of course.But I was not born a sprinter so I am better off improving the things that I really can increase right?.
Not that I am riding...but what are the areas of biggest gains usually?....ftp then descending I suppose?.

There's always room to improve one's sprint. You are not aiming to be the best sprinter of the whole bunch. Just of those remaining in the race for the win (which could be just one rider). And sprinting is much more than the physiological element. Plenty of fast guys lose sprints to slower but craftier riders.

[foo on patrol]

^^ Very true! ^^

[toolonglegs]

Well said.