I've ridden enough Etapes and races to know that sometimes, even if I've prepared properly, eaten and slept well, and am fit, there will some mornings when I wake up and my legs feel like lead on the start line. Other times, in otherwise similar conditions, they have plenty of zip.

I'm wondering if there's an actual physiological reason behind having 'good' or 'bad' race legs? Is it to do with energy levels? Rest? Or is it all in the mind? Can any sports scientists enlighten me?

Good nights sleep.

There almost certainly is but sports science hasn't worked it out yet.

It can be in the mind but equally the body's far more complex than we fully undertstand at the moment so there are things like this that we just don't have an answer for.

A good night's sleep the night before an event has been shown to be pretty unimportant in determining your performance – that may well be different for multi-day events though.

Biorhythms? Could be twaddle, but who knows.

Glycogen storage is also a factor I think. You need to make sure you're eating enough complex carbohydrates in the 48 hours before you race/ride. I saw an article online recently with the exact amounts, but I can't find it now.

See a sports nutritionist if you want the full details.

good legs:

what theflatboy said.
good legs = well-defined toblerone slot
bad legs = cankles

being on your feet for most of the previous day doesn't help at all.

PMT?

totally agree with the concept of having good legs (and very often bad legs too) but i don't think even the pro's know the answer hence often in the TDF teams will push hard if their key rider/sprinter has good legs but on other days he will pass the message up the line that he doesn't feel so good and they will let other teams do the work.

It's like sh*t, it just happens…

Often wondered this. However I would say that waking up with legs like lead doesn't always correspond to poor performance on the bike – sometimes quite the opposite for me. Strange eh?

Absolutely right Mr Wolf – some of my best racing performances have been on days when I felt the worst at the start and even sometimes right the way through but somehow seem to be performing better than makes sense.

I think a key point is plenty of rest; i.e. non riding in the days before and this is more impt than having a big sleep the night before.

As Mr Wolf says feeling dead doesn't always translate directly into poor performance during the day. I think all that carb loading can leave one feeling a bit leaden but after a few hours riding the largeness wears off and the stored energy kicks in and off you go.

On a slightly different theme why can't I sleep well after a hard days ride – I tend to lie there with twitchy legs and then wake up early and struggle to get back to sleep despite not feeling very awake – strange things bodies.

I looked like this on saturday after an 8 hour battle with the stump. On the sunday I had one of my best races, I am not a racer just dabble with a bit of XC at a low level.
I actually damaged the nerves in my hand I think as the first 2 laps of the race sunday I could barely hold on or change gear and both sat and sunday nights were an agony of pins and needles.

Nice one theflatboy! 😆