I posted this in part to the "Did You Ride Today" thread, but that's not really a way to get a response, so here it is again, slightly longer.

My road bike was in the shop last week, so I was riding my commuter for non-commuter rides, which has strapless steal toe clips. It's a slower bike with a much more upright position, but I noticed that I maybe had more power on modest hills than with my "better" bike. I got to thinking about it and thought I'd experiment with my foot position. On my road bike, with SPD pedals, my foot is generally all the way back (meaning the cleats are all the way forward). So as an experiment, I moved the cleats to an intermediate position. I took an easy 20 mile test ride (no hammering) and this seemed to be fine, though I wasn't entirely sure that it was an improvement either.

So the next day I went on a 75 mile route with some more demanding riding, and my legs were were really hurting me, particularly for the first 30 miles. It wasn't the normal fatigue, which I feel chiefly in my quads, but rather in the upper part of my calves and the upper inner part of my thighs.

Could the change in cleat position really make that much difference? If so, will I get used to it quickly and be better for the adjustment? Or should I just move the cleats back to the original position?

And to the original question, do any of you think that cleat position makes a big difference to your efficiency and power?

There is a lot of information on the internet about cleat position and power. I have not found anyone reliable to say it makes a difference. In general, the cleat is positioned on the shoe so that the pedal spindle is under the middle of the ball of the foot. I believe that some trackies move it back to get a better spin. However, minute changes in setup have a huge impact on body mechanics when riding long distances. One will pedal hundreds of revolutions and a new position will require some adaptation.

cleat position and rotation have a huge effect.
even if the prior position wasn't the optimum for you, making a big change and goin out for a 75 miler could have caused some serious issues and even injury...
the internet is not the best way to sus out what can work for you...
if you;re not sure yourself, how to proceed. find some good advise and proceed slowly.

one thing about oldstyle clips without being really cinched in tightly with straps - if the general fore-aft position is ok, then your foot can also find the the most 'natural' orientation/rotation angle for your foot and leg.
This is how I determine how to position cleats on my shoes.
I put oldstyle road pedals with toeclips, on the bike, regardless of what eventually will be on there. I then wear the new shoes without cleats installed, lightly cinch the straps so the shoes don't wander too easily, and go for a 5 mile ride.
The pedal cage (rear one) will leave a 'mark' line which I will use to align the cleat rotation.
Cleat, for me, is set so my ball of foot is dead over the pedal spindle.
Has worked for me, with old nail-on, or now screw-on cleats for 40+ yrs and no knee injuries because of it...
YMMV
There's some Bio-mechanics discussion out there on positioning the pedal spindle directly under the foot arch. SOme interesting reading, but considering the implications for injury, it's not experimentation I'm ever gonna try.

Hmmm, it's true, there's lots of discussion on the internet. To my surprise, Joe Friel recommends an even more radical shift in cleat position -all the way back to the mid-foot! https://www.trainingbible.com/joesblo...-position.html

I"m not ready for any where near such a radical change, but reading the comments on the blog made me realize that I should have moved my seat down a little when I moved the cleats. hmmmm...

I moved my cleats all the way back several years ago. It works for me, but I'm no great shakes either.

If you watch a beginning bicycler, most often the natural position they automatically find is under the arch. I've never tried it, but I have read about it and seen it recommended before by others than Friel.

https://bicyclingaustralia.com/node/77

Moved my cleats back as far as they would go to eliminate a "hot spot". Took care of the hot spot but took a few rides for my muscles to accomodate. Now I would never go back to spindle under the ball of the foot. Too bad I can't try moving the cleat even further back.

Try shorter rides for a couple of weeks to see if you can adjust.

When you move your cleats significantly you also need to adjust you saddle height. Cleats back=saddle down, I believe it is. And +1 to the idea that a 75 miler was not a great idea without some adaptation to this change.

+1 on rearward cleat position and hotspots

I found the blog post and the comments interesting. Generally, I defer to those with credentials, experience and in the business of coaching. When I had my Retul fit, we discussed cleat position and my fitter coach dismissed the cleat position as not adding a lot of value. He attends seminars put on by USA cycling and keeps up to date on latest stuff. To think that one can get a lot more power by moving a cleat seems questionable. However, I just ride these things and rely on third parties for advice. My advice would be... be very careful in changing fit and allow a lot of adaptation time to prevent injury.

Just a post-mortem on this thread. I've now moved my cleats to a position intermediate between their original position and the position I had for the ride in which my legs were hurting. I also lowered my seat just a bit. The leg discomfort has gone away, and I think I have just a little more power (especially out of the saddle) then compared to the original position. But I don't think I have it perfect. So now the strategy is to make small modifications until I either find the perfect position or get tired of experimenting.