531colin wrote: ↑27 Dec 2023, 10:49pm
pjclinch wrote: ↑27 Dec 2023, 2:24pm
arnsider wrote: ↑24 Dec 2023, 8:40am
It seems counter intuitive to move my saddle back. I would have thought that doing this would result in stretching the upper body further and putting more weight on the bars.
It does seem counter-intuitive... but try the following:
Stand a couple of feet back from a table and lean on to it, putting the weight on your hands. Now take the weight off your hands without moving your feet. You do that by moving your bum
back.
There is a catch, which is your
core and neck muscles have to do more work, but as catches go it's probably smaller than having painful elbows!
My favourite is the "Paulatic manoeuvre" here
viewtopic.php?t=157406&hilit=Paulatic......scroll down to Paulatic's post near bottom of page....
.....which demonstrates (I think unequivocally) that his centre of mass is over the pedals, as is mine.
...."core and neck muscles have to do more work".....more work than what?
More work than sitting in an armchair? More work than sitting at the computer?
Not necessarily more work than sitting on a bike in an uncomfortable position.
The "Paulatic manoeuvre" is a variation of pretty standard drill for descending technical stuff on a mountain bike, sometimes known as "the hinge", see for example...
So in a hinge your chest can be quite close to the bars but there's practically no weight on your hands. But it does take core muscles to maintain because the further you are out of vertical the more work muscles have to do to keep the skeleton from sagging. If you do a long trail in a hinge you're feeling it at the bottom!
Sat on the saddle it's less work for your legs, obviously, but it's typically less work for the core because the position is less extreme and not so far from vertical. But we've evolved to stand straight by default for the simple reason that it's less work than standing bent over. Yes, your CoM is over the pedals, but that doesn't mean you're not doing any work to maintain your position. It takes work just to stand up straight (which is why standing desks are increasingly recommended for building exercise in to a working day). It takes more work to stand in a crouch, and that's why if you're not worried about aero (like a typical Dutch commuter) then sitting bolt-upright is the most relaxed cycling posture shy of a recumbent where it's the seat holding you up, not your muscles.
Cycling in a crouch is a good exercise for cycling in a crouch: if you regularly ride in a crouch you're exercising your core. But it
is an adaptation, and the need for a strong core doesn't vanish just because your weight is over the pedals. If your body is cantilevered out from the saddle (to take weight off your hands), you need something going on to stop your spine sagging, and that's muscles doing work. The more you're leaned over, the more work they have to do. You don't get something for nothing, and if you're not leaning on your hands you have to take that weight back to the saddle by holding your body straight with muscle power.
Pete.
Often seen riding a bike around Dundee...
