Ergonomics - road cycling on mountain bike I am new to cycling and have recently started to bike to work.
The distance is about 20 kms each way and I find that by the end of it my lower back starts to hurt.
I do work at a desk job and I probably do already have a bad sitting posture; which I'm trying to correct.
I was wondering what is the proper posture to ride on a mountain bike comfortably for about 1 hour ride. Or if this lower back pain is due to my back simply not being strong enough to lift my upper body as I'm sitting on the bike.
I'm looking for rule of thumb tips such as your seat should be high enough so that your leg is just reaching the pedal at a full extension.
Thanks!!
If you're rocking your hips while pedalling then your saddle is too high relative to the pedals, for your leg length.
Raise your saddle until you do start rocking while riding, and then lower it a couple cm or an inch.
If you now can't reach the road with your foot when stopped, then you will need to lean the bike, or get off the saddle at a red light.
This is not specific to MTB, but having a saddle that high might make MTB riding less controllable.  If you ride off road, lower your saddle again by a bit.  Draw two lines on the seatpost to help find your heights when adjusting.