On a long climb, I will be seated for a while, and then stand up for a while.
After a few of these, I become reluctant to sit down due to the rythym and subsequent speed loss.
In either case, my abdominals, obliques, lats and delts are tensed up to provide stability for my glutes and leg flexors; as Bill says.
Incidentally, I have found standing up and performing a 'stair climbing' exercise more natural than sitting on a saddle doing a 'cycling' exercise.
After a few of these, I become reluctant to sit down due to the rythym and subsequent speed loss.
In either case, my abdominals, obliques, lats and delts are tensed up to provide stability for my glutes and leg flexors; as Bill says.
Incidentally, I have found standing up and performing a 'stair climbing' exercise more natural than sitting on a saddle doing a 'cycling' exercise.