Also, in a sitting position, one tends to adjust the neck and mpc at an angle to compensate for the legs (most common with tenor, and most young altoists.) When one stands with the horn while it's set up for this angle, it will be quite uncomfortable to play. Try bringing your neck back to the left a little so that it's more in line with the body/bell position. Then, readjust your mpc so that it's more parallel to the floor. When you find the ballance you should be able to stand (with just the neck strap on and mpc in your mouth) and not need to hold on to it. Sounds wierd, but, ballanced like this, you will use the least amount of muscle energy to hold the horn in position... JUST MAKE SURE THE NECK STRAP IS SECURE!!! Tsax_player is correct about the advantages of standing, with the addition of one thing; standing also allows one to expressively move with the music, but just don't get carried away :) Tsax_player and definition are also right about the strap... it should be adjusted so that when you're standing upright (and not slouched) you just need to bring the horn back to you. If you find that you're reaching forward to reach the horn, the strap is too low (this applies to a sitting position as well). Good luck, and don't worry. As tsax_player mentioned, the more you practice while standing, the more natural it will feel for you.

To make standing and playing easier in the short term try a harness support system instead of a neck strap. using the harness for my new selmer baritone sax has added the necessary control that my fingers dont need to worry about. Yuibob 2 - Washington, DC

I used to have trouble with this too. Your not the only one out there. Anyway, i would just make sure you raise the strap more than if you were sitting. I would also say to put more weight on the strap, and practice standing up.