Hi, does anybody know if there are any exercies to strenght the mouth muscles ? I can't play more than 40 minutes, because i start leaking air :-(

I think the only thing is just to keep doing it, and keep doing it. Your muscles will gradually get stronger. Are you playing with a hard reed? Maybe switching to a soft or medium soft when your lip gets tired, then switching back - I don't know, I've never tried that, just now thought it up.

Have you tried dipping the reed in water every now and then when it starts feeling hard? I have a film canister of water that never leaves my side. I used to have to re-dip it loads but over time I've found I don't need it so much. It just makes it easier to vibrate, but don't over-soak it.

join a band where you are required to play for great lengths of time, my concert band practice goes for 1 1/2 hours . i couldnt do it at first , but i got better as i played more.

Thank you all for your answers... yes, i'm practising every day, and tree times a week in a local band, plus classes, once every 15 days. About over soaking, It is true. To over soak the reed, is contraproducent. the reed blades gets heavier, and pitch lows. But, over soaking, depends on every reed... I do a try-and-error test with every reed. By the way, aquanix reeds on e-bay are exellent !!! (a little expensive, but very good) and need almost no soaking :-)

(sorry for my bad english)

I've had this problem too, sometimes I just get "leaky" after a while. I find sometimes changing your embouchure around a little bit as you play lets you build up more muscles. Slight changes can help to make sure you don't tire out as quickly.

As other people have said, it's something that gets easier with practice. The more you play, the longer you will able to play.