Hand hurts when playing this part?

[chopinfrederic]

Hi everybody, I'm currently working on Mozart's Sonata k 309.
My left hand hurts when trying to play this part (it's really fast).


Any suggestion on how to play it fast yet comfortably?
Thank you in advance.

[j_menz]

It's Allegro con spirito, so not that fast. It's also a pretty bog standard alberti bass, and not the first time it has appeared in this piece, though the first prolonged passage of it. Do any of the earlier slightly shorter ones give you any discomfort?

Check that you aren't trying to double the speed here; it sometimes happens.

That aside, if this is hurting, you are doing something wrong physically. If you have a teacher, talk to them about it. If you don't, post a video so we can see what's going on.

[indianajo]

yeah, teachers teach proper position, you won't get that from the internet.  Wrists straight, fingers curved down naturally, arms drooping evenly down from the shoulders, neck straight, eyes straight ahead.  Same posture for typists in an industrial ergonomics text, strangely enough.  
If you are getting muscle pain, not joint or tendon pain, you didn't do your exercises, did you? That bass line is a common exercise in the Schmitt book from Schirmer.  I ground through 15 minutes of Schmitt a day my first couple of years of piano lessons with Mother, although when I got a professional piano teacher she moved me on to Edna Mae Berman exercises.  Nothing like the muscle building of infinite reps of those Schmitt exercises, though.  Lots of work on fingers four and five, which is key.  I used to read novels when I had these memorized, it is like lifting weights at the gym, not an intellectual exercise, Schmitt exercises are for muscles and coordination only.  

[lazyfingers]

My left hand hurts when trying to play this part (it's really fast).

I'm uncertain what you mean when you say "hurts". Does this mean you get tired, you feel muscular pain, tendonitis, arthritic pain, or something else?

Even when playing fast, you should not feel any pain. The worse you should possibly do is to stumble. If you do feel pain, then something else is wrong. I suggest you seek professional help, maybe even medical help.

[worov]

I just listened to Claudio Arrau's recording (Philips) : it's not that fast.

[kaystephaniex]

There's nothing technically demanding in the left-hand part. It's just standard Alberti bass. You'll need to be more specific. Which part of your arm/hand hurts? Please describe it. I think your hand may not be in a proper position and you're tensed when playing it. And it's not that fast. It's Allegro con spirito.