/ic/ - Artwork/Critique

>doing a hand study
>hand begins to go numb/sore after about 4-8 minutes in and it gets difficult to hold the position
>eventually have to stretch out
>hand no longer in the same position
How do you guys keep your hands/feet/etc. in the same position for more than 15 minutes at a time without getting sore or shaking? I find that it's really cutting into my studying because it's so difficult to do a study that lasts longer than 10 minutes.