Here are a few tips to prevent the dreaded repetitive stress syndrome often plaguing knitters:

1. Use circular needles(even when knitting flat pieces) as the weight of the fabric will sit in your lap as opposed to the straight needle which you are struggling to hold up.

2. Change projects and needle sizes often; both will change your biomechanics

3. THE SECOND that you feel fatigue or discomfort, stop for at least 15-30 minutes