If you're planning a marathon crocheting session, please remind yourself to stop every 30-45 minutes to stretch your wrists, arms, and shoulders to avoid getting stiff and aggravating any repetitive motion injuries. It only takes a few moments, and it'll make a lot of difference in maintaining physical comfort while crocheting.
Here are a few stretches to try:
1) Stretch your arms out, shoulder height and palms facing down, and flex your hands upward, like you're telling someone to stop. Then, bend your hands down, with your fingers pointing to the floor. Now, twist your arms so that your palms are facing up towards the ceiling. Then, bend your hands toward you, so that you are looking at your palms, then bend your hands backwards so that our palms are facing away from you and your fingers are pointing downwards. As you change positions, be sure to wiggle your fingers and relax them as well.
2) Drape your right arm over your head, so that your right hand covers your left ear. Gently bend your head towards your right shoulder and hold for at least 10 to 15 seconds. Switch sides.
3) Stand up and place your hands on your hips. Gently twist to the right and then to the left, while trying to keep your hips facing forward. Do that a few times to work out the kinks. Take a few gentle squats as well to get the blood flowing again.
Now, you're ready to sit and crochet some more!