Over the years, there has been some debate on what roll the wrist should play in the basic fly cast. Different casting instructors have different methods. However, most casting experts will tell you that the wrist should be locked and bend very little.

Here are some reasons why you shouldn't bend your wrist excessively during fly casting:

Your arm is stronger than your wrist.
Wrist bending often contributes to wide, inefficient loops.
Wrist bending often contributes to tailing loops.
Wrist bending often contributes to less casting accuracy than a firm wrist.
Wrist bending can accelerate the progression into carpal tunnel syndrome.

Most folks use their wrist when casting ... It's also true that many are not even aware of the wrist's action. For many, the snap of the wrist is the power stroke in casting. However, it's critically important that the wrist's movement be controlled within a very narrow angle. During the back cast, the elbow should bend much more than the wrist. The wrist should remain in the locked position until the rod is almost even with the ear. We usually refer to this as the 11:00 position. Now, from 11:00 to 12:00 you should bend your wrist in a snapping back motion in order to create our power stroke. It’s also important that you abruptly end this power stroke at 12:00. This sudden burst of backward power is what will quickly hurl the fly line back behind you while maintaining a tight loop. When the line straitens out behind and the rod begins to load, start your forward cast with your wrist again in the licked position. The wrist retains this position until called upon to make the power stroke at the end of the forward cast.

I know an angler, who at the beginning of his casting journey, would put a thick rubber band on his wrist. Next he would take his rod and hold it the proper way and then just slip the rod butt in the rubber band. He said this would really help him in getting his mind to concentrate on not bending his wrist too much in the cast.

For my casting students who have trouble with severe wrist bending problems, I have them wear a long sleeve shirt and stick the butt of the rod just under their sleeve. That holds the wrist pretty firm. Special wrist bands are available just for that purpose and are available at many fly shops. You can also buy Velcro straps for wrapping water hoses, extension cords and such. You can get these almost anywhere. They will wrap around the wrist and the fly rod handle and offer good support.

OK, let's refresh our memory on my position here. A little wrist bending is not necessarily a bad thing. A lot of wrist building is always a bad thing when it comes to good fly casting. The main thing however is getting the fly out where the fish can get it. If you can do this, you’ll catch fish. This is what is most important anyway. After all, the fish don't care whether you bend your wrist or not.