A couple of weeks ago I was watching and interview, on Floswimming.org, with some coaches of the Australian National Team. The Aussies were training in Tucson and tuning up for the Santa Clara International. One of the coaches, who was working with the distance/mid-distance group, had the swimmers warming up with a snorkel, paddles, and a buoy.
I grew up with coaches that avoided using paddles during warm-ups. They were afraid of shoulder injuries that could occur with the added stress of the paddles on the cold shoulder muscles. However, after watching the Aussie distance swimmers I decided to take give it a shot.
I primarily work with HS age boys, some of whom are small enough that a buoy would actually mess with their body position, so I avoid using the, but I do have some Finis Swimmer's Snorkels and some TYR Catch Paddles. I have liked using the snorkels to, among other things, allow for a smoother, more connected, stroke, and I like the catch paddles because they promote an extended stroke and proper catch without putting much strain on the shoulders.
By giving the boys a long warm-up with an easy-to-moderate interval, they can relax into some beautiful strokes right at the beginning of practice. By the time they complete it, they have essentially done a long technique swim without much fuss. I have been using the snorkel/paddle combination in warm-ups for about 2.5 weeks now, and I am liking the results. The guys are able to keep their strokes in-line/connected and are able to establish a nice catch early in the practice.
Watch the video, listen to Coach Vince Raleigh, consider giving it a try.