Is there a standard number of repititions to be completed when doing resistance training in the water?
When using buoys or noodles in an aqua class, are the standards the same for training as on land? For example, 3 sets of 10-12 reps, to fatigue. Is it "normal" to do 40+ "abdominal shoot throughs or crunches" with a noodle? My concern is lack of good form and/or injury. Also are any good articles or information regarding this that I can read and share?
Overload principles are the same whether on land or on water- it's how you achieve the overload that may be different. Keep in mind that the water has several variables you won't find on land, such as buoyancy instead of gravity, drag and surface area to increase resistance (in addition to the weight variable of resistance you'd have on land). I wouldn't say that there is a "standard number of repetitions" for resistance training in water. As Marc says, gauging client exertion will be key in determining what's appropriate for your client or group.
As far as risk of injury/ poor technique, the water is generally very forgiving. Since exercise in water has far less impact than land the main concern is usually hyperextension of joints rather than acute injury (because the water continues to exert force on a joint even after the motion of that joint has stopped). This is why I make all my class participants aware they should not "lock" knees or elbows. I find that the resistance of noodles & buoys doesn't really compare with the resistance you'd get on land, say in a weight room setting. For that reason, I don't usually use the "3 sets of 10-12 reps", but I certainly bring my participants to the point of fatigue. It's not uncommon for instructors in an aqua setting to do many repetitions with noodles or buoys, just as you might see instructors in a step class doing 40+ "repeater knees".
Regarding available resources, check out the Aquatic Exercise Association's standards for exercise: http://aeawave.com/PublicPages/Education/StandardsGuidelines.aspx
The most applicable sections are probably "Intensity", "Cadence" and "Equipment Considerations". They also publish a monthly magazine with some great articles regarding water safety & research in the field if you'd like to subscribe. If you're considering a certification, I highly recommend their Aquatic Fitness Professional cert. I really hope this is helpful! Feel free to contact me through my profile if you'd like to discuss this or any other topic further.