George Block
@GeorgeBlock
President
World Swimming Coaches Assn.
36 year career in club and high school coaching and administration.
4 hours per day is pretty typical for 14-17-year-olds, so it does not seem out of line to me. A detailed answer would require more information. Does he do that schedule EVERY day (i.e., 7 days a week)?
Is he having any problems that led you to ask this question (academics, physical, appetite, sleep)?
I think this answer comes in two parts. Most coaches structure their training sessions to progressively prepare their swimmers for their "main sets,"i.e. the most intense sets that are the critical objectives for that practice. Roughly, that gradual build-up would be 20-25% of that session's total volume.
Before that, when the athletes are standing on deck, dry and warm, their coach will ask them to "warm-up." What is occuring there is moving the large amount of blood that is in our skin, through the internal organs, to the working muscles. That takes about 8-10 minutes. If the "teenager" is 18 or 19, probably 8-12 minutes would be appropriate. If the teenager is 13-17, their attention spans and ability to warm-up independently are much shorter, so the coach will probably prescribe a 4-6 minute swim to "get the blood moving," then move into their series of preparatory swims leading to their main sets for the session.
I would agree with George. Generally if the session is early in the morning, the warmup should be more dynamic and active. Static stretches are less effective. Get them moving and "working" the different muscles groups to get that blood flowing well.
If you can give me your location, I can send you information about Disability Clinics. Most are in the US, but we could also develop one for your area, if needed.
If I were picturing a plate, I would think a quarter of the plate would be protein, a quarter vegetables and half carbs. If you are a parent asking this, your plate should almost be the reverse of this, a quarter carbs, a quarter veggies and half protein. You could also eat on a salad plate while your swimmer ate on a serving platter!
All the typical caveats apply. Don't drink sodas with the meal. The very best thing they can drink is water with some lemon or lime squeezed in to it. Chocolate milk is better than sports drinks (and cheaper).