Psychicanimal:
That's asking to get spinal & joint injuries. Your trainer's ripping you off, dude!
Some real backpacking & Yoga/Tai Chi will help you MUCH more. As for boxing, don't even try it unless you have a qualified professional/olympic boxing coach. Even then, the risk of rotator cuff injury due to heavy bag workouts is very high--even with a water filled heavy bag and proper hand wrapping. It's not worth it, especially at your age.
Most of martial arts training is unrelated to diving, unless you want to become a Navy SEAL.
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Ahemmmmm....
I'm 52, and I hit both fill heavy bags and hydrocores, daily -- I've been slamming the standard fill for years. As long as you have a few initial pointers on how to throw the basic straight punches, jabs, hooks, *and* kicks, if you're so inclined, you do *not* need Evander Holyfield looking over your shoulder to keep you from getting a boo-boo...
Hand wraps have absolutely nothing to do with rotater cuff injuries -- they support your wrists, and protect your knuckles, to some small degree, if you're not using gloves in conjunction. My mother-in-law had both shoulders operated on for rotater cuff injuries, and the closest she's ever come to a hook was on the golf course.
Like anything else, there's the right way, and the wrong way. Without any guidance you can tear yourself up with an innocent stretching exercise. You can always live in a bubble, never push yourself beyond shuffleboard, and stay blissfully injury free. Of course, if that's your mindset, you have no business diving...
No one said the benefits of martial arts, or boxing workouts, were directly related to diving. However, I challenge you to find a workout that is as cardio-intense as boxing, and cardio improvement ultimately benefits your SAC rate (as well as many other activities -- including generally staying alive longer, both above and below the surface)...
I have no doubt Yoga and Tai Chi do wonders for flexibility, joint lubrication, tendon health, balance, and stress reduction. Qigong, along the same lines, also supplements physical health. Any of these can, and probably should, be practiced *in conjunction* with cardio. However, for cardio, which benefits heart and lung function like nothing else, movements no faster than grass growing that work to lower, as oppose to raise, cardio activity, just don't cut it by themselves...
