The Raytheon XOS 2 is a second generation exoskeleton design for USArmy use. It allows the wearer to enhance his strength to carry heavy equipment much easier and for much longer. You'll note power cables snaking away from the suit because it's still a beta test unit.
BUT, the concept of the BUDS instructor asking you to flutter-kick for an hour (politely) would be a thing of the past if you were wearing the exoskeleton. I suspect that you'd have a pre-set and the suit could do it for you... I don't know much flotation you'd need to offset the weight of the metal/carbon fiber suit if you were a frogman. But it would be an interesting exercise. There is also the problem of getting tangled in kelp or nets and the concern that it would set off any sea mines in the area. -- but they're getting closer to true bionic every day.