Training for power sports involves a two tier approach. The one exception is Powerlifting where the exercises used to maximize strength are the same ones used for competition.
In power sports the emphasis is more on muscle strength rather than muscle size, although increased strength invariably results in increased muscle size. However, since in many power sports, and in fact any competitive sports, the underlying premise is to maximize strength per pound of body weight, whether or not the sport has weight classes or not, it's best to keep muscle hypertrophy at a minimum while increasing muscle strength. The only exception is in sports with a heavyweight or super heavyweight division with no weight limitations. In this case the extra weight, even though it's often accompanied by extra body fat, can increase performance. An example of this is seen in powerlifting where more weight can be lifted the heavier the lifter regardless of increased body fat. In fact the increased abdominal fat can be an asset in the squat.
Muscle cells can be considered to have two basic components, the contractile filaments or myofibrils, and the rest of the sarcoplasm (like the cytoplasm of other cells), which contains mitochondria, myoglobin, lipid droplets, glycogen, and other components. Depending on the type of training you can be somewhat selective on what parts of the sarcoplasm you target. And what you target determines the balance between strength and overall hypertrophy of muscle cells.
To make is simple, using powerlifting like training develops the contractile elements of the cells relatively more than the rest of the sarcoplasm. As such, you can develop strength without over developing overall muscle hypertrophy.
If what you're after is maximum muscle size, then the bodybuilding training routines, with more volume - lower weights but higher reps and sets, is the way to go.
It's my feeling that any sport where maximum performance depends on maximum strength per pound of body weight, should be using weight training to maximize that strength, mainly by the three powerlifting lifts, and any other that will help their sport, with an emphasis on maximizing strength BUT not using weight lifting movements that try to mimic the sport, except for powerlifting.
Perfecting their performance then involves specific training for their sport doing what they do when they're competing.
Developing the maximum amount of strength per pound of body weight also means minimizing body fat, not to the level of competitive bodybuilders but certainly maintaining body fat in the single digits.
All components of course requires that you combine your training with a proper lifestyle, diet, and nutritinal supplements as needed for the sport.