Different intensities or loads of strength training will produce different results. This is an essential principle in strength training. The selection of load for an exercise then needs to be based on the training objective. Strength training can improve muscular endurance, size of the muscle, called hypertrophy, max (or basic) strength and power.
Power is differentiated from strength by the speed of action; the term power is used to refer to high-speed strength. In physics terms power is equal to Force times velocity, so faster application of force equals higher power. In combat sports and swordplay power is most often our objective.
Each of these can and should be trained as part of a comprehensive training regimen. How to incorporate them all is part of a periodization scheme - a topic to be covered later.
Note that any strength training will improve all four capacities: endurance, size, strength and power. However, a given load will develop a particular characteristic more than others.
The primary variable in the periodization of strength training is the weight being lifted and the number of times that weight can be lifted. This will generally be described with the concept of Repetition Maximum (RM). RM is the max weight that can be lifted a given number of times. So a 10 RM weight is one that I can lift 10 times and then I need to stop. A 1RM weight is on that I can lift only once and then I need a break.
For each exercise different weights will be necessary to produce different RM's. There are resources for estimating these, but most folks can just as easily figure it out by trial and error. Start low and work upwards in small increments until the objective is reached.
Loads of 12RM to 20RM or more will mostly produce gains in endurance, not maximum strength. Of note is the fact that endurance is achieved with different muscle cells than strength so the gains in strength will be minimal. Endurance training will also produce a modest increase in size of the muscle but this is not the optimal load for that objective.
Hypertrophy is the increase in size of a muscle that comes with training. It is primarily the result of the body building more muscle fibers at the molecular scale. The body will also adapt by increasing the blood vessels in the muscle. Hypertrophy is achieved at all levels of strength training but is optimally achieved with 8-15RM loads. The goal of the hypertrophy phase is to produce more muscle tissue to be used in the other phases of training. Loads of 6RM to 12RM will also increase muscular endurance. For swordfighters the amount of muscular endurance needed is not great and so this range of loads will usually be sufficient for endurance training.
The force that an individual muscle fiber can produce is based entirely on it's cross-sectional area. So hypertrophy is a necessary part of achieving maximum strength. Higher loads will further train the coordination of separate muscle fibers, so that the fibers work together better.
Loads in the 1RM to 6RM range will produce gains in maximum strength primarily by training the neuromuscular aspects to use the muscles more efficiently. Maximum strength increases maximum speed of action because strength refers, in physics terms, to Force. Force is mass times acceleration, so increases in force production are increases in the ability to accelerate. Therefore increases in strength will increase the speed with which an attack can be executed. Max strength training provides a foundation on which high-speed strength can be added.
Hypertrophy will continue to occur at these loads but to a lesser degree. There will be little increase in muscular endurance but endurance gained in earlier phases will be maintained. However, endurance will be increased secondarily. The weight of your hand or foot or sword does not increase so as max strength increase the percentage of strength necessary to hold it up or move it decreases.
Power - High-Speed Strength
Power is well trained by high loads in the 1RM to 5RM range. Additionally, training at higher speeds will develop power. There are several ways to incorporate such into your training. In the weight room you can move the weights at higher speed. Instead of pushing the weight up over a 1 or 2 count, you can explosively lift the weight as fast as you can. When moving the weight faster you should expect to get fewer reps out of each set. So a 8RM weight will become a 5RM load when done explosively.
Other options include Olympic lifts, squat jumps, bench press throws, chains and resistance bands etc. All of these are topics for future posts. But don't forget that high weight loads will still do much to increase power. These more complex methods are not necessary for power development - they are used to refine a strong athlete to maximum potential.
Baechle, T.R. & Earle, R.W. (Eds.). (2008). Essentials of Strength Training and Conditioning (3rd ed.) . Human Kinetics. Champaign, IL