One of the most important factors in muscle training is the amount of repetitions done per set of any exercise. This is largely due to the types of muscle fibers that are present in the body.
The muscle fibers of the human body are classified into 2 general types: type 1 muscle fibers and type 2 muscle fibers. The type 1 fibers are the muscle fibers that are also referred to as the slow twitch fibers. These muscle fibers are smaller than type 2 muscle fibers, they have less capacity for force than type 2 muscle fibers but they have a greater capacity for endurance. Thus, type 1 muscle fibers are the dominant type of muscle fibers in athletes that excel in endurance sports such as long distance cycling, running, and even swimming. The type 2 fibers on the other hand are larger than the type 1 muscle fibers and they have a much larger capacity for force, although they lag behind in terms of capacity for endurance. Because of this characteristic, type 2 muscle fibers are the more dominant type of muscle fiber in athletes that excel in power sports such as jumping and throwing events. In terms of muscle training, these characteristics mean that type 1 muscle fibers can do more repetitions of a given exercise than type 2 muscle fibers.
To get the best results in strength training, the recommended procedure is to use just the right amount of resistance that will be able to cause your muscles to fatigue within a span of 30 to 90 seconds. As a general rule, people with dominant type 1 muscle fibers should exercise using approximately 70 to 90 seconds per set. This means that if it takes 6 seconds to complete 1 repetition (i.e. 4 seconds for the upward motion and 2 seconds for the downward motion), one set should be composed of 12 to 15 repetitions. For people with type 2 muscle fibers as the dominant muscle fiber type, one set of the exercise should last for approximately 30 to 50 seconds. Again, if it takes 6 seconds to complete 1 repetition, one set for this type of athlete should have 5 to 8 repetitions.
Most people though usually possess an equal amount of type 1 and type 2 muscle fibers. For these persons, an exercise time of 50 to 70 seconds per set would be the most ideal plan.
The key then to effective strength training and development is anaerobic exercise involving maximum effort. The resistance being used should be enough to fatigue the target muscles within the range of 30 to 90 seconds depending on the dominant muscle fibers in the body. For most people, this is best reached by using a progressive training program that uses 8 to 12 repetitions per set. Choose a starting resistance that can fatigue your muscles within 8 to 10 repetitions then train with this resistance until you can complete 12 repetitions. For the second stage of training add to the resistance and train with it in the same way as the first stage until you can reach 12 repetitions. You will be able to reach your maximum potential much faster and safer with this kind of systematic training.
