Timed sets refers to a method of physical training in which as many repetitions as possible of a given exercise are performed in a specified period of time. After an appropriate period of rest, a second, third, and so on, set of that exercise is done in an equal or lesser time period. The exercise period, recovery period, and the number of sets done should be selected to make sure that an overload of the involved muscle groups occurs. The use of timed sets, unlike exercises performed in cadence or for a specific number of repetitions, helps to ensure that each person does as many repetitions of an exercise as possible within a period of time. It does not hold back the more capable performer by restricting the number of repetitions he may do. Instead, soldiers at all levels of fitness can individually do the number of repetitions they are capable of and thereby be sure they obtain an adequate training stimulus.
Flexibility is an important area that is all too often neglected. Flexibility can be defined as the ability to flex, extend or circumduct the body's joints through their extented range of motion without loss of strength. On the flip side, you can also bee too flexible; increasing the probability of muscle tears and pulls. Most people get stiffer with age as muscles and tendons tend to get shorter with disuse. The remedy for this stiffness is to be more active and use some of the techniques described below. This flexibility though cannot be achieved overnight, and takes time to achieve.