The Navy SEAL Physical Fitness Guide 163
The overload principal is the basis for any training program whether it be
cardiovascular training or the development of muscular strength, endurance, or power. The
three basic variables used in the overload principal include the frequency, volume (or
duration), and intensity of training. By increasing any one or a combination of these
variables within a training program, one can continuously and safely overload the system
that is to be trained (i.e., cardiovascular, muscular, neuromuscular).
Frequency
Frequency is the number of workouts per week (or other unit of time). For
plyometric training, the range is usually from one to three sessions per week, depending on
the sport and season. A plyometric training program for the Naval Special Warfare
community should consist of two training sessions per week when operational demands
require such training. Allow 2-3 days for recovery between workouts to avoid overtraining
or injury.
Volume or Duration
The volume for plyometric training is defined as the number of foot contacts
or landings per session.
" Beginners: 80-100 landings per session.
" Intermediate: 100-120 landings per session.
" Advanced: 120-140 landings per session.
Intensity
The intensity for plyometrics training is the level of stress placed on the
neuromuscular system, the connective tissue, and the joints, and is determined by the type
of exercises performed. For example, skipping is a low intensity exercise while in-depth
box jumps are of higher intensity. Some guidelines are provided as follows:
" Vertical jumps are more stressful than horizontal jumps.
" One leg landings are more stressful than landings on two feet.
" The higher off the ground the body, the more forceful the landing and the
more stressful the exercise." Adding external weight to the body also increases the stress.
When designing a program, it is best to increase only one variable per session to
reduce the likelihood of injury. Generally frequency is held constant while either the
volume or the intensity is increased. In advanced plyometrics, when high intensity
exercises are performed, volume should decrease since these exercises place significant