After you have developed a good base of strength and strength-speed as described in the previous posts in this series, you will have the necessary force production capability to focus your efforts on developing maximum muscular power as will be described in this post.
Muscular power (sometimes also known as explosive strength) is often considered one of the most important components of success in many sports. Power is the ability to generate large amounts of force quickly. Peak muscular power is produced at lower resistances (less than approximately 30% of 1RM) and even higher velocities of movement than strength-speed.
Power is essential when an athlete must overcome gravity to propel their body forward from a complete standstill (as in acceleration) or when high levels of force must be produced in a short period of time (such as during the brief foot contacts in sprinting).
Lower body plyometrics are a form of resistance training that is designed to increase muscular power through jumping type exercises. Plyometrics are effective because they train the stretch shortening cycle (SSC) – a series of movements that store and then re-use stored energy.
During the SSC the muscle is pre-stretched by performing a countermovement. The stretched muscles store a certain amount of energy that can be released when a muscular contraction immediately follows the stretch. You can think of the stretched muscle like a stretched rubber band, which after being released will snap back to its original length, thus releasing the energy that was stored in it when it was stretched.
Sprinting is a ballistic, single leg movement in which force is primarily directed in the horizontal direction. Therefore, single leg plyometrics emphasizing horizontal, as opposed to vertical or lateral movement, are most task-specific to sprinting. For example, single leg broad jumps, scissor jumps, and bounding drills have a high transfer of training to speed. However, double leg jumps such as depth jumps and multiple response squat jumps are also beneficial for improving speed because they train the short ground contact times necessary for speed.
Plyometrics: The Rules
Volume: Plyometrics are a high intensity exercise, which can involve a lot of pounding on the lower body if overdone. Thus, it is important to monitor the volume of plyometric training that is typically measured in the number of foot contacts per session. Below are volume recommendations based on amount of previous experience with plyometric training:
Progression: As with any other type of training it is important to have a progression with plyometrics. Start with double leg jumps in place, then progress to single leg, multiple jumps/directions, and then add bounding, box jumps, and depths jumps. (Note: it is not recommended for athletes over 220lbs to depth jump from a height greater than 18 inches)
Rest Periods: Plyometrics should not be used for conditioning. Each effort should be maximal and therefore adequate rest between sets and/or reps is required. A 1:12-1:20 work to rest ratio is suggested for exercises aimed at maximizing power.
Training Surfaces: Soft surfaces whenever possible- grass, suspended floors such as basketball courts, and padded plyometric boxes if available
Training order: Plyometrics should be performed before all other types of training sessions when the athlete is still fresh and can deliver maximal effort and focus.
This concludes the series on training to improve speed. So remember: develop maximal strength first, and then work on using that strength explosively!
Baechle, T. R., and R. W. Earle. Essentials of Strength Training and Conditioning. Champaign, IL: Human Kinetics, 2008. Print.