The Powerflex Performance Cord will train all the accelerator and decelerator muscles used in a skill with ONE exercise. Because of the two-point attachment, the cord can warm up and strengthen all the muscles involved in the skill in 2.5 minutes. Arm speed can increase 2-5 mph.
Training all the muscles involved in a skill in the exact way it is performed will balance out the strength among the muscles, with high-speed movement. By doing this, the athlete increases their odds of not injuring their arm.
The PowerFlex Performance Cord should be used by athletes of all ages, but it is critical for youth development because young athletes should not go into the weight room to train.
It is well documented that a majority of overhead arm injuries happen on the deceleration phase of the skill (for example, volleyball, baseball, softball, water polo, tennis, and swimming). Ninety percent of all arm injuries occur during deceleration.
Having weakness in the accelerator muscles (supraspinatus, latissmas dorsi, pecs) and decelerators (teres minor, infraspinatus and posterior deltoids) is a good predictor of a chance for an arm injury during the season.
A good analogy for this is when a car has Nascar accelerators with used Volkswagen brakes.
Optimal training is using the progressive resistance technique in the exact biomedical way you perform a skill. This type of training cannot be duplicated in the weight room.