Must Strength Exercises be Specific to be Effective? by Paul M. Juris, Ed.D
The foundation of functional training is the idea that strength exercises must be specific to be effective. This means that strength gains will be transferred to a particular skill only when it is paired with a particular movement. Is this commonly held belief true?
Research has shown that movement specific strength enhancement has little impact on movement accuracy, except for conditions in which force production is a necessary component of the skill. For example, performing overhead press and wrist curl exercises only improved basketball shooting accuracy from three-point range, no closer shots. In addition, there are many studies that demonstrate exercises with little to no similarity to a motor task can improve performance in that task.
If exercises such as the bench press have been shown to increase bat swing speed, just how movement-specific must strength training be? The common link in all of the research studies that have demonstrated functional gains, regardless of whether the strength training was movement-specific, was the focus on power development. Power is a function of resistance and speed; therefore, working with higher loads at higher speeds appears to have the best transfer to a functional goal.
Introducing resistance to a movement (such as adding donuts to a baseball bat) might not be the most effective method of increasing bat speed unless it is performed with the intent of higher speed and thus, higher power. Research has shown that exercises, even isolated ones such a knee extension machine, can improve functional performance as long as they are performed at higher speeds.
By introducing high loading to complex motions, it is possible that we are significantly reducing our power output by demanding a decrease in the speed of that motion. Building strength and power should be left to the weight room, while developing skill with specific movements on the practice fields and courts. In this way, strength and power can be increased, and these attributes will contribute to gains in performance with increased skill from movement-specific practice.