by NSCA's Guide to Tests and Assessments
Kinetic Select June 2017
The following is an exclusive excerpt from the book NSCA's Guide to Tests and Assessments, published by Human Kinetics. All text and images provided by Human Kinetics.
Among many practitioners and the general public, the term power has emerged as a nonspecific designation of movement encompassing factors of speed, strength, or both. In athletic contexts, various permutations of the word power are used to characterize movement qualities or capacities ranging from very-high-load, slow movement patterns (e.g., powerlifting) to very-low-load, high-velocity activities (e.g., a powerful tennis serve). Despite the lack of a mainstream consensus definition for power, it is recognized as a clustering of neuromuscular factors related to maximal force production and rate of force development.
The expression of power through coordinated movement is also contingent on external morphological and biomechanical factors including type of muscle action, mass lifted (which may include body mass or limb mass plus an external load), anthropometric characteristics (e.g., limb lengths), muscle architecture (e.g., fiber composition, muscle pennation angle, fiber cross-sectional area, and number of active sarcomeres in series), tendon and connective tissue stiffness, joint range(s) of motion, and movement distance (Cormie et al. 2011a). Despite these many factors that contribute to power, athletes and practitioners have derived arbitrary means of “power training,” with the intent to facilitate an adaptive response that translates to augmented explosive movement capacity.
Considering that the term power typically evokes the perception of high-speed movement, many people are inclined to take the tenets of specificity to literally mean “train fast, be fast.” However, to create the most strategic methods of training and adaptation, it is vital to compartmentalize power into the primary testable and trainable elements.
With the growing popularity of power training among strength and conditioning coaches, personal trainers, and athletes, a standardized evaluation of power output or explosive movement performance is critical. Existing methods range from basic field tests, to elaborate biomechanical assessments in human performance laboratories, to in vitro activation and measurement of force development in biopsied muscle fibers. Moreover, the industry response to this increased interest in power testing and training has been a surplus of products available to the public. Certainly, greater visibility reflects a positive change in the field of exercise science and the performance enhancement industry; however, methods of evaluating power must be systematic and standardized to ensure the collection of valid, reliable data. Such a system of testing would allow professionals to share norm-referenced standards and to make formal, cross-sectional inspections of physiological and performance attributes (e.g., regression modeling to identify the association between maximal force production and jumping ability across athletic populations, while controlling for age, sex, body dimensions, and training status).
Developed by the National Strength and Conditioning Association (NSCA), this comprehensive text offers extensive information on performance-related assessment and testing for strength and conditioning professionals in measuring key fitness components. The book is available in bookstores everywhere, as well online at the NSCA Store.