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General Concepts and Training Principles for Athlete Development
Published in Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan, Strength and Conditioning in Sports, 2023
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan
An important aspect of a training stimulus and the ability to sustain an overload for long periods deals with the development of adequate levels of strength. While resistance exercise commonly aims to increase maximum strength, strength entails substantially more than how much force you can produce or how much you can lift. Conceptually, strength should be viewed as a “vehicle” that transports a substantial number of characteristics that can positively impact sport performance. Thus, the principle of overload applied to improve strength and its dependent qualities encompasses more than traditional, heavy resistance training. As a result, increasing maximum strength can make a marked difference in performance outcomes (2, 3, 12, 20, 33–35, 43, 52, 64, 96, 141, 147, 150, 155, 161). Maximum strength is related to: Alterations in tissue CSA, architecture, stiffness, and tensile strength, which can enhance force transmission and may reduce injury potential.The magnitude of force production with greater peak and average forces that can allow for higher velocities and power outputs to be achieved when using submaximal loads.The RFD, which is associated with faster muscle activation with resultant greater force production during critical time periods (e.g., foot contact time) – may be a product of training and partially be independent from maximum strength.Greater absolute and perhaps relative endurance, especially high-intensity exercise endurance (HIEE), resulting from both metabolic alterations and reduced “central” (nervous system) fatigue (i.e., more total work can be accomplished).Greater peak and average power; work (F × d) is accomplished at a higher rate.Greater ability to develop and respond to stretch-shortening cycles (SSC).Greater postural strength, enhancing the ability to hold static and dynamic positions better during performance, resulting in enhanced technical skill capability.Some evidence indicates that force modulation, sensitivity, and sensation are enhanced (may be a result of strength training and partially independent of maximum strength development).An enhanced ability to gain RFD, power, and speed of movement.
The effect of an interval fatigue protocol on Vestibular/Ocular Motor Screening (VOMS) performance
Published in Brain Injury, 2020
Jenna Ratka, Kelly Cheever, Jamie L. Mansell, Ryan T. Tierney
From previous studies, it can be seen that many concussion diagnostic sideline assessments are known to be affected by fatigue. This may be due to a phenomenon known as central fatigue. Exercise has been shown to reduce overall voluntary muscle force production and cause biomechanical changes in skeletal muscle while also involving a decreased neural drive to working muscle (25). Fatigue of the muscular system is proportional to the duration of the activity as well as a physiological reduction in energy metabolism and impairment of excitation-contraction coupling (13). Muscular system fatigue leads to peripheral nervous system fatigue and eventually central nervous system fatigue which causes a cascade of effects that is termed central fatigue (13). Central fatigue has been shown to produce vascular changes, hypoxia, decreased cerebral oxygenation, and cerebral cortical activity changes in the brain (12–15). This changes overall sensory inflow and alters central processing of afferent input (13). Connell et al. found that there was impaired control of eye movement by examining ocular motor system function through saccadic eye movements after a strenuous cycling bout of exercise (25). In addition, Fery et al. reported that cerebral hypoxia was seen to debilitate central aspects of the visual system during strenuous exercise (12). Although effects of central fatigue are documented, methodological inconsistencies and timeliness of studies limits the accuracy of our current knowledge regarding the central fatigue phenomenon.