Evaluating the effects of under loaded and overloaded warm ups on subsequent swing velocity.Miller Ryan M.; Heishman, Aaron D.; Freitas, Eduardo D.S.; Bemben, Michael G.Journal of Strength & Conditioning Research: Post Acceptance: August 26, 2017 doi: 10.1519/JSC.0000000000002206 Original Research: PDF Only Abstract Several attempts to identify the optimal on deck procedure to enhance swing velocity in baseball have been made. However, inconsistent findings continue to constitute much of the body of literature. Additionally, the emergence of athlete monitoring in sport has led to the exploration of more sport specific tasks to potentially identify athlete fatigue and readiness to perform. Therefore, the purpose of this investigation was to examine three different bat weight warm up protocols on subsequent swing velocity and to examine the reliability of swing velocity measurements to allude to its potential a sport specific athlete monitoring metric. Thirty-two recreational male baseball players 20.3 +/- 2.0years, 179.6 +/- 7.1cm and 89.6+/- 11.1kg completed the study. Subjects completed three testing visits that included warming up with a control bat ([CB] 32in, 29oz), plastic bat ([PB] 31in, 6.4oz), or heavy bat ([HB] 32in, 57oz). Testing visits began with three CB swing trials followed by three intervention bat trials, then concluded with three additional CB swings. Swing velocity was assessed using visual 3D technology. Analyses of variance indicate that following the PB (26.6 +/- 2.0m/s) and CB interventions (26.2 +/- 1.7m/s) significantly faster (p<0.001) swing velocities were generated when compared to the traditional HB intervention (24.1 +/- 2.2m/s). When assessed for reliability, the average ICC was 0.681 and Chronbach's alpha was 0.95 indicating exceptional reliability. Congruent to previous research, this data bolsters the notion that warming up with a HB can hinder swing velocity. However, in contrast to previous research this data suggests that using a PB can increase swing velocity significantly. Furthermore, visual 3D can be designated as an exceptionally reliable device to measure swing velocity. Copyright (C) 2017 by the National Strength & Conditioning Association.