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Nakamura F.Y.,Nucleus of High Performance in Sport NAR | Nakamura F.Y.,State University Londrina | Flatt A.A.,University of Alabama | Pereira L.A.,Nucleus of High Performance in Sport NAR | And 3 more authors.
Journal of Sports Science and Medicine | Year: 2015

The aim of this study was to test the possibility of the ultra-short-term lnRMSSD (measured in 1-min post-1-min stabiliza-tion period) to detect training induced adaptations in futsal players. Twenty-four elite futsal players underwent HRV as-sessments pre- and post-three or four weeks preseason training. From the 10-min HRV recording period, lnRMSSD was ana-lyzed in the following time segments: 1) from 0-5 min (i.e., stabilization period); 2) from 0-1 min; 1-2 min; 2-3 min; 3-4 min; 4-5 min and; 3) from 5-10 min (i.e., criterion period). The lnRMSSD was almost certainly higher (100/00/00) using the magnitude-based inference in all periods at the post- moment. The correlation between changes in ultra-short-term lnRMSSD (i.e., 0-1 min; 1-2 min; 2-3 min; 3-4 min; 4-5 min) and lnRMSSDCriterion ranged between 0.45 - 0.75, with the highest value (p = 0.75; 90% CI: 0.55 – 0.85) found between ultra-short-term lnRMDSSD at 1-2 min and lnRMSSDCriterion. In conclu-sion, lnRMSSD determined in a short period of 1-min is sensi-tive to training induced changes in futsal players (based on the very large correlation to the criterion measure), and can be used to track cardiac autonomic adaptations. © Journal of Sports Science and Medicine. Source

Gallardo-Fuentes F.,University of Los Lagos | Gallardo-Fuentes J.,University of Los Lagos | Ramirez-Campillo R.,University of Los Lagos | Balsalobre-Fernandez C.,Autonomous University of Madrid | And 9 more authors.
Journal of Strength and Conditioning Research | Year: 2016

The purpose of this study was to analyze the concurrent validity and reliability of the iPhone app named My Jump for measuring jump height in 40-cm drop jumps (DJs), countermovement jumps (CMJs), and squat jumps (SJs). To do this, 21 male and female athletes (age, 22.1 ± 3.6 years) completed 5 maximal DJs, CMJs, and SJs on 2 separate days, which were evaluated using a contact platform and the app My Jump, developed to calculate jump height from flight time using the high-speed video recording facility on the iPhone. A total of 630 jumps were compared using the intraclass correlation coefficient (ICC), Bland-Altman plots, Pearson's product moment correlation coefficient (r), Cronbach's alpha (α), and coefficient of variation (CV). There was almost perfect agreement between the measurement instruments for all jump height values (ICC 0.97-0.99), with no differences between the instruments (p > 0.05; mean difference of 0.2 cm). Almost perfect correlation was observed between the measurement instruments for SJs, CMJs, and DJs (r 0.96-0.99). My Jump showed very good within-subject reliability (α 0.94-0.99; CV 3.8-7.6) and interday reliability (r 0.86-0.95) for SJs, CMJs, and DJs in all subjects. Therefore, the iPhone app named My Jump provides reliable intersession and intrasession data, as well as valid measurements for maximal jump height during fast (i.e., DJs) and slow (i.e., CMJs) stretch-shortening cycle muscle actions, and during concentric-only explosive muscle actions (i.e., SJs), in both male and female athletes in comparison with a professional contact platform. © 2015 National Strength and Conditioning Association. Source

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