title: Effects of additional repeated sprint training during preseason on performance, heart rate variability, and stress symptoms in futsal players: a randomized controlled trial.
abstract: The aim of this study was to investigate whether supplementing regular preseason futsal training with weekly sessions of repeated sprints (RS) training would have positive effects on repeated sprint ability (RSA) and field test performance. Thirteen players from a professional futsal team (22.6 ± 6.7 years, 72.8 ± 8.7 kg, 173.2 ± 6.2 cm) were divided randomly into 2 groups (AddT: n = 6 and normal training group: n = 7). Both groups performed a RSA test, Yo-Yo intermittent recovery test level 1 (YoYo IR1), squat (SJ) and countermovement jumps (CMJ), body composition, and heart rate variability (HRV) measures at rest before and after 4 weeks of preseason training. Athletes weekly stress symptoms were recorded by psychometric responses using the Daily Analysis of Life Demands for Athletes questionnaire and subjective ratings of well-being scale, respectively. The daily training load (arbitrary units) was assessed using the session of rating perceived exertion method. After the preseason training, there were no significant changes for body composition, SJ, CMJ, and RSAbest. The YoYo IR1, RSAmean, RSAworst, and RSAdecreament were significantly improved for both groups (p ≤ 0.05). The HRV parameters improved significantly within both groups (p ≤ 0.05) except for high frequency (HF, absolute and normalized units, [n.u.]), low frequency (LF) (n.u.), and the LF/HF ratio. A moderate effect size for the AddT group was observed for resting heart rate and several HRV measures. Training load and psychometric responses were similar between both groups. Additional RS training resulted in slightly greater positive changes for vagal-related HRV with similar improvements in performance and training stress during the preseason training in futsal players.
authors.affiliation: 1Physiological Adaptations to Training Research Group (GEAFIT), Sport and Physical Education Center, Londrina State University (UEL), Londrina, Parana, Brazil; 2Research Centre on Health Sciences, Department of Physical Education, University of Northern Parana (UNOPAR), Londrina, Parana, Brazil; 3Integrado College, Department of Physical Education, Campo Mourão, Parana, Brazil; 4Biological Science Center, Department of Physiology, Maringa State University (UEM), Maringa, Parana, Brazil; and 5Institute of Sport and Exercise Science, James Cook University, Townsville, Australia.
authors.forename: Lúcio F
authors.initials: LF
authors.lastname: Soares-Caldeira
authors.forename: Eberton A
authors.initials: EA
authors.lastname: de Souza
authors.forename: Victor H
authors.initials: VH
authors.lastname: de Freitas
authors.forename: Solange M F
authors.initials: SM
authors.lastname: de Moraes
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Leicht
authors.forename: Fábio Y
authors.initials: FY
authors.lastname: Nakamura
mesh_terms: D000293:Adolescent; D000328:Adult; D054874:Athletic Performance; D001823:Body Composition; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D064797:Physical Conditioning, Human / Q000379:methods / Q000502:physiology* / Q000523:psychology; D005082:Physical Exertion; D011569:Psychiatric Status Rating Scales; D012420:Running / Q000502:physiology*; D012916:Soccer / Q000502:physiology*; D013315:Stress, Psychological / Q000209:etiology; D055815:Young Adult