title: Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase.
abstract: Resisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm)) on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg) performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak), a peak rate of force development (RFDpeak) and time to RFD (TRFD) in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001) in sprint times (20 and 30 m sprint) for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s-1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s-1, p ≤ 0.01). Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration.
authors.affiliation: UCAM Research Center of High Performance Sport, San Antonio Catholic University of Murcia, Guadalupe, Murcia, Spain.
authors.forename: María Asunción
authors.initials: MA
authors.lastname: Martínez-Valencia
authors.affiliation: Faculty of Sport Sciences, Department of Sport and Physical Activity, San Antonio Catholic University of Murcia, Guadalupe, Murcia, Spain.
authors.forename: Salvador
authors.initials: S
authors.lastname: Romero-Arenas
authors.affiliation: Sport Research Center, University Miguel Hernández, Elche, Spain.
authors.forename: José L L
authors.initials: JL
authors.lastname: Elvira
authors.affiliation: Sport Performance Lab, Faculty of Sport Science, University of Castilla La-Mancha, Toledo, Spain.
authors.forename: José María
authors.initials: JM
authors.lastname: González-Ravé
authors.affiliation: Sport Performance Lab, Faculty of Sport Science, University of Castilla La-Mancha, Toledo, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Navarro-Valdivielso
authors.affiliation: UCAM Research Center of High Performance Sport, San Antonio Catholic University of Murcia, Guadalupe, Murcia, Spain. ; Faculty of Sport Sciences, Department of Sport and Physical Activity, San Antonio Catholic University of Murcia, Guadalupe, Murcia, Spain.
authors.forename: Pedro E
authors.initials: PE
authors.lastname: Alcaraz
keywords: load cell; maximal running; resisted sprint; speed training