Núñez Sánchez, Francisco JavierDe Hoyo, MoisésMuñoz López, AlejandroSañudo, BorjaOtero Esquina, CarlosSánchez, HugoGonzalo Skok, Oliver2020-04-062020-04-062019-08-21Int J Sports Med. 2019 Nov;40(12):796-8021439-396410.1055/a-0977-5478http://hdl.handle.net/10433/8130The aims of this study were to analyse the effect of chronic strength training over concentric power (CON), eccentric power (ECC), ECC/CON ratio, and 20¿m linear sprint performance in elite young soccer players. Twenty young elite Spanish soccer players were assigned to an experimental group (CPG) which performed a front-step exercise using a conical pulley, 2¿3 sets of 6 repetitions each leg, during 9 weeks (CPG, n=10) in addition to its usual strength training, or to a control group (CG, n=10). The improvements in the ECC mean power (36%, ES=1.61), and ECC / CON ratio (17%, ES=1.77) were substantially greater in the CPG than in the CG while the CON mean power (16%, ES=0.83) was substantially greater in the CG than in the CPG. The sprinting time for 10¿m (2.8%, ES=0.78) and the 10¿m flying time between 10¿20¿m (1.72%, ES=0.41) were substantially enhanced in CPG and CG respectively. To be efficient when defining a functional strength training and performance increments using an inertial device, the mean power output need to be measured during the CON and ECC phases and an analysis of the ECC / CON ratio should be included.application/pdfenRotatory inertial deviceMean powerSprint performanceForce-vector trainingResistance trainingYoung soccer playersCIRFD - Centro de Investigación en Rendimiento Físico y DeportivoCIRFD - RDDCjournal articleopen access