title: Imposing a pause between the eccentric and concentric phases increases the reliability of isoinertial strength assessments.
abstract: This study analysed the effect of imposing a pause between the eccentric and concentric phases on the biological within-subject variation of velocity- and power-load isoinertial assessments. Seventeen resistance-trained athletes undertook a progressive loading test in the bench press (BP) and squat (SQ) exercises. Two trials at each load up to the one-repetition maximum (1RM) were performed using 2 techniques executed in random order: with (stop) and without (standard) a 2-s pause between the eccentric and concentric phases of each repetition. The stop technique resulted in a significantly lower coefficient of variation for the whole load-velocity relationship compared to the standard one, in both BP (2.9% vs. 4.1%; P = 0.02) and SQ (2.9% vs. 3.9%; P = 0.01). Test-retest intraclass correlation coefficients (ICCs) were r = 0.61-0.98 for the standard and r = 0.76-0.98 for the stop technique. Bland-Altman analysis showed that the error associated with the standard technique was 37.9% (BP) and 57.5% higher (SQ) than that associated with the stop technique. The biological within-subject variation is significantly reduced when a pause is imposed between the eccentric and concentric phases. Other relevant variables associated to the load-velocity and load-power relationships such as the contribution of the propulsive phase and the load that maximises power output remained basically unchanged.
authors.affiliation: a Exercise Physiology Laboratory , University of Castilla-La Mancha , Toledo , Spain.
authors.forename: Jesús G
authors.initials: JG
authors.lastname: Pallarés
authors.forename: Luis
authors.initials: L
authors.lastname: Sánchez-Medina
authors.forename: Carlos Esteban
authors.initials: CE
authors.lastname: Pérez
authors.forename: Ernesto
authors.initials: E
authors.lastname: De La Cruz-Sánchez
authors.forename: Ricardo
authors.initials: R
authors.lastname: Mora-Rodriguez
mesh_terms: D000328:Adult; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D015203:Reproducibility of Results; D055070:Resistance Training / Q000379:methods*; D013647:Task Performance and Analysis; D014891:Weight Lifting / Q000502:physiology*; D016474:Weight-Bearing; D055815:Young Adult