The assessment of vertical leg stiffness is an important consideration given its relationship to performance. Vertical stiffness is most commonly assessed during a bilateral hopping task. The current study sought to determine the intersession reliability, quantified by the coefficient of variation, of vertical stiffness during bilateral hopping when assessed for the left and right limbs independently, which had not been previously investigated. On 4 separate occasions, 10 healthy males performed 30 unshod bilateral hops on a dual force plate system with data recorded independently for the left and right limbs. Vertical stiffness was calculated as the ratio of peak ground reaction force to the peak negative displacement of the center of mass during each hop and was averaged over the sixth through tenth hops. For vertical stiffness, average coefficients of variation of 15.3% and 14.3% were observed for the left and right limbs, respectively. An average coefficient of variation of 14.7% was observed for bilateral vertical stiffness. The current study reports that calculations of unilateral vertical stiffness demonstrate reliability comparable to bilateral calculations. Determining unilateral vertical stiffness values and relative discrepancies may allow a coach to build a more complete stiffness profile of an individual athlete and better inform the training process.

Los instrumentos de categorización de pacientes son útiles porque permiten asignar los profesionales y recursos materiales de acuerdo con el perfil real de los pacientes. El objetivo del presente estudio es adecuar y validar el instrumento “Categorización de usuarios según dependencia y riesgo de cuidados” (CUDYR) en hemodiálisis crónica (HDC). El instrumento para pacientes en HDC se denominó “CUDYR-DIAL” y quedó constituido por dos subescalas y catorce ítems. La muestra estuvo conformada por 150 pacientes seleccionados en forma estratificada y al azar de cinco unidades de diálisis, a los que se les aplicó un total de 620 veces el CUDYR-DIAL. Se encontró que todos los ítems muestran correlaciones significativas (> 0,3) con el puntaje total obtenido en la escala, y que la confiabilidad de la escala se mantiene estable al ir eliminando uno a uno los ítems, fluctuando entre 0,86 y 0,87. La confiabilidad total del instrumento muestra un alfa de Cronbach de 0,878. Los usuarios en HDC presentan cuatro perfiles de dependencia (parcial a total) y riesgo (mediano a alto). Se concluye que el instrumento CUDYR-DIAL presenta una buena confiabilidad y constituye un aporte para la categorización de pacientes en HDC según dependencia y riesgo.

It has previously been shown that pre-conditioning interventions can augment change of direction speed (CODS). However, the mechanistic nature of these augmentations has not been well considered. The current study sought to determine the effects of pre-conditioning interventions designed to augment vertical stiffness on CODS.Following familiarization, ten healthy males (age: 22 ± 2 years; height: 1.78 ± 0.05 m; body mass: 75.1 ± 8.7 kg) performed three different stiffness interventions in a randomized and counterbalanced order. The interventions were: a) bilateral-focused, b) unilateral-focused, and c) a control of CODS test practice. Vertical stiffness and joint stiffness was determined pre-and post-intervention using a single leg drop jump task. CODS test performance was assessed post-intervention using a double 90 o cutting task. Performances following the unilateral intervention were significantly faster than control (1.7%; P = 0.011; d = -1.08), but not significantly faster than the bilateral intervention (1.0% faster; P = 0.14; d = -0.59). Versus control, vertical stiffness was 14% greater (P = 0.049; d = 0.39) following the unilateral intervention and 11% greater (P = 0.019; d = 0.31) following the bilateral intervention; there was no difference between unilateral and bilateral interventions (P = 0.94; d = -0.08). The findings of the current study suggest that unilateral pre-conditioning interventions designed to augment vertical stiffness improve CODS within this experimental cohort.