Ricardo Peterson Silveira

Validity of a portable force platform for assessing biomechanical parameters in three different tasks

Abstract The aim of this study was to determine the precision and accuracy of the vertical and anterior–posterior force components of the portable PASCO PS-2142 force plate. Impulse, peak force, and time to peak force were assessed and compared to a gold standard force plate in three different tasks: vertical jump, forward jump, and sprint start. Two healthy male participants performed ten trials for each task, resulting in 60 trials. Data analyses revealed good precision and accuracy for the vertical component of the portable force plate, with relative bias and root mean square (RMS) error values nearly the same in all tasks for the impulse, time to peak force, and peak force parameters. Precision and accuracy of the anterior–posterior component were lower for the impulse and time to peak force, with relative bias and RMS error values nearly the same between tasks. Despite the lower precision and accuracy of the anterior–posterior component of the portable force plate, these errors were systematic, reflecting a good repeatability of the measure. In addition, all variables presented good agreement between the portable and gold standard platforms. Our results provide a good perspective for using the aforementioned portable force plate in sports and clinical biomechanics.

Key determinants of time to 5 m in different ventral swimming start techniques

Abstract The aim of this study was to determine the biomechanical parameters that explain ventral start performance in swimming. For this purpose, 13 elite swimmers performed different variants of the ventral start technique. Two-dimensional video analyses of the aerial and underwater phases were used to assess 16 kinematic parameters from the starting signal to 5 m, and an instrumented starting block was used to assess kinetic data. A Lasso regression was used to reduce the number of parameters, providing the main determinants to starting performance, revealing different combinations of key determinants, depending on the variant (r² ≥ 0.90), with flight distance being the most relevant to all variants (r ≤ −0.80; p < .001). Also, special attention should be given to the total horizontal impulse in the grab start (r = −0.79; p < .001) and to the back foot action in the track and kick starts (r ≤ 0.61; p < .001). In addition, we provide two equations that could be easily used to predict starting performance by assessing block time and flight time (r² = 0.66) or block time and flight distance (r² = 0.83). These data provide relevant contributions to the further understanding of the biomechanics of swimming starts as well as insights for performance analysis and targeted interventions to improve athlete performance.

Comparison of incremental intermittent and time trial testing in age-group swimmers.

Abstract Zacca, R, Azevedo, R, Peterson Silveira, R, Vilas-Boas, JP, Pyne, DB, Castro, FAdS, and Fernandes, RJ. Comparison of incremental intermittent and time trial testing in age-group swimmers. J Strength Cond Res 33(3): 801–810, 2019—The aim of this study was to compare physiological and biomechanical characteristics between an incremental intermittent test and a time trial protocol in age-group swimmers. Eleven national level age-group swimmers (6 men and 5 women) performed a 7 × 200-m incremental intermittent protocol (until exhaustion; 30-second rest) and a 400-m test (T400) in front crawl on separate days. Cardiorespiratory variables were measured continuously using a telemetric portable gas analyzer. Swimming speed, stroke rate, stroke length, and stroke index were assessed by video analysis. Physiological (oxygen uptake, heart rate, and lactate concentrations) and biomechanical variables between seventh 200-m step (in which the minimal swimming speed that elicits maximal oxygen uptake—vV[Combining Dot Above]O2max was identified) and T400 (time trial/fixed distance) were compared with a paired students t test, Pearsons product-moment correlation, Passing-Bablok regression, and Bland-Altman plot analyses. There were high level of agreement and high correlations (r-values ∼0.90; p ⩽ 0.05) for all physiological variables between the seventh 200-m step and T400. Similarly, there were high level of agreements and high correlations (r-values ∼0.90; p ⩽ 0.05) for all biomechanical variables and only trivial bias in swimming speed (0.03 m·s−1; 2%). Primary physiological and biomechanical responses between incremental intermittent and representative time trial protocols were similar, but best practice dictates protocols should not be used interchangeably to minimize errors in prescribing swimming training speeds. The T400 is a valid, useful, and easier to administer test for aerobic power assessment in age-group swimmers.

Coordenação do nado borboleta: estudo piloto sobre os efeitos da velocidade de nado e das ações inspiratórias

The purpose of this pilot study was to describe the effects of pace and breathing actions on the coordinative parameters of the butterfly stroke. Four regional level swimmers participated of this study (mean performance level: 69 ± 3.6 % of the world record in the 100-m butterfly). Increasing speed, similar results were observed for both frontal breathing and non-breathing conditions. From the 200m pace to the maximal speed trial, there is a decrease in the absolute duration of arm stroke (from 2.01 ± 0.43s to 1.07 ± 0,09s), increasing the relative duration of propulsive phases (pull phase: from 14.6 ± 3.2% to 22.8 ± 4.7%; push phase: from 12.9 ± 1.0 to 19.1 ± 0.9%). Regarding to the inter-limb coordination, there is a higher continuity between the arm and leg stroke key points.

Butterfly stroke coordination: a pilot study about effects on speed and on inspiratory actions

The purpose of this pilot study was to describe the effects of pace and breathing actions on the coordinative parameters of the butterfly stroke. Four regional level swimmers participated of this study (mean performance level: 69 ± 3.6 % of the world record in the 100-m butterfly). Increasing speed, similar results were observed for both frontal breathing and non-breathing conditions. From the 200m pace to the maximal speed trial, there is a decrease in the absolute duration of arm stroke (from 2.01 ± 0.43s to 1.07 ± 0,09s), increasing the relative duration of propulsive phases (pull phase: from 14.6 ± 3.2% to 22.8 ± 4.7%; push phase: from 12.9 ± 1.0 to 19.1 ± 0.9%). Regarding to the inter-limb coordination, there is a higher continuity between the arm and leg stroke key points.

Coordinación del estilo mariposa: estudio previo sobre los efectos de la velocidad de nado y de las acciones inspiratorias

The purpose of this pilot study was to describe the effects of pace and breathing actions on the coordinative parameters of the butterfly stroke. Four regional level swimmers participated of this study (mean performance level: 69 ± 3.6 % of the world record in the 100-m butterfly). Increasing speed, similar results were observed for both frontal breathing and non-breathing conditions. From the 200m pace to the maximal speed trial, there is a decrease in the absolute duration of arm stroke (from 2.01 ± 0.43s to 1.07 ± 0,09s), increasing the relative duration of propulsive phases (pull phase: from 14.6 ± 3.2% to 22.8 ± 4.7%; push phase: from 12.9 ± 1.0 to 19.1 ± 0.9%). Regarding to the inter-limb coordination, there is a higher continuity between the arm and leg stroke key points.