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Purpose: To examine the longitudinal relationships between shoulder internal and external rotation (IR and ER) strength, maturity status, and swim performance (aim 1). To determine whether maturity status mediated (partially/fully) the relationship between shoulder IR/ER strength and performance in age-group swimmers (aim 2). Methods: Using a repeated-measures design, anthropometrics, maturity status, shoulder IR/ER strength, and 200-m front-crawl velocity were assessed over 3 competition seasons in N = 82 Australian male competitive swimmers (10–15 y). For aim 1, linear mixed models examined longitudinal relationships between assessed variables. For aim 2, causal mediation analyses examined proportional (in)direct contributions of maturity status between shoulder IR strength and swim performance. Results: For aim 1, linear mixed models identified a significant relationship between shoulder IR strength and swim performance over time (F1,341.25 = 16.66, P <.001, marginal R2 =.13, conditional R2 =.91). However, maturity status was influential (ΔAkaike information criterion = −75.8, χ2 = 19.98, P <.001), suggesting removal of the shoulder IR strength–swim velocity relationship (F1,214.1 = 0.02, P =.88). For aim 2, mediation analyses identified maturity status as fully mediating the shoulder IR strength–swim velocity relationship (92.30%, P <.001). Conclusions: Shoulder IR and ER strength did not account for variance in longitudinal age-group swim performance independent of maturity status. Interindividual differences in maturity status fully explained the relationship between shoulder IR/ER strength and swim performance. For practitioners, findings promote the need to account for maturation status and question the rationale for upper-limb strength assessment during maturational years. [ABSTRACT FROM AUTHOR]

In this work, nanocomposites based on a UV-curable polymeric resin and different inorganic fillers were developed for use in UV-assisted three-dimensional (UV-3D) printing. This technology consists in the additive multilayer deposition of a UV-curable resin for the fabrication of 3D macro structures and microstructures of arbitrary shapes. A systematic investigation on the effect of filler concentration on the rheological properties of the polymer-based nanocomposites was performed. In particular, the rheological characterization of these nanocomposites allowed to identify the optimal printability parameters for these systems based on the shear rate of the materials at the extrusion nozzle. In addition, photocalorimetric measurements were used to assess the effect of the presence of the inorganic fillers on the thermodynamics and kinetics of the photocuring process of the resins. By direct deposition of homogeneous solvent-free nanocomposite dispersions of different fillers in a UV-curable polymeric resin, the effect of UV-3D printing direction, fill density, and fill pattern on the mechanical properties of UV-3D printed specimens was investigated by means of uniaxial tensile tests. Finally, examples of 3D macroarchitectures and microarchitectures, spanning features, and planar transparent structures directly formed upon UV-3D printing of such nanocomposite dispersions were reproducibly obtained and demonstrated, clearly highlighting the suitability of these nanocomposite formulations for advanced UV-3D printing applications. POLYM. COMPOS., 38:1662-1670, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Purpose: To examine the longitudinal relationships between shoulder internal and external rotation (IR and ER) strength, maturity status, and swim performance (aim 1). To determine whether maturity status mediated (partially/fully) the relationship between shoulder IR/ER strength and performance in age-group swimmers (aim 2)., Methods: Using a repeated-measures design, anthropometrics, maturity status, shoulder IR/ER strength, and 200-m front-crawl velocity were assessed over 3 competition seasons in N = 82 Australian male competitive swimmers (10-15 y). For aim 1, linear mixed models examined longitudinal relationships between assessed variables. For aim 2, causal mediation analyses examined proportional (in)direct contributions of maturity status between shoulder IR strength and swim performance., Results: For aim 1, linear mixed models identified a significant relationship between shoulder IR strength and swim performance over time (F1,341.25 = 16.66, P < .001, marginal R2 = .13, conditional R2 = .91). However, maturity status was influential (ΔAkaike information criterion = -75.8, χ2 = 19.98, P < .001), suggesting removal of the shoulder IR strength-swim velocity relationship (F1,214.1 = 0.02, P = .88). For aim 2, mediation analyses identified maturity status as fully mediating the shoulder IR strength-swim velocity relationship (92.30%, P < .001)., Conclusions: Shoulder IR and ER strength did not account for variance in longitudinal age-group swim performance independent of maturity status. Interindividual differences in maturity status fully explained the relationship between shoulder IR/ER strength and swim performance. For practitioners, findings promote the need to account for maturation status and question the rationale for upper-limb strength assessment during maturational years.