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To analyze the morphological response induced by high-volume, high-intensity ladder-based resistance training (LRT) on the ultrastructure of the radial (forelimb) and sciatic (hindlimb) nerves of adults Wistar rats. Twenty rats were equally distributed into groups: sedentary (SED) and LRT. After the rodents were subjected to the maximum load (ML) carrying test, the LRT group performed 6-8 progressive climbs (2 × 50% ML, 2 × 75% ML, 2 × 100% ML, and 2 × 100% ML + 30 g) three times per week. After 8 weeks, the radial and sciatic nerves were removed and prepared for transmission electron microscopy. In the radial nerve, myelinated axons cross-sectional area (CSA), unmyelinated axons CSA, myelin sheath thickness, and Schwann cells nuclei area were statistically larger in the LRT group than SED (p < 0.05). Also, the number of microtubules and neurofilaments per field were statistically higher in the LRT group than in SED (p < 0.01). For sciatic nerve, myelinated fibers CSA, unmyelinated axons CSA, myelin sheath thickness, Schwann cells nuclei area, and the number of neurofilaments per field were statistically larger in the LRT group compared to the SED group (p < 0.05). LRT with high-volume and high-intensity effectively induce similar changes in adult Wistar rats' radial and sciatic nerves' ultrastructure.

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The gluteus maximus (GMax) is one of the primary hip extensors. Several exercises have been performed by strength and conditioning practitioners aiming to increase GMax strength and size. This systematic review aimed to describe the GMax activation levels during strength exercises that incorporate hip extension and use of external load. A search of the current literature was performed using PubMed/Medline, SportDiscuss, Scopus, Google Scholar, and Science Direct electronic databases. Sixteen articles met the inclusion criteria and reported muscle activation levels as a percentage of a maximal voluntary isometric contraction (MVIC). The exercises classified as very high level of GMax activation (>60% MVIC) were step-up, lateral step-up, diagonal step-up, cross over step-up, hex bar deadlift, rotational barbell hip thrust, traditional barbell hip thrust, American barbell hip thrust, belt squat, split squat, in-line lunge, traditional lunge, pull barbell hip thrust, modified single-leg squat, conventional deadlift, and band hip thrust. We concluded that several exercises could induce very high levels of GMax activation. The step-up exercise and its variations present the highest levels of GMax activation followed by several loaded exercises and its variations, such as deadlifts, hip thrusts, lunges, and squats. The results of this systematic review may assist practitioners in selecting exercised for strengthening GMax.

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The present systematic review aimed to analyze the activation of the muscles involved in the barbell hip thrust (BHT) and its transfer to sports activities that include horizontal displacement. A search of the current literature was performed using the PubMed, SPORTDiscuss, Scopus and Google Scholar databases. The inclusion criteria were: (a) descriptive studies, (b) physically trained participants, (c) analyzed muscle activation using normalized EMG signals or as a percentage of maximal voluntary isometric contraction (MVIC) and (d) acute or chronic transfer of the BHT to horizontal displacement activity. Twelve articles met the inclusion criteria and the following results were found: 1) neuromuscular activation: hip extensor muscles (gluteus maximus and biceps femoris) demonstrated greater activation in the BHT compared to the squat. The straight bar deadlift exercise demonstrated greater biceps femoris activation than BHT; 2) Regardless of the BHT variation and intensity used, the muscle excitation sequence is gluteus maximus, erector spinae, biceps femoris, semitendinosus, vastus lateralis, gluteus medius, vastus medialis and rectus femoris; 3) acute transfer: four studies demonstrated a significant improvement in sprinting activities after BHT exercise; 4) as for the chronic transfer: two studies demonstrated improvement of the sprint time, while other two studies failed to present such effect. We concluded that: a) the mechanics of BHT favors greater activation of the hip extensor muscles compared to more conventional exercises; b) regardless of the variation of BHT used, the muscle excitation sequence is gluteus maximus, erector spinae, hamstrings, and quadriceps femoris; c) the acute transfer of the post-activation potentiation of the BHT is significant, improving the sprinting time; and d) despite training with BHT submaximal loads can improve sprint times, further investigations are needed.

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The aim of this research was to investigate the effect of testosterone propionate administration in the liver of rats. The rats were divided in the following groups: Initial control (SC), Aged control (SE) and Anabolic group (SA). Testosterone propionate was administered three times per week during 16 weeks. Using morphoquantitative techniques, we quantified the volume densities of lobular and non-lobular parenchyma, area and number of nuclei of hepatocytes. The data were analyzed statistically using mean and standard deviation, ANOVA one-way and level of significance about p0.05. Our results showed an increase in capillaries, perisinusoidal spaces and biliary ducts in SE group compared to SC. SA group showed a decrease in hepatic cells, non-lobular volume density and hepatocytes nuclei area, but also an increase in capillaries, perisinusoidal spaces, biliary ducts, number of hepatocytes and non-hepatocyte nuclei compared to SC. We conclude that a direct toxicity may have occurred, with consequent loss of the cells.

El objetivo fue investigar el efecto de la administración de propionato de testosterona en el hígado de ratas. Las ratas se dividieron en los siguientes grupos: control inicial (CI), control de Edad (CE) y grupo anabólico (GA). El propionato de testosterona se administró tres veces por semana durante 16 semanas. Utilizando técnicas morfocuantitativas, determinamos las densidades de volumen del parénquima lobular y no lobular, área y número de núcleos de los hepatocitos. Los datos fueron analizados estadísticamente con la media y desviación estándar, la prueba de ANOVA de una vía y un nivel de significación p0,05. Nuestros resultados mostraron un aumento en los capilares, espacios perisinusoidales y conductos biliares en el grupo CE en comparación con CI. El GA mostró una disminución en las células hepáticas, la densidad de volumen no lobular y el área de los núcleos de hepatocitos, como también un aumento en los capilares, espacios perisinusoidales, conductos biliares, número de hepatocitos y núcleos no hepatocíticos en comparación AL CI. Concluimos que una toxicidad directa puede haber ocurrido, con la consiguiente pérdida de las células.

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