Relationship between muscle mass and neuromuscular function in the muscular strength of elderly women practicing and non-practicing physical activities

Objective. To verify the correlation between muscle mass and neuromuscular function in muscle strength of women practicing and not practicing physical activities. Methods. This is a cross-sectional study conducted with older women (60 and over), physically active (fa) and physically inactive (fi). The muscle strength of the upper limb (handgrip strength - hgs; resisfor test) and lower limb (30 second chair stand test) were evaluated; as well as muscle mass (calf circumference - cc); and neuromuscular activity (semg) of the following muscles: flexor carpi radialis (fcr) and biceps brachii (bb) (upper limb); vastus lateralis (vl), vastus medialis (vm) and tibialis anterior (ta) (lower limb). The student t test and multiple linear regression were used (95%; p <.05). Results. Overall, 59 women were evaluated (71.5 ± 7.1 years), 31 fa and 28 fi. Fa women had significantly better values ​​in dynamic muscular strength tests of the upper (p=.001) and lower limbs (p<.0001). There was no significant difference in muscle mass between groups. After adjustment for covariates, there was relationship between cc and activity of fcr muscle with hgs (r2adj.= 0.64), and cc with the 30 second chair stand test (r2adj.= .39) in fa women. Among fi women, there was significant correlation between activity of fcr muscle and hgs (r2adj.= .35) and cc and neural activity of fcr with resisfor (r2adj.= .66). Conclusion. Physical exercise was related to higher dynamic muscle strength. Differences in the relationship between muscle mass and neuromuscular activity with strength in each test indicate physiological differences for each strength exercise applied.

Sigma-1 Receptor is a Pharmacological Target to Promote Neuroprotection in the SOD1G93A ALS Mice

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disorder characterized by the death of motoneurons (MNs) with a poor prognosis. There is no available cure, thus, novel therapeutic targets are urgently needed. Sigma-1 receptor (Sig-1R) has been reported as a target to treat experimental models of degenerative diseases and, importantly, mutations in the Sig-1R gene cause several types of motoneuron disease (MND). In this study we compared the potential therapeutic effect of three Sig-1R ligands, the agonists PRE-084 and SA4503 and the antagonist BD1063, in the SOD1G93A mouse model of ALS. Pharmacological administration was from 8 to 16 weeks of age, and the neuromuscular function and disease progression were evaluated using nerve conduction and rotarod tests. At the end of follow up (16 weeks), samples were harvested for histological and molecular analyses. The results showed that PRE-084, as well as BD1063 treatment was able to preserve neuromuscular function of the hindlimbs and increased the number of surviving MNs in the treated female SOD1G93A mice. SA4503 tended to improve motor function and preserved neuromuscular junctions (NMJ), but did not improve MN survival. Western blot analyses revealed that the autophagic flux and the endoplasmic reticulum stress, two pathways implicated in the physiopathology of ALS, were not modified with Sig-1R treatments in SOD1G93A mice. In conclusion, Sig-1R ligands are promising tools for ALS treatment, although more research is needed to ascertain their mechanisms of action.

Efectos del entrenamiento con movimientos de halterofilia en el rendimiento de esprint, salto y cambio de dirección en deportistas: Una revisión sistemática (Effects of weightlifting training on sprint, jump and change of direction performance in athlete

La capacidad de generar máxima potencia neuromuscular es el factor más importante y determinante en el rendimiento atlético. Debido a esto, el entrenamiento con movimientos de Halterofilia (EMH) y sus derivados es uno de los métodos más usados, ya que la evidencia muestra que genera adaptaciones de fuerza-potencia superiores comparadas con el entrenamiento de fuerza tradicional, de salto y de kettlebells. Objetivo: Identificar los efectos del EMH en la capacidad de salto, esprint y cambio de dirección (COD) en población deportista. Método: Se realizó una búsqueda exhaustiva en diferentes bases de datos, como PUBMED, Sportdiscus (EBSCO), Scopus y Web of Science (WOS) bajo modelo PRISMA. Los trabajos revisados fueron experimentales con y sin grupo de control, entre los años 2000 y 2020. Resultados: El EMH produce mejoras significativas en las capacidades de salto, de esprint y de COD en población deportista. Conclusión: El EMH genera mejoras significativas en el rendimiento de salto, carreras y cambio de dirección bajo distintos protocolos. Existe evidencia que sustenta la aplicación de EMH, recomendando sus derivados centrados en el segundo tirón y aquellos que utilicen el ciclo de estiramiento-acortamiento en sus variantes colgantes. Abstract: The ability to generate maximum power is the most important and determining neuromuscular function in sports performance. Therefore, weightlifting training (WT) and its derivatives is one of the most widely used methods, generating superior strength-power adaptations compared to traditional strength training, jumping and kettlebell training. Objective: To identify the effects of WT on the ability to jump, sprint and change of direction (COD) in athletes. Method: An exhaustive search was carried out in different databases, such as PUBMED, Sportdiscus (EBSCO), Scopus and Web of Science (WOS) under the PRISMA model. The reviewed papers were experimental with and without a control group, between the years 2000 and 2020. Results: The WT produces significant improvements in jump, sprint and in change of direction capacities in the sport population. Conclusion: WT generates significant improvements in jumping, running and change of direction performance under different protocols. There is evidence supporting the use of WT, suggesting its derivatives focused on the second pull and those that use the stretch-shortening cycle in their hanging variants.

The Impact of ACTN3 Gene Polymorphisms on Susceptibility to Exercise-Induced Muscle Damage and Changes in Running Economy Following Downhill Running

This study aimed to investigate if ACTN3 gene polymorphism impacts the susceptibility to exercise-induced muscle damage (EIMD) and changes in running economy (RE) following downhill running. Thirty-five healthy men were allocated to the two groups based on their ACTN3 gene variants: RR and X allele carriers. Neuromuscular function [knee extensor isometric peak torque (IPT), rate of torque development (RTD), and countermovement, and squat jump height], indirect markers of EIMD [muscle soreness, mid-thigh circumference, knee joint range of motion, and serum creatine kinase (CK) activity], and RE (oxygen uptake, minute ventilation, blood lactate concentration, and perceived exertion) for 5-min of running at a speed equivalent to 80% of individual maximal oxygen uptake speed were assessed before, immediately after, and 1–4 days after a 30-min downhill run (−15%). Neuromuscular function was compromised (P &lt; 0.05) following downhill running with no differences between the groups, except for IPT, which was more affected in the RR individuals compared with the X allele carriers immediately (−24.9 ± 6.9% vs. −16.3 ± 6.5%, respectively) and 4 days (−16.6 ± 14.9% vs. −4.2 ± 9.5%, respectively) post-downhill running. EIMD manifested similarly for both the groups except for serum CK activity, which was greater for RR (398 ± 120 and 452 ± 126 U L–1 at 2 and 4 days following downhill running, respectively) compared with the X allele carriers (273 ± 121 and 352 ± 114 U L–1 at the same time points). RE was compromised following downhill running (16.7 ± 8.3% and 11 ± 7.5% increases in oxygen uptake immediately following downhill running for the RR and X allele carriers, respectively) with no difference between the groups. We conclude that although RR individuals appear to be more susceptible to EIMD following downhill running, this does not extend to the changes in RE.

Effect of partial substitution of fishmeal with insect meal (Hermetia illucens) on gut neuromuscular function in Gilthead sea bream (Sparus aurata)

Alternative nutrient sources to fishmeal for fish feed, such as insect meals, represent a promising sustainable supply. However, the consequences for fish digestive function have not been exhaustively investigated. In the present study we evaluated the effect of partial fishmeal substitution with 10% Hermetia illucens (Hi10) larvae meal on the neuromuscular function of proximal and distal intestine in gilthead sea bream. In animals fed with insect meal, weight and growth parameters were similar to controls fed with conventional fishmeal. In addition, no anomalies in intestinal gross morphology and no overt signs of inflammation were observed. The gastrointestinal transit was significantly reduced in Hi10 fed animals. In the proximal and distal intestine longitudinal muscle, Hi10 feeding downregulated the excitatory cholinergic and serotoninergic transmission. Sodium nitroprusside-induced inhibitory relaxations increased in the proximal intestine and decreased in the distal intestine after Hi10 meal. Changes in the excitatory and inhibitory components of peristalsis were associated with adaptive changes in the chemical coding of both proximal and distal intestine myenteric plexus. However, these neuromuscular function alterations were not associated with considerable variations in morphometric growth parameters, suggesting that 10% Hi meal may represent a tolerable alternative protein source for gilthead sea bream diets.

Comparison of Bleeding Profiles of Sugammadex and Neostigmine in Orthotopic Liver Transplantation

In the era of “fast-track’ liver transplantation (LT), neuromuscular blockade (NMB) antagonists such as neostigmine or sugammadex are used to achieve the restoration of neuromuscular function. While sugammadex reverses NMB faster than neostigmine, it has been shown to prolong prothrombin time (PT) and activated thromboplastin time (aPTT). However, this agent’s impact on coagulation during LT is not understood. We compare bleeding risk associated with sugammadex versus neostigmine during liver transplantation. This is a single-center, retrospective review of LT patients who received NMB antagonists intraoperatively between 01/01/2015 to 05/31/2018 at Mayo Clinic in Florida. The primary outcomes were postoperative day (POD) 0-1 bleeding events and POD 0 values of aPTT and INR. Total 241 patients were included, with 135 patients in the neostigmine group (NG) and 106 in the sugammadex group (SG). POD 0-1 postoperative bleeding requiring transfusion occurred in 20% of NG versus 10.4% in SG. POD 0-1 re-operation for bleeding occurred in 1.5% in NG vs. 0% in SG. POD 0 mean INR was 2.0±0.4 in both groups. POD 0 mean aPTT was 45.5±7.9 in NG vs. 49.3±9.0 in SG. Our retrospective study suggests that sugammadex is not associated with an increased risk of bleeding compared to neostigmine use.

Effects of Low Temperature on Shrimp and Crab Physiology, Behavior, and Growth: A Review

As important aquaculture species worldwide, shrimps and crabs are thermophilic animals with a feeble thermoregulation ability. Changes in environmental factors are the main reason for the decrease in the immunity and disease resistance ability of cultured organisms. Water temperature is one of the most common abiotic stress factors for aquatic ectotherms. It influences nearly all biochemical and physiological processes in crustaceans, resulting in an imbalance in ion and water homeostasis, neuromuscular function loss, cellular dehydration, and altered metabolic pathways. The present review summarizes the current knowledge on the effects of low temperature on the physiological response, and the behavior, development, and growth of shrimp and crab. We suggest a deeper research to understand the physiological processes involved in thermoregulation; this knowledge could be used to reduce the adverse effects in the shrimps and crabs during the culture.