From “sliding” to “winding” filaments theory: A narrative review of mechanisms behind skeletal muscle contraction

The physiological mechanisms behind muscle contraction are a main concept in sport medicine and rehabilitation. The sarcomere is the functional unit of skeletal muscle and several proteins definite its complex structure. The most common theory to explain muscle contraction was proposed in the last 50’s and has become widely popular and accepted: the “sliding filaments” theory. Even if this hypothesis was able to justify some form of muscle contraction, other processes are not fully described by it. Eccentric contraction and some phenomena, like the “force enhancement during stretch” concept described in the 2002, are not explicable according to the sliding filament theory. Therefore, several hypotheses have been suggested over the years, such as the “popping sarcomeres” theory and the “winding filament” theory. Some other proteins, like titin, have gained a main role in the physiology of the sarcomere and should be relevant to explain mechanisms of eccentric contraction, where the sarcomere generates highest level of tension while it is lengthening. The aim of this review is to summarize the physiological theories of muscle contraction and to define concepts applicable in sport medicine and in rehabilitation areas

Pilates Improvement the Individual Basics of Service and Smash in Volleyball

A sample of 20 players 12-to 14-year old young male volleyball athletes participated in this study to test the improvement of agonistic performance, especially for the individual basics of the service and smash, using Pilates method in additional training sessions. The research was conducted with observation and manual and computerized detection for six months with tests for explosive strength detection and smash precision. The measuring the length of the lower limbs with the ASIS method showed a diff erence of a few millimetres between the two lower limbs and hypertrophy of the longest limb and hypotrophy of the shortest one. The athletes were divided into group A control (10 athletes) and group B (10 athletes). Only Group B participated in 20 additional training sessions with the Pilates method. The study showed improvement in performances with particular reference to the average percentage of crushing between 4 and 7%. Group B athletes, they found a uniform muscle toning and improved breathing control. The A group, motivated to perform the workouts with greater concentration, showed a performance improvement of a few percentage points. These athletes can improve the eff ectiveness of using unconventional methods to improve sports performance in a Team Sport

The core curriculum in the university training of the teacher of physical education in Italy

Structural, organizational and normative developments in the school setting in Italy, in the last fifty years, suggest that teachers role should be considered throughout the social, cultural and scientific innovations that lead these changes. Based on this theoretical proposition, the purpose of the present study was to identify some key elements of Physical Education Teacher Training Core Curriculum in Italy. The study takes a documental-based approach to the development of teaching skills and lists action supported by Italian Ministry of Education in the last decades to foster adequate teacher training programs, with particular reference to Physical Education teacher training in the low and high school, since the earlier courses in 18th century till now. The results revealed that teacher training programs in Italy sometimes lacked of adequate methods and significant contents, so it is very important to underline the value of a new approach in teacher training that aim to ensure the acquisition of key competence, according to Recommendation of the European Parliament and to create a cooperation between University and the Italian Olympic Committee. In conclusion, a new approach in teacher training could foster a broad advance in specialization and professional development of physical education teacher, adjusting our educational path to the European best practices

Physical-technical conditions, coaching and nutrition: An integrated approach to promote cohesion in sports team

The aim was verified that the level of cohesion of a sports group is conditioned by numerous variables, which affect the athletes performance and lead to difficulties in adults relationships. The sample physical-technical and nutritional conditions and the help for the cohesion of a technique such as coaching were evaluated. Coaching can understand as the process in which individuals, mostly athletes, supported for their improvement and development in order to achieve performance high levels. 40 adults, aged between 35 and 45 years old, practicing football at amateur level for eight months, belonging to two different sports groups (blue and red group), have been observed. The results showed about 2.5% increase for blue group in Cooper test and about 1% in Sargent test, while for red group the improvement was approximately 1.5% in Cooper test and about 0.5% in Sargent test. 37 athletes correctly followed the nutrition specialists indications while 3 athletes showed negative responses. The personalized diets success confirmed by the decrease, in terms of kg, of the average percentage of athletes' body weight. All sample highlighted, with the answers to the 14 items of the questionnaire, significant percentage variations in lifestyles and relationships between group members

Use and attitudes toward dietary supplements and drugs amongst Italian elite athletes and its correlation with banned doping substances

Athletes frequently use dietary supplements (DS) to find better results as soon as possible. Moreover, they also will be occurring in “polypharmacy” or in substances prohibited for doping. The aim of this retrospective sectional study was to explore use and attitudes toward drugs and dietary supplements (DS) in Italian Sports Federations and its correlation with banned doping substances token amongst elite athletes. The data shows the results from 2012 to 2017, among Italian Sports Federations elite athletes and the analysis of the anti-doping controls from the Ministry of Health annual reports. The results show that the largest number of supplements consumption declarations was recorded in 2014 in sport as cycling and athletics. Moreover, in the same year and in 2012 there were 48 and 42 declarations on 58 and 52 doped athletes. Among the Italian federations, three are particularly controlled: FCI - cycling, FIDAL - athletics and FIGC – football. Most of the consumers subjects are male athletes. So maybe there is a link between NS and positive results in anti-doping test. The consumption of health products is constantly expanding and educational interventions will be needed to improve drugs and DS use about elite athletes as well in amateur athletes

Overtraining syndrome, stress and nutrition in football amateur athletes

In competitive sports is important optimizing and improving the recovery-stress state. We aimed to investigate the overtraining syndrome in the football, modulating the agonistic training and evaluating the nutritional status of the young amateur soccer players, thought monitoring of the capacity of endurance and strength in a sample of twenty athletes between the ages of 18 and 33 (mean 22 +/- 4.43 SD). Overtraining syndrome is a condition of physical, behavioural and emotional stress in sports and occurs when the physical activity is so intense as to prevent the athlete from performing a correct recovery totally eliminating the sense of fatigue. The athletes, from September 2016 to April 2017 were monitored with anthropometric tests (BMI calculation), nutritional tests (Recall test) and sportive (Cooper and Sargent test) to prevention of the overtraining syndrome with initial, intermediate and final measurements. Each player, during the observational period, performed normal athletic training sessions and participating two additional monthly sessions, for a total of sixteen sessions, with free overloads and, after intermediate verification, the exercises has been modified to reduce overtraining phenomenon. Tests initial results have been positive for defenders and midfielders while at the end of the search goalkeepers and forwards have significantly improved the performances. The total percentage increase of sample is around +/- 4% and the study confirmed that by modulating the intensity of training and controlling the athletes' diet, it is possible to reduce or eliminate overtraining effects

Identification of dust outbreaks on infrared msg-seviri data by using a Robust Satellite Technique (RST)

Dust storms are meteorological phenomena of great interest for scientific community because of their potential impact on climate changes, for the risk that may pose to human health and due to other issues as desertification processes and reduction of the agricultural production. Satellite remote sensing, thanks to global coverage, high frequency of observation and low cost data, may highly contribute in monitoring these phenomena, provided that proper detection methods are used. In this work, the known Robust Satellite Techniques (RST) multitemporal approach, used for studying and monitoring several natural/environmental hazards, is tested on some important dust events affecting Mediterranean region in May 2004 and Arabian Peninsula in February 2008. To perform this study, data provided by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) have been processed, comparing the generated dust maps to some independent satellite-based aerosol products. Outcomes of this work show that the RST technique can be profitably used for detecting dust outbreaks from space, providing information also about areas characterized by a different probability of dust presence. They encourage further improvements of this technique in view of its possible implementation in the framework of operational warning systems

Jump and balance test in judo athletes with or without visual impairments

The study was conducted for four months with 8 judo athletes: 4 sighted people (4 M) and 4 visual impairment people (3 M and 1 F), aged between 18 and 52 (30.75 ± 12.74). According to the IBSA Visual Classification, all visual impairment subjects participating in our study were covered in the B1 category of visual deficit. This is a group represented by patients with no light perception in either eye up to light perception, and with an inability to recognize the shape of a hand at any distance or in any direction. From our cohort it was excluded subjects who have had low extremities musculoskeletal, neurological, or orthopaedic disorders in the previous six months. The aim of the study was to evaluate their balance with both closed and opened eyes and to set their lower limbs’ strength: these are indispensable characteristics to carry out technical actions of judo. Anthropometric measures were compared between groups and data about jump protocol and balance protocol were analysed. Results of current research showed that postural stability is different in function of assessment with closed and open eyes. The result of the jump tests differs because the data do not show significant differences between long jump and high jump. The comparison between blinded and sighted judo athletes highlighted greater difficulties with eyes closed for sighted athletes than blinded ones

Pengaruh Kuat Arus Dan Waktu Pengelasan Pada Proses Las Titik (Spot Welding) Terhadap Kekuatan Tarik Dan Mikrostuktur Hasil Las Dari Baja Fasa Ganda (Feritte-Martensite)

This research was conducted to investigate the appropiate spot welding variable to get the maximum tensile strength. The highest of tensile strength referred as good quality of weldment.The plate was made from low carbon steel with phase ferrite and martensite. The current of welding used 0.9 kA, 1.6 kA, dan 1.85 kA with welding time were 0.25, 0.5 , 0.75 and 1 second. Mechanical properties testing done involved tensile strength to know shear strength of weld joint. Microstructure test used optical microscope.The results show that spot welding with thecurrent of 1.85kA and welding time of 1 second has the highest tensile strength (about 237.04N/mm2). On the other hand, the lowest tensile strength (150 N/mm2) was produced by combination of 0.9 kA and 0.25 second welding time. It was caused by recrystallization phasedeformation on steel

Selinexor in Advanced, Metastatic Dedifferentiated Liposarcoma: A Multinational, Randomized, Double-Blind, Placebo-Controlled Trial

PURPOSE Antitumor activity in preclinical models and a phase I study of patients with dedifferentiated liposarcoma (DD-LPS) was observed with selinexor. We evaluated the clinical benefit of selinexor in patients with previously treated DD-LPS whose sarcoma progressed on approved agents. METHODS SEAL was a phase II-III, multicenter, randomized, double-blind, placebo-controlled study. Patients age 12 years or older with advanced DD-LPS who had received two-five lines of therapy were randomly assigned (2:1) to selinexor (60 mg) or placebo twice weekly in 6-week cycles (crossover permitted). The primary end point was progression-free survival (PFS). Patients who received at least one dose of study treatment were included for safety analysis (ClinicalTrials.gov identifier: ). RESULTS Two hundred eighty-five patients were enrolled (selinexor, n = 188; placebo, n = 97). PFS was significantly longer with selinexor versus placebo: hazard ratio (HR) 0.70 (95% CI, 0.52 to 0.95; one-sided P = .011; medians 2.8 v 2.1 months), as was time to next treatment: HR 0.50 (95% CI, 0.37 to 0.66; one-sided P < .0001; medians 5.8 v 3.2 months). With crossover, no difference was observed in overall survival. The most common treatment-emergent adverse events of any grade versus grade 3 or 4 with selinexor were nausea (151 [80.7%] v 11 [5.9]), decreased appetite (113 [60.4%] v 14 [7.5%]), and fatigue (96 [51.3%] v 12 [6.4%]). Four (2.1%) and three (3.1%) patients died in the selinexor and placebo arms, respectively. Exploratory RNA sequencing analysis identified that the absence of CALB1 expression was associated with longer PFS with selinexor compared with placebo (median 6.9 v 2.2 months; HR, 0.19; P = .001). CONCLUSION Patients with advanced, refractory DD-LPS showed improved PFS and time to next treatment with selinexor compared with placebo. Supportive care and dose reductions mitigated side effects of selinexor. Prospective validation of CALB1 expression as a predictive biomarker for selinexor in DD-LPS is warranted. (C) 2022 by American Society of Clinical Oncolog