Search results for "DICS"

Rethinking the role of fat oxidation: substrate utilisation during high-intensity interval training in well-trained and recreationally trained runners

2015

Background Although carbohydrate is the predominant fuel source supporting high-intensity exercise workloads, the role of fat oxidation, and the degree to which it may be altered by training status, is less certain. Methods We compared substrate oxidation rates, using indirect calorimetry, during a high-intensity interval training (HIT) session in well-trained (WT) and recreationally trained (RT) runners. Following preliminary testing, 9 WT (VO2max 71±5 mL/min/kg) and 9 RT (VO2max 55±5 mL/min/kg) male runners performed a self-paced HIT sequence consisting of six, 4 min work bouts separated by 2 min recovery periods on a motorised treadmill set at a 5% gradient. Results WT and RT runners per…

Cardiovascular and Autonomic Responses to a Maximal Exercise Test in Elite Youngsters

2017

AbstractTo analyze cardiovascular and autonomic responses in elite youngsters, 13 male cyclists (15.43±0.51 years) performed a graded-test until voluntary exhaustion. Oxygen consumption (VO2), blood lactate (BLa), arterial oxygen saturation (SaO2), respiratory exchange ratio (RER) and rating of perceived exertion (RPE) were collected, while heart rate (HR) was registered for heart rate variability (HRV) analyses, looking for linear and nonlinear comparisons. Cyclists reached maximal exertion [RPE: 19.14±0.94; BLa: 8.92±2.51 mmol.L−1; RER: 1.04±0.03; SaO2: 92.43±2.5%] and high-level performance (4.41±0.46 W·Kg−1; 60.77±6.87 ml·Kg·min−1) once over 95% of age-predicted HRmax. VO2 and RPE incre…

2021

ObjectivesTo assess the ability to predict individual unfavourable future status and development in the 20m shuttle run test (20MSRT) during adolescence with machine learning (random forest (RF) classifier).MethodsData from a 2-year observational study (2013‒2015, 12.4±1.3 years, n=633, 50% girls), with 48 baseline characteristics (questionnaires (demographics, physical, psychological, social and lifestyle factors), objective measurements (anthropometrics, fitness characteristics, physical activity, body composition and academic scores)) were used to predict: (Task 1) unfavourable future 20MSRT status (identification of individuals in the lowest 20MSRT tertile after 2 years), and (Task 2) u…

Stretch-shortening cycle: a powerful model to study normal and fatigued muscle.

2000

Stretch-shortening cycle (SSC) in human skeletal muscle gives unique possibilities to study normal and fatigued muscle function. The in vivo force measurement systems, buckle transducer technique and optic fiber technique, have revealed that, as compared to a pure concentric action, a non-fatiguing SSC exercise demonstrates considerable performance enhancement with increased force at a given shortening velocity. Characteristic to this phenomenon is very low EMG-activity in the concentric phase of the cycle, but a very pronounced contribution of the short-latency stretch-reflex component. This reflex contributes significantly to force generation during the transition (stretch-shortening) pha…

Preferential Type II Muscle Fiber Damage From Plyometric Exercise

2012

Context: Plyometric training has been successfully used in different sporting contexts. Studies that investigated the effect of plyometric training on muscle morphology are limited, and results are controversial with regard to which muscle fiber type is mainly affected. Objective: To analyze the skeletal muscle structural and ultrastructural change induced by an acute bout of plyometric exercise to determine which type of muscle fibers is predominantly damaged. Design: Descriptive laboratory study. Setting: Research laboratory. Patients or Other Participants: Eight healthy, untrained individuals (age = 22 ± 1 years, height = 179.2 ± 6.4 cm, weight = 78.9 ± 5.9 kg). Intervention(s): Partici…

The effect of wind on jumping distance in ski jumping depends on jumpers’ aerodynamic characteristics

2022

Several studies have suggested re-evaluation of the wind compensation system (WCS) of the International Ski Federation (FIS). It was introduced in 2009, and since then, the system has been modified considerably, but major shortcomings have still remained. The present study compared the effect of tail/head wind on two reference jumps with different aerodynamic properties (Cd and Cl) during the flight phase. Jump distance and total tangential wind speed data of world cup competitions of the season 2020/2021 were used to analyse the FIS WCS and to offer basic information of wind effects. The correlation between the total tangential wind speed and the jump distance varied strongly among the ana…

Marche et démences

2008

Resume Objectifs Decrire les troubles de la marche (TM) au cours des demences primitives, leurs consequences et l’interet de leur prevention et reeducation. Methode Analyse des articles les plus pertinents disponibles sur Medline concernant la marche et la demence. Resultats La prevalence des TM et de l’equilibre dans la demence de type Alzheimer varie de 9 a 52 %. Les marches frontale et apraxique y sont decrites. Dans la demence vasculaire, les TM a type de marches hemiparetique, frontale et unsteady, sont observes chez plus de 71 % de patients et sont probablement un marqueur precoce de cette demence. Bien qu’en pratique clinique les TM semblent frequents dans la demence a corps de Lewy …

Long-term results after operative treatment of femoral neck fractures with ceramic head prostheses.

2001

ABSTRACT From 1 985-1 990, a total of 277 elderly patients underwent hemiarthroplasty using a ceramic head prosthesis. Average patient age was 81.7 years. Of these, 77 patients were available for follow-up examination in 1993. A standardized score was calculated assessing activity, gait, and hip pain; the average score was 58 out of 78 possible points. Three patients had hip pain, and in 4 patients, radiographic examination revealed protrusio acetabuli. Two of 4 patients underwent revision surgery for replacement of the cup, leaving the stem in situ. Because of the small number of prosthetic-related complications, hemiarthroplasty using a ceramic head prosthesis is the recommended surgical …

EFFECT OF THE INTRODUCTION OF PAUSES BETWEEN REPETITIONS IN THE CAPACITY TO SUSTAIN MAXIMAL MAGNITUDES OF PEAK VELOCITY DURING BENCH PRESS

2013

Background An important number of sport modalities sustain its performance in the capacity to repeat efficiently a sport movement without fatigue. However, it is a fact that this mechanism will appear and affect the athletes9 velocity magnitudes. The aim of this study was to compare the Peak Velocity (PV) in two protocols: Traditional Training (TT) vs. 20 s inter-repetition rest (IRR) with the Optimal Load (OL) for the maximal Power output (OL: 50.7±8.0% of 1-RM). Methods Fifteen male, physical education students, participated in this study (age: 23.1±1.6 years; height: 177.1±7.7 cm; mass: 76.2±9.2 kg; 1-RM: 93.8±14.3 kg; 1-RM/mass: 1.24±0.21). After the validation of the bench press 1-RM a…

EFFECT OF THE INTER-REPETITION REST LENGTH IN THE CAPACITY TO REPEAT PEAK POWER OUTPUT

2013

Background High volumes of work affect the movement technical quality, reducing the muscular capacity to develop high magnitudes of force. One of the most important parameters that we can use to regulate the training loads are the inter-repetition rests (IRR). The purpose of this study was to compare the Peak Power output (PP) magnitudes in three different inter-repetition length sets with Optimal Load (OL) in Bench Press (BP). Methods Our sample was formed by 16 male physical education students (age: 23.6±2.1 years; height: 178.2±6.9 cm; mass: 78.3±7.2 kg; 1RM: 90.2±13.9 kg; 1RM/mass: 1.15±0.16), who performed the BP test with different IRR with OL (48.8±7.2% of 1RM; 44.2±11.5 kg). After e…