Fidal

About: Fidal is a other organization based out in Courbevoie, France. It is known for research contribution in the topics: European union & Athletes. The organization has 40 authors who have published 28 publications receiving 617 citations.

Blood free radical antioxidant enzymes and lipid peroxides following long-distance and lactacidemic performances in highly trained aerobic and sprint athletes.

Abstract: OBJECTIVE We have determined the differences of the influence of prolonged exercise or higher intensity lactacidemic exercise, on plasma lipid peroxidation and on erythrocyte antioxidant enzymatic defence system. EXPERIMENTAL DESIGN We measured plasma indices of lipid peroxidation, conjugated dienes (CD) and malondialdehyde (MDA) and erythrocyte enzymes superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase (CAT). The biochemical evaluations were performed in six healthy control males (C) and twelve athletes: six marathon runners (MR) and six sprint-trained athletes (STA) at rest and after a half-marathon (MR) and a training session of 6 x 150 m (STA). RESULTS In resting conditions MDA was higher in STA and MR than in C (p < 0.01), while only the MR showed significantly elevated levels of CD (p < 0.05). In STA the enzymatic scavenging capacity showed a significantly higher SOD (p < 0.01) and GSHPx (p < 0.01), while CAT was lower than in controls (p < 0.05). In MR only SOD (p < 0.01) was significantly higher than in C. It increased significantly immediately after half-marathon, while CAT decreased 24 and 48 hours postexercise respectively. In these athletes the lipoperoxidative indices increased in the early postexercise phase, while at 24 and 48 hrs both CD and MDA levels decreased. In STA enzyme activities were not modified by anaerobic performance while CD showed a peak 6 hrs postexercise and the MDA showed a progressive increase until 48 hrs afterwards. CONCLUSIONS Both strenuous long duration exercise and exhaustive sprint training overwhelm our capacity to detoxify ROS, producing oxidative stress. Thus an adequate supply of antioxidants could be appropriate.

Relationship between the efficiency of muscular work during jumping and the energetics of running.

Abstract: The running economy of seventeen athletes was studied during running at a low speed (3.3 m · s−1) on a motor-driven treadmill. The net energetic cost during running expressed in kJ·kg−1·km−1 was on average 4.06. As expected, a positive relationship was found between the energetic cost and the percentage of fast twitch fibres (r=0.60,n=17,p<0.01). In addition, the mechanical efficiency during two different series of jumps performed with and without prestretch was measured in thirteen subjects. The effect of prestretch on muscle economy was represented by the ratio between the efficiency of muscular work performed during prestretch jumps and the corresponding value calculated in no prestretch conditions. This ratio demonstrated a statistically significant relationship with energy expenditure during running (r=−0.66,n=13,P<0.01), suggesting that the elastic behaviour of leg extensor muscles is similar in running and jumping if the speeds of muscular contraction during eccentric and concentric work are of similar magnitudes.

The influence of extra load on the mechanical behavior of skeletal muscle.

Abstract: Eleven international jumpers and throwers engaged in year round training were divided into experimental (n = 6) and control (n = 5) groups. The experimental group was tested before and after a 3 weeks simulated hypergravity period, and again 4 weeks after the hypergravity period. The high gravity condition was created by wearing a vest weighing about 13% of the subjects body weight. The vest was worn from morning to evening including the training sessions, and only removed during sleep. The daily training of all subjects consisted of classical weight training and jumping drills. No changes in the ordinary training program were allowed in the experimental group, except for the use of the vest. Vertical jumps, drop jumps and a 15 s continuous jumping test were used to measure the explosive power characteristics of the subjects. After the hypergravity period the experimental subjects demonstrated significant (5-10%, P less than 0.05-0.01) improvements in most of the variables studied: however, 4 weeks after cessation of the high gravity period they tended to return towards the starting values. No changes were observed in the results of the control group. The improvement observed in the experimental subjects was explained as fast adaptation to the simulated high gravity field. It is suggested that adaptation had occurred both in neuromuscular functions and in metabolic processes.

The effect of pre-stretch on mechanical efficiency of human skeletal muscle.

Abstract: The mechanical efficiency of positive work was studied in six subjects performing three different types of exercises. On the first occasion the subjects ran on a motor-driven treadmill at 3.33 m s-1; the second and the third exercises consisted of performing rhythmical vertical jumps for 1 min both in rebound (RJ) and no-rebound (NRJ) conditions. The mechanical efficiency calculated in NRJ, which reflects only the conversion of biochemical energy into mechanical work, was found to be lower than the corresponding observation in RJ, 17.2 vs. 27.8% (P less than 0.001), respectively. These differences could not be explained by only the storage and recoil of elastic energy occurring in RJ compared with NRJ. The calculated extra work delivered 'free' was greater than the potential elastic energy which could be stored within the leg extensor muscles (187 vs. 124 J for each jump, P less than 0.05). It is likely that other factors might be responsible for the extra work found in NRJ. It was suggested that the difference in the length of time to perform positive work between a simple shortening contraction and a stretch-shortening muscular activity could be also responsible for the enhanced efficiency observed in RJ. This suggestion was supported by the high relationship (P less than 0.001) found between the time to perform positive work and the mechanical efficiency measured in jumping and estimated during running.