Search

Study aim: To investigate the effect of fatigue, induced by a volleyball training game on the risk of Anterior Cruciate Ligament (ACL) injury. Material and methods: Thirteen female volleyball college athletes, ages 18 to 21 years old, completed jump landings from a box 30 cm height, prior and post a 60-minute volleyball training game. The clinical tool Landing Error Scoring System (LESS) was employed in order to evaluate the technique of landing prior and post the game. The level of fatigue induced by the volleyball game was assessed by vertical jump test and Borg Rating of Perceived Exertion (RPE) Scale pre and post-game. In order to compare measurements pre and post-game t-tests for dependent samples were used. Results: Participants performed lower vertical jumps post-game with a Confidence Interval of 26.2 ± 2.3 cm (pre-game) and 24.9 ± 2.2 cm (post game). The difference between pre and post-game was found to be statistically significant with a t12 = 2.55 and a p-value of 0.026. In the case of assessing fatigue, the Borg RPE scale scores were found to be statistically significant (t12 = 14.05, p < 0.001) higher post-game (10.2 ± 0.6), as compared to pre-game (6.5 ± 0.4). Similarly, LESS scores increased significantly (t12 = 2.21, p = 0.047), post-game (6.3 ± 1.1) compared to pre-game (5.8 ± 1.0) that prove poorer landing ability. Conclusion: It seems that a short duration volleyball training game induces fatigue and negatively affects the jumping and landing ability.

The present study investigated the effect of Corinthian currant pre-exercise supplementation on metabolism, performance and blood redox status during, and after prolonged exercise. Eleven healthy participants (21-45y) performed a 90-min constant-intensity (60–70% VO2max) submaximal-trial, plus a time-trial (TT) to exhaustion (95% VO2max) after consuming an isocaloric (1.5g CHO/kg BM) amount of randomly assigned Corinthian currant or glucose-drink, or water (control). Blood was drawn at baseline, pre-exercise, 30min, 60min, 90min of submaximal-trial, post-TT, and 1h post-TT. Post-ingestion blood glucose (GLU) under Corinthian currant was higher compared with water, and similar compared with glucose-drink throughout the study. Respiratory quotient under Corinthian currant was similar with glucose-drink and higher than water throughout the submaximal trial. Accordingly, higher CHO and lower fat oxidation were observed under Corinthian currant compared with water. The TT performance was similar betwee...

Spirulina plantensis is a popular supplement which has been shown to have antioxidant and performance enhancing properties. The purpose of this study was to evaluate the effects of spirulina supplementation on (a) redox status (b) muscle performance and (c) muscle damage following an eccentric bout of exercise that would induce muscle damage. Twenty-four healthy, recreationally trained males participated in the study and were randomly separated into two groups: a spirulina supplementation (6 g per day) and a placebo group. Both groups performed an eccentric bout of exercise consisting of 5 sets and 15 maximum reps per set. Blood was collected at 24, 48, 72 and 96 h after the bout and total antioxidant capacity (TAC) and protein carbonyls (PC) were assessed in plasma. Delayed onset muscle soreness (DOMS) was also assessed at the same aforementioned time points. Eccentric peak torque (EPT) was evaluated immediately after exercise, as well as at 24, 48, 72 and 96 h post exercise. Redox status indices (TAC and PC) did not change significantly at any time point post exercise. DOMS increased significantly 24 h post exercise and remained elevated until 72 h and 96 h post exercise for the placebo and spirulina group, respectively. EPT decreased significantly and immediately post exercise and remained significantly lower compared to baseline until 72 h post exercise. No significant differences between groups were found for DOMS and EPT. These results indicate that spirulina supplementation following a muscle damaging protocol does not confer beneficial effects on redox status, muscle performance or damage.

Exercise induced muscle damage (EIMD), is usually experienced in i) humans who have been physically inactive for prolonged periods of time and then begin with sudden training trials and ii) athletes who train over their normal limits. EIMD is not so easy to be detected and quantified, by means of commonly measurement tools and methods. Thermography has been used successfully as a research detection tool in medicine for the last 6 decades but very limited work has been reported on EIMD area. The main purpose of this research is to assess and characterize EIMD, using thermography and image processing techniques. The first step towards that goal is to develop a reliable segmentation technique to isolate the region of interest (ROI). A semi-automatic image processing software was designed and regions of the left and right leg based on superpixels were segmented. The image is segmented into a number of regions and the user is able to intervene providing the regions which belong to each of the two legs. In order to validate the image processing software, an extensive experimental investigation was carried out, acquiring thermographic images of the rectus femoris muscle before, immediately post and 24, 48 and 72 hours after an acute bout of eccentric exercise (5 sets of 15 maximum repetitions), on males and females (20-30 year-old). Results indicate that the semi-automated approach provides an excellent bench-mark that can be used as a clinical reliable tool.

Exercise-induced skeletal muscle microtrauma is characterized by loss of muscle cell integrity, marked aseptic inflammatory response, and oxidative stress. We examined if iron supplementation would alter redox status after eccentric exercise. In a randomized, double blind crossover study, that was conducted in two cycles, healthy adults (n=14) and children (n=11) received daily either 37 mg of elemental iron or placebo for 3 weeks prior to and up to 72 h after an acute eccentric exercise bout. Blood was drawn at baseline, before exercise, and 72 h after exercise for the assessment of iron status, creatine kinase activity (CK), and redox status. Iron supplementation at rest increased iron concentration and transferrin saturation (p<0.01). In adults, CK activity increased at 72 h after exercise, while no changes occurred in children. Iron supplementation increased TBARS at 72 h after exercise in both adults and children; no changes occurred under placebo condition. Eccentric exercise decreased bilirubin concentration at 72 h in all groups. Iron supplementation can alter redox responses after muscle-damaging exercise in both adults and children. This could be of great importance not only for healthy exercising individuals, but also in clinical conditions which are characterized by skeletal muscle injury and inflammation, yet iron supplementation is crucial for maintaining iron homeostasis. This study was registered at Clinicaltrials.gov Identifier:NCT02374619.

The procedure for blood sampling in doping control, implemented for the first time as part of the official foren- sic testing programme in the Athens 2004 Summer Olympic Games is described. 743 whole blood and serum samples from 37 sports were analyzed. In serum human growth hormone and hemoglobin based oxygen carriers were screened for. In whole blood samples heterologous blood transfusion was detected. Routine haematological parameters (hematocrit, haemoglobin) were followed in a very limited range only in Modern Pentathlon under the responsibility of the respective International Federation. The majority of the blood samples collected concerned events in athletics. Endurance sports accounted for 81% of the whole blood sampling. Athletics, swimming and rowing represented 55% of the serum samples analyzed. Extension of testing for oxygen transport enhancing agents in anaerobic sports should be seriously considered by future organizers and the International Olympic Committee. The mean time for an athlete to report to the Doping Control Station for blood collection was 6.1 hours; 27% of the ath- letes tested (from 19 sports) failed to appear within the 12-hours time limit set. Training of the phlebotomists was proven effective. Only 25 athletes of those tested (3%) reported to have felt uncomfort- able. The majority of complaints (47%) concerned the prolonged waiting period and the long blood collection time (48%). Finally, an earlier agreement between all involved parties, attempts to decrease the time to appear at the site of blood col- lection and shortening of the duration of blood collection and sealing of the samples are recommended.

To gather data and examine the use by elite Olympic athletes of food supplements and pharmaceutical preparations in total and per sport, country, and gender.Survey study.Athens 2004 Olympic Games (OG).Data from 2 sources were collected: athletes' declaration of medications/supplements intake recorded on the Doping Control Official Record during sample collection for doping control, and athletes' application forms for granting of a therapeutic use exemption (TUE) and through the abbreviated TUE process (aTUE).Classification of declared food supplements according to the active ingredient and medications according to therapeutic actions and active compounds.24.3% of the athletes tested for doping control declared no use of medications or food supplements. Food supplements (45.3%) continue to be popular, with vitamins (43.2%) and proteins/aminoacids (13.9%) in power sports being most widely used. Nonsteroidal antiinflammatory agents and analgesics were also commonly used by athletes (11.1% and 3.7%, respectively). The use of the hemoderivative actovegin and several nonprohibited anabolic preparations are discussed. The prevalence of medication use for asthma and the dangers of drug interactions are also presented.Laboratory analysis data reveal that of the aTUEs received for inhaled glucocorticosteroids, only budesonide was detectable in significant percentage (10.0%). Only 6.5% of the 445 athletes approved to inhale beta2-agonists led to an adverse analytical finding.This review demonstrates that overuse of food supplements was slightly reduced compared to previous OGs and a more rational approach to the use of medication is being adopted.

Objective: The aim of this study was to investigate physical fitness in relation to fatness in urban and rural Greek children by means of allometric scaling. Methods: The sample consisted of 360 (189 urban and 171 rural; age 12.3±0.42 years) boys and 247 (125 urban and 122 rural; age 12.3±0.43 years) girls. The sample was highly representative (32–64%) of all 12 year old children registered in the prefecture of Trikala, Greece. All volunteers were assessed for BMI and % body fat, as well as sit and reach, basketball throw (BT), vertical jump (VJ), handgrip strength (HG), 40 m sprint, agility run, and 20 m shuttle run. To correct for possible associations between fatness and fitness, a single cause allometric scaling was employed using the natural logarithms (ln) of fitness parameters that were significantly correlated with the ln body fat. Results: Independent-samples t tests revealed that VJ (p

Many exercise models have demonstrated associations between eccentric muscle actions and muscle damage. However, the magnitude of muscle damage varies among the models. It appears that responses to eccentric exercise are different between leg and arm muscles but this has not been systematically clarified. This study compared leg and arm eccentric exercises of the same relative intensity for indices of muscle damage. Eleven healthy untrained males [Age: 21.2 (1.0) years, Height: 179.4 (3.0) cm, Weight: 78.4 (3.1) kg] performed a sub-maximal eccentric exercise of the knee extensors (LEGS) and the elbow flexors (ARMS), separately. Both LEGS and ARMS consisted of six sets of 12 repetitions with an intensity corresponding to 75% of the predetermined maximal eccentric peak torque (EPT) of each muscle. Range of motion (ROM), delayed onset muscle soreness (DOMS), serum creatine kinase (CK) and lactate dehydrogenase (LDH) activities, myoglobin (Mb) concentration, and muscle strength [EPT and isometric peak torque (IPT)] were assessed before and 24, 48, 72, and 96 h following exercise. Significant (P < 0.05) changes in DOMS and ROM were observed up to 96 h after both exercise bouts, and the magnitude of the change was similar between LEGS and ARMS. Increases in CK and Mb were significantly (P < 0.05) larger after ARMS than LEGS at 72 and 96 h post-exercise. EPT and IPT were significantly (P < 0.05) lower than the baseline up to 96 h post-exercise for ARMS but were fully recovered by 96 h post-exercise for LEGS. Decreases in muscle strength were significantly (p < 0.05) larger following ARMS than LEGS at 48, 72, and 96 h post-exercise for EPT, and from 24 h to 96 h post-exercise for IPT. These results suggest that the magnitude of muscle damage is greater and the recovery of muscle function was slower after eccentric exercise of arm elbow flexors than the knee extensors.