Diana Ruiz-Vicente

The ingestion of a caffeinated energy drink improves jump performance and activity patterns in elite badminton players

Abstract The aim of this study was to investigate the effectiveness of a caffeine-containing energy drink to enhance physical and match performance in elite badminton players. Sixteen male and elite badminton players (25.4 ± 7.3 year; 71.8 ± 7.9 kg) participated in a double-blind, placebo-controlled and randomised experiment. On two different sessions, badminton players ingested 3 mg of caffeine per kg of body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed the following tests: handgrip maximal force production, smash jump without and with shuttlecock, squat jump, countermovement jump and the agility T-test. Later, a 45-min simulated badminton match was played. Players’ number of impacts and heart rate was measured during the match. The ingestion of the caffeinated energy drink increased squat jump height (34.5 ± 4.7 vs. 36.4 ± 4.3 cm; P < 0.05), squat jump peak power (P < 0.05), countermovement jump height (37.7 ± 4.5 vs. 39.5 ± 5.1 cm; P < 0.05) and countermovement jump peak power (P < 0.05). In addition, an increased number of total impacts was found during the badminton match (7395 ± 1594 vs. 7707 ± 2033 impacts; P < 0.05). In conclusion, the results show that the use of caffeine-containing energy drink may be an effective nutritional aid to increase jump performance and activity patterns during game in elite badminton players.

The Use of Compression Stockings During a Marathon Competition to Reduce Exercise-Induced Muscle Damage: Are They Really Useful?

STUDY DESIGN Case-control study; ecological study. OBJECTIVES To examine the efficacy of wearing compression stockings to prevent muscle damage and to maintain running performance during a marathon competition. BACKGROUND Exercise-induced muscle damage has been identified as one of the main causes of the progressive decrease in running and muscular performance found during marathon races. METHODS Thirty-four experienced runners were pair-matched for age, anthropometric data, and best race time in the marathon, and randomly assigned to a control group (n = 17) of runners who wore conventional socks or to a group of runners who wore foot-to-knee graduated compression stockings (n = 17). Before and after the race, a sample of venous blood was obtained, and jump height and leg muscle power were measured during a countermovement jump. Serum myoglobin and creatine kinase concentrations were determined as blood markers of muscle fiber damage. RESULTS Total race time was not different between the control group and the compression stockings group (210 ± 23 and 214 ± 22 minutes, respectively; P = .58). Between the control group and the compression stockings group, postrace reductions in leg muscle power (-19.8% ± 17.7% versus -24.8% ± 18.4%, respectively; P = .37) and jump height (-25.3% ± 14.1% versus -32.5% . 20.4%, respectively; P = .27) were similar. At the end of the race, there were no differences between the control group and the compression stockings group in serum myoglobin (568 ± 347 ng·mL(-1) versus 573 ± 270 ng·mL(-1), respectively; P = .97) and creatine kinase concentration (390 ± 166 U·L(-1) versus 487 ± 227 U·L(-1), respectively; P = .16). CONCLUSION The use of compression stockings did not improve running pace and did not prevent exercise-induced muscle damage during the marathon. Wearing compression stockings during long-distance running events is an ineffective strategy to avoid the deleterious effects of muscle damage on running performance. LEVEL OF EVIDENCE Therapy, level 2b.

CYP1A2 Genotype Variations Do Not Modify the Benefits and Drawbacks of Caffeine during Exercise: A Pilot Study.

Previous investigations have determined that some individuals have minimal or even ergolytic performance effects after caffeine ingestion. The aim of this study was to analyze the influence of the genetic variations of the CYP1A2 gene on the performance enhancement effects of ingesting a moderate dose of caffeine. In a double-blind randomized experimental design, 21 healthy active participants (29.3 ± 7.7 years) ingested 3 mg of caffeine per kg of body mass or a placebo in testing sessions separated by one week. Performance in the 30 s Wingate test, visual attention, and side effects were evaluated. DNA was obtained from whole blood samples and the CYP1A2 polymorphism was analyzed (rs762551). We obtained two groups: AA homozygotes (n = 5) and C-allele carriers (n = 16). Caffeine ingestion increased peak power (682 ± 140 vs. 667 ± 137 W; p = 0.008) and mean power during the Wingate test (527 ± 111 vs. 518 ± 111 W; p < 0.001) with no differences between AA homozygotes and C-allele carriers (p > 0.05). Reaction times were similar between caffeine and placebo conditions (276 ± 31 vs. 269 ± 71 milliseconds; p = 0.681) with no differences between AA homozygotes and C-allele carriers. However, 31.3% of the C-allele carriers reported increased nervousness after caffeine ingestion, while none of the AA homozygotes perceived this side effect. Genetic variations of the CYP1A2 polymorphism did not affect the ergogenic effects and drawbacks derived from the ingestion of a moderate dose of caffeine.

Effects of oral salt supplementation on physical performance during a half-ironman: A randomized controlled trial

The aim of this study was to investigate the effectiveness of oral salt supplementation to improve exercise performance during a half‐ironman triathlon. Twenty‐six experienced triathletes were matched for age, anthropometric data, and training status, and randomly placed into the salt group (113 mmol Na+ and 112 mmol Cl−) or the control group (cellulose). The experimental treatments were ingested before and during a real half‐ironman triathlon competition. Pre‐ and post‐race body mass, maximal force during a whole‐body isometric strength test, maximal height during a countermovement jump, were measured, and blood samples were obtained. Sweat samples were obtained during the running section. Total race time was lower in the salt group than in the control group (P = 0.04). After the race, whole‐body isometric strength (P = 0.17) and jump height (P = 0.49) were similarly reduced in both groups. Sweat loss (P = 0.98) and sweat Na+ concentration (P = 0.72) were similar between groups. However, body mass tended to be less reduced in the salt group than in the control group (P = 0.09) while post‐race serum Na+ (P = 0.03) and Cl− (P = 0.03) concentrations were higher in the salt group than in the control group. Oral salt supplementation was effective to lessen body mass loss and increase serum electrolyte concentration during a real half‐ironman.

Changes in Serum Free Amino Acids and Muscle Fatigue Experienced during a Half-Ironman Triathlon.

The aim of this study was to investigate the relationship between changes in serum free amino acids, muscle fatigue and exercise-induced muscle damage during a half-ironman triathlon. Twenty-six experienced triathletes (age = 37.0 ± 6.8 yr; experience = 7.4 ± 3.0 yr) competed in a real half-ironman triathlon in which sector times and total race time were measured by means of chip timing. Before and after the race, a countermovement jump and a maximal isometric force test were performed, and blood samples were withdrawn to measure serum free amino acids concentrations, and serum creatine kinase levels as a blood marker of muscle damage. Total race time was 320 ± 37 min and jump height (-16.3 ± 15.2%, P < 0.001) and isometric force (-14.9 ± 9.8%; P = 0.007) were significantly reduced after the race in all participants. After the race, the serum concentration of creatine kinase increased by 368 ± 187% (P < 0.001). In contrast, the serum concentrations of essential (-27.1 ± 13.0%; P < 0.001) and non-essential amino acids (-24.4 ± 13.1%; P < 0.001) were significantly reduced after the race. The tryptophan/BCAA ratio increased by 42.7 ± 12.7% after the race. Pre-to-post changes in serum free amino acids did not correlate with muscle performance variables or post-race creatine kinase concentration. In summary, during a half-ironman triathlon, serum amino acids concentrations were reduced by > 20%. However, neither the changes in serum free amino acids nor the tryptophan/BCAA ratio were related muscle fatigue or muscle damage during the race.

Acute consumption of a caffeinated energy drink enhances aspects of performance in sprint swimmers

This study investigated the effect of a caffeinated energy drink on various aspects of performance in sprint swimmers. In a randomised and counterbalanced order, fourteen male sprint swimmers performed two acute experimental trials after the ingestion of a caffeinated energy drink (3 mg/kg) or after the ingestion of the same energy drink without caffeine (0 mg/kg; placebo). After 60 min of ingestion of the beverages, the swimmers performed a countermovement jump, a maximal handgrip test, a 50 m simulated competition and a 45 s swim at maximal intensity in a swim ergometer. A blood sample was withdrawn 1 min after the completion of the ergometer test. In comparison with the placebo drink, the intake of the caffeinated energy drink increased the height in the countermovement jump (49.4 (SD 5.3) v. 50.9 (SD 5.2) cm, respectively; P<0.05) and maximal force during the handgrip test with the right hand (481 (SD 49) v. 498 (SD 43) N; P<0.05). Furthermore, the caffeinated energy drink reduced the time needed to complete the 50 m simulated swimming competition (27.8 (SD 3.4) v. 27.5 (SD 3.2) s; P<0.05), and it increased peak power (273 (SD 55) v. 303 (SD 49) W; P <0.05) and blood lactate concentration (11.0 (SD 2.0) v. 11.7 (SD 2.1) mM; P<0.05) during the ergometer test. The caffeinated energy drink did not modify the prevalence of insomnia (7 v. 7%), muscle pain (36 v. 36%) or headache (0 v. 7%) during the hours following its ingestion (P>0.05). A caffeinated energy drink increased some aspects of swimming performance in competitive sprinters, whereas the side effects derived from the intake of this beverage were marginal at this dosage.

Muscle damage produced during a simulated badminton match in competitive male players.

The purpose of the study was to assess the occurrence of muscle damage after a simulated badminton match and its influence on physical and haematological parameters. Sixteen competitive male badminton players participated in the study. Before and just after a 45-min simulated badminton match, maximal isometric force and badminton-specific running/movement velocity were measured to assess muscle fatigue. Blood samples were also obtained before and after the match. The badminton match did not affect maximal isometric force or badminton-specific velocity. Blood volume and plasma volume were significantly reduced during the match and consequently haematite, leucocyte, and platelet counts significantly increased. Blood myoglobin and creatine kinase concentrations increased from 26.5 ± 11.6 to 197.3 ± 70.2 µg·L−1 and from 258.6 ± 192.2 to 466.0 ± 296.5 U·L−1, respectively. In conclusion, a simulated badminton match modified haematological parameters of whole blood and serum blood that indicate the occurrence of muscle fibre damage. However, the level of muscle damage did not produce decreased muscle performance.

Sweat sodium loss influences serum sodium concentration in a marathon

The aim of this investigation was to determine the influence of sweat electrolyte concentration on body water and electrolyte homeostasis during a marathon. Fifty‐one runners completed a marathon race in a warm and dry environment (24.4 ± 3.6 °C). Runners were classified as low‐salt sweaters (n = 21; <30 mmol/L of sweat Na+ concentration), typical sweaters (n = 20; ≥30 and <60 mmol/L of sweat Na+ concentration), and salty sweaters (n = 10; ≥60 mmol/L of sweat Na+ concentration). Before and after the race, body mass and a sample of venous blood were obtained. During the race, sweat samples were collected by using sweat patches, and fluid and electrolyte intake were recorded by using self‐reported questionnaires. Low‐salt, typical and salty sweaters presented similar sweat rates (0.93 ± 0.2, 0.92 ± 0.29, 0.99 ± 0.21 L/h, respectively), body mass changes (−3.0 ± 1.0, −3.3 ± 1.0, −3.2 ± 0.8%), total Na+ intake (12.7 ± 8.1, 11.5 ± 9.7, 14.5 ± 16.6 mmol), and fluid intake (1.3 ± 0.8, 1.2 ± 0.8, 1.2 ± 0.6 L) during the race. However, salty sweaters presented lower post‐race serum Na+ concentration (140.8 ± 1.3 vs 142.5 ± 1.1, 142.4 ± 1.4 mmol/L; P < 0.01) and serum osmolality (297 ± 6 vs 299 ± 5, 301 ± 6 mOsm/kg; P < 0.05) than low‐salt and typical sweaters. Sweat electrolyte concentration could influence post‐race serum electrolyte concentration in the marathon. However, even the saltiest sweaters did not develop exercise‐associated hyponatremia or associated symptoms.

CFTR genotype‐related body water and electrolyte balance during a marathon

The aim of this investigation was to determine the influence of CFTR genotype on body water and electrolyte balance during a marathon. Fifty‐one experienced runners completed a marathon race. Before and after the race, body mass and a sample of venous blood were obtained. During the race, sweat samples were collected using sweat patches, and fluid and electrolyte intake were obtained using self‐reported questionnaires. Thirty‐eight participants (74.5% of the total) were 7T/7T homozygotes, 11 (21.6%) were 7T/9T heterozygotes, and one participant presented the rare genotype 5T/7T. Another participant with 9T/9T presented the mutation p.L206W. Participants with 7T/7T showed higher sweat sodium concentrations (42.2 ± 21.6 mmol/L) than 7T/9T (29.0 ± 24.7 mmol/L; P = 0.04). The runner with the 5T/7T genotype (10.2 mmol/L) and the participant with the p.L206W mutation (20.5 mmol/L) exhibited low‐range sweat sodium concentrations. However, post‐race serum sodium concentration was similar in 7T/7T and 7T/9T (142.1 ± 1.3 and 142.4 ± 1.6 mmol/L, respectively; P = 0.27) and did not show abnormalities in participants with the 5T/7T genotype (140.0 mmol/L) and the p.L206W mutation (143.0 mmol/L). Runners with the CFTR‐7T/7T genotype exhibited increased sweat sodium concentrations during a marathon. However, this phenotype was not related with increased likelihood of suffering body water and electrolyte imbalances during real competitions.

Obesity Status and Physical Activity Level in Children and Adults with Autism Spectrum Disorders: A Pilot Study

The purpose of the present study was to compare body composition and physical activity level between children and adults with Autism Spectrum Disorders (ASD). A sample of 78 children, adolescents and adults participated in the study. Anthropometrics and physical activity, using GT1M accelerometer, were assessed. Overweight and obesity prevalence was higher in men vs. male children (p < 0.001) and in men vs. women (p = 0.035). Children recorded more moderate to vigorous physical activity (p = 0.040) than adults. Normal-weight children and adolescents combined as one age group, accomplished more moderate to vigorous physical activity, steps and less sedentary time compared to their overweight and obese counterparts during the weekend. Obesity status may negatively affect physical activity level in ASD individuals.