237 research outputs found
The Effect Of Warm-Up Modalities on Trampoline Flight Time Performance
Trampoline flight time is a recent addition to Olympic scoring and was sufficient in weight to displace a formed medal winner from a podium placement at the 2012 Olympics. The aim of our study was to examine different warm-up routines on trampoline flight time. We examined ten elite, female trampolinists (mean ± SD: age 19.2 ±5.4 y) who performed six different warm-up routines in a randomised, cross-over, counter-balanced manner: (a) static stretching (STAT, control), (b) STAT+10 trampoline bounces, (c) dynamic stretching (DYN), (d) DYN+10 trampoline bounces, (e) DYN+Drop jumps (DYN+DJ) and (f) DYN+isometric mid-thigh pulls (DYN+IP). Data were analysed using general linear models, Dunnett-HSU post-hoc tests vs. Control/STAT and magnitude based inferences vs. control. Our analysis demonstrated that total flight time following DYN 10 (17.29 ±0.52s, 83% likely beneficial, P < 0.002) was significantly longer versus STAT (16.59 ±0.49 s), with a trend toward significance for DYN (16.97 ±0.20 s; 22% likely beneficial, P = 0.077). The DYN-IP (14.04 ± 0.48 s) and DYN-DJ (14.15 ±0.66 s) produced the shortest vs. all warm-up forms (P < 0.005). To the contrary, the DYN+DJ and DYN+IP conditions were >99% likely to be detrimental to performance. Our results demonstrate a clear improvement in flight times when using a dynamic warm-up coupled with a trampoline specific bouncing task (DYN+10)
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The Effects of Energy Drink Consumption on Cognitive and Physical Performance in Elite League of Legends Players.
To examine the cognitive and physical changes associated with consuming an energy drink concurrent to video gaming, we examined a convenience sample of nine elite League of Legends (LoL) e-sport players (21 ± 2 y, BMI 25.6 ± 3.4 kg/m2) consuming an energy drink (ReloadTM) or placebo (Placebo) in a randomized, double-blind, placebo-controlled cross-over trial. Participants completed the same test battery prior to treatment consumption and after playing each of three competitive LoL games. Primary outcomes included measures of attention (Erikson Flanker Test), reaction time (Go/No-Go test) and working memory (n-back test). Secondary outcomes examined fatigue (hand grip strength and finger tap speed). Statistical analysis was performed by repeated-measures analysis of variance (RM-ANOVA) and reported as the mean (standard deviation [SD]) or mean change (95% confidence interval [CI]). Participants reported sleeping 8.1 (1.2) h/night, playing LoL 10.3 (2.1) h/d, playing other video games 1.8 (2.8) h/d, and exercising 4.2 (1.7) times per week. Overall, we observed no significant time, group, or group-by-time interactions for any measured performance index with the exception of a significant improvement for the n-back test, where the Reload group demonstrated a significant within-group improvement: Reload [-171 ms (95% CI, -327.91, -14.09), p < 0.004], Placebo [-92 ms (95% CI, -213.63, 29.63)]. However, no between-group differences were noted (38.50 ms, 95% CI, -141.89, 64.89, p = 0.803). Our findings suggest that elite eSport athletes do not demonstrate a mental or physical improvement in performance relative to the treatment supplement or indices measured in this study
Effect of carbohydrate mouth rinsing on multiple sprint performance
Background:
Research suggests that carbohydrate mouth rinsing (CMR) improves endurance performance; yet, little is known regarding the effect of CMR on multiple sprint efforts. As many sports involve multiple sprinting efforts, followed by periods of recovery, the aim of our current study was to investigate the influence of CMR on multiple sprint performance.
Methods:
We recruited eight active males (Age; 22 ± 1 y; 75.0 ± 8.8 kg; estimated VO2max 52.0 ± 3.0 ml/kg/min) to participate in a randomly assigned, double-blind, counterbalanced study administering a CMR (6.4% Maltodextrin) or similarly flavoured placebo solution. Primary outcomes for our study included: (a) time for three repeated sprint ability tests (RSA) and (b) the Loughborough Intermittent Shuttle Test (LIST). Time was expressed in seconds (sec). Secondary outcomes included ratings of perceived exertion (RPE) and blood glucose concentration. Tertiary outcomes included two psychological assessments designed to determine perceived activation (i.e., arousal) and pleasure-displeasure after each section of the LIST. We analysed our data using a two-way analysis of variance (ANOVA) for repeated measures, a Bonferroni adjusted post hoc t-test to determine significant differences in treatment, and a liberal 90% confidence interval between treatment conditions. Effect sizes were calculated between trials and interpreted as ≤ 0.2 trivial, > 0.2 small, > 0.6 moderate, > 1.2 large, > 2 very large and > 4 extremely large. Data are means ± SD. Overall statistical significance was set as P < 0.05; yet, modified accordingly when Bonferroni adjustments were made.
Results:
Overall, we observed no significant difference in average (3.46 ± 0.2 vs. 3.44 ± 0.17; P = 0.11) or fastest time (3.38 ± 0.2 vs. 3.37 ± 0.2; P = 0.39) in the RSA test for the placebo vs. CMR conditions, respectively. Similar findings were also noted for the placebo vs. CMR, respectively, during the LIST test (3.52 ± 0.2 vs. 3.54 ± 0.2 sec; P = 0.63). Despite a significantly higher within group RPE during the 3rd and 4th sections of the LIST (< 0.05), no between group differences were otherwise noted. No differences were noted for blood glucose concentrations throughout the testing protocol. Lastly, from a psychological perspective, we observed no differences in pleasure-displeasure or perceived activation.
Conclusions:
The results of our current study suggest that CMR does not improve exercise performance, RPE or perceived pleasure-displeasure during high intensity activity requiring repeated, intermittent, sprint efforts
Sex Differences in Step Count-Blood Pressure Association: A Preliminary Study in Type 2 Diabetes
BACKGROUND: Walking and cardiovascular mortality are inversely associated in type 2 diabetes, but few studies have objectively measured associations of walking with individual cardiovascular risk factors. Such information would be useful for "dosing" daily steps in clinical practice. This study aimed to quantify decrements in blood pressure and glycated hemoglobin (A1C) per 1,000 daily step increments. METHODOLOGY/PRINCIPAL FINDINGS: Two hundred and one subjects with type 2 diabetes underwent assessments of step counts (pedometer-measured), blood pressure, A1C and anthropometric parameters. Due to missing data, the final analysis was conducted on 83 women and 102 men, with a mean age of 60 years. Associations of daily steps with blood pressure and A1C were evaluated using sex-specific multivariate linear regression models (adjusted for age, ethnicity, and BMI). Potential sex differences were confirmed in a combined model (women and men) with interaction terms. Mean values for daily steps, blood pressure, A1C and BMI were 5,357 steps/day; 137/80 mm Hg; 7.7% and 30.4 kg/m(2) respectively. A 1,000 daily step increment among women was associated with a -2.6 (95% CI: -4.1 to -1.1) mm Hg change in systolic and a -1.4 (95% CI: -2.2 to -0.6) mm Hg change in diastolic blood pressure. Among men, corresponding changes were -0.7 (95% CI: -2.1 to 0.7) and -0.6 (95% CI: -1.4 to 0.3) mm Hg, respectively. Sex differences were confirmed in combined models. Step counts and A1C did not demonstrate clinically important associations. CONCLUSIONS/SIGNIFICANCE: A 1,000 steps/day increment is associated with important blood pressure decrements among women with type 2 diabetes but the data were inconclusive among men. Targeted "dose increments" of 1,000 steps/day in women may lead to measurable blood pressure reductions. This information may be of potential use in the titration or "dosing" of daily steps. No associations were found between step count increments and A1C
Carbohydrates alone or mixing with beef or whey protein promote similar training outcomes in resistance training males: A double blind, randomized controlled clinical trial
Beef powder is a new high-quality protein source scarcely researched relative to exercise performance. The present study examined the impact of ingesting hydrolyzed beef protein, whey protein, and carbohydrate on strength performance (1RM), body composition (via plethysmography), limb circumferences and muscular thickness (via ultrasonography), following an 8-week resistance-training program. After being randomly assigned to one of the following groups: Beef, Whey, or Carbohydrate, twenty four recreationally physically active males (n = 8 per treatment) ingested 20 g of supplement, mixed with orange juice, once a day (immediately after workout or before breakfast). Post intervention changes were examined as percent change and 95% CIs. Beef (2.0%, CI, 0.2–2.38%) and Whey (1.4%, CI, 0.2–2.6%) but not Carbohydrate (0.0%, CI, -1.2–1.2%) increased fat-free mass. All groups increased vastus medialis thickness: Beef (11.1%, CI, 6.3–15.9%), Whey (12.1%, CI, 4.0, -20.2%), Carbohydrate (6.3%, CI, 1.9–10.6%). Beef (11.2%, CI, 5.9–16.5%) and Carbohydrate (4.5%, CI, 1.6–7.4%), but not Whey (1.1%, CI, -1.7–4.0%), increased biceps brachialis thickness, while only Beef increased arm (4.8%, CI, 2.3–7.3%) and thigh (11.2%, 95%CI 0.4–5.9%) circumferences. Although the three groups significantly improved 1RM Squat (Beef 21.6%, CI 5.5–37.7%; Whey 14.6%, CI, 5.9–23.3%; Carbohydrate 19.6%, CI, 2.2–37.1%), for the 1RM bench press the improvements were significant for Beef (15.8% CI 7.0–24.7%) and Whey (5.8%, CI, 1.7–9.8%) but not for carbohydrate (11.4%, CI, -0.9-23.6%). Protein-carbohydrate supplementation supports fat-free mass accretion and lower body hypertrophy. Hydrolyzed beef promotes upper body hypertrophy along with similar performance outcomes as observed when supplementing with whey isolate or maltodextrin
A multi-ingredient containing carbohydrate, proteins L-glutamine and L-carnitine attenuates fatigue perception with no effect on performance, muscle damage or immunity in soccer players
We investigated the effects of ingesting a multi-ingredient (53g carbohydrate, 14.5g whey protein, 5g glutamine, 1.5g L-carnitine-L-tartrate) supplement, carbohydrate only, or placebo on intermittent performance, perception of fatigue, immunity, and functional and metabolic markers of recovery. Sixteen amateur soccer players ingested their respective treatments before, during and after performing a 90-min intermittent repeated sprint test. Primary outcomes included time for a 90-min intermittent repeated sprint test (IRS) followed by eleven 15 m sprints. Measurements included creatine kinase, myoglobin, interleukine-6, Neutrophil; Lymphocytes and Monocyte before (pre), immediately after (post), 1h and 24h after exercise testing period. Overall, time for the IRS and 15 m sprints was not different between treatments. However, the perception of fatigue was attenuated (P<0.001) for the multi-ingredient (15.9±1.4) vs. placebo (17.8±1.4) but not for the carbohydrate (17.0±1.9) condition. Several changes in immune/inflammatory indices were noted as creatine kinase peaked at 24h while Interleukin-6 and myoglobin increased both immediately after and at 1h compared with baseline (P<0.05) for all three conditions. However, Myoglobin (P<0.05) was lower 1h post-exercise for the multi-ingredient (241.8±142.6 ng·ml-1) and CHO (265.4±187.8 ng·ml-1) vs. placebo (518.6±255.2 ng·ml-1). Carbohydrate also elicited lower neutrophil concentrations vs. multi-ingredient (3.9±1.5 109/L vs. 4.9±1.8 109/L, P = 0.016) and a reduced (P<0.05) monocytes count (0.36±0.09 109/L) compared to both multi-ingredient (0.42±0.09 109/L) and placebo (0.42±0.12 109/L). In conclusion, multi-ingredient and carbohydrate supplements did not improve intermittent performance, inflammatory or immune function. However, both treatments did attenuate serum myoglobin, while only carbohydrate blunted post-exercise leukocytosis
Ejercicio dosis-respuesta de la pendiente V? E / V?CO 2 en mujeres posmenopáusicas en el estudio DREW
Purpose: Being overweight/obese, having hypertension, and being postmenopausal are risk factors for the development of congestive heart failure (CHF). A characteristic of CHF is an abnormal V?E/V?CO2 slope, which is predictive of mortality in patients with CHF. Although the V?E/V?CO2 slope is well established in CHF patients, little is known regarding interventions for 'at-risk' populations. Methods: We examined the V?E/V?CO2 slope in 401 sedentary, overweight, moderately hypertensive women randomized to 6 m of nonexercise (control) or 4 kcal·kg?1·wk?1 (KKW), 8 KKW, or 12 KKW of exercise at an intensity corresponding to 50% of baseline V?O2max. We examined trends in exercise treatment dose versus change in mean V?E/V?CO2 slope using a linear regression model (KKW vs V?E/V?CO2 slope) and a linear mixed model. Results: Regression analysis showed a significant trend for a reduction in the V?E/V?CO2 slope from baseline (mean ± SD: 32.6 ± 6.3; P < 0.004). When expressed as mean change (95% confidence interval (CI)) from baseline, we observed significant reductions in the V?E/V?CO2 slope for the 8-KKW (?1.14; 95% CI, ?1.5 to ?0.2) and 12-KKW (?1.67; 95% CI, ?2.3 to ?0.3) groups. No significant effect was noted for the 4-KKW (?0.4; 95% CI, ?1.2 to 0.15) group. Conclusion: Moderate-intensity aerobic exercise at doses of 8 KKW or greater seems to present an adequate dose of exercise to promote small but significant reductions in the V?E/V?CO2 slope in postmenopausal women who exhibit risk factors associated with the development of CHF
Effect of Deer Antler Velvet on Aerobic, Anaerobic and Strength Performance
Deer antler velvet (DAV) supplementation purportedly increases athletic performance; however, little data support this claim. The primary aim of our study is to examine DAV and exercise performance. We randomized 32 men (18–35 y) participating exclusively in resistance training (>4 y) to 10-weeks of randomly assigned, double blind, DAV (1350 mg, 2×/day) or placebo treatments. Primary outcomes included maximal aerobic capacity (VO2max), maximal strength (1RM; bench press and squat) and anaerobic cycling power. Secondary outcomes included comprehensive blood profiles and body composition. We used general linear models to determine changes following treatment. Eighteen participants (n = 9) completed the study with DAV participants showing significant improvements in VO2max (4.30 ±0.45 to 4.72 ±0.60 L/min, P < 0.04). The placebo and DAV groups increased bench press and squat 1RM (both, P < 0.04); yet, when expressed relative to body mass, only the DAV group showed significant bench press (4%) and squat (10%; both, P < 0.02). Neither group improved cycling performance or showed adverse changes in blood chemistries. We did observe a significant reduction in LDL-C (12%) accompanying DAV supplementation and both groups significantly reduced percent body fat (P < 0.05). Our results suggest that DAV may have ergogenic effects in men participating solely in resistance training
Heart Rate Variability and Exercise in Aging Women
Background: Our group has shown a positive dose-response in maximal cardiorespiratory exercise capacity (VO2max) and heart rate variability (HRV) to 6 months of exercise training but no improvement in VO2max for women ≥60 years. Here, we examine the HRV response to exercise training in postmenopausal women younger and older than 60 years.
Methods: We examined 365 sedentary, overweight, hypertensive, postmenopausal women randomly assigned to sedentary control or exercise groups exercising at 50% (4 kcal/kg/week, [KKW]), 100% (8 KKW) and 150% (12 KKW) of the National Institute of Health (NIH) Consensus Development Panel physical activity guidelines. Primary outcomes included time and frequency domain indices of HRV.
Results: Overall, our analysis demonstrated a significant improvement in parasympathetic tone (rMSSD and high frequency power) for both age strata at 8 KKW and 12 KKW. For rMSSD, the age-stratified responses were: control, \u3c60 years, 0.20 ms, 95% confidence interval (CI) - 2.40, 2.81; ≥60 years, 0.07 ms, 95% CI - 3.64, 3.79; 4 KKW, \u3c60 years, 3.67 ms, 95% CI 1.55, 5.79; ≥60 years, 1.20 ms, 95% CI - 1.82, 4.22; 8-KKW, \u3c60 years, 3.61 ms, 95% CI 0.88, 6.34; ≥60 years, 5.75 ms, 95% CI 1.89, 9.61; and 12-KKW, \u3c60 years, 5.07 ms, 95% CI 2.53, 7.60; ≥60 years, 4.28 ms, 95% CI 0.42, 8.14.
Conclusions: VO2max and HRV are independent risk factors for cardiovascular disease (CVD) mortality. Despite no improvement in VO2max, parasympathetic indices of HRV increased in women ≥60 years. This is clinically important, as HRV has important VCD risk and neurovisceral implications beyond cardiorespiratory function
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