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Caffeine mouth rinse has no effects on anaerobic energy yield during a Wingate Test.
Marinho, AH, Mendes, EV, Vilela, RA, Bastos-Silva, VJ, Araujo, GG, Balikian, P
The Journal of sports medicine and physical fitness. 2020;(1):69-74
Abstract
BACKGROUND The purpose was to investigate the effect of caffeine (CAF) mouth rinse on peak power (PP), mean power (MP), peak power relative to body mass (rel PP), mean power relative to body mass (rel MP), fatigue index (FI) and anaerobic contribution in the Wingate Test. METHODS Ten healthy men (age: 24.8±3.7 years; body mass: 71.0±7.8 kg; height: 170±3 cm; body fat: 17.02±4.9%; VO2max: 44.15±5.5 ml·kg-1·min=) were recruited. A randomized, double-blind, cross-over design was employed. Participants were instructed to complete Wingate Test in the fastest time possible under 2 conditions: CAF (25 ml of mint syrup with 1.2% of CAF, equivalent to 300 mg of CAF) and placebo (PLA) (25 ml of mint syrup without CAF). RESULTS There was no difference at PP (P=0.66), MP (P=0.16), rel PP (P=0.82), rel MP (P=0.18), FI (P=0.19), anaerobic alactic (P=0.71), anaerobic lactic (P=0.25), total energy expenditure (P=0.41) and peak plasma lactate concentration (P=0.57). CONCLUSIONS CAF mouth rinse did not increase peak power (PP), mean power (MP), peak power relative to body mass (rel PP), mean power relative to body mass (rel MP), Fatigue Index (FI) nor anaerobic contribution in the Wingate Test.
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Peak oxygen uptake measured during a perceptually-regulated exercise test is reliable in community-based manual wheelchair users.
Hutchinson, MJ, MacDonald, MJ, Eston, R, Goosey-Tolfrey, VL
Journal of sports sciences. 2019;(6):701-707
Abstract
This study compares test-retest reliability and peak exercise responses from ramp-incremented (RAMP) and maximal perceptually-regulated (PRETmax) exercise tests during arm crank exercise in individuals reliant on manual wheelchair propulsion (MWP). Ten untrained participants completed four trials over 2-weeks (two RAMP (0-40 W + 5-10 W · min-1) trials and two PRETmax. PRETmax consisted of five, 2-min stages performed at Ratings of Perceived Exertion (RPE) 11, 13, 15, 17 and 20). Participants freely changed the power output to match the required RPE. Gas exchange variables, heart rate, power output, RPE and affect were determined throughout trials. The V̇O2peak from RAMP (14.8 ± 5.5 ml · kg-1 · min-1) and PRETmax (13.9 ± 5.2 ml · kg-1 · min-1) trials were not different (P = 0.08). Measurement error was 1.7 and 2.2 ml · kg-1 · min-1 and coefficient of variation 5.9% and 8.1% for measuring V̇O2peak from RAMP and PRETmax, respectively. Affect was more positive at RPE 13 (P = 0.02), 15 (P = 0.01) and 17 (P = 0.01) during PRETmax. Findings suggest that PRETmax can be used to measure V̇O2peak in participants reliant on MWP and leads to a more positive affective response compared to RAMP.
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Effects of caffeine ingestion on the diurnal variation of cognitive and repeated high-intensity performances.
Souissi, Y, Souissi, M, Chtourou, H
Pharmacology, biochemistry, and behavior. 2019;:69-74
Abstract
The purpose of this study was to evaluate the effects of caffeine ingestion on the daily variation of cognitive (i.e., reaction time (RT), attention) and repeated high-intensity exercise performances. Fifteen active males (age: 20 ± 1 years, height: 174.3 ± 4.3 cm, body-mass: 70.8 ± 3.5 kg) performed cognitive and physical tasks under two different circumstances [after a placebo or caffeine ingestion (6 mg/kg of body-mass)] at six different time-of-day (07 h00, 09 h00, 11 h00, 13 h00, 15 h00 and 17 h00) in a randomized double-blind balanced crossover design. During each session, RT, attention and 5-m multiple shuttles run test' performances were recorded. During both the placebo and the caffeine conditions, a significant diurnal variation was found with improvement of cognitive performances recorded at 11 h00 (e.g., RT: 0.37 ± 0.02-s and 0.36 ± 0.02-s for placebo and caffeine respectively) and 17 h00 (e.g., RT: 0.37 ± 0.02-s and 0.35 ± 0.03-s for placebo and caffeine respectively) compared to (i.e., worst performances) 07 h00 (e.g., RT: 0.41 ± 0.02-s and 0.38 ± 0.02-s for placebo and caffeine respectively) and 13 h00 (e.g., RT: 0.41 ± 0.02-s and 0.38 ± 0.02-s for placebo and caffeine respectively) (p < 0.05). For physical performance, improved values were recorded at 17 h00 (e.g., total distance: 730.00 ± 43.92-m and 733.93 ± 43.08-m for placebo and caffeine respectively) compared to 07 h00 (e.g., total distance: 698.14 ± 45.39-m and 709.21 ± 43.78-m for placebo and caffeine respectively) (p < 0.05). Compared to placebo, cognitive (e.g., RT: by 6.4% at 07 h00, 4.1% at 09 h00, 3.4% at 11 h00, 6.0% at 13 h00, 3.8% at 15 h00 and 3.8% at 17 h00) and physical (e.g., total distance: 1.6% at 07 h00, 0.9% at 09 h00, 0.1% at 11 h00 (p > 0.05), 0.5% at 13 h00, 1.0% at 15 h00 and 0.5% at 17 h00) performances increased at all time-of-day (p < 0.05). In conclusion, cognitive and physical performances are time-of-day dependent and caffeine is an effective ergogenic aid to improves both cognitive and physical performances especially at the moment of their lowest values.
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Creatine supplementation improves performance above critical power but does not influence the magnitude of neuromuscular fatigue at task failure.
Schäfer, LU, Hayes, M, Dekerle, J
Experimental physiology. 2019;(12):1881-1891
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NEW FINDINGS What is the central question of this study? Does the magnitude of neuromuscular fatigue depend on the amount of work done (W') at task failure when cycling above critical power (CP)? What is the main finding and its importance? Creatine supplementation increases W' and enhances supra-CP performance, but induces similar magnitudes of neuromuscular fatigue at task failure compared to placebo. Increased W' does not lead to higher levels of neuromuscular fatigue. This supports the notion of a critical level of neuromuscular fatigue at task failure and challenges a direct causative link between W' depletion and neuromuscular fatigue. ABSTRACT The present study examined the effect of creatine supplementation on neuromuscular fatigue and exercise tolerance when cycling above critical power (CP). Eleven males performed an incremental cycling test with four to five constant-load trials to task failure (TTF) to obtain asymptote (CP) and curvature constant (W') of the power-duration relationship, followed by three constant-load supra-CP trials: (1) one TTF following placebo supplementation (PLA); (2) one TTF following creatine supplementation (CRE); and (3) one trial of equal duration to PLA following creatine supplementation (ISO). Neuromuscular assessment of the right knee extensors was performed pre- and post-exercise to measure maximal voluntary contraction (MVC), twitch forces evoked by single (Qpot ) and paired high- (PS100) and low- (PS10) frequency stimulations and voluntary activation. Creatine supplementation increased TTF in CRE vs. PLA by ∼11% (P = 0.017) and work done above CP by ∼10% (P = 0.015), with no difference (P > 0.05) in reductions in MVC (-24 ± 8% vs. -20 ± 9%), Qpot (-39 ± 13% vs. -32 ± 14%), PS10 (-42 ± 14% vs. -36 ± 13%), PS100 (-25 ± 10% vs. -18 ± 12%) and voluntary activation (-7 ± 8% vs. -5 ± 7%). No significant difference was found between ISO and either PLA or CRE (P > 0.05). These findings suggest similar levels of neuromuscular fatigue can be found following supra-CP cycling despite increases in performance time and amount of work done above CP, supporting the notion of a critical level of neuromuscular fatigue and challenging a direct causative link between W' depletion and neuromuscular fatigue.
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Protein supplementation enhances cerebral oxygenation during exercise in elite basketball players.
Ho, CF, Jiao, Y, Wei, B, Yang, Z, Wang, HY, Wu, YY, Yang, C, Tseng, KW, Huang, CY, Chen, CY, et al
Nutrition (Burbank, Los Angeles County, Calif.). 2018;:34-37
Abstract
OBJECTIVE The aim of the present study was to examine cerebral oxygenation during high-intensity exercise in elite basketball players who consumed supplements with different whey protein contents after a short postexercise recovery to determine whether changing whey protein content in carbohydrate-based supplementation influences cerebral hemodynamic response when the supplement was consumed during a 2-h recovery after a 1-h exercise challenge. METHODS This was a randomized, counterbalanced crossover study. Fifteen Division 1 collegiate basketball players (18-20 y) consumed 6.25 kcal/kg of either high-protein (36% protein in total calorie) or an isocaloric low-protein (12% protein in total calorie) control supplement in a carbohydrate-based drink immediately after a 1-h cycling (70% of maximal oxygen consumption [VO2max]). After a 2-h rest, the athletes were challenged on a cycloergometer at 80% VO2max. Blood perfusion (total hemoglobin) and oxygen saturation of frontal brain were continuously measured by near-infrared spectroscopy during the cycling. RESULTS Before the cycloergometer test, high-protein supplementation increased peak insulin response and lowered glucose increases during the recovery compared with the low-protein trial. High-protein supplementation enhanced increases in cerebral oxygen saturation (P < 0.01) and attenuated increases in cerebral blood perfusion (total hemoglobin; P < 0.01) during the cycloergometer exercise; and resulted in a 16% longer cycling time (from 474 ± 49 s to 553 ± 78 s, P < 0.05), compared with the low-protein trial. CONCLUSION Enhanced fatigue recovery after consumption of a high-protein supplement is associated with enhanced cerebral oxygenation against exercise challenge, which spares brain blood demand for periphery.
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The effects of upper and lower limb exercise on the microvascular reactivity in limited cutaneous systemic sclerosis patients.
Mitropoulos, A, Gumber, A, Crank, H, Akil, M, Klonizakis, M
Arthritis research & therapy. 2018;(1):112
Abstract
BACKGROUND Aerobic exercise in general and high-intensity interval training (HIIT) specifically is known to improve vascular function in a range of clinical conditions. HIIT in particular has demonstrated improvements in clinical outcomes, in conditions that have a strong macroangiopathic component. Nevertheless, the effect of HIIT on microcirculation in systemic sclerosis (SSc) patients is yet to be investigated. Therefore, the purpose of the study was to compare the effects of two HIIT protocols (cycle and arm cranking) on the microcirculation of the digital area in SSc patients. METHODS Thirty-four limited cutaneous SSc patients (65.3 ± 11.6 years old) were randomly allocated in three groups (cycling, arm cranking and control group). The exercise groups underwent a 12- week exercise program twice per week. All patients performed the baseline and post-exercise intervention measurements where physical fitness, functional ability, transcutaneous oxygen tension (ΔTcpO2), body composition and quality of life were assessed. Endothelial-dependent as well as -independent vasodilation were assessed in the middle and index fingers using LDF and incremental doses of acetylcholine (ACh) and sodium nitroprusside (SNP). Cutaneous flux data were expressed as cutaneous vascular conductance (CVC). RESULTS Peak oxygen uptake increased in both exercise groups (p < 0.01, d = 1.36). ΔTcpO2 demonstrated an increase in the arm-cranking group only, with a large effect, but not found statistically significant,(p = 0.59, d = 0.93). Endothelial-dependent vasodilation improvement was greater in the arm-cranking (p < 0.05, d = 1.07) in comparison to other groups. Both exercise groups improved life satisfaction (p < 0.001) as well as reduced discomfort and pain due to Raynaud's phenomenon (p < 0.05). Arm cranking seems to be the preferred mode of exercise for study participants as compared to cycling (p < 0.05). No changes were observed in the body composition or the functional ability in both exercise groups. CONCLUSIONS Our results suggest that arm cranking has the potential to improve the microvascular endothelial function in SSc patients. Also notably, our recommended training dose (e.g., a 12-week HIIT program, twice per week), appeared to be sufficient and tolerable for this population. Future research should focus on exploring the feasibility of a combined exercise such as aerobic and resistance training by assessing individual's experience and the quality of life in SSc patients. TRIAL REGISTRATION ClinicalTrials.gov (NCT number): NCT03058887 , February 23, 2017.
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Effects of time-of-day on oxidative stress, cardiovascular parameters, biochemical markers, and hormonal response following level-1 Yo-Yo intermittent recovery test.
Aloui, K, Abedelmalek, S, Chtourou, H, Wong, DP, Boussetta, N, Souissi, N
Physiology international. 2017;(1):77-90
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The aim of this study was to investigate the effect of time-of-day on oxidative stress, cardiovascular parameters, muscle damage parameters, and hormonal responses following the level-1 Yo-Yo intermittent recovery test (YYIRT). A total of 11 healthy subjects performed an intermittent test (YYIRT) at two times-of-day (i.e., 07:00 h and 17:00 h), with a recovery period of ≥36 h in-between, in a randomized order. Blood samples were taken at the rest (baseline) and immediately (post-YYIRT) after the YYIRT for measuring oxidative stress, biochemical markers, and hormonal response. Data were statistically analyzed using one-way and two-way repeated measures ANOVA and Bonferroni test at p < 0.05. Observed power (α = 0.05) and partial eta-squared were used. Our results showed that oxygen uptake (VO2max), maximal aerobic speed, and the total distance covered tended to be higher in the evening (17:00 h). There was also a main effect of time-of-day for cortisol and testosterone concentration, which were higher after the YYIRT in the morning (p < 0.05). The heart rate peak and the rating of perceived exertion scales were lower in the morning (p < 0.05). However, the plasma glucose (p < 0.01), malondialdehyde, creatine kinase (p < 0.01), lactate dehydrogenase (p < 0.05), high-density lipoprotein (p < 0.01), total cholesterol (p < 0.01), and triglycerides (p < 0.05) were higher after the YYIRT in the evening. Low-density lipoprotein, systolic blood pressure, diastolic blood pressure, and lactate levels (p > 0.05) were similar for the morning and evening test. In conclusion, our findings suggest that aerobic performance presents diurnal variation with great result observed in the evening accompanied by an improvement of hormonal, metabolic, and oxidative responses. These data may help to guide athletes and coaches and contribute to public health recommendations on exercise and muscle damage particularly in the competitive periods.
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The effects of dietary nitrate supplementation on the adaptations to sprint interval training in previously untrained males.
Muggeridge, DJ, Sculthorpe, N, James, PE, Easton, C
Journal of science and medicine in sport. 2017;(1):92-97
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OBJECTIVES Dietary nitrate can improve repeated high-intensity and supramaximal exercise performance, although the effect on adaptations to training has received limited attention. The purpose of this study was to investigate the effects of dietary nitrate on the response to 3-weeks of sprint interval training (SIT). DESIGN Randomized control trial. METHODS Twenty-seven untrained males (Age: 28±7 y, V⋅O2Max: 42±7mlkg-1min-1) completed an incremental exercise test at the beginning and end of the study. Participants were matched for V⋅O2Max and randomly assigned to a control group (CON; n=8), SIT+placebo group (PLA; n=10), or SIT+nitrate group (NIT; n=9). The SIT comprised 4-6 repeated 15 s all out sprints on a cycle ergometer, interspersed with 4min active recovery, 3-times per week. Approximately 2.5h prior to exercise, participants consumed gels containing ∼0.1mmol (PLA) or ∼8mmol nitrate (NIT). RESULTS Following SIT, V⋅O2Max (PLA: 5%, p=0.057, d=0.34; NIT: 6.3%, p=0.041, d=0.34) and ventilatory threshold (VT) increased to a similar extent in both SIT groups. Maximum work rate tended to increase to a greater extent in NIT (8.7%, d=0.55) compared to PLA (4.7%, d=0.31, p=0.073). Fatigue index, calculated by the change in mean power from the first to the last sprint, tended to be reduced following SIT in NIT compared to PLA (PLA: 7.3±7.4%, NIT: 0.5±7.1%, p=0.058). CONCLUSIONS While dietary nitrate supplementation does not augment improvements to V⋅O2Max and VT following SIT, it may improve WRmax and indices of repeated high-intensity exercise.
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Acute effects of exercise on appetite, ad libitum energy intake and appetite-regulatory hormones in lean and overweight/obese men and women.
Douglas, JA, King, JA, Clayton, DJ, Jackson, AP, Sargeant, JA, Thackray, AE, Davies, MJ, Stensel, DJ
International journal of obesity (2005). 2017;(12):1737-1744
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BACKGROUND Acute exercise does not elicit compensatory changes in appetite parameters in lean individuals; however, less is known about responses in overweight individuals. This study compared the acute effects of moderate-intensity exercise on appetite, energy intake and appetite-regulatory hormones in lean and overweight/obese individuals. METHODS Forty-seven healthy lean (n=22, 11 females; mean (s.d.) 37.5 (15.2) years; 22.4 (1.5) kg m-2) and overweight/obese (n=25, 11 females; 45.0 (12.4) years, 29.2 (2.9) kg m-2) individuals completed two, 8 h trials (exercise and control). In the exercise trial, participants completed 60 min treadmill exercise (59 (4)% peak oxygen uptake) at 0-1 h and rested thereafter while participants rested throughout the control trial. Appetite ratings and concentrations of acylated ghrelin, peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) were measured at predetermined intervals. Standardised meals were consumed at 1.5 and 4 h and an ad libitum buffet meal was provided at 7 h. RESULTS Exercise suppressed appetite (95% confidence interval (CI) -3.1 to -0.5 mm, P=0.01), and elevated delta PYY (95% CI 10 to 17 pg ml-1, P<0.001) and GLP-1 (95% CI 7 to 10 pmol l-1, P<0.001) concentrations. Delta acylated ghrelin concentrations (95% CI -5 to 3 pg ml-1, P=0.76) and ad libitum energy intake (95% CI -391 to 346 kJ, P=0.90) were similar between trials. Subjective and hormonal appetite parameters and ad libitum energy intake were similar between lean and overweight/obese individuals (P⩾0.27). The exercise-induced elevation in delta GLP-1 was greater in overweight/obese individuals (trial-by-group interaction P=0.01), whereas lean individuals exhibited a greater exercise-induced increase in delta PYY (trial-by-group interaction P<0.001). CONCLUSIONS Acute moderate-intensity exercise transiently suppressed appetite and increased PYY and GLP-1 in the hours after exercise without stimulating compensatory changes in appetite in lean or overweight/obese individuals. These findings underscore the ability of exercise to induce a short-term energy deficit without any compensatory effects on appetite regardless of weight status.
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Addition of vitamin B12 to exercise training improves cycle ergometer endurance in advanced COPD patients: A randomized and controlled study.
Paulin, FV, Zagatto, AM, Chiappa, GR, Müller, PT
Respiratory medicine. 2017;:23-29
Abstract
Vitamin B12 is essential in the homocysteine, mitochondrial, muscle and hematopoietic metabolisms, and its effects on exercise tolerance and kinetics adjustments of oxygen consumption (V'O2p) in rest-to-exercise transition in COPD patients are unknown. This randomized, double-blind, controlled study aimed to verify a possible interaction between vitamin B12 supplementation and these outcomes. After recruiting 69 patients, 35 subjects with moderate-to-severe COPD were eligible and 32 patients concluded the study, divided into four groups (n = 8 for each group): 1. rehabilitation group; 2. rehabilitation plus B12 group; 3. B12 group; and 4. placebo group. The primary endpoint was cycle ergometry endurance before and after 8 weeks and the secondary endpoints were oxygen uptake kinetics parameters (time constant). The prevalence of vitamin B12 deficiency was high (34.4%) and there was a statistically significant interaction (p < 0.05), favoring a global effect of supplementation on exercise tolerance in the supplemented groups compared to the non-supplemented groups, even after adjusting for confounding variables (p < 0.05). The same was not found for the kinetics adjustment variables (τV'O2p and MRTV'O2p, p > 0.05 for both). Supplementation with vitamin B12 appears to lead to discrete positive effects on exercise tolerance in groups of subjects with more advanced COPD and further studies are needed to establish indications for long-term supplementation.