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1.
Flattened cola improves high-intensity interval performance in competitive cyclists.
Fowles, JR, O'Brien, MW, Comeau, KG, Thurston, B, Petrie, HJ
European journal of applied physiology. 2021;(10):2859-2867
Abstract
PURPOSE Some cyclists consume flattened cola during competitive events, but limited research has investigated if cola beverages elicit ergogenic effects, particularly on high-intensity exercise performance. Whether the potentially beneficial effects of cola are due to the caffeine and/or the carbohydrate content is also unclear. This study assessed the ergogenic effects of different cola beverages on performance during a constant power bout (CPB) and subsequent high-intensity interval efforts in competitive cyclists. METHODS In a randomized, double-blind, cross-over design, competitive cyclists (n = 13; [Formula: see text]O2max 65.7 ± 5.9 ml kg-1 min-1) completed a 45-min CPB at 69% of maximum workload (Wmax), followed by four maximal 1-min high-intensity intervals (HII) against a resistance of 0.5 N kg-1. Participants consumed 16 ml kg-1 total (intermittantly at four time points) of flattened decaffinated diet cola (PLA), caffeinated diet cola (CAF) or cola containing caffeine and carbohydrates (CAF + CHO). RESULTS During the CPB, ratings of perceived exertion were lower in the CAF + CHO and CAF conditions compared to PLA (both, P < 0.04). Compared to PLA, CAF + CHO and CAF similarly increased (all, P < 0.049) mean power (CAF + CHO: 448 ± 51 W; CAF: 448 ± 50 W; PLA: 434 ± 57 W), minimum power (CAF + CHO: 353 ± 45 W; CAF: 352 ± 51 W; PLA: 324 ± 49 W) and total work (CAF + CHO: 26.9 ± 3.1 kJ; CAF: 26.9 ± 3.0 kJ; PLA: 26.0 ± 3.4 kJ), but not peak power (CAF + CHO: 692 ± 117 W; CAF: 674 ± 114 W; PLA: 670 ± 113 W; all, P > 0.57) during the HII. CONCLUSION Cola containing caffeine with or without carbohydrates favorably influenced perceived effort during the CPB and enhanced mean and minimum power during repeated maximal intervals. We provide evidence supporting the consumption of commercially available cola for high-intensity cycling in competitive cyclists.
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2.
Enhanced Cycling Time-Trial Performance During Multiday Exercise With Higher-Pressure Compression Garment Wear.
Williams, ER, McKendry, J, Morgan, PT, Breen, L
International journal of sports physiology and performance. 2021;(2):287-295
Abstract
PURPOSE Compression garments are widely used as a tool to accelerate recovery from intense exercise and have also gained traction as a performance aid, particularly during periods of limited recovery. This study tested the hypothesis that increased pressure levels applied via high-pressure compression garments would enhance "multiday" exercise performance. METHODS A single-blind crossover design, incorporating 3 experimental conditions-loose-fitting gym attire (CON), low-compression (LC), and high-compression (HC) garments-was adopted. A total of 10 trained male cyclists reported to the laboratory on 6 occasions, collated into 3 blocks of 2 consecutive visits. Each "block" consisted of 3 parts, an initial high-intensity protocol, a 24-hour period of controlled rest while wearing the applied condition/garment (CON, LC, and HC), and a subsequent 8-km cycling time trial, while wearing the respective garment. Subjective discomfort questionnaires and blood pressure were assessed prior to each exercise bout. Power output, oxygen consumption, and heart rate were continuously measured throughout exercise, with plasma lactate, creatine kinase, and myoglobin concentrations assessed at baseline and the end of exercise, as well as 30 and 60 minutes postexercise. RESULTS Time-trial performance was significantly improved during HC compared with both CON and LC (HC = 277 [83], CON = 266 [89], and LC = 265 [77] W; P < .05). In addition, plasma lactate was significantly lower at 30 and 60 minutes postexercise on day 1 in HC compared with CON. No significant differences were observed for oxygen consumption, heart rate, creatine kinase, or subjective markers of discomfort. CONCLUSION The pressure levels exerted via lower-limb compression garments influence their effectiveness for cycling performance, particularly in the face of limited recovery.
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3.
Comparison of two different cooling systems in alleviating thermal and physiological strain during prolonged exercise in the heat.
Keller, S, Kohne, S, Bloch, W, Schumann, M
Ergonomics. 2021;(1):129-138
Abstract
This study compared the efficacy of an ice vest comprising of water (WATER) or a water-carbon (CARBON) emulsion on thermophysiological responses to strenuous exercise in the heat. Twelve male cyclists completed three 50-minute constant workload trials (55% of peak power output, ambient temperature 30.4 ± 0.6°C) with WATER, CARBON, and without ice vest (CONTROL), respectively. The increase in core body temperature (Tcore) was lower in WATER at 40 (-0.49 ± 0.34 °C) and 50 minutes (-0.48 ± 0.48 °C) and in CARBON at 30 (-0.41 ± 0.48 °C), 40 (-0.54 ± 0.51 °C), and 50 minutes (-0.67 ± 0.62 °C) as compared to CONTROL (p < 0.05, ES > 0.8). While heart rate and blood lactate kinetics did not differ between the conditions, statistical main effects in favour of both WATER and CARBON were found for thermal sensation (condition p < 0.001 and interaction p < 0.01) and rating of perceived exertion (condition p < 0.05). Per-cooling with CARBON and WATER similarly reduced Tcore but not physiological strain during prolonged exercise in the heat. Practitioner Summary: Exercise in the heat is characterised by increases in thermophysiological strain. Both per-cooling with a novel carbon-based and a conventional water-based ice vest were shown to reduce core temperature significantly. However, due to its lower mass, the carbon-based system may be recommended especially for weight-bearing sports.
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4.
The effect of β-alanine supplementation on high intensity cycling capacity in normoxia and hypoxia.
Patel, KA, Farias de Oliveira, L, Sale, C, James, RM
Journal of sports sciences. 2021;(11):1295-1301
Abstract
The availability of dietary beta-alanine (BA) is the limiting factor in carnosine synthesis within human muscle due to its low intramuscular concentration and substrate affinity. Carnosine can accept hydrogen ions (H+), making it an important intramuscular buffer against exercise-induced acidosis. Metabolite accumulation rate increases when exercising in hypoxic conditions, thus an increased carnosine concentration could attenuate H+ build-up when exercising in hypoxic conditions. This study examined the effects of BA supplementation on high intensity cycling capacity in normoxia and hypoxia. In a double-blind design, nineteen males were matched into a BA group (n = 10; 6.4 g·d-1) or a placebo group (PLA; n = 9) and supplemented for 28 days, carrying out two pre- and two post-supplementation cycling capacity trials at 110% of powermax, one in normoxia and one in hypoxia (15.5% O2). Hypoxia led to a 9.1% reduction in exercise capacity, but BA supplementation had no significant effect on exercise capacity in normoxia or hypoxia (P > 0.05). Blood lactate accumulation showed a significant trial x time interaction post-supplementation (P = 0.016), although this was not significantly different between groups. BA supplementation did not increase high intensity cycling capacity in normoxia, nor did it improve cycling capacity in hypoxia even though exercise capacity was reduced under hypoxic conditions.
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5.
Physiology of handcycling: A current sports perspective.
Stephenson, BT, Stone, B, Mason, BS, Goosey-Tolfrey, VL
Scandinavian journal of medicine & science in sports. 2021;(1):4-20
Abstract
Handcycling is a mode of mobility, and sport format within Para-cycling, for those with a lower limb impairment. The exercise modality has been researched extensively in the rehabilitation setting. However, there is an emerging body of evidence detailing the physiological responses to handcycling in the competitive sport domain. Competitive handcyclists utilize equipment that is vastly disparate to that used for rehabilitation or recreation. Furthermore, the transferability of findings from early handcycling research to current international athletes regarding physiological profiles is severely limited. This narrative review aims to map the landscape within handcycling research and document the growing interest at the elite end of the exercise spectrum. From 58 experimental/case studies and four doctoral theses, we provide accounts of the aerobic capacity of handcyclists and the influence training status plays; present research regarding the physiological responses to handcycling performance, including tests of sprint performance; and discuss the finite information on handcyclists' training habits and efficacy of bespoke interventions. Furthermore, given the wide variety of protocols employed and participants recruited previously, we present considerations for the interpretation of existing research and recommendations for future work, all with a focus on competitive sport. The majority of studies (n = 21) reported aerobic capacity, detailing peak rates of oxygen uptake and power output, with values >3.0 L min-1 and 240 W shown in trained, male H3-H4 classification athletes. Knowledge, though, is lacking for other classifications and female athletes. Similarly, little research is available concerning sprint performance with only one from eight studies recruiting athletes with an impairment.
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6.
Acute citrulline-malate supplementation is ineffective during aerobic cycling and subsequent anaerobic performance in recreationally active males.
Gills, JL, Glenn, JM, Gray, M, Romer, B, Lu, H
European journal of sport science. 2021;(1):77-83
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Abstract
Citrulline-malate (CM) purportedly increases exercise performance through increased nitric oxide production. The effects of CM on muscular strength performance are well-documented; however, the benefits of CM on aerobic and anaerobic biking performance are not well researched. Therefore, the present investigation examined the acute CM supplementation effects on aerobic and anaerobic cycling performance in recreationally active males. Methods: 28 recreationally active males (20.9 ± 2.8 years) completed randomized, double-blind, crossover trials consuming CM (12g dextrose + 8g CM) or a placebo (12g dextrose). Participants performed an aerobic cycling protocol (time-to-exhaustion [TTE]), followed by a subsequent 30-second Wingate cycling test, 60-minutes after supplement consumption. Results: Dependent t-tests showed no significant differences (p > 0.05) for TTE (PLA: 315.4 s ± 137.7 s; CM: 314.1 s ± 107.1 s) and Total Work Completed (TWC) (PLA: 74.7 ± 34.1 kilojoules (kJ); CM: 74.1 ± 26.4 kJ) during the aerobic cycling protocol. Dependent t-tests also showed no significant differences (p > 0.05) for mean watts (PLA: 586.1 ± 87.7 Watts (W); CM: 588.0 ± 93.0 W), peak watts (PLA: 773.0 ± 136.7 W; CM: 786.7 ± 133.0 W), and fatigue index (PLA: 12.9 ± 6.4 FI; CM: 14.3 ± 7.2 FI) during the Wingate protocol. Repeated-measures ANOVA results indicated a significant effect between each 5 s interval (p < 0.001), but no differences were observed between trials (p > 0.05). Conclusion: Acute CM supplementation in recreationally active males provides no ergogenic benefit in aerobic cycling performance followed by an anaerobic cycling test.
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Habitual Caffeine Consumption Does Not Affect the Ergogenicity of Coffee Ingestion During a 5 km Cycling Time Trial.
Clarke, ND, Richardson, DL
International journal of sport nutrition and exercise metabolism. 2021;(1):13-20
Abstract
There is growing evidence that caffeine and coffee ingestion prior to exercise provide similar ergogenic benefits. However, there has been a long-standing paradigm that habitual caffeine intake may influence the ergogenicity of caffeine supplementation. The aim of the present study was to investigate the effect of habitual caffeine intake on 5-km cycling time-trial performance following the ingestion of caffeinated coffee. Following institutional ethical approval, in a double-blind, randomized, crossover, placebo-controlled design, 46 recreationally active participants (27 men and 19 women) completed a 5-km cycling time trial on a cycle ergometer 60 m in following the ingestion of 0.09 g/kg coffee providing 3 mg/kg of caffeine, or a placebo. Habitual caffeine consumption was assessed using a caffeine consumption questionnaire with low habitual caffeine consumption defined as <3 and ≥6 mg · kg-1 · day-1 defined as high. An analysis of covariance using habitual caffeine intake as a covariant was performed to establish if habitual caffeine consumption had an impact on the ergogenic effect of coffee ingestion. Sixteen participants were classified as high-caffeine users and 30 as low. Ingesting caffeinated coffee improved 5-km cycling time-trial performance by 8 ± 12 s; 95% confidence interval (CI) [5, 13]; p < .001; d = 0.30, with low, 9±14 s; 95% CI [3, 14]; p = .002; d = 0.18, and high, 8 ± 10 s; 95% CI [-1, 17]; p = .008; d = 0.06, users improving by a similar magnitude, 95% CI [-12, 12]; p = .946; d = 0.08. In conclusion, habitual caffeine consumption did not affect the ergogenicity of coffee ingestion prior to a 5-km cycling time trial.
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Individual Participant Data Meta-Analysis Provides No Evidence of Intervention Response Variation in Individuals Supplementing With Beta-Alanine.
Esteves, GP, Swinton, P, Sale, C, James, RM, Artioli, GG, Roschel, H, Gualano, B, Saunders, B, Dolan, E
International journal of sport nutrition and exercise metabolism. 2021;(4):305-313
Abstract
Currently, little is known about the extent of interindividual variability in response to beta-alanine (BA) supplementation, nor what proportion of said variability can be attributed to external factors or to the intervention itself (intervention response). To investigate this, individual participant data on the effect of BA supplementation on a high-intensity cycling capacity test (CCT110%) were meta-analyzed. Changes in time to exhaustion (TTE) and muscle carnosine were the primary and secondary outcomes. Multilevel distributional Bayesian models were used to estimate the mean and SD of BA and placebo group change scores. The relative sizes of group SDs were used to infer whether observed variation in change scores were due to intervention or non-intervention-related effects. Six eligible studies were identified, and individual data were obtained from four of these. Analyses showed a group effect of BA supplementation on TTE (7.7, 95% credible interval [CrI] [1.3, 14.3] s) and muscle carnosine (18.1, 95% CrI [14.5, 21.9] mmol/kg DM). A large intervention response variation was identified for muscle carnosine (σIR = 5.8, 95% CrI [4.2, 7.4] mmol/kg DM) while equivalent change score SDs were shown for TTE in both the placebo (16.1, 95% CrI [13.0, 21.3] s) and BA (15.9, 95% CrI [13.0, 20.0] s) conditions, with the probability that SD was greater in placebo being 0.64. In conclusion, the similarity in observed change score SDs between groups for TTE indicates the source of variation is common to both groups, and therefore unrelated to the supplement itself, likely originating instead from external factors such as nutritional intake, sleep patterns, or training status.
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Pre-Exercise Carbohydrate or Protein Ingestion Influences Substrate Oxidation but Not Performance or Hunger Compared with Cycling in the Fasted State.
Rothschild, JA, Kilding, AE, Broome, SC, Stewart, T, Cronin, JB, Plews, DJ
Nutrients. 2021;(4)
Abstract
Nutritional intake can influence exercise metabolism and performance, but there is a lack of research comparing protein-rich pre-exercise meals with endurance exercise performed both in the fasted state and following a carbohydrate-rich breakfast. The purpose of this study was to determine the effects of three pre-exercise nutrition strategies on metabolism and exercise capacity during cycling. On three occasions, seventeen trained male cyclists (VO2peak 62.2 ± 5.8 mL·kg-1·min-1, 31.2 ± 12.4 years, 74.8 ± 9.6 kg) performed twenty minutes of submaximal cycling (4 × 5 min stages at 60%, 80%, and 100% of ventilatory threshold (VT), and 20% of the difference between power at the VT and peak power), followed by 3 × 3 min intervals at 80% peak aerobic power and 3 × 3 min intervals at maximal effort, 30 min after consuming a carbohydrate-rich meal (CARB; 1 g/kg CHO), a protein-rich meal (PROTEIN; 0.45 g/kg protein + 0.24 g/kg fat), or water (FASTED), in a randomized and counter-balanced order. Fat oxidation was lower for CARB compared with FASTED at and below the VT, and compared with PROTEIN at 60% VT. There were no differences between trials for average power during high-intensity intervals (367 ± 51 W, p = 0.516). Oxidative stress (F2-Isoprostanes), perceived exertion, and hunger were not different between trials. Overall, exercising in the overnight-fasted state increased fat oxidation during submaximal exercise compared with exercise following a CHO-rich breakfast, and pre-exercise protein ingestion allowed similarly high levels of fat oxidation. There were no differences in perceived exertion, hunger, or performance, and we provide novel data showing no influence of pre-exercise nutrition ingestion on exercise-induced oxidative stress.
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Wearing compression tights post-exercise enhances recovery hemodynamics and subsequent cycling performance.
Lee, DCW, Sheridan, S, Ali, A, Sutanto, D, Wong, SHS
European journal of applied physiology. 2021;(7):2091-2100
Abstract
PURPOSE To investigate sports compression garment (CG)-induced recovery hemodynamics and their potential impact on subsequent cycling performance. METHODS In a randomized crossover design, 13 physically active men (20.9 ± 1.4 years; 65.9 ± 7.8 kg; 173.3 ± 4.8 cm; peak power output 254.2 ± 27.2 W) underwent 2 experimental trials. During each experimental trial, the subjects performed 20-min fatiguing preload cycling followed by 60-min passive recovery wearing either a sports CG (28.6 ± 9.4 mmHg) or gymnastic pants (CON). A 5-min all-out cycling performance test was subsequently conducted and power output and cadence were recorded. Cardiac output (CO) and stroke volume (SV) were measured using Doppler ultrasound (USCOM®). Heart rate (HR), blood lactate [BLa-], ratings of perceived exertion (RPE), leg muscle soreness (LMS), mean arterial pressure (MAP) and systemic vascular resistance (SVR) were monitored at 5, 15, 30, 45, 60 min during passive recovery. RESULTS During the subsequent 5-min all-out cycling performance test, power output (215.2 ± 24.0 vs. 210.8 ± 21.5 W, CG vs. CON) and cadence (72.5 ± 3.8 vs. 71.2 ± 4.8 rpm, CG vs. CON) were higher in CG than CON (P < 0.05). SV was higher at 15, 30 and 45 min (P < 0.05), CO was higher at 5 and 45 min (P < 0.05), HR was lower at 15 and 30 min (P < 0.05) and [BLa-] was lower at 5 and 15 min (P < 0.05) during passive recovery, while LMS was lower at all time-points (P < 0.05) compared with CON. CONCLUSION Sports CG improves subsequent cycling performance by enhancing hemodynamic responses and attenuating perceived muscle soreness during passive recovery in physically active men.