Dr Danny Brown

Background/objectives: The functional threshold power (FTP) 20-min test (FTP20) is popular amongst cyclists and coaches due to the theory it can predict the power output that can be sustained for 60-mins. However, little is known in terms of the reliability and validity of this construct, therefore the aim of this study was to assess the reliability of the FTP20 test and the construct validity of this test to predict 60-min power. Methods: Twenty-two male trained cyclists (age = 32 ± 10 years, body mass (BM) = 77.2 ± 6.8 kg, maximal oxygen uptake (V̇O2max) = 59.4 ± 5.6 ml.kg-1.min-1 BM) completed four trials consisting of a V̇O2max test, a familiarisation trial of the FTP20, two experimental FTP20 tests, and a time to volitional exhaustion (TLIM) at 95% FTP20. Results: The repeatability for mean power output (MPO) during the FTP20 was excellent (r = 0.94, CI 0.82, 0.98, p<0.001). Mean TLIM (at 95% FTP20) was 42 ± 17-min, with six participants within 10-min of the 60-min suggested threshold. Conclusions: These results suggest that the FTP20 is reliable, however it does not predict 60-min power with a high level of validity. Future research should explore adapting the calculation of FTP whereby the intensity may be lowered (i.e., 80-90% MPO of FTP20), particularly as most participants’ TLIM was far below the suggested 60-min time frame.

Dehydration of >3% body mass impairs endurance performance irrespective of the individual's knowledge of their hydration status, but whether knowledge of hydration status influences performance at lower levels of dehydration is unknown. This study examined whether perception of hydration status influenced endurance performance. After familiarisation, nine active males (age 25 ± 2 y, V̇O2peak 52.5 ± 9.1 mL·kg·min-1) completed two randomised trials at 34°C. Trials involved an intermittent exercise preload (8 × 10 min cycling/5 min rest), followed by a 15 min all-out cycling performance test. During the preload in both trials, water was ingested orally every 10 min (0.3 mL·kg body mass-1), with additional water infused into the stomach via gastric feeding tube to produce dehydration of ∼1.5% body mass pre-performance test. Participants were told intra-gastric infusion was manipulated to produce euhydration (0% dehydration; Perceived-EUH) or dehydration (2% dehydration; Perceived-DEH) pre-performance test, which was told to them pre-preload and confirmed after body mass measurement pre-performance test. Body mass loss during the preload (Perceived-EUH 1.6 ± 0.2%, Perceived-DEH 1.7 ± 0.2%; P=0.459), heart rate, gastrointestinal temperature and RPE (P≥0.110) were not different between trials. Thirst was greater at the end of the preload and performance test in Perceived-DEH (P≤0.040). Work completed during the performance test was 5.6 ± 6.1% lower in Perceived-DEH (187.4 ± 37.0 kJ vs. 176.9 ± 36.0 kJ; P=0.038). These results suggest that at lower levels of dehydration (<2% body mass), an individual's perception of their hydration status could impair their performance, as well as their thirst perception.

Objectives This study aimed to investigate whether supplementation with 12 mg⋅day−1 astaxanthin for 7 days can improve exercise performance and metabolism during a 40 km cycling time trial. Design A randomised, double-blind, crossover design was employed. Methods Twelve recreationally trained male cyclists (VO2peak: 56.5 ± 5.5 mL⋅kg−1⋅min−1, Wmax: 346.8  ± 38.4 W) were recruited. Prior to each experimental trial, participants were supplemented with either 12 mg⋅day−1 astaxanthin or an appearance-matched placebo for 7 days (separated by 14 days of washout). On day 7 of supplementation, participants completed a 40 km cycling time trial on a cycle ergometer, with indices of exercise metabolism measured throughout. Results Time to complete the 40 km cycling time trial was improved by 1.2 ± 1.7% following astaxanthin supplementation, from 70.76 ± 3.93 min in the placebo condition to 69.90 ± 3.78 min in the astaxanthin condition (mean improvement = 51 ± 71 s, p = 0.029, g = 0.21). Whole-body fat oxidation rates were also greater (+0.09 ± 0.13 g⋅min−1, p = 0.044, g = 0.52), and the respiratory exchange ratio lower (−0.03 ± 0.04, p = 0.024, g = 0.60) between 39–40 km in the astaxanthin condition. Conclusions Supplementation with 12 mg⋅day−1 astaxanthin for 7 days provided an ergogenic benefit to 40 km cycling time trial performance in recreationally trained male cyclists and enhanced whole-body fat oxidation rates in the final stages of this endurance-type performance event.

Abstract

Objective: To quantify the effects of acute hypoxic exposure on exercise capacity and performance, which includes continuous and intermittent forms of exercise. Design: A systematic review was conducted with a three‐level mixed effects meta‐regression. The ratio of means method was used to evaluate main effects and moderators providing practical interpretations with percentage change. Data sources: A systemic search was performed using three databases (Google scholar, PubMed and SPORTDiscus). Eligibility criteria for selecting studies: Inclusion was restricted to investigations that assessed exercise performance (time trials (TTs), sprint and intermittent exercise tests) and capacity (time to exhaustion test, TTE) with acute hypoxic (<24 h) exposure and a normoxic comparator. Results: Eighty‐two outcomes from 53 studies (N = 798) were included in this review. The results show an overall reduction in exercise performance/capacity −17.8 ± 3.9% (95% CI −22.8% to −11.0%), which was significantly moderated by −6.5 ± 0.9% per 1000 m altitude elevation (95% CI −8.2% to −4.8%) and oxygen saturation (−2.0 ± 0.4%; 95% CI −2.9% to −1.2%). TT (−16.2 ± 4.3%; 95% CI −22.9% to −9%) and TTE (−44.5 ± 6.9%; 95% CI −51.3% to −36.7%) elicited a negative effect, whilst indicating a quadratic relationship between hypoxic magnitude and both TTE and TT performance. Furthermore, exercise less than 2 min exhibited no ergolytic effect from acute hypoxia.

Summary/Conclusion: This review highlights the ergolytic effect of acute hypoxic exposure, which is curvilinear for TTE and TT performance with increasing hypoxic levels, but short duration intermittent and sprint exercise seem to be unaffected.

During periods of heavy exercise training and competition, lipid, protein, and nucleic molecules can become damaged due to an overproduction of reactive oxygen and nitrogen species (RONS) within the exercising organism. As antioxidants can prevent and delay cellular oxidative damage through removing, deactivating, and preventing the formation of RONS, supplementation with exogenous antioxidant compounds has become a commercialized nutritional strategy commonly adopted by recreationally active individuals and athletes. The following review is written as a critical appraisal of the current literature surrounding astaxanthin and its potential application as a dietary supplement in exercising humans. Astaxanthin is a lipid-soluble antioxidant carotenoid available to supplement through the intake of Haematococcus pluvialis-derived antioxidant products. Based upon in vitro and in vivo research conducted in mice exercise models, evidence would suggest that astaxanthin supplementation could potentially improve indices of exercise metabolism, performance, and recovery because of its potent antioxidant capacity. In exercising humans, however, these observations have yet to be consistently realized, with equivocal data reported. Implicated, in part, by the scarcity of well-controlled, scientifically rigorous research, future investigation is necessary to enable a more robust conclusion in regard to the efficacy of astaxanthin supplementation and its potential role in substrate utilization, endurance performance, and acute recovery in exercising humans.

PURPOSE: Exacerbated hydrogen cation (H+) production is suggested to be a key determinant of fatigue in acute hypoxic conditions. This study, therefore, investigated the effects of NaHCO3 ingestion on repeated 4 km TT cycling performance and post-exercise acid-base balance recovery in acute moderate hypoxic conditions. METHODS: Ten male trained cyclists completed four repeats of 2 × 4 km cycling time trials (TT1 and TT2) with 40 min passive recovery, each on different days. Each TT series was preceded by supplementation of one of the 0.2 g kg-1 BM NaHCO3 (SBC2), 0.3 g kg-1 BM NaHCO3 (SBC3), or a taste-matched placebo (0.07 g kg-1 BM sodium chloride; PLA), administered in a randomized order. Supplements were administered at a pre-determined individual time to peak capillary blood bicarbonate concentration ([HCO3-]). Each TT series was also completed in a normobaric hypoxic chamber set at 14.5% FiO2 (~ 3000 m). RESULTS: Performance was improved following SBC3 in both TT1 (400.2 ± 24.1 vs. 405.9 ± 26.0 s; p = 0.03) and TT2 (407.2 ± 29.2 vs. 413.2 ± 30.8 s; p = 0.01) compared to PLA, displaying a very likely benefit in each bout. Compared to SBC2, a likely and possible benefit was also observed following SBC3 in TT1 (402.3 ± 26.5 s; p = 0.15) and TT2 (410.3 ± 30.8 s; p = 0.44), respectively. One participant displayed an ergolytic effect following SBC3, likely because of severe gastrointestinal discomfort, as SBC2 still provided ergogenic effects. CONCLUSION: NaHCO3 ingestion improves repeated exercise performance in acute hypoxic conditions, although the optimal dose is likely to be 0.3 g kg-1 BM.

This study evaluated the chronic effects of nitrate (NO3-) ingestion over three days, on 40 km TT performance in 11trained cyclists (VO2max: 60.8 ± 7.4 ml.kg-1.min-1; age: 36 ± 9 years; height: 1.80 ± 0.06 m; body mass: 87.2 ± 12.0 kg). Utilising a double-blind randomised cross-over design, participants completed three 40 km TT on a Velotron® ergometer following the ingestion of either a 140 ml of "BEET It sport®" NO3- shot containing 12.8 mmol or 800 mg of NO3-, a placebo drink or nothing (control). Performance, oxygen consumption (VO2), blood bicarbonate (HCO3-), pH and lactate (BLa) and ratings of perceived exertion (RPE) were measured every 10 km throughout the TT. The present findings show that NO3- ingestion had no effect on TT performance (NO3-: 4098.0 ± 209.8 vs. Placebo: 4161.9 ± 263.3 s, p = 0.296, ES = 0.11), or VO2 (p = 0.253, ES = 0.13). Similarly, blood lactate and RPE were also unaffected by the experimental conditions (p = 0.522, ES = 0.06; p = 0.085, ES = 0.30) respectively. Therefore, these results suggest that a high dose of NO3- over three days has limited efficacy as an ergogenic aid for 40 km TT cycling performance in trained cyclists.

It is unclear whether engagement with Virtual Learning Environment (VLE) self-directed study can enhance the learning process and augment academic achievement. As such, the current study aims to investigate the relationship between VLE self-directed study provision in a Sports Therapy module and subsequent academic summative assessment success. The sample was comprised of 232 undergraduate BSc (Hons) Sports Therapy students (113 male, 119 female) across three separate student cohorts (2015, 2016, 2017). Each cohort was provided with differing VLE self-directed study. Analysis was conducted on its effect on achievement during both practical and written modes of summative assessment. The results of the current study suggest that while digital technology did not attenuate academic achievement, accurate alignment to the intended learning outcomes and summative assessments may be required for its successful integration into Higher Education pedagogy.

This study investigated the effects of two separate doses of sodium bicarbonate (NaHCO3) on 4 km time trial (TT) cycling performance and post-exercise acid base balance recovery in hypoxia. Fourteen club-level cyclists completed four cycling TT's, followed by a 40 min passive recovery in normobaric hypoxic conditions (FiO2 = 14.5%) following one of either: two doses of NaHCO3 (0.2 g.kg-1 BM; SBC2, or 0.3 g.kg-1 BM; SBC3), a taste-matched placebo (0.07 g.kg-1 BM sodium chloride; PLA), or a control trial in a double-blind, randomized, repeated-measures and crossover design study. Compared to PLA, TT performance was improved following SBC2 (p = 0.04, g = 0.16, very likely beneficial), but was improved to a greater extent following SBC3 (p = 0.01, g = 0.24, very likely beneficial). Furthermore, a likely benefit of ingesting SBC3 over SBC2 was observed (p = 0.13, g = 0.10), although there was a large inter-individual variation. Both SBC treatments achieved full recovery within 40 min, which was not observed in either PLA or CON following the TT. In conclusion, NaHCO3 improves 4 km TT performance and acid base balance recovery in acute moderate hypoxic conditions, however the optimal dose warrants an individual approach.

Purpose: The purpose of this study was to investigate whether mouth rinsing with a pink non-caloric, artificially sweetened solution can improve self-selected running speed and distance covered during a 30min running protocol. Methods: Ten healthy and habitually active individuals (six males, four females) completed two experimental trials in a randomised, single-blind, crossover design. Each experimental trial consisted of a 30min treadmill run at a self-selected speed equivalent to 15 (hard/heavy) on the rating of perceived exertion scale. During exercise, participants mouth rinsed with either a pink or a clear non-caloric, artificially sweetened solution, with performance, perceptual and physiological measures obtained throughout. Results: Self-selected running speed (+0.4 ± 0.5 km·h−1, p = 0.024, g = 0.25) and distance covered (+213 ± 247m, p = 0.023, g = 0.25) during the 30min running protocol were both improved by 4.4±5.1%when participants mouth rinsed with the pink solution when compared to the clear solution. Feelings of pleasure were also enhanced during the 30min treadmill run when participants mouth rinsed with the pink solution, with ratings increased from 3.4 ± 0.7 in the clear condition to 3.8 ± 0.6 in the pink condition (+0.4 ± 0.5, p = 0.046, g = 0.54). Conclusion: Mouth rinsing with a pink non-caloric, artificially sweetened solution improved self-selected running speed, total distance covered, and feelings of pleasure obtained during a 30min running protocol when compared to an isocaloric and taste-matched clear solution.