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Blackcurrant juices and extracts containing anthocyanin may provide ergogenic benefits to sports performance. However, there are no studies examining the effects of coingestion of blackcurrant and caffeine. This investigation examined the effects of acute supplementation with a proprietary blackcurrant beverage administered in isolation or in combination with caffeine on repeated high-intensity cycling. Twelve well-trained male cyclists (mean ± SD: age, 39.5 ± 11.4 years; height, 177.9 ± 5.7 cm; weight, 78.2 ± 8.9 kg; and peak oxygen consumption, 4.71 ± 0.61 L/min) completed experimental sessions consisting of repeated (8 × 5 min) maximal intensity efforts. Four experimental treatments were administered in a double-blind, balanced Latin square design: blackcurrant + caffeine, blackcurrant + placebo, caffeine + placebo and placebo + placebo. Differences in power output, heart rate, oxygen consumption, muscle oxygen saturation, rate of perceived exertion, and cognitive function (Stroop) were compared between treatments using two-way repeated-measures analysis of variance and effect size analysis. There were no significant differences (p >.05) in either physiological or cognitive variables with any supplement treatment (blackcurrant + caffeine, blackcurrant + placebo, and caffeine + placebo) relative to placebo + placebo. Moreover, any observed differences were deemed trivial (d < 0.2) in magnitude. However, power output was lower (p <.05) in blackcurrant + placebo compared with blackcurrant + caffeine. A blackcurrant extract beverage administered in isolation or combination with caffeine provided no beneficial effect on cycling performance or physiological measures relative to a placebo control. [ABSTRACT FROM AUTHOR]

Purpose: Leading a 4-km team pursuit (TP) requires high-intensity efforts above critical power (CP) that deplete riders' finite work capacity (W′), whereas riders following in the aerodynamic draft may experience some recovery due to reduced power demands. This study aimed to determine how rider ability and CP and W′ measures impact TP performance and the extent to which W′ can reconstitute during recovery positions in a TP race. Methods: Three TP teams, each consisting of 4 males, completed individual performance tests to determine their CP and W′. Teams were classified based on their performance level as international (INT), national (NAT), or regional (REG). Each team performed a TP on an indoor velodrome (INT: 3:49.9; NAT: 3:56.7; and REG: 4:05.4; min:s). Ergometer-based TP simulations with an open-ended interval to exhaustion were performed to measure individual ability to reconstitute W′ at 25 to 100 W below CP. Results: The INT team possessed higher CP (407 [4] W) than both NAT (381 [13] W) and REG (376 [15] W) (P <.05), whereas W′ was similar between teams (INT: 27.2 [2.8] kJ; NAT: 29.3 [2.4] kJ; and REG: 28.8 [1.6] kJ; P >.05). The INT team expended 104% (5%) of their initial W′ during the TP and possessed faster rates of recovery than NAT and REG at 25 and 50 W below CP (P <.05). Conclusions: The CP and rate of W′ reconstitution have a greater impact on TP performance than W′ magnitude and can differentiate TP performance level. [ABSTRACT FROM AUTHOR]

Blood flow restriction (BFR) is increasingly being used to enhance aerobic performance in endurance athletes. This study examined physiological responses to BFR applied in recovery phases within a high‐intensity interval training (HIIT) session in trained cyclists. Eleven competitive road cyclists (mean ± SD, age: 28 ± 7 years, body mass: 69 ± 6 kg, peak oxygen uptake: 65 ± 9 mL · kg−1 · min−1) completed two randomised crossover conditions: HIIT with (BFR) and without (CON) BFR applied during recovery phases. HIIT consisted of six 30‐s cycling bouts at an intensity equivalent to 85% of maximal 30‐s power (523 ± 93 W), interspersed with 4.5‐min recovery. BFR (200 mmHg, 12 cm cuff width) was applied for 2‐min in the early recovery phase between each interval. Pulmonary gas exchange (V̇O2, V̇CO2, and V̇E), tissue oxygen saturation index (TSI), heart rate (HR), and serum vascular endothelial growth factor concentration (VEGF) were measured. Compared to CON, BFR increased V̇CO2 and V̇E during work bouts (both p < 0.05, dz < 0.5), but there was no effect on V̇O2, TSI, or HR (p > 0.05). In early recovery, BFR decreased TSI, V̇O2, V̇CO2, and V̇E (all p < 0.05, dz > 0.8) versus CON, with no change in HR (p > 0.05). In late recovery, when BFR was released, V̇O2, V̇CO2, V̇E, and HR increased, but TSI decreased versus CON (all p < 0.05, dz > 0.8). There was a greater increase in VEGF at 3‐h post‐exercise in BFR compared to CON (p < 0.05, dz > 0.8). Incorporating BFR into HIIT recovery phases altered physiological responses compared to exercise alone. Highlights: Blood flow restriction (BFR) during high‐intensity interval training recovery phases increased acute physiological perturbations and angiogenic markers compared to interval training alone.During the early recovery phases of high‐intensity interval cycling, BFR decreased muscle oxygenation, V̇O2, V̇CO2, and V̇E compared to CON condition with unrestricted recovery. [ABSTRACT FROM AUTHOR]

Purpose: Ischemic preconditioning (IPC) and postactivation potentiation (PAP) are warm-up strategies proposed to improve high-intensity sporting performance. However, only few studies have investigated the benefits of these strategies compared with an appropriate control (CON) or an athlete-selected (SELF) warm-up protocol. Therefore, this study examined the effects of 4 different warm-up routines on 1-km time-trial (TT) performance with competitive cyclists. Methods: In a randomized crossover study, 12 well-trained cyclists (age 32 [10] y, mass 77.7 [4.6] kg, peak power output 1141 [61] W) performed 4 different warm-up strategies—(CON) 17 minutes CON only, (SELF) a self-determined warm-up, (IPC) IPC + CON, or (PAP) CON + PAP—prior to completing a maximal-effort 1-km TT. Performance time and power, quadriceps electromyograms, muscle oxygen saturation (SmO2), and blood lactate were measured to determine differences between trials. Results: There were no significant differences (P >.05) in 1-km performance time between CON (76.9 [5.2] s), SELF (77.3 [6.0] s), IPC (77.0 [5.5] s), or PAP (77.3 [5.9] s) protocols. Furthermore, there were no significant differences in mean or peak power output between trials. Finally, electromyogram activity, SmO2, and recovery blood lactate concentration were not different between conditions. Conclusions: Adding IPC or PAP protocols to a short CON warm-up appears to provide no additional benefit to 1-km TT performance with well-trained cyclists and is therefore not recommended. Furthermore, additional IPC and PAP protocols had no effect on electromyograms and SmO2 values during the TT or peak lactate concentration during recovery. [ABSTRACT FROM AUTHOR]

Coconut water is used as an alternative to conventional sports drinks for hydration during endurance cycling; however, evidence supporting its use is limited. This study determined if drinking coconut water compared to a sports drink altered cycling performance and physiology. In a randomized crossover trial, 19 experienced male (n = 15) and female (n = 4) cyclists (age 30 ± 9 years, body mass 79 ± 11 kg, V ̇ O2 peak 55 ± 8 mL·kg−1·min−1) completed two experimental trials, consuming either a commercially available sports drink or iso-calorific coconut water during 90 min of sub-maximal cycling at 70% of their peak power output, followed by a simulated, variable gradient, 20 km time trial. Blood glucose, lactate, sweat loss, and heart rate were monitored throughout the 90 min of sub-maximal cycling, as well as the time trial performance (seconds) and average power (watts). A repeated measures analysis of variance and effect sizes (Cohen's d) analysis were applied. There were no significant differences (p ≥ 0.05) between the treatments for any of the measured physiological or performance variables. Additionally, the effect size analysis showed only trivial (d ≤ 0.2) differences between the treatments for all the measured variables, except blood glucose, which was lower in the coconut water trial compared to the sports drink trial (d = 0.31). Consuming coconut water had a similar effect on the cycling time trial performance and the physiological responses to consuming a commercially available sports drink. [ABSTRACT FROM AUTHOR]

Stryd is a foot pod that reliably estimates running power. Our objectives were to examine the efficacy of the website-generated Stryd critical power (CPSTRYD) as a meaningful parameter for runners. 20 runners performed their regular training while wearing Stryd for a minimum of 6 weeks to generate CPSTRYD. Runners completed laboratory graded exercise testing, and outdoor 1500 m and 5000 m time trails. CPSTRYD was most similar to the second ventilatory threshold (VT2) or the onset of blood lactate accumulation (OBLA) and is highly predictive of running performance. Stryd ground contact time (GCT) was a predictor of performance when comparing runners at the same submaximal treadmill speed. CPSTRYD generated from outdoor running is equivalent to that calculated using an established CP model. However, variance between different methods of CP estimation must be a consideration for runners and coaches. Stryd offers meaningful data for runners including a realistic estimate of CP. [ABSTRACT FROM AUTHOR]

Purpose: Caffeine is frequently used by athletes as an ergogenic aid. Various alternate forms of caffeine administration are available, which may produce different effects. This investigation compares the effects of different forms of caffeine supplementation on 5-km running performance, and the relationship between athlete ability and degree of enhancement attained. Methods: Fourteen amateur runners completed a series of self-paced outdoor time trials following unknown ingestion of a placebo (P) or one of 3 alternate forms of caffeine supplement. Trials were randomized in a crossover design with caffeine (approximately 3–4.5 mg·kg−1) administered 15 minutes before each trial via chewing gum (CG), dissolvable mouth strips (CS), or tablet (CT). Results: Compared with P, all caffeine supplements led to worthwhile enhancements in running performance with a mean (±95% confidence limit) overall effect across all supplements of 1.4% ± 0.9%. Individual caffeine treatment effects (CG = 0.9% ± 1.4%, CS = 1.2% ± 1.0%, and CT = 2.0% ± 1.1%) were not significantly different (P >.05) from each other; however, CT trials produced the largest gain and was significantly different (P =.02) compared with P. There was no significant difference in heart rate or rate of perceived exertion across the performance trials. The magnitude of caffeine enhancement was also strongly correlated (r =.87) with no-treatment performance time. Conclusions: The findings showed that irrespective of delivery form, moderate dose of caffeine supplementation produces worthwhile gains in 5-km running performance compared with a P. Furthermore, the magnitude of caffeine enhancement is highly individualized, but it appears related to athlete performance ability. [ABSTRACT FROM AUTHOR]

New Zealand has low levels of the essential trace elements selenium and a growing concern with increasing exposure to cadmium, one of the most toxic pollutants worldwide. Both elements are highly implicated in health and disease and have links with the central nervous system. Selenium levels have previously been shown to have a relationship with psychological stress and is also known to protect against cadmium neurotoxicity. We sort to examine the impact of selenium and cadmium as factors for perceived stress in a New Zealand population, with a high proportion of tertiary students. All participants completed a validated questionnaire for perceived stress and had nail clippings analysed for cadmium and selenium using inductively coupled plasma mass spectrometry. Factors for increased perceived stress are younger age, lower selenium concentrations and higher cadmium concentrations. Both selenium and cadmium are likely to be important considerations to reduce perceived stress levels in this population. [ABSTRACT FROM AUTHOR]

Purpose: Aerobic economy is an important factor that affects the performance of competitive cyclists. It has been suggested that placing the foot more anteriorly on the bicycle pedals may improve economy over the traditional foot position by improving pedaling efficiency. The current study examines the effects of changing the anterior-posterior pedal foot position on the physiology and performance of well-trained cyclists. Methods: In a crossover study, 10 competitive cyclists completed two maximal incremental and two submaximal tests in either their preferred (control) or a forward (arch) foot position. Maximum oxygen consumption and peak power output were determined from the incremental tests for both foot positions. On two further occasions, cyclists also completed a two-part 60-min submaximal test that required them to maintain a constant power output (equivalent to 60% of their incremental peak power) for 30 min during which respiratory and blood lactate samples were taken at predetermined intervals. Thereafter, subjects completed a 30-min self-paced maximal effort time trial. Results: Relative to the control, the mean changes (±90% confidence limits) in the arch condition were as follows: maximum oxygen consumption, -0.5% (±2.0%); incremental peak power output, -0.8% (±1.3%); steady-state oxygen consumption at 60%, -2.4% (±1.1%); steady-state heart rate 60%, 0.4% (±1.7%); lactate concentration 60%, 8.7% (±14.4%); and mean time trial power, -1.5% (±2.9%). Conclusions: We conclude that there was no substantial physiological or performance advantage in this group using an arch-cleat shoe position in comparison with a cyclist's normal preferred condition. [ABSTRACT FROM AUTHOR]

In a recent study competitive road cyclists experienced substantial gains in sprint and endurance performance when sessions of high-intensity interval training were added to their usual training in the competitive phase of a season. The current study reports the effect of this type of training on performance of 20 distance runners randomized to an experimental or control group for 5 to 7 weeks of training. The experimental group replaced part of their usual competitive-phase training with 10 X 30-minute sessions consisting of 3 sets of explosive single-leg jumps (20 for each leg) alternating with 3 sets of resisted treadmill sprints (5 X 30-second efforts alternating with 30-second recovery). Before and after the training period all runners completed an incremental treadmill test for assessment of lactate threshold and maximum running speed, 2 treadmill runs to exhaustion for prediction of 800- and 1500-m times, and a 5-km outdoor time trial. Relative to the control group, the mean changes (±90% confidence limits) in the experimental group were: maximum running speed, 1.8% (± 1.1%); lactate-threshold speed, 3.5% (±3.4%); predicted 800-m speed, 3.6% (± 1.8%); predicted 1500-m speed, 3.7% (± 3.0%); and 5-km time-trial speed, 1.2% (± 1.1%). We conclude that high-intensity resistance training in the competitive phase is likely to produce beneficial gains in performance for most distance runners. [ABSTRACT FROM AUTHOR]