Refining Treatment Strategies for Iron Deficient Athletes.

Iron deficiency (ID) is a prevailing nutritional concern amongst the athletic population due to the increased iron demands of this group. Athletes' ability to replenish taxed iron stores is challenging due to the low bioavailability of dietary sources, and the interaction between exercise and hepcidin, the primary iron-regulatory hormone. To date, copious research has explored the link between exercise and iron regulation, with a more recent focus on optimising iron treatment applications. Currently, oral iron supplementation is typically the first avenue of iron replacement therapy beyond nutritional intervention, for treatment of ID athletes. However, many athletes encounter associated gastrointestinal side-effects which can deter them from fulfilling a full-term oral iron treatment plan, generally resulting in sub-optimal treatment efficacy. Consequently, various strategies (e.g. dosage, composition, timing) of oral iron supplementation have been investigated with the goal of increasing fractional iron absorption, reducing gastric irritation, and ultimately improving the efficacy of oral iron therapy. This review explores the various treatment strategies pertinent to athletes and concludes a contemporary strategy of oral iron therapy entailing morning supplementation, ideally within the 30 min following morning exercise, and in athletes experiencing gut sensitivity, consumed on alternate days or at lower doses.

The Effectiveness of Daily and Alternate Day Oral Iron Supplementation in Athletes With Suboptimal Iron Status (Part 2).

The authors compared the effectiveness of daily (DAY) versus alternate day (ALT) oral iron supplementation in athletes with suboptimal iron. Endurance-trained runners (nine males and 22 females), with serum ferritin (sFer) concentrations <50 µg/L, supplemented with oral iron either DAY or ALT for 8 weeks. Serum ferritin was measured at baseline and at fortnightly intervals. Hemoglobin mass (Hbmass) was measured pre- and postintervention in a participant subset (n = 10). Linear mixed-effects models were used to assess the effectiveness of the two strategies on sFer and Hbmass. There were no sFer treatment (p = .928) or interaction (p = .877) effects; however, sFer did increase (19.7 µg/L; p < .001) over the 8-week intervention in both groups. In addition, sFer was 21.2 µg/L higher (p < .001) in males than females. No Hbmass treatment (p = .146) or interaction (p = .249) effects existed; however, a significant effect for sex indicated that Hbmass was 140.85 g higher (p = .004) in males compared with females. Training load (p = .001) and dietary iron intake (p = .015) also affected Hbmass. Finally, there were six complaints of severe gastrointestinal side effects in DAY, but only one in ALT. In summary, both supplement strategies increased sFer in athletes with suboptimal iron status; however, the ALT approach was associated with lower incidence of gastrointestinal upset.

The Effectiveness of Transdermal Iron Patches in Athletes With Suboptimal Iron Status (Part 1).

The authors compared the effectiveness of two modes of daily iron supplementation in athletes with suboptimal iron stores: oral iron (PILL) versus transdermal iron (PATCH). Endurance-trained runners (nine males and 20 females), with serum ferritin concentrations <50 µg/L, supplemented with oral iron or iron patches for 8 weeks, in a parallel group study design. Serum ferritin was measured at baseline and fortnightly intervals. Hemoglobin mass and maximal oxygen consumption (V˙O2max) were measured preintervention and postintervention in PATCH. A linear mixed effects model was used to assess the effectiveness of each mode of supplementation on sFer. A repeated-measures analysis of variance was used to assess hemoglobin mass and V˙O2max outcomes in PATCH. There was a significant time effect (p < .001), sex effect (p = .013), and Time × Group interaction (p = .009) for sFer. At Week 6, PILL had significantly greater sFer compared with PATCH (15.27 µg/L greater in PILL; p = .019). Serum ferritin was 15.53 µg/L greater overall in males compared with females (p = .013). There were no significant differences in hemoglobin mass (p = .727) or V˙O2max (p = .929) preintervention to postintervention in PATCH. Finally, there were six complaints of severe gastrointestinal side effects in PILL and none in PATCH. Therefore, this study concluded that PILL effectively increased sFer in athletes with suboptimal iron stores, whereas PATCH showed no beneficial effects.

The effect of beetroot juice supplementation on repeat-sprint performance in hypoxia.

This investigation assessed the effect of dietary nitrate (NO3-) supplementation, in the form of beetroot juice (BR), on repeat-sprint performance in normoxia and normobaric hypoxia. 12 male team-sport athletes (age 22.3 ± 2.6 y, VO2peak 53.1 ± 8.7 mL.kg-1.min-1) completed three exercise trials involving a 10 min submaximal warm-up and 4 sets of cycling repeat-sprint efforts (RSE; 9 × 4 s) at sea level (CON), or at 3000 m simulated altitude following acute supplementation (140 mL) with BR (HYPBR; 13 mmol NO3-) or NO3-depleted BR placebo (HYPPLA). Peak (PPO) and mean (MPO) power output, plus work decrement were recorded during the RSE task, while oxygen consumption (VO2) was measured during the warm-up. There were no significant differences observed between HYPBR and HYPPLA for PPO or MPO; however, work decrement was reduced in the first RSE set in HYPBR compared with HYPPLA. There was a moderate effect for VO2 to be lower following BR at the end of the 10 min warm-up (ES = 0.50 ± 0.51). Dietary NO3- may not improve repeat-sprint performance in hypoxia but may reduce VO2 during submaximal exercise. Therefore, BR supplementation may be more effective for performance improvement during predominantly aerobic exercise.

Effect of dietary nitrate supplementation on thermoregulatory and cardiovascular responses to submaximal cycling in the heat.

PURPOSE: This study investigated whether reported improvements in blood flow distribution, and the possible related effects on thermoregulation during exercise following supplementation with beetroot juice (BR), a rich source of dietary nitrate (NO3-), are mitigated in the heat. METHODS: 12 male endurance-trained cyclists (age 27 ± 6 years, VO2peak 68.6 ± 8.1 ml kg-1 min-1) completed two 60 min submaximal cycling trials at 60% of VO2peak power output. Trials were performed in hot environmental conditions (33.3 ± 0.4 °C, 48.8 ± 3.0% RH) following 3 days of supplementation with either NO3--rich BR (6.5 mmol NO3- for 2 days and 13 mmol NO3- on the final day) or NO3--depleted placebo (PLA). Salivary NO3- and nitrite (NO2-) were measured before and after the supplementation period. During exercise, cutaneous blood flow, blood pressure (MAP), core temperature (Tc), mean skin temperature (Tsk), indices of muscle oxygenation and oxygen (O2) consumption were measured. RESULTS: Salivary NO3- and NO2- increased significantly following BR by 680 and 890%, respectively. There were no significant differences observed for cutaneous blood flow, MAP, Tc, Tsk, muscle oxygenation, or O2 consumption between BR and PLA. CONCLUSION: This investigation shows that the ergogenic effects and health benefits of BR supplementation, such as augmented cutaneous blood flow, reduced MAP, increased muscle oxygenation, and improved aerobic efficiency may be attenuated when exercise is performed in hot conditions.

Dietary nitrate supplementation does not improve cycling time-trial performance in the heat.

This investigation examined the effect of beetroot juice (BR) supplementation, a source of dietary nitrate (NO3-), on cycling time-trial (TT) performance and thermoregulation in the heat. In a double-blind, repeated-measures design, 12 male cyclists (age 26.6 ± 4.4 years, VO2peak 65.8 ± 5.5 mL.kg-1.min-1) completed four cycling TTs (14 kJ.kg-1) in hot (35°C, 48% relative humidity) and euthermic (21°C, 52%) conditions, following 3 days supplementation with BR (6.5 mmol NO3- for 2 days and 13 mmol NO3- on the final day), or NO3-depleted placebo (PLA). Salivary NO3- and nitrite, core (Tc) and mean skin temperature (Tsk) were measured. Salivary NO3- and nitrite increased significantly post-BR supplementation (p < 0.001). Average TT completion time (mm:ss) in hot conditions was 56:50 ± 05:08 with BR, compared with 58:30 ± 04:48 with PLA (p = 0.178). In euthermic conditions, average completion time was 53:09 ± 04:35 with BR, compared with 54:01 ± 04:05 with PLA (p = 0.380). The TT performance decreased (p < 0.001), and Tc (p < 0.001) and Tsk (p < 0.001) were higher in hot compared with euthermic conditions. In summary, BR supplementation has no significant effect on cycling TT performance in the heat.

Interleukin-6 and Hepcidin Levels during Hormone-Deplete and Hormone-Replete Phases of an Oral Contraceptive Cycle: A Pilot Study.

BACKGROUND: In the past, elevated estradiol levels were reported to downregulate the iron regulatory hormone hepcidin, thereby potentially improving iron metabolism. As estrogen plays a role in regulating the menstrual cycle and can influence the cytokine interleukin-6 (IL-6; a hepcidin up-regulator), this investigation examined the effects of estradiol supplementation achieved by the use of a monophasic oral contraceptive pill (OCP) on IL-6, hepcidin levels and iron status during the hormone-deplete versus hormone-replete phases within an oral contraceptive cycle (OCC). METHODS: Fifteen healthy female OCP users were recruited and provided a venous blood sample on 2 separate mornings during a 28-day period. These included (a) days 2-4 of the OCC, representing a hormone-free withdrawal period (WD); (b) days 12-14 of the OCC, representing the end of the first week of active hormone therapy (AHT). RESULTS: IL-6 and hepcidin levels were not significantly different at WD and AHT. Serum ferritin was significantly higher (p = 0.039) during AHT as compared to WD. CONCLUSIONS: Fluctuations in OCP hormones (estradiol and/or progestogen) had no effect on basal IL-6 and hepcidin levels in young women. Nevertheless, elevated ferritin levels recorded during AHT may indicate that OCP hormones can positively influence iron stores within an OCC despite unchanged hepcidin levels.

The Effects of the Removal of Electronic Devices for 48 Hours on Sleep in Elite Judo Athletes.

This study examined the effects of evening use of electronic devices (i.e., smartphones, etc.) on sleep quality and next-day athletic and cognitive performance in elite judo athletes. Over 6 consecutive days and nights, 23 elite Australian judo athletes were monitored while attending a camp at the Australian Institute of Sport (AIS). In 14 athletes, all electronic devices were removed on days 3 and 4 (i.e., for 48 hours: the "device-restricted group"), whereas 9 were permitted to use their devices throughout the camp (the "control group"). All athletes wore an activity monitor (Readiband) continuously to provide measures of sleep quantity and quality. Other self-reported (diary) measures included time in bed, electronic device use, and rate of perceived exertion during training periods. Cognitive performance (Cogstate) and physical performance (single leg triple hop test) were also measured. When considering night 2 as a "baseline" for each group, removal of electronic devices on nights 3 and 4 (device-restricted group) resulted in no significant differences in any sleep-related measure between the groups. When comparing actigraphy-based measures of sleep to subjective measures, all athletes significantly overestimated sleep duration by 58 ± 85 minutes (p = 0.001) per night and underestimated time of sleep onset by 37 ± 72 minutes (p = 0.001) per night. No differences in physical or cognitive function were observed between the groups. CONCLUSION: This study has shown that the removal of electronic devices for a period of two nights (48 hours) during a judo camp does not affect sleep quality or quantity or influence athletic or cognitive performance.

Effect of tart cherry juice on recovery and next day performance in well-trained Water Polo players.

BACKGROUND: Tart Montmorency cherries contain high concentrations of phytochemicals and anthocyanins, which have recently been linked to improved athletic recovery and subsequent performance. To date however, previous work reporting promising results has focused on land-based endurance sports, with any potential benefits to team sports remaining unknown. As such, this investigation set-out to examine the effect of supplemental tart cherry juice (CJ) on recovery and next day athletic performance in highly-trained water-based team sport athletes over seven days. METHODS: In a randomised, double-blind, repeated measures, crossover design, nine male Water Polo athletes were supplemented with CJ or a placebo equivalent (PLA) for six consecutive days. Prior to, and at the completion of the supplementation period, water-based performance testing was conducted. On day 6, participants also undertook a fatiguing simulated team game activity. Venous blood samples were collected (Pre-exercise: day 1, 6 and 7; Post-exercise: day 6) to investigate markers of inflammation [Interleukin-6 (IL-6); C-reactive protein (CRP)] and oxidative stress [Uric Acid (UA); F2-Isoprostane (F2-IsoP)]. A daily diary was also completed (total quality of recovery, delayed onset muscle soreness) as a measure of perceptual recovery. RESULTS: In both conditions, day 6 post-exercise IL-6 was significantly higher than pre-exercise and day 7 (p < 0.05); CRP was greater on day 7 as compared to day 6 pre- and post-exercise (p < 0.05); F2-IsoP was significantly lower on day 7 as compared to day 1 and day 6 (p < 0.05); UA remained unchanged (p > 0.05). No differences were found for any performance or recovery measures. CONCLUSIONS: The lack of difference observed in the blood markers between groups may reflect the intermittent, non-weight bearing demands of Water Polo, with such activity possibly unable to create a substantial inflammatory response or oxidative stress (over 7 days) to impede performance; thereby negating any potential beneficial effects associated with CJ supplementation. TRIAL REGISTRATION: This trial was registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR). Registration number: ACTRN12616001080415. Date registered: 11/08/2016, retrospectively registered.

Effects of sodium phosphate and caffeine ingestion on repeated-sprint ability in male athletes.

OBJECTIVES: To assess the effects of sodium phosphate (SP) and caffeine supplementation on repeated-sprint performance. DESIGN: Randomized, double-blind, Latin-square design. METHODS: Eleven team-sport males participated in four trials: (1) SP (50mgkg(-1) of free fat-mass daily for six days) and caffeine (6mgkg(-1) ingested 1h before exercise); SP+C, (2) SP and placebo (for caffeine), (3) caffeine and placebo (for SP) and (4) placebo (for SP and caffeine). After loading, participants performed a simulated team-game circuit (STGC) consisting of 2×30min halves, with 6×20-m repeated-sprint sets performed at the start, half-time and end of the STGC. RESULTS: There were no interaction effects between trials for first-sprint (FS), best-sprint (BS) or total-sprint (TS) times (p>0.05). However, SP resulted in the fastest times for all sprints, as supported by moderate to large effect sizes (ES; d=0.51-0.83) and 'likely' to 'very likely' chances of benefit, compared with placebo. Compared with caffeine, SP resulted in 'possible' to 'likely' chances of benefit for FS, BS and TS for numerous sets and a 'possible' chance of benefit compared with SP+C for BS (set 2). Compared with placebo, SP+C resulted in moderate ES (d=0.50-0.62) and 'possible' to 'likely' benefit for numerous sprints, while caffeine resulted in a moderate ES (d=0.63; FS: set 3) and 'likely' chances of benefit for a number of sets. CONCLUSIONS: While not significant, ES and qualitative analysis results suggest that SP supplementation may improve repeated-sprint performance when compared with placebo.

Effects of sodium phosphate and beetroot juice supplementation on repeated-sprint ability in females.

INTRODUCTION: Sodium phosphate (SP) and beetroot juice (BJ) supplementation was assessed on repeated-sprint ability (RSA). METHODS: Thirteen female team-sport participants completed four trials: (1) SP and BJ (SP + BJ), (2) SP and placebo (for BJ), (3) BJ and placebo (for SP) and (4) placebo (for SP + BJ), with ~21 days separating each trial. After each trial, participants performed a simulated team-game circuit (STGC) consisting of four 15 min quarters, with a 6 × 20-m repeated-sprint set performed at the start, half-time and end. RESULTS: Total sprint times were between 0.95-1.30 and 0.83-1.12 s faster for each RSA set and 3.25 and 3.12 s faster overall (~5% improvement) after SP compared with placebo and BJ, respectively (p = 0.02 for sets 1, 2 and overall; Cohen's effect size: d = -0.51 to -0.90 for all sets and overall). Additionally, total sprint times were 0.48 s faster after SP + BJ compared with placebo (set 2; p = 0.05, ~2% improvement). Furthermore, best sprints were 0.13-0.23 and 0.15-0.20 s faster (~6% improvement; p < 0.01) after SP compared with placebo and BJ, respectively, for all sets (d = -0.54 to -0.89). CONCLUSION: SP improved RSA in team-sport, female athletes when fresh (set 1) and during the later sets of a STGC (sets 2 and 3). Specifically, total and best sprint times were faster after SP compared with placebo and BJ.

Effects of sodium phosphate and caffeine loading on repeated-sprint ability.

The effects of sodium phosphate and caffeine supplementation were assessed on repeated-sprint ability. Using a randomised, double-blind, Latin-square design, 12 female, team-sport players participated in four trials: (1) sodium phosphate and caffeine, (2) sodium phosphate and placebo (for caffeine), (3) caffeine and placebo (for sodium phosphate) and (4) placebo (for sodium phosphate and caffeine), with ~21 days separating each trial. After each trial, participants performed a simulated team-game circuit (4 × 15 min quarters) with 6 × 20-m repeated-sprints performed once before (Set 1), at half-time (Set 2), and after end (Set 3). Total sprint times were faster after sodium phosphate and caffeine supplementation compared with placebo (Set 1: P = 0.003; Set 2: d = -0.51; Set 3: P < 0.001; overall: P = 0.020), caffeine (Set 3: P = 0.004; overall: P = 0.033) and sodium phosphate (Set 3: d = -0.67). Furthermore, total sprint times were faster after sodium phosphate supplementation compared with placebo (Set 1: d = -0.52; Set 3: d = -0.58). Best sprint results were faster after sodium phosphate and caffeine supplementation compared with placebo (Set 3: P = 0.007, d = -0.90) and caffeine (Set 3: P = 0.024, d = -0.73). Best sprint times were also faster after sodium phosphate supplementation compared with placebo (d = -0.54 to -0.61 for all sets). Sodium phosphate and combined sodium phosphate and caffeine loading improved repeated-sprint ability.

Effect of beta-alanine supplementation on 800-m running performance.

UNLABELLED: Beta-alanine supplementation has been shown to improve exercise performance in short-term, high-intensity efforts. PURPOSE: The aim of this study was to assess if beta-alanine supplementation could improve 800 m track running performance in male recreational club runners (n = 18). METHODS: Participants completed duplicate trials (2 presupplementation, 2 postsupplementation) of an 800 m race, separated by 28 days of either beta-alanine (n = 9; 80 mg·kg-1BM·day-1) or placebo (n = 9) supplementation. RESULTS: Using ANCOVA (presupplementation times as covariate), postsupplementation race times were significantly faster following beta-alanine (p = .02), with post- versus presupplementation race times being faster after beta-alanine (-3.64 ± 2.70 s, -2.46 ± 1.80%) but not placebo (-0.59 ± 2.54 s, -0.37 ± 1.62%). These improvements were supported by a moderate effect size (d = 0.70) and a very likely (99%) benefit in the beta-alanine group after supplementation. Split times (ANCOVA) at 400 m were significantly faster (p = .02) postsupplementation in the beta-alanine group, compared with placebo. This was supported by large effect sizes (d = 1.05-1.19) and a very likely (99%) benefit at the 400 and 800 m splits when comparing pre- to postsupplementation with beta-alanine. In addition, the first and second halves of the race were faster post- compared with presupplementation following beta-alanine (1st half -1.22 ± 1.81 s, likely 78% chance of benefit; 2nd half -2.38 ± 2.31 s, d = 0.83, very likely 98% chance of benefit). No significant differences between groups or pre- and postsupplementation were observed for postrace blood lactate and pH. CONCLUSION: Overall, 28 days of beta-alanine supplementation (80 mg·kg-1BM·day-1) improved 800 m track performance in recreational club runners.

Sodium phosphate as an ergogenic aid.

Legal nutritional ergogenic aids can offer athletes an additional avenue to enhance their performance beyond what they can achieve through training. Consequently, the investigation of new nutritional ergogenic aids is constantly being undertaken. One emerging nutritional supplement that has shown some positive benefits for sporting performance is sodium phosphate. For ergogenic purposes, sodium phosphate is supplemented orally in capsule form, at a dose of 3-5 g/day for a period of between 3 and 6 days. A number of exercise performance-enhancing alterations have been reported to occur with sodium phosphate supplementation, which include an increased aerobic capacity, increased peak power output, increased anaerobic threshold and improved myocardial and cardiovascular responses to exercise. A range of mechanisms have been posited to account for these ergogenic effects. These include enhancements in 2,3-Diphosphoglycerate (2,3-DPG) concentrations, myocardial efficiency, buffering capacity and adenosine triphosphate/phosphocreatine synthesis. Whilst there is evidence to support the ergogenic benefits of sodium phosphate, many studies researching this substance differ in terms of the administered dose and dosing protocol, the washout period employed and the fitness level of the participants recruited. Additionally, the effect of gender has received very little attention in the literature. Therefore, the purpose of this review is to critically examine the use of sodium phosphate as an ergogenic aid, with a focus on identifying relevant further research.

Effect of Beta alanine and sodium bicarbonate supplementation on repeated-sprint performance.

This study aimed to investigate if combining beta alanine (BA) and sodium bicarbonate (NaHCO3) supplementation could lead to enhanced repeated-sprint performance in team-sport athletes, beyond what is possible with either supplement alone. Participants (n = 24) completed duplicate trials of a repeated-sprint test (3 sets; 6 × 20 m departing every 25 seconds, 4 minutes active recovery between sets) and were then allocated into 4 groups as follows: BA only (n = 6; 28 days BA, acute sodium chloride placebo); NaHCO3 only (n = 6; 28 days glucose placebo, acute NaHCO3); BA/NaHCO3 (n = 6; 28 days BA, acute NaHCO3); placebo only (n = 6; 28 days glucose placebo, acute sodium chloride placebo), then completed duplicate trials postsupplementation. Sodium bicarbonate alone resulted in moderate effect size (d = 0.40-0.71) and "likely" and "very likely" benefit for overall total sprint times (TST) and for each individual set and for first sprint (sets 2 and 3) and best sprint time (sets 2 and 3). Combining BA and NaHCO3 resulted in "possible" to "likely" benefits for overall TST and for sets 2 and 3. First sprint (set 3) and best sprint time (sets 2 and 3) also showed "likely" benefit after this trial. The BA and placebo groups showed no differences in performance after supplementation. In conclusion, these results indicate that supplementation with acute NaHCO3 improved repeated-sprint performance more than either a combination of NaHCO3 and BA or BA alone.

Effect of beta-alanine supplementation on 2000-m rowing-ergometer performance.

UNLABELLED: Beta-alanine supplementation has been shown to improve exercise performance in short-term high-intensity efforts. However, whether supplementation with beta-alanine is ergogenic to actual sporting events remains unclear and should be investigated in field testing or race simulations. PURPOSE: The aim of this study was to assess if beta-alanine supplementation could improve 2,000-m rowing-ergometer performance in well-trained male rowers. METHODS: Participants (N = 16) completed duplicate trials (2 × before supplementation and 2 × after supplementation) of a 2,000-m rowing-ergometer race separated by 28 days of either beta-alanine (n = 7; 80 mg · kg-1 BM · d-1) or placebo (n = 9; glucose) supplementation. RESULTS: Beta-alanine group (pooled) race times improved by 2.9 ± 4.1 s and placebo group slowed by 1.2 ± 2.9 s, but these results were inconclusive for performance enhancement (p = .055, ES = 0.20, smallest worthwhile change = 49% beneficial). Race split times and average power outputs only significantly improved with beta-alanine at the 750-m (time -0.7 s, p = .01, power +3.6%, p = .03) and 1,000-m (time -0.5 s, p = .01, power +2.9%, p = .02) distances. Blood La- and pH postrace values were not different between groups before or after supplementation. CONCLUSIONS: Overall, 28 d of beta-alanine supplementation with 80 mg · kg-1 BM · d-1 (~7 g/d) did not conclusively improve 2,000-m rowing-ergometer performance in well-trained rowers.

Effect of repeated sodium phosphate loading on cycling time-trial performance and VO2peak.

Research into supplementation with sodium phosphate has not investigated the effects of a repeated supplementation phase. Therefore, this study examined the potential additive effects of repeated sodium phosphate (SP) supplementation on cycling time-trial performance and peak oxygen uptake (VO2peak). Trained male cyclists (N = 9, M ± SD VO2peak = 65.2 ± 4.8 ml · kg-1 · min-1) completed baseline 1,000-kJ time-trial and VO2peak tests separated by 48 hr, then ingested either 50 mg · kg fat-free mass-1 · d-1 of tribasic SP or a combined glucose and NaCl placebo for 6 d before performing these tests again. A 14-d washout period separated the end of one loading phase and the start of the next, with 2 SP and 1 placebo phase completed in a counterbalanced order. Although time-trial performance (55.3-56.5 min) was shorter in SP1 and SP2 (~60-70 s), effect sizes and smallest-worthwhile-change values did not differ in comparison with baseline and placebo. However, mean power output was greater than placebo during time-trial performance at the 250-kJ and 500-kJ time points (p < .05) after the second SP phase. Furthermore, mean VO2peak values (p < .01) were greater after the SP1 (3.5-4.3%), with further improvements (p < .01) found in SP2 (7.1-7.7%), compared with baseline and placebo. In summary, repeated SP supplementation, ingested either 15 or 35 d after initial loading, can have an additive effect on VO2peak and possibly time-trial performance.

Reliability and effect of sodium bicarbonate: buffering and 2000-m rowing performance.

PURPOSE: The aim of this study was to determine the effect and reliability of acute and chronic sodium bicarbonate ingestion for 2000-m rowing ergometer performance (watts) and blood bicarbonate concentration [HCO3-]. METHODS: In a crossover study, 7 well-trained rowers performed paired 2000-m rowing ergometer trials under 3 double-blinded conditions: (1) 0.3 grams per kilogram of body mass (g/kg BM) acute bicarbonate; (2) 0.5 g/kg BM daily chronic bicarbonate for 3 d; and (3) calcium carbonate placebo, in semi-counterbalanced order. For 2000-m performance and [HCO3-], we examined differences in effects between conditions via pairwise comparisons, with differences interpreted in relation to the likelihood of exceeding smallest worthwhile change thresholds for each variable. We also calculated the within-subject variation (percent typical error). RESULTS: There were only trivial differences in 2000-m performance between placebo (277 ± 60 W), acute bicarbonate (280 ± 65 W) and chronic bicarbonate (282 ± 65 W); however, [HCO3-] was substantially greater after acute bicarbonate, than with chronic loading and placebo. Typical error for 2000-m mean power was 2.1% (90% confidence interval 1.4 to 4.0%) for acute bicarbonate, 3.6% (2.5 to 7.0%) for chronic bicarbonate, and 1.6% (1.1 to 3.0%) for placebo. Postsupplementation [HCO3-] typical error was 7.3% (5.0 to 14.5%) for acute bicarbonate, 2.9% (2.0 to 5.7%) for chronic bicarbonate and 6.0% (1.4 to 11.9%) for placebo. CONCLUSION: Performance in 2000-m rowing ergometer trials may not substantially improve after acute or chronic bicarbonate loading. However, performances will be reliable with both acute and chronic bicarbonate loading protocols.

Effect of contrast water therapy duration on recovery of running performance.

PURPOSE: To investigate whether contrast water therapy (CWT) assists acute recovery from high-intensity running and whether a dose-response relationship exists. METHODS: Ten trained male runners completed 4 trials, each commencing with a 3000-m time trial, followed by 8 × 400-m intervals with 1 min of recovery. Ten minutes postexercise, participants performed 1 of 4 recovery protocols: CWT, by alternating 1 min hot (38°C) and 1 min cold (15°C) for 6 (CWT6), 12 (CWT12), or 18 min (CWT18), or a seated rest control trial. The 3000-m time trial was repeated 2 h later. RESULTS: 3000-m performance slowed from 632 ± 4 to 647 ± 4 s in control, 631 ± 4 to 642 ± 4 s in CWT6, 633 ± 4 to 648 ± 4 s in CWT12, and 631 ± 4 to 647 ± 4 s in CWT18. Following CWT6, performance (smallest worthwhile change of 0.3%) was substantially faster than control (87% probability, 0.8 ± 0.8% mean ± 90% confidence limit), however, there was no effect for CWT12 (34%, 0.0 ± 1.0%) or CWT18 (34%, -0.1 ± 0.8%). There were no substantial differences between conditions in exercise heart rates, or postexercise calf and thigh girths. Algometer thigh pain threshold during CWT12 was higher at all time points compared with control. Subjective measures of thermal sensation and muscle soreness were lower in all CWT conditions at some post-water-immersion time points compared with control; however, there were no consistent differences in whole body fatigue following CWT. CONCLUSIONS: Contrast water therapy for 6 min assisted acute recovery from high-intensity running; however, CWT duration did not have a dose-response effect on recovery of running performance.

Induced alkalosis and caffeine supplementation: effects on 2,000-m rowing performance.

INTRODUCTION: The purpose of this investigation was to determine the effect of ingested caffeine, sodium bicarbonate, and their combination on 2,000-m rowing performance, as well as on induced alkalosis (blood and urine pH and blood bicarbonate concentration [HCO3-]), blood lactate concentration ([La-]), gastrointestinal symptoms, and rating of perceived exertion (RPE). METHODS: In a double-blind, crossover study, 8 well-trained rowers performed 2 baseline tests and 4 × 2,000-m rowing-ergometer tests after ingesting 6 mg/kg caffeine, 0.3 g/kg body mass (BM) sodium bicarbonate, both supplements combined, or a placebo. Capillary blood samples were collected at preingestion, pretest, and posttest time points. Pairwise comparisons were made between protocols, and differences were interpreted in relation to the likelihood of exceeding the smallest worthwhile-change thresholds for each variable. A likelihood of >75% was considered a substantial change. RESULTS: Caffeine supplementation elicited a substantial improvement in 2,000-m mean power, with mean (± SD) values of 354 ± 67 W vs. placebo with 346 ± 61 W. Pretest [HCO3-] reached 29.2 ± 2.9 mmol/L with caffeine + bicarbonate and 29.1 ± 1.9 mmol/L with bicarbonate. There were substantial increases in pretest [HCO3-] and pH and posttest urine pH after bicarbonate and caffeine + bicarbonate supplementation compared with placebo, but unclear performance effects. CONCLUSIONS: Rowers' performance in 2,000-m efforts can improve by ~2% with 6 mg/kg BM caffeine supplementation. When caffeine is combined with sodium bicarbonate, gastrointestinal symptoms may prevent performance enhancement, so further investigation of ingestion protocols that minimize side effects is required.