The Efficacy of Chlorella Supplementation on Multiple Indices of Cycling Performance

This study investigated the effects of chlorella supplementation on submaximal endurance, time trial performance, lactate threshold, and power indices during a repeated sprint performance test by fourteen male trained cyclists. Participants ingested 6 g/day of chlorella or placebo for 21-days in a double-blinded randomized counter-balanced cross-over design, with a fourteen-day washout period between trials. Each completed a 2-day testing period comprising a 1-hour submaximal endurance test at 55% external power output max and a 16.1 km time trial (Day-1), followed by a lactate threshold (Dmax) and repeated sprint performance tests (3 X 20 s sprints interspersed by 4-mins) (Day-2). Heart rate (b.min-1), RER, V̇O2 (ml·kg-1·min-1), lactate and glucose (mmol/L), time (secs), power output (W/kg), and hemoglobin (g/L) were compared across conditions. Following chlorella supplementation (chlorella vs. placebo for each measurement) average lactate and heart rate were significantly lower (p < 0.05) during submaximal endurance tests (1.68 ± 0.50 mmol/L vs. 1.91 ± 0.65 mmol/L & 138 ± 11b.min-1 vs. 144 ± 10b.min-1), average power and peak power (W/kg) were significantly higher during repeated sprint bouts (9.5 ± 0.7 W/kg vs. 9.0 ± 0.7 W/kg & 12.0 ± 1.2 W/kg vs. 11.4 ± 1.4 W/kg), hemoglobin significantly increased (149.1 ± 10.3 g/L) in comparison to placebo (143.4 ± 8.7 g/L) (p = 0.05). No differences existed between conditions for all oxygen consumption values, 16.1 km time trial measures and lactate threshold tests (p > 0.05). In conclusion, chlorella may pose as an additional supplement for cyclists to consider, particularly for those cyclists who want to improve their sprinting.

Algae Supplementation for Exercise Performance: Current Perspectives and Future Directions for Spirulina and Chlorella

Nutritional clinical trials have reported algae such as spirulina and chlorella to have the capability to improve cardiovascular risk factors, anemia, immune function, and arterial stiffness. With positive results being reported in clinical trials, researchers are investigating the potential for algae as an ergogenic aid for athletes. Initial studies found spirulina and chlorella supplementation to increase peak oxygen uptake and time to exhaustion, with the mechanistic focus on the antioxidant capabilities of both algae. However, a number of oxidative stress biomarkers reported in these studies are now considered to lack robustness and have consequently provided equivocal results. Considering the nutrient complexity and density of these commonly found edible algae, there is a need for research to widen the scope of investigation. Most recently algae supplementation has demonstrated ergogenic potential during submaximal and repeated sprint cycling, yet a confirmed primary mechanism behind these improvements is still unclear. In this paper we discuss current algae supplementation studies and purported effects on performance, critically examine the antioxidant and ergogenic differing perspectives, and outline future directions.

Twenty-one days of spirulina supplementation lowers heart rate during submaximal cycling and augments power output during repeated sprints in trained cyclists

Spirulina supplementation has been reported to improve time to exhaustion and maximal oxygen consumption (V̇O2max). However, there is limited information on its influence over the multiple intensities experienced by cyclists during training and competition. Fifteen trained males (age 40 ± 8 years, V̇O2max 51.14 ± 6.43 mL/min/kg) ingested 6 g/day of spirulina or placebo for 21 days in a double-blinded randomised crossover design, with a 14-day washout period between trials. Participants completed a 1-hour submaximal endurance test at 55% external power output max and a 16.1-km time trial (day 1), followed by a lactate threshold test and repeated sprint performance tests (RSPTs) (day 2). Heart rate (bpm), respiratory exchange ratio, oxygen consumption (mL/min/kg), lactate and glucose (mmol/L), time (seconds), power output (W), and hemoglobin (g/L) were compared across conditions. Following spirulina supplementation, lactate and heart rate were significantly lower (P < 0.05) during submaximal endurance tests (2.05 ± 0.80 mmol/L vs 2.39 ± 0.89 mmol/L and 139 ± 11 bpm vs 144 ± 12 bpm), hemoglobin was significantly higher (152.6 ± 9.0 g/L) than placebo (143.2 ± 8.5 g/L), and peak and average power were significantly higher during RSPTs (968 ± 177 W vs 929 ± 149 W and 770 ± 117 W vs 738 ± 86 W). No differences existed between conditions for all oxygen consumption values, 16.1-km time trial measures, and lactate threshold tests (P > 0.05). Spirulina supplementation reduces homeostatic disturbances during submaximal exercise and augments power output during RSPTs. Novelty: Spirulina supplementation lowers heart rate and blood lactate during ∼1-hour submaximal cycling. Spirulina supplementation elicits significant augmentations in hemoglobin and power outputs during RSPTs.

Functionality of the Crosswise Model for Assessing Sensitive or Transgressive Behavior: A Systematic Review and Meta-Analysis

Tools for reliable assessment of socially sensitive or transgressive behavior warrant constant development. Among them, the Crosswise Model (CM) has gained considerable attention. We systematically reviewed and meta-analyzed empirical applications of CM and addressed a gap for quality assessment of indirect estimation models. Guided by the PRISMA protocol, we identified 45 empirical studies from electronic database and reference searches. Thirty of these were comparative validation studies (CVS) comparing CM and direct question (DQ) estimates. Six prevalence studies exclusively used CM. One was a qualitative study. Behavior investigated were substance use and misuse (k = 13), academic misconduct (k = 8), and corruption, tax evasion, and theft (k = 7) among others. Majority of studies (k = 39) applied the "more is better" hypothesis. Thirty-five studies relied on birthday distribution and 22 of these used P = 0.25 for the non-sensitive item. Overall, 11 studies were assessed as high-, 31 as moderate-, and two as low quality (excluding the qualitative study). The effect of non-compliance was assessed in eight studies. From mixed CVS results, the meta-analysis indicates that CM outperforms DQ on the "more is better" validation criterion, and increasingly so with higher behavior sensitivity. However, little difference was observed between DQ and CM estimates for items with DQ prevalence estimate around 50%. Based on empirical evidence available to date, our study provides support for the superiority of CM to DQ in assessing sensitive/transgressive behavior. Despite some limitations, CM is a valuable and promising tool for population level investigation.

Performance determinants, running energetics and spatiotemporal gait parameters during a treadmill ultramarathon

Purpose

The objective of this study was to investigate the changes in metabolic variables, running energetics and spatiotemporal gait parameters during an 80.5 km treadmill ultramarathon and establish which key predictive variables best determine ultramarathon performance.

Methods

Twelve participants (9 male and 3 female, age 34 ± 7 years, and maximal oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O_2max) 60.4 ± 5.8 ml·kg⁻¹·min⁻¹) completed an 80.5 km time trial on a motorised treadmill in the fastest possible time. Metabolic variables: oxygen consumption (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O₂), carbon dioxide production (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙CO₂) and pulmonary ventilation (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙_E) were measured via indirect calorimetry every 16.1 km at a controlled speed of 8 km·h⁻¹ and used to calculate respiratory exchange ratio (RER), the energy cost of running (Cr) and fractional utilisation of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O_2max (F). Spatiotemporal gait parameters: stride length (SL) and cadence (SPM) were calculated via tri-axial accelerometery.

Results

Trial completion time was 09:00:18 ± 01:14:07 (hh:mm:ss). There were significant increases in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O₂, Cr, F, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙_E and heart rate (HR) (p < 0.01); a significant decrease in RER (p < 0.01) and no change in SL and SPM (p > 0.05) across the measured timepoints. F and Cr accounted for 61% of the variance in elapsed finish time (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_{{{\text{adj}}}}^{{2}}$$\end{document}Radj2 = 0.607, p < 0.01).

Conclusion

A treadmill ultramarathon elicits significant changes in metabolic variables, running energetics and spatiotemporal gait parameters. With F and Cr explaining 61% of variance in finish time. Therefore, those able to maintain a higher F, while adopting strategies to minimise an increase in Cr may be best placed to maximise ultramarathon performance.

Spirulina supplementation improves oxygen uptake in arm cycling exercise

PURPOSE

Spirulina has previously been reported to improve high-intensity exercise performance and hemoglobin. However, spirulina's effect on arm cycling exercise has yet to be investigated. The purpose of this study was to investigate the responses of spirulina supplementation on hemoglobin and on oxygen uptake, RER and HR during seated arm cycling exercise.

METHODS

In a double-blinded randomized crossover design, eleven males untrained in arm cycling ingested 6 g/day of spirulina or placebo for seven days. Seated on the Arm Crank Ergometer, each participant performed a baseline V̇O2max test, and then after supplementation, 2 × 30-min submaximal exercise bouts corresponding to 55% of their V̇O2max, followed by an incremental test to fatigue. A seven-day wash-out period was required between conditions. Oxygen uptake, RER and HR were measured continuously during exercise and hemoglobin measured prior to exercise after both conditions.

RESULTS

Spirulina significantly (p < 0.05) increased Hb in comparison to Placebo (144.1 g/l ± 10.5 Vs 154.5 g/l ± 6.9). After spirulina supplementation, during the 30-min exercise bouts, oxygen uptake and HR were significantly lower (2170 ml/min ± 173 Vs 2311 ml/min ± 189 and 154 bpm ± 14 Vs 149 bpm ± 17), RER was not significantly different. In comparison to placebo, Spirulina significantly increased oxygen uptake at time of fatigue (34.10 ml/min/kg ± 6.03 Vs 37.37 ml/min/kg ± 5.98). Time taken to fatigue was not different.

CONCLUSION

Spirulina supplementation significantly reduces oxygen uptake and HR during arm cycling submaximal exercise, allowing for an increased oxygen uptake during an incremental test to fatigue.

Genes and Elite Marathon Running Performance: A Systematic Review

Genetics has long been considered to associate with many exercise-related traits and sport performance phenotypes. A genetic basis for elite international marathon running performance exists due to the heritability of endurance-related traits. This has prompted a generation of genomic study to identify marathon success. The aim of this study was to systematically review the evidence of genes, and their polymorphisms, that may play a role in marathon running performance. A search strategy was implemented on systematic databases following PRISMA guidelines. Studies were case-control, cohort or genome-wide association designs and provided data on the genotypes associated with elite marathon athlete status and/or marathon running performance. The search identified 241 studies, from which, 14 studies were deemed suitable for inclusion. A total of 160 different polymorphisms in 27 genes were identified in 10,442 participants, of which 2,984 were marathon distance runners. The review identified a possible 16 single nucleotide polymorphisms (SNPs) in 14 genes associated with marathon running performance. While multiple genes and their polymorphisms have been associated with marathon running performance, predicting future marathon success based on genomic data is premature due to the lack of replicated studies. There is limited replication of genotype-phenotype associations and there is possible publication bias, thus, further studies are required to strengthen our understanding of the genes involved in marathon running. Future research utilising genome-wide technologies in large cohorts is required to elucidate the multiple genetic factors that govern complex endurance-related traits and the impact of epigenetics should be considered.

Comparative efficacy of active recovery and cold water immersion as post-match recovery interventions in elite youth soccer

The current study compared cold-water immersion (CWI) and active recovery (AR) to static stretching (SS) on muscle recovery post-competitive soccer matches in elite youth players (n = 15). In a controlled crossover design, participants played a total of nine competitive soccer games, comprising three 80 minute games for each intervention (SS, CWI and AR). Muscle oedema, creatine kinase (CK), countermovement jump performance (CMJA) and perceived muscle soreness (PMS) were assessed pre-, immediately post-, and 48 hours post-match and compared across time-intervals and between interventions. Following SS, all markers of muscle damage remained significantly elevated (P < 0.05) compared to baseline at 48 hours post-match. Following AR and CWI, CMJA returned to baseline at 48 hours post-match, whilst CK returned to baseline following CWI at 48 hours post-match only. Analysis between recovery interventions revealed a significant improvement in PMS (P < 0.05) at 48 hours post-match when comparing AR and CWI to SS, with no significant differences between AR and CWI observed (P > 0.05). Analysis of %change for CK and CMJA revealed significant improvements for AR and CWI compared to SS. The present study indicated both AR and CWI are beneficial recovery interventions for elite young soccer players following competitive soccer matches, of which were superior to SS.

Emotional intelligence and mood states impact on the stress response to a treadmill ultramarathon

OBJECTIVES

Participants of ultramarathon events experience a complex interaction of psychophysiological stressors. Therefore, the purpose of this study was to investigate the role of trait emotional intelligence (trait EI) on mood states and serum cortisol responses to a 80.5km treadmill ultramarathon.

DESIGN

Twelve participants completed an 80.5km time-trial on a motorised treadmill in the fastest possible time.

METHODS

Participants' trait EI was measured prior to the trial. A mood state questionnaire was completed prior (baseline: within two weeks of treadmill ultramarathon), immediately prior (pre: within 30min of commencing treadmill ultramarathon), at 40.25km (halfway: during standardised 10min rest period to allow for venous blood sampling) and on completion of 80.5km (post: immediately on completion of treadmill ultramarathon), along with serum cortisol concentrations measured at the same time points.

RESULTS

Completion time was 09:00:18±01:14:07 (hhmmss). Significant increase in serum cortisol and total mood disturbance (TMD) was observed throughout the treadmill ultramarathon (p<0.05). Participants with higher trait EI displayed a higher post cortisol concentration (p=0.01) with no change in TMD, compared to those with low trait EI who displayed a significant increase in TMD between pre and halfway (p=0.02).

CONCLUSIONS

The treadmill ultramarathon elicited a significant increase in serum cortisol concentration, which was significantly greater in those with a higher trait EI. Those individuals with higher trait EI were more effective at managing their mood, with little change total mood disturbance and perceived effort compared to those with lower trait EI.

Static stretching does not enhance recovery in elite youth soccer players

Background

Static stretching (SS) is a recovery intervention used for the reduction of muscle soreness postexercise. The effects of SS on elite young footballers have received little attention, and therefore the aim of this study was to assess the effects of SS on muscle recovery following competitive soccer matches in elite young footballers.

Methods

Ten male participants (16±1 years) were recruited from an English Premier League professional soccer academy. Using a controlled crossover design, participants followed one of two recovery interventions (SS or passive recovery (PR)) immediately following completion of competitive soccer matches. Muscle oedema, creatine kinase (CK), countermovement jump with arms (CMJA) performance and perceived muscle soreness were assessed before, immediately after and 48 hours postmatch.

Results

Competitive soccer matches significantly induced muscle damage, with time intervals of perceived soreness and CK showing significant increases (p<0.05), and CMJA showing significant decreases between prematch, postmatch and 48 hours postmatch for both SS and PR (p<0.05). Comparisons of the absolute effects of SS with PR only revealed significant decreases for CK 48 hours postmatch (p<0.05) as a result of SS intervention.

Conclusion

The current study demonstrated competitive soccer matches induced muscle damage, which may have detrimental effects on future performance within 24–48 hours postmatch. Furthermore, there was limited evidence to suggest SS would assist in the reduction of muscle soreness postexercise. Therefore, it can be argued that SS is not a beneficial recovery option for elite youth soccer players.

Dark chocolate supplementation reduces the oxygen cost of moderate intensity cycling

Background

Dark chocolate (DC) is abundant in flavanols which have been reported to increase the bioavailability and bioactivity of nitric oxide (NO). Increasing NO bioavailability has often demonstrated reduced oxygen cost and performance enhancement during submaximal exercise.

Methods

Nine moderately-trained male participants volunteered to undertake baseline (BL) measurements that comprised a cycle \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \overset{.}{V}{O}_{2 max} $$\end{document}V.O2max test followed by cycling at 80 % of their established gas exchange threshold (GET) for 20-min and then immediately followed by a two-minute time-trial (TT). Using a randomised crossover design participants performed two further trials, two weeks apart, with either 40 g of DC or white chocolate (WC) being consumed daily. Oxygen consumption, RER, heart rate and blood lactate (BLa) were measured during each trial.

Results

DC consumption increased GET and TT performance compared to both BL and WC (P < 0.05). DC consumption increased \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \overset{.}{V}{O}_{2 max} $$\end{document}V.O2max by 6 % compared to BL (P < 0.05), but did not reach statistical significance compared to WC. There were no differences in the moderate-intensity cycling for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \overset{.}{V}{O}_2 $$\end{document}V.O2_, RER, BLa and heart rate between conditions, although, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \overset{.}{V}{O}_2 $$\end{document}V.O2 and RER exhibited consistently lower trends following DC consumption compared to BL and WC, these did not reach statistical significance.

Conclusion

Chronic supplementation with DC resulted in a higher GET and enhanced TT performance. Consequently, ingestion of DC reduced the oxygen cost of moderate intensity exercise and may be an effective ergogenic aid for short-duration moderate intensity exercise.

A single dose of beetroot juice enhances cycling performance in simulated altitude

INTRODUCTION

Increasing nitric oxide bioavailability via supplementation with nitrate-rich beetroot juice (BR) has been shown to attenuate the negative effect of hypoxia on peripheral oxygen saturation and exercise tolerance.

PURPOSE

We investigated the effects of a single dose of concentrated BR on the physiological responses to submaximal exercise and time trial (TT) performance in trained cyclists exposed to moderate simulated altitude (approximately 2500 m).

METHODS

Nine competitive amateur male cyclists (age, 28 ± 8 yr; V˙O2peak at altitude, 51.9 ± 5.8 mL·kg·min) completed four exercise trials consisting of an initial graded test to exhaustion and three performance trials on a cycle ergometer. The performance trials comprised 15 min of submaximal steady-state exercise at 60% maximum work rate and a 16.1-km TT. The second and third trials were preceded by ingestion of either 70 mL of BR or nitrate-depleted BR (PLA) 3 h before exercise.

RESULTS

Plasma nitrate (PLA, 39.1 ± 3.5 µM; BR, 150.5 ± 9.3 µM) and nitrite (PLA, 289.8 ± 27.9 nM; BR, 678.1 ± 103.5 nM) measured immediately before exercise were higher after ingestion of BR compared with that after PLA (P < 0.001, P = 0.004). V˙O2 during steady-state exercise was lower in the BR trial (2542 ± 114 mL·min) than that in the PLA trial (2727 ± 85 mL·min, P = 0.049). TT performance was significantly faster after BR (1664 ± 14 s) than that after PLA (1702 ± 15 s, P = 0.021).

CONCLUSION

A single dose of BR lowered V˙O2 during submaximal exercise and enhanced TT performance of trained cyclists in normobaric hypoxia. Consequently, ingestion of BR may be a practical and effective ergogenic aid for endurance exercise at altitude.

Influence of pre-exercise glucose ingestion of two concentrations on paraplegic athletes

In this study, we assessed the influence that pre-exercise glucose ingestion of two concentrations has on the physiological responses of paraplegic athletes. Eight men with paraplegia ingested a drink containing 4% (low) or 11% (high) carbohydrate in a randomized double-blind crossover design, 20 min before exercise. The participants performed wheelchair exercise at 65% of peak oxygen uptake for 1 h followed by a 20 min performance test. During both trials, the physiological responses were similar and indicated steady-state exercise. At the onset of exercise, blood glucose concentrations in both trials increased after carbohydrate ingestion (P < 0.05) before returning to resting values after 20 min of exercise and there were no differences between trials. Free fatty acid concentrations increased from rest to 1 h of exercise in both trials, with a greater increase during the low carbohydrate trial that led to a difference in free fatty acids between trials at the end of the 1 h tests (P < 0.05). There was a tendency for the performance distances and power outputs achieved during the high carbohydrate trial to be greater than those achieved during the low carbohydrate trial (P= 0.08). In conclusion, when paraplegic athletes ingested low and high carbohydrate drinks before exercise, the decline in blood glucose concentrations was similar. The tendency for higher blood glucose concentrations, respiratory exchange ratios and power outputs and lower free fatty acid concentrations (P < 0.05) during the high carbohydrate trial suggests that a higher concentration of carbohydrate in a sports drink might be a better choice for paraplegic athletes.

Effects of fatigue on the torque-velocity relation in muscle

BACKGROUND

The extent to which fatigue is related to the velocity of shortening is still not fully understood.

OBJECTIVES

To examine the effects of fatigue induced by maximal intensity exercise at different velocities on subsequent torque-velocity relations in muscle.

METHODS

Ten men (mean (SD) age 25 (3) years; stature 1.78 (0.34) m; body mass 80.6 (14.5) kg) provided written informed consent and, over a five day period in a randomised manner, performed 16 fatiguing bouts of maximal intensity exercise on an isokinetic dynamometer each followed by one repetition maximum action. Concentric peak torque of the preferred leg was assessed at angular velocities of 0.52, 1.05, 2.09, and 3.14 rad/s. Mechanical work performed for all fatiguing bouts was held at 3050-3150 J. After a 45 second rest, a maximum effort was performed at one of the preset velocities. As a baseline, dependent variables of peak torque (N.m), angle of peak torque (rad), and mean torque (N.m) were measured at each velocity. An analysis of covariance was used to compare torque-velocity relations, and one factor, within subject analyses of variance with repeated measures investigated differences from baseline.

RESULTS

Torque-velocity relations for all dependent variables did not differ (p>0.05). Similarly, angles at which peak torque occurred were not velocity dependent and did not differ from baseline and subsequent exercise measures (p>0.05). Generally, fatiguing exercise at low velocities led to reductions in peak and mean torque in subsequent exercise at higher velocities (p<0.05).

CONCLUSIONS

Torque-velocity relations fundamentally remain intact after fatigue induced at any velocity, although the magnitude changes. The results suggest that the greater decline in torque during subsequent exercise at high velocities could be due to greater exhaustion of fatigue sensitive type II fibres, whereas low velocity subsequent exercise is less affected because of the greater use of type I fibres.

The effect of glucose ingestion on endurance upper-body exercise and performance

The physiological responses to glucose supplementation during arm crank exercise were investigated. Ten subjects of mean age 28 +/- 8 years; stature 180.8 +/- 6.5 cm; mass 82.7 +/- 11.5 kg, .VO(2) peak 3.10 +/- 0.50 l x min(-1) were tested on two occasions separated by a week. A 7.6% glucose drink or placebo was administered in a blind crossover design 20 min prior to exercise. Subject's arm cranked for 60 min at an exercise intensity of 65% .VO(2)peak followed by a 20 min performance test. Rate of ventilation, oxygen uptake, RER, heart rate and blood lactate demonstrated similar responses between trials throughout the course of the hour. The blood glucose concentrations at rest were similar between trials increasing after glucose ingestion to show a significant difference (p < 0.05) to the placebo trial at the onset of exercise, then returning to resting values after 20 min. The 20 min performance tests revealed that after glucose ingestion athletes achieved a greater mean distance of 12.55 +/- 1.29 km than in the placebo trial of 11.50 +/- 1.68 km (p < 0.05). In conclusion, the results showed that after one-hour of arm crank exercise, performance over a further twenty minutes was improved when glucose was ingested twenty minutes prior to exercise.