Blood lactate and ventilatory thresholds in wheelchair athletes with tetraplegia and paraplegia

Toward a Standardized and Individualized Laboratory-Based Protocol for Wheelchair-Specific Exercise Capacity Testing in Wheelchair Athletes: A Scoping Review

ABSTRACT

Previous studies on handrim wheelchair-specific (an)aerobic exercise capacity in wheelchair athletes have used a diversity of participants, equipment, and protocols. Therefore, test results are difficult to compare among studies. The first aim of this scoping review is to provide an overview of the populations studied, the equipment and protocols used, and the reported outcomes from all laboratory-based studies on wheelchair-specific exercise capacity in wheelchair athletes. The second aim is to synthesize these findings into a standardized, yet individualized protocol. A scoping literature search resulted in 10 anaerobic and 38 aerobic protocols. A large variety in equipment, protocol design, and reported outcomes was found. Studies that systematically investigated the influence of protocol features are lacking, which makes it difficult to interpret and compare test outcomes among the heterogeneous group of wheelchair athletes. Protocol design was often dependent on a priori participant knowledge. However, specific guidelines for individualization were missing. However, the common protocol features of the different studies were united into guidelines that could be followed when performing standardized and individualized wheelchair-specific exercise capacity tests in wheelchair athletes. Together with guidelines regarding reporting of participant characteristics, used equipment, and outcome measures, we hope to work toward more international agreement in future testing.

Shoulder Tendon Adaptations Following a Graded Exercise Test to Exhaustion in Highly Trained Wheelchair Rugby Athletes With Different Impairments

Objective

This study aimed to identify acute changes in biceps and supraspinatus tendon characteristics before and after a graded exercise test to exhaustion (GXT) in highly trained wheelchair rugby (WR) athletes. A secondary aspect was to define chronic tendon adaptations related to the impairment of the athlete and the occupation of the tendon within the subacromial space (occupation ratio).

Methods

Twelve WR athletes with different impairments (age = 32 ± 6 years; body mass = 67.2 ± 11.2 kg; 9.0 ± 3.6 years competing) volunteered for this study. Performance Corrected Wheelchair Users Shoulder Pain Index was used to quantify shoulder pain. Quantitative Ultrasound Protocols (QUS) were used to define supraspinatus and biceps tendon thickness, echogenicity, and echogenicity ratio of both dominant and non-dominant shoulder before and after the GXT including 22 ± 3.1 min submaximal propulsion and 10.2 ± 1.7 min maximal propulsion on a treadmill. Furthermore, the acromio-humeral distance (AHD) defined from ultrasound (US) images was used to calculate the occupation ratios.

Results

A mixed-effect multilevel analysis that included shoulder as grouping variable, demonstrated a significant reduction in the echogenicity of the biceps following GXT whilst controlling for impairment [spinal cord injury (SCI) and non-SCI] and the occupation ratio (β = −9.01, SEβ = 2.72, p = 0.001, 95% CI = [−14.34; −3.68]). This points toward fluid inflow into the tendon that may be related to overload and acute inflammation. In addition, persons with a SCI (n = 8) had a thicker supraspinatus tendon in comparison to persons with non-SCI (n = 3) which may be related to chronic tendon adaptations (β = −0.53 mm, SEβ = 0.26, p = 0.038, 95% CI = [−1.04; −0.03]). Finally, a greater occupation ratio was associated with signs of tendinopathy (i.e., greater biceps and supraspinatus tendon thickness, and lower supraspinatus echogenicity and echogenicity ratio).

Conclusion

Acute biceps tendon adaptations in response to the GXT in highly trained WR athletes were evident with chronic adaptations in the supraspinatus tendon being related to the impairment of the athlete. Ultrasound can be used to monitor tendon adaptations in WR athletes for medical diagnosis to assist the scheduling and type of training.

A Reappraisal of Ventilatory Thresholds in Wheelchair Athletes With a Spinal Cord Injury: Do They Really Exist?

The ventilatory threshold (VT) separates low- from moderate-intensity exercise, the respiratory compensation point (RCP) moderate- from high-intensity exercise. Both concepts assume breakpoints in respiratory data. However, the objective determination of the VT and RCP using breakpoint models during upper-body modality exercise in wheelchair athletes with spinal cord injury (SCI) has received little attention. Therefore, the aim of this study was to compare the fit of breakpoint models (i.e., two linear regression lines) with continuous no-breakpoint models (i.e., exponential curve/second-order polynomial) to respiratory data obtained during a graded wheelchair exercise test to exhaustion. These fits were compared employing adjusted R², and blocked bootstrapping was used to derive estimates of a median and 95% confidence intervals (CI). V̇O₂-V̇CO₂ and V̇E/V̇O₂-time data were assessed for the determination of the VT, and V̇CO₂-V̇E and V̇E/V̇CO₂-time data for the determination of the RCP. Data of 9 wheelchair athletes with tetraplegia and 8 with paraplegia were evaluated. On an overall group-level, there was an overlap in the adjusted R² median ± 95% CI between the breakpoint and the no-breakpoint models for determining the VT (V̇O₂-V̇CO₂: 0.991 ± 0.003 vs. 0.990 ± 0.003; V̇E/V̇O₂-time: 0.792 ± 0.101 vs. 0.782 ± 0.104, respectively) and RCP (V̇E-V̇CO₂: 0.984 ± 0.004 vs. 0.984 ± 0.004; V̇E/V̇CO₂-time: 0.729 ± 0.064 vs. 0.691 ± 0.063, respectively), indicating similar model fit. We offer two lines of reasoning: (1) breakpoints in these respiratory data exist but are too subtle to result in a significant difference in adjusted R² between the investigated breakpoint and no-breakpoint models; (2) breakpoints do not exist, as has been argued previously.

Criterion Validity of a Field-Based Assessment of Aerobic Capacity in Wheelchair Rugby Athletes

PURPOSE

To confirm whether peak aerobic capacity determined during laboratory testing could be replicated during an on-court field-based test in wheelchair rugby players.

METHODS

Sixteen wheelchair rugby players performed an incremental speed-based peak oxygen uptake (V˙O2peak) test on a motorized treadmill (TM) and completed a multistage fitness test (MFT) on a basketball court in a counterbalanced order, while spirometric data were recorded. A paired t test was performed to check for systematic error between tests. A Bland-Altman plot for V˙O2peak illustrated the agreement between the TM and MFT results and how this related to the boundaries of practical equivalence.

RESULTS

No significant differences between mean V˙O2peak were reported (TM: 1.85 [0.63] vs MFT: 1.81 [0.63] L·min-1; P = .33). Bland-Altman plot for V˙O2peak suggests that the mean values are in good agreement at the group level; that is, the exact 95% confidence limits for the ratio systematic error (0.95-1.02) are within the boundaries of practical equivalence (0.88-1.13) showing that the group average TM and MFT values are interchangeable. However, consideration of the data at the level of the individual athlete suggests that the TM and MFT results were not interchangeable because the 95% ratio limits of agreement either coincide with the boundaries of practical equivalence (upper limit) or fall outside (lower limit).

CONCLUSIONS

Results suggest that the MFT provides a suitable test at a group level with this cohort of wheelchair rugby players for the assessment of V˙O2peak (range 0.97-3.64 L·min-1), yet caution is noted for interchangeable use of values between tests for individual players.

Comparison of two Borg exertion scales for monitoring exercise intensity in able-bodied participants, and those with paraplegia and tetraplegia

STUDY DESIGN

Cross-sectional cohort study.

OBJECTIVES

To compare ratings of perceived exertion (RPE) on Borg's 6-20 RPE scale and Category Ratio 10 (CR10) in able-bodied (AB) participants during upper and lower body exercise, and recreationally active participants with paraplegia (PARA) and athletes with tetraplegia (TETRA) during upper body exercise only.

SETTING

University and rehabilitation centre-based laboratories in UK and Netherlands.

METHODS

Twenty-four participants were equally split between AB, PARA, and TETRA. AB performed maximal tests using cycle (AB-CYC) and handcycle (AB-HC) ergometry. PARA and TETRA performed maximal handcycle and wheelchair propulsion tests, respectively. Oxygen uptake (V̇O₂) and blood lactate concentration were monitored throughout. RPE was rated each stage on Borg's RPE scale and CR10. Thresholds were identified according to log-V̇O₂ plotted against log-blood lactate (LT₁), and 1.5 mmol L^-1 greater than LT₁ (LT₂).

RESULTS

RPE from both scales were best fit against each other using a quadratic model, with high goodness of fit between scales that was independent of exercise mode and participant group (range R²: 0.965-0.970, P < 0.005). Though percentage peak V̇O₂ was significantly greater in TETRA (P < 0.005), there was no difference in RPE at LT₁ or LT₂ between groups on Borg's RPE scale or CR10.

CONCLUSION

Strong association between Borg's RPE scale and CR10 suggests they can be used interchangeably. RPE at lactate thresholds were independent of mode of exercise and level of spinal cord injury. However, inter-individual variation precludes from making firm recommendations about using RPE for prescribing homogenous exercise intensity.

Effect of wheelchair-modified rowing exercise on cardiometabolic risk factors in spinal cord injured wheelchair users: protocol for a randomised controlled trial

INTRODUCTION

Cardiovascular and metabolic diseases are a growing concern for individuals with spinal cord injury (SCI). Physical inactivity contributes to cardiometabolic morbidity and mortality in the SCI population. However, previous studies have shown mixed results regarding the effects of exercise on cardiometabolic risk factors in individuals with SCI. This discrepancy could be influenced by insufficient exercise stimuli. Recent guidelines recommend 30 min of moderate-to-vigorous intensity aerobic exercise, three times per week, for improvement in cardiometabolic health in individuals with SCI. However, to date, no studies have implemented an exercise intervention matching the new recommendations to examine the effects on cardiometabolic risk factors. Therefore, the primary objective of this study is to determine the effects of 12 weeks of wheelchair user-modified upper-body rowing exercise on both traditional (constituents of the metabolic syndrome) and novel (eg, vascular structure and function) cardiometabolic risk factors in manual wheelchair users with SCI.

METHODS AND ANALYSIS

A randomised controlled trial will compare 12 weeks of upper-body rowing exercise, 30 min three times per week, with a control group continuing their normal lifestyle. Outcome measurements will be performed immediately before (baseline), after 6 weeks (halfway), 12 weeks of training (post) and 6 months after the termination of the intervention period (follow-up). Outcomes will include inflammatory (eg, C reactive protein) and metabolic biomarkers determined from venous blood (with serum fasting insulin as primary outcome), body composition, arterial blood pressure, cardiorespiratory fitness level, brachial artery vascular structure and function and autonomic nervous system function.

ETHICS AND DISSEMINATION

This trial is reported to the Danish Data Protection Agency (J.nr. 2019-899/10-0406) and approved by the Committees on Health Research Ethics in The North Denmark Region on 12 December 2019 (J.nr. N-20190053). The principal investigator will collect written informed consent from all participants prior to inclusion. Irrespective of study outcomes, the results will be submitted to peer-reviewed scientific journals for publication.

TRIAL REGISTRATION NUMBER

NCT04390087.

Physiological responses during simulated 16 km recumbent handcycling time trial and determinants of performance in trained handcyclists

Purpose

To characterise the physiological profiles of trained handcyclists, during recumbent handcycling, to describe the physiological responses during a 16 km time trial (TT) and to identify the determinants of this TT performance.

Methods

Eleven male handcyclists performed a sub-maximal and maximal incremental exercise test in their recumbent handbike, attached to a Cyclus II ergometer. A physiological profile, including peak aerobic power output (PO_Peak), peak rate of 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_2Peak), aerobic lactate threshold (AeLT) and PO at 4 mmol L⁻¹ (PO₄), were determined. Participants also completed a 16 km simulated TT using the same experimental set-up. Determinants of TT performance were identified using stepwise multiple linear regression analysis.

Results

Mean values of PO_Peak = 252 ± 9 W, \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_2Peak = 3.30 ± 0.36 L min⁻¹ (47.0 ± 6.8 mL kg⁻¹ min⁻¹), AeLT = 87 ± 13 W and PO₄ = 154 ± 14 W were recorded. The TT was completed in 29:21 ± 0:59 min:s at an intensity equivalent to 69 ± 4% PO_Peak and 87 ± 5% \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_2Peak. PO_Peak (r = − 0.77, P = 0.006), PO₄ (r = − 0.77, P = 0.006) and AeLT (r = − 0.68, P = 0.022) were significantly correlated with TT performance. PO₄ and PO_Peak were identified as the best predictors of TT performance (r = 0.89, P < 0.001).

Conclusion

PO_Peak, PO₄ and AeLT are important physiological TT performance determinants in trained handcyclists, differentiating between superior and inferior performance, whereas \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_2peak was not. The TT took place at an intensity corresponding to 69% PO_Peak and 87% \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_2peak.

The influence of protocol design on the identification of ventilatory thresholds and the attainment of peak physiological responses during synchronous arm crank ergometry in able-bodied participants

Purpose

To examine the effects of stage duration on power output (PO), oxygen uptake (VO₂), and heart rate (HR) at peak level and ventilatory thresholds during synchronous arm crank ergometry.

Methods

Nineteen healthy participants completed a ramp, 1-min stepwise, and 3-min stepwise graded arm crank exercise test. PO, VO_2, and HR at the first and second ventilatory threshold (VT1, VT2) and peak level were compared among the protocols: a repeated measures analysis of variance was performed to test for systematic differences, while intraclass correlation coefficients (ICC) and Bland–Altman plots were calculated to determine relative and absolute agreement.

Results

Systematic differences among the protocols were found for PO at VT1, VT2, and peak level. At peak level, PO differed significantly among all protocols (ramp: 115 ± 37 W; 1-min stepwise: 108 ± 34 W; 3-min stepwise: 94 ± 31 W, p ≤ 0.01). No systematic differences for HR or VO₂ were found among the protocols. VT1 and VT2 were identified at 52% and 74% of VO₂peak, respectively. The relative agreement among protocols varied (ICC 0.02–0.97), while absolute agreement was low with small-to-large systematic error and large random error.

Conclusions

PO at VTs and peak level was significantly higher in short-stage protocols compared with the 3-min stepwise protocol, whereas HR and VO₂ showed no differences. Therefore, training zones based on PO determined in short-stage protocols might give an overestimation. Moreover, due to large random error in HR at VTs between the protocols, it is recommended that different protocols should not be used interchangeably within individuals.

Analysis of Physiological and Kinematic Demands of Wheelchair Basketball Games-A Review

Seron, BB, Oliveira de Carvalho, EM, and Greguol, M. Analysis of physiological and kinematic demands of wheelchair basketball games-A review. J Strength Cond Res 33(5): 1453-1462, 2019-In wheelchair basketball (WB), knowledge of the specificities of the game is essential for efficient planning of training strategies for high performance. This study aimed to review the literature concerning studies that have investigated physiological and kinematic measures during WB games. The literature search took place in 4 electronic databases: Scopus, MEDLINE-PubMed, SPORTDiscus, and CINAHL. The inclusion criteria for this review were as follows: (a) articles that evaluated the behavior of physiological and kinematic variables during WB games; (b) athletes aged at least 18 years; and (c) participants with a minimum of 1 year in the modality practice. The selected studies (n = 16) were divided into 2 groups: physiological analysis (n = 11) and kinematic analysis (n = 5). In analyzing the studies, it was observed that the WB game is very demanding in relation to cardiovascular requirements (∼65% of the time is spent in zones of high heart rate [HR] intensity and 70% of V[Combining Dot Above]O2peak). Edwards and Stagno methods seem to be adequate for the control of internal loads imposed on WB players, and moderate correlations were found between rating of perceived exertion measures and HR-based methods. Considering the methodological limitations, kinematic analysis in WB games is rather inconsistent (distance traveled between 2.6 and 5 km; average speed between 1.8 and 2.0 m·s; maximum speed = 4 m·s). Despite the gaps observed in this context, the execution of rotational movements seems to have great relevance for WB. We can conclude that different methods have been adequate for the internal load control in WB games. However, the results of the external demands are not enough to determine a profile nor to serve as parameters for the training prescription for athletes of the modality.

Interrater and intrarater reliability of ventilatory thresholds determined in individuals with spinal cord injury

STUDY DESIGN

Cross-sectional.

OBJECTIVES

Individualized training regimes are often based on ventilatory thresholds (VTs). The objectives were to study: (1) whether VTs during arm ergometry could be determined in individuals with spinal cord injury (SCI), (2) the intrarater and interrater reliability of VT determination.

SETTING

University research laboratory.

METHODS

Thirty graded arm crank ergometry exercise tests with 1-min increments of recreationally active individuals (tetraplegia (N = 11), paraplegia (N = 19)) were assessed. Two sports physicians assessed all tests blinded, randomly, in two sessions, for VT1 and VT2, resulting in 240 possible VTs. Power output (PO), heart rate (HR), and oxygen uptake (VO₂) at each VT were compared between sessions or raters using paired samples t-tests, Wilcoxon signed-rank tests, intraclass correlation coefficients (ICC, relative agreement), and Bland-Altman plots (random error, absolute agreement).

RESULTS

Of the 240 VTs, 217 (90%) could be determined. Of the 23 undetermined VTs, 2 (9%) were VT1 and 21 (91%) were VT2; 7 (30%) among individuals with paraplegia, and 16 (70%) among individuals with tetraplegia. For the successfully determined VTs, there were no systematic differences between sessions or raters. Intrarater and interrater ICCs for PO, HR, and VO₂ at each VT were high to very high (0.82-1.00). Random error was small to large within raters, and large between raters.

CONCLUSIONS

For VTs that could be determined, relative agreement was high to very high, absolute agreement varied. For some individuals, often with tetraplegia, VT determination was not possible, thus other methods should be considered to prescribe exercise intensity.

Examination of gas exchange and blood lactate thresholds in Paralympic athletes during upper-body poling

Objectives

The primary aim was to compare physiological and perceptual outcome parameters identified at common gas exchange and blood lactate (BLa) thresholds in Paralympic athletes while upper-body poling. The secondary aim was to compare the fit of the breakpoint models used to identify thresholds in the gas exchange thresholds data versus continuous linear and curvilinear (no-breakpoint) models.

Methods

Fifteen elite Para ice hockey players performed seven to eight 5-min stages at increasing workload until exhaustion during upper-body poling. Two regression lines were fitted to the oxygen uptake (VO₂)-carbon dioxide (VCO₂) and minute ventilation (VE)/VO₂ data to determine the ventilatory threshold (VT), and to the VCO₂-VE and VE/VCO₂ data to determine the respiratory compensation threshold (RCT). The first lactate threshold (LT1) was determined by the first rise in BLa (+0.4mmol·L^-1 and +1.0mmol·L^-1) and a breakpoint in the log-log transformed VO₂-BLa data, and the second lactate threshold (LT2) by a fixed rise in BLa above 4mmol·L^-1 and by employing the modified D_max method. Paired-samples t-tests were used to compare the outcome parameters within and between the different threshold methods. The fit of the two regression lines (breakpoint model) used to identify thresholds in the gas exchange data was compared to that of a single regression line, an exponential and a 3^rd order polynomial curve (no-breakpoint models) by Akaike weights.

Results

All outcome parameters identified with the VT (i.e., breakpoints in the VO₂-VCO₂ or VE/VO₂ data) were significantly higher than the ones identified with a fixed rise in BLa (+0.4 or +1.0mmol·L^-1) at the LT1 (e.g. BLa: 5.1±2.2 or 4.9±1.8 vs 1.9±0.6 or 2.3±0.5mmol·L^-1,p<0.001), but were not significantly different from the log-log transformed VO₂-BLa data (4.3±1.6mmol·L^-1,p>0.06). The outcome parameters identified with breakpoints in the VCO₂-VE data to determine the RCT (e.g. BLa: 5.5±1.4mmol·L^-1) were not different from the ones identified with the modified D_max method at the LT2 (5.5±1.1mmol·L^-1) (all p>0.53), but were higher compared to parameters identified with VE/VCO₂ method (4.9±1.5mmol·L^-1) and a fixed BLa value of 4mmol·L^-1 (all p<0.03). Although we were able to determine the VT and RCT via different gas exchange threshold methods with good fit in all 15 participants (mean R²>0.931), the continuous no-breakpoint models had the highest probability (>68%) of being the best models for the VO₂-VCO₂ and the VCO₂-VE data.

Conclusions

In Paralympic athletes who exercise in the upper-body poling mode, the outcome parameters identified at the VT and the ones identified with fixed methods at the LT1 showed large differences, demonstrating that these cannot be used interchangeably to estimate the aerobic threshold. In addition, the close location of the VT, RCT and LT2 does not allow us to distinguish the aerobic and anaerobic threshold, indicating the presence of only one threshold in athletes with a disability exercising in an upper-body mode. Furthermore, the better fit of continuous no-breakpoint models indicates no presence of clear breakpoints in the gas exchange data for most participants. This makes us question if breakpoints in the gas exchange data really exist in an upper-body exercise mode in athletes with disabilities.

Peak oxygen uptake in Paralympic sitting sports: A systematic literature review, meta- and pooled-data analysis

Background

Peak oxygen uptake (VO_2peak) in Paralympic sitting sports athletes represents their maximal ability to deliver energy aerobically in an upper-body mode, with values being influenced by sex, disability-related physiological limitations, sport-specific demands, training status and how they are tested.

Objectives

To identify VO_2peak values in Paralympic sitting sports, examine between-sports differences and within-sports variations in VO_2peak and determine the influence of sex, age, body-mass, disability and test-mode on VO_2peak.

Design

Systematic literature review and meta-analysis.

Data sources

PubMed, CINAHL, SPORTDiscus^TM and EMBASE were systematically searched in October 2016 using relevant medical subject headings, keywords and a Boolean.

Eligibility criteria

Studies that assessed VO_2peak values in sitting sports athletes with a disability in a laboratory setting were included.

Data synthesis

Data was extracted and pooled in the different sports disciplines, weighted by the Dersimonian and Laird random effects approach. Quality of the included studies was assessed with a modified version of the Downs and Black checklist by two independent reviewers. Meta-regression and pooled-data multiple regression analyses were performed to assess the influence of sex, age, body-mass, disability, test mode and study quality on VO_2peak.

Results

Of 6542 retrieved articles, 57 studies reporting VO_2peak values in 14 different sitting sports were included in this review. VO_2peak values from 771 athletes were used in the data analysis, of which 30% participated in wheelchair basketball, 27% in wheelchair racing, 15% in wheelchair rugby and the remaining 28% in the 11 other disciplines. Fifty-six percent of the athletes had a spinal cord injury and 87% were men. Sports-discipline-averaged VO_2peak values ranged from 2.9 L∙min^-1 and 45.6 mL∙kg^-1∙min^-1 in Nordic sit skiing to 1.4 L∙min^-1 and 17.3 mL∙kg^-1∙min^-1 in shooting and 1.3 L∙min^-1 and 18.9 mL∙kg^-1∙min^-1 in wheelchair rugby. Large within-sports variation was found in sports with few included studies and corresponding low sample sizes. The meta-regression and pooled-data multiple regression analyses showed that being a man, having an amputation, not being tetraplegic, testing in a wheelchair ergometer and treadmill mode, were found to be favorable for high absolute and body-mass normalized VO_2peak values. Furthermore, high body mass was favourable for high absolute VO_2peak values and low body mass for high body-mass normalized VO_2peak values.

Conclusion

The highest VO_2peak values were found in Nordic sit skiing, an endurance sport with continuously high physical efforts, and the lowest values in shooting, a sport with low levels of displacement, and in wheelchair rugby where mainly athletes with tetraplegia compete. However, VO_2peak values need to be interpreted carefully in sports-disciplines with few included studies and large within-sports variation. Future studies should include detailed information on training status, sex, age, test mode, as well as the type and extent of disability in order to more precisely evaluate the effect of these factors on VO_2peak.

Assessment of peak oxygen uptake during handcycling: Test-retest reliability and comparison of a ramp-incremented and perceptually-regulated exercise test

Purpose

To examine the reliability of a perceptually-regulated maximal exercise test (PRET_max) to measure peak oxygen uptake (V˙O2peak) during handcycle exercise and to compare peak responses to those derived from a ramp-incremented protocol (RAMP).

Methods

Twenty recreationally active individuals (14 male, 6 female) completed four trials across a 2-week period, using a randomised, counterbalanced design. Participants completed two RAMP protocols (20 W·min^-1) in week 1, followed by two PRET_max in week 2, or vice versa. The PRET_max comprised five, 2-min stages clamped at Ratings of Perceived Exertion (RPE) 11, 13, 15, 17 and 20. Participants changed power output (PO) as often as required to maintain target RPE. Gas exchange variables (oxygen uptake, carbon dioxide production, minute ventilation), heart rate (HR) and PO were collected throughout. Differentiated RPE were collected at the end of each stage throughout trials.

Results

For relative V˙O2peak, coefficient of variation (CV) was equal to 4.1% and 4.8%, with ICC_(3,1) of 0.92 and 0.85 for repeated measures from PRET_max and RAMP, respectively. Measurement error was 0.15 L·min^-1 and 2.11 ml·kg^-1·min^-1 in PRET_max and 0.16 L·min^-1 and 2.29 ml·kg^-1·min^-1 during RAMP for determining absolute and relative V˙O2peak, respectively. The difference in V˙O2peak between PRET_max and RAMP was tending towards statistical significance (26.2 ± 5.1 versus 24.3 ± 4.0 ml·kg^-1·min^-1, P = 0.055). The 95% LoA were -1.9 ± 4.1 (-9.9 to 6.2) ml·kg^-1·min^-1.

Conclusion

The PRET_max can be used as a reliable test to measure V˙O2peak during handcycle exercise in recreationally active participants. Whilst PRET_max tended towards significantly greater V˙O2peak values than RAMP, the difference is smaller than measurement error of determining V˙O2peak from PRET_max and RAMP.

Effects of cooling before and during simulated match play on thermoregulatory responses of athletes with tetraplegia

OBJECTIVES

Athletes with high level spinal cord injuries (tetraplegia) are under greater thermal strain during exercise than the able-bodied. The purpose of this study was to investigate the effectiveness of pre-cooling using an ice vest and the combination of pre-cooling and cooling during play using water sprays in athletes with tetraplegia.

DESIGN

Counter-balanced, cross-over design.

METHODS

Eight wheelchair rugby players with tetraplegia completed a 60min intermittent sprint protocol (ISP) on a wheelchair ergometer in 20.2°C±0.2°C and 33.0%±3.1% relative humidity. The ISP was conducted on three occasions; no cooling (NC), pre-cooling with an ice vest (P) and pre-cooling with an ice vest and water sprays between quarters (PW). Gastrointestinal (T_gi) temperature, mean skin temperature (T_sk) and perceptual responses were measured throughout.

RESULTS

At the end of pre-cooling, the change in T_gi was not significantly different between conditions (P>0.05) but the change in T_sk was significantly greater in P and PW compared to NC (P<0.001). The change in T_gi over the ISP was significantly lower in PW and P compared to NC (P<0.05), whilst the change in T_sk was lower in PW compared to P and NC (P<0.05). Cooling had no effect on performance or perceptual responses (P>0.05).

CONCLUSIONS

Water spraying between quarters combined with pre-cooling using an ice vest lowers thermal strain to a greater degree than pre-cooling only in athletes with tetraplegia, but has no effect on simulated wheelchair rugby performance or perceptual responses.

Perspective: Does Laboratory-Based Maximal Incremental Exercise Testing Elicit Maximum Physiological Responses in Highly-Trained Athletes with Cervical Spinal Cord Injury?

The physiological assessment of highly-trained athletes is a cornerstone of many scientific support programs. In the present article, we provide original data followed by our perspective on the topic of laboratory-based incremental exercise testing in elite athletes with cervical spinal cord injury. We retrospectively reviewed our data on Great Britain Wheelchair Rugby athletes collected during the last two Paralympic cycles. We extracted and compared peak cardiometabolic (heart rate and blood lactate) responses between a standard laboratory-based incremental exercise test on a treadmill and two different maximal field tests (4 min and 40 min maximal push). In the nine athletes studied, both field tests elicited higher peak responses than the laboratory-based test. The present data imply that laboratory-based incremental protocols preclude the attainment of true peak cardiometabolic responses. This may be due to the different locomotor patterns required to sustain wheelchair propulsion during treadmill exercise or that maximal incremental treadmill protocols only require individuals to exercise at or near maximal exhaustion for a relatively short period of time. We acknowledge that both field- and laboratory-based testing have respective merits and pitfalls and suggest that the choice of test be dictated by the question at hand: if true peak responses are required then field-based testing is warranted, whereas laboratory-based testing may be more appropriate for obtaining cardiometabolic responses across a range of standardized exercise intensities.

Individualized Internal and External Training Load Relationships in Elite Wheelchair Rugby Players

Aim: The quantification and longitudinal monitoring of athlete training load (TL) provides a scientific explanation for changes in performance and helps manage injury/illness risk. Therefore, accurate and reliable monitoring tools are essential for the optimization of athletic performance. The aim of the present study was to establish the relationship between measures of internal [heart rate (HR) and session RPE (sRPE)] and external TL specific to wheelchair rugby (WR).

Methods: Fourteen international WR athletes (age = 29 ± 7 years; body mass = 58.9 ± 10.9 kg) were monitored during 18 training sessions over a 3 month period during the competitive phase of the season. Activity profiles were collected during each training session using a radio-frequency based indoor tracking system (ITS). External TL was quantified by total distance (m) covered as well as time spent and distance covered in a range of classification-specific arbitrary speed zones. Banister's TRIMP, Edwards's summated HR zone (SHRZ), and Lucia's TRIMP methods were used to quantify physiological internal TL. sRPE was calculated as the product of session duration multiplied by perceived exertion using the Borg CR10 scale. Relationships between external and internal TL were examined using correlation coefficients and the 90% confidence intervals (90% CI).

Results: sRPE (r = 0.59) and all HR-based (r > 0.80) methods showed large and very large relationships with the total distance covered during training sessions, respectively. Large and very large correlations (r = 0.56 − 0.82) were also observed between all measures of internal TL and times spent and distances covered in low and moderate intensity speed zones. HR-based methods showed very large relationships with time (r = 0.71−0.75) and distance (r = 0.70−0.73) in the very high speed zone and a large relationship with the number of high intensity activities (HIA) performed (r = 0.56−0.62). Weaker relationships (r = 0.32−0.35) were observed between sRPE and all measures of high intensity activity. A large variation of individual correlation co-efficient was observed between sRPE and all external TL measures.

Conclusion: The current findings suggest that sRPE and HR-based internal TL measures provide a valid tool for quantifying volume of external TL during WR training but may underestimate HIA. It is recommended that both internal and external TL measures are employed for the monitoring of overall TL during court-based training in elite WR athletes.

Comparison Between 30-15 Intermittent Fitness Test and Multistage Field Test on Physiological Responses in Wheelchair Basketball Players

The intermittent nature of wheelchair court sports suggests using a similar protocol to assess repeated shuttles and recovery abilities. This study aimed to compare performances, physiological responses and perceived rating exertion obtained from the continuous multistage field test (MFT) and the 30-15 intermittent field test (30-15IFT). Eighteen trained wheelchair basketball players (WBP) (WBP: 32.0 ± 5.7 y, IWBF classification: 2.9 ± 1.1 points) performed both incremental field tests in randomized order. Time to exhaustion, maximal rolling velocity (MRV), VO2peak and the peak values of minute ventilation (V Epeak), respiratory frequency (RF) and heart rate (HRpeak) were measured throughout both tests; peak and net blood lactate (Δ[Lact(-)] = peak-rest values) and perceived rating exertion (RPE) values at the end of each exercise. No significant difference in VO2peak, VEpeak, and RF was found between both tests. 30-15IFT was shorter (12.4 ± 2.4 vs. 14.9 ± 5.1 min, P < 0.05) but induced higher values of MRV and Δ[Lact(-)] compared to MFT (14.2 ± 1.8 vs. 11.1 ± 1.9 km·h(-1) and 8.3 ± 4.2 vs. 6.9 ± 3.3 mmol·L(-1), P < 0.05). However, HRpeak and RPE values were higher during MFT than 30-15IFT(172.8 ± 14.0 vs. 166.8 ± 13.8 bpm and 15.3 ± 3.8 vs.13.8 ± 3.5, respectively, P < 0.05). The intermittent shuttles intercepted with rest period occurred during the 30-15IFT could explain a greater anaerobic solicitation. The higher HR and overall RPE values measured at the end of MFT could be explained by its longer duration and a continuous load stress compared to 30-15IFT. In conclusion, 30-15IFT has some advantages over MFT for assess in addition physical fitness and technical performance in WBP.

Upper limb aerobic training improves aerobic fitness and all-out performance of America's Cup grinders

This research on "America's Cup" grinders investigated the effects of a specific eight-week long-arm cranking ergometer (ACE) training on upper body (UB) aerobic fitness (ventilatory threshold - Tvent, respiratory compensation point- RCP, -oxygen uptake peak - VO₂peak) and high intensity working capacity. The training consisted of sessions carried out for 20-30 mins, three times per week, at an intensity between the UB-Tvent and UB-RCP, and replaced part of a typical lower limb aerobic training whilst maintaining the usual weekly schedule of callisthenics, resistance training and sailing. Seven sailors, including four grinders and three mastmen (age 30 ± 5.5 years, height 1.9 ± 0.04 m, body mass 102 ± 3.6 kg), were evaluated through both an ACE cardiopulmonary maximal exercise test (CPET) and an ACE all-out up to exhaustion exercise test, before and after the ACE training. UB aerobic fitness improved significantly: UB-VO₂peak increased from 4.29 ± 0.442 to 4.52 ± 0.522 l·min(-1) (6.4 ± 3.66%), VO₂ at UB-Tvent from 2.42 ± 0.282 to 2.97 ± 0.328 l·min(-1) (22.8 ± 5.09%) and VO₂ at UB-RCP from 3.25 ± 0.402 to 3.75 ± 0.352 l·min(-1) (16.1 ± 10.83%). Peak power at the ACE CPET increased from 351 ± 27.5 to 387 ± 33.5 W (10.5 ± 6.93%). The all-out test total mechanical work increased from 28.9 ± 2.35 to 40.1 ± 3.76 kJ (72.1 ± 4.67%). In conclusion, a high intensity aerobic ACE training can be effective in improving grinding performance by increasing UB aerobic fitness and all-out working capacity.