Handbike configurations and the prevalence of experienced sitting and riding-related problems in recreational handcyclists training for the HandbikeBattle.

Implications for rehabilitationA large variety in handbike configurations is seen in recreationally-active handcyclists.Although the majority of the recreationally-active handcyclists seemed to be satisfied with their handbike configurations, 31-50% of them thought that their handbike configuration could be improved.Evidence-based guidelines for handbike fitting should be developed in the future.

The impact of lower-limb function on upper-limb pull and push strength in elite handcycling athletes.

This study investigated the impact of performing a closed kinetic chain with the lower limbs on isometric upper-limb pull and push strength. Sixty-two elite handcyclists were assessed with the Manual Muscle Test and allocated to groups with partial to normal (LLF) or no lower-limb (no-LLF) function. Both groups performed upper-limb strength measurements under two kinetic-chain conditions. During the closed-chain condition, the lower limbs were attached to two footrests, providing horizontal and vertical support. During the open-chain condition, the footrests were removed and the limbs were supported vertically by a horizontal plate. Repeated-measures ANOVA were conducted to investigate main effects (open vs. closed chain, LLF vs. no-LLF) and their interaction. During pull, LLF performed better (p < 0.001, +11%) by pushing against the footrests. However, this increase in pulling strength during a closed-chain condition was not observed in the no-LLF. Therefore, findings suggest an advantage for the least impaired athletes by being able to perform lower-limb closed chains during pulling. Handcyclists with LLF can maximise pulling performance by adjusting the footrests. The classification system should consider the implications of these findings on the allocation of athletes with different levels of LLF and/or on the equipment regulation.

Changes in body satisfaction during and after a 5-month handcycle training period and associations with physical capacity and body composition in individuals with a physical impairment.

PURPOSE: To investigate: (1) changes in body satisfaction during five months of handcycle training and one year after the training period; (2) whether longitudinal changes are dependent on sex, waist circumference and severity of the physical impairment; (3) associations between changes in physical capacity or body composition, and body satisfaction. MATERIALS AND METHODS: Individuals (N = 143) with health conditions such as spinal cord injury filled out the Adult Body Satisfaction Questionnaire: at the start of the training (T1), directly after the training period (T2); and four months (T3) and one year after the training period (T4). At T1 and T2, physical capacity was determined with an upper-body graded exercise test, and waist circumference was measured. Handcycling classification was used as a proxy for the severity of impairment. RESULTS: Multilevel regression analyses showed that body satisfaction significantly increased during the training period and significantly decreased back to pre-training levels at follow-up. Individuals with more severe impairments showed a larger decrease at T4. Improvements in physical capacity and waist circumference were significantly associated with improvements in body satisfaction. CONCLUSIONS: Body satisfaction significantly increased during the training period, but significantly decreased during follow-up. Additional efforts might be necessary to keep individuals engaged in long-term exercise.

Body image disturbances are frequently described in individuals with a physical impairment.An increase in body image can be achieved by improvements in physical capacity and waist circumference as a consequence of training.It is important to keep individuals engaged in exercise, as body satisfaction decreases after termination of the training period.For individuals with severe physical impairments additional efforts are necessary to keep them engaged in exercise.

External and Internal Work Load During a Mountain Time Trial in Trained Handcyclists Versus a World-Class Handcyclist and Determinants of Performance.

OBJECTIVES: The aims of the study were to evaluate the external and internal work load of trained handcyclists during a mountain time trial, to compare the results with a world-class handcyclist, and to identify time trial performance determinants. DESIGN: Ten trained and one world-class handcyclists performed a graded exercise test to determine power output and heart rate at the (first and second) ventilatory thresholds and exhaustion. Power output and heart rate were continuously measured during the race. RESULTS: The mean absolute power output during the race (119 ± 21 vs. 203 W, P < 0.001) was lower in the trained handcyclists compared with the world-class handcyclist. The absolute and relative heart rate during the race (86 ± 7% vs. 88%, P = 0.40) and relative power output during the race (66 ± 10% vs. 62%, P = 0.24) were similar. Trained handcyclists cycled significantly less time at a power output between first and second ventilatory thresholds (48% vs. 64%, P = 0.02) and more at a power output greater than second ventilatory threshold (34% vs. 11%, P = 0.005). Power output at the second ventilatory threshold showed the strongest correlation with finish time ( r = -0.78) and peak power output with mean power output of the race ( r = 0.90). CONCLUSIONS: The laboratory outcome peak power output and power output at the second ventilatory threshold are important performance determinants for longer time trials in handcyclists, and it is, therefore, important to improve these outcomes with training. Because the trained handcyclists cycled most of the race in intensity zones 2 and 3, it is recommended to incorporate these zones also in the training.

Effect of Training for an Athletic Challenge on Illness Cognition in Individuals with Chronic Disability: A Prospective Cohort Study.

Illness cognitions (IC) influence how a patient adapts to a chronic disease. The aim was (1) to determine if training for a handcycling mountain time trial (HandbikeBattle) improves IC and (2) to identify factors associated with IC change scores. Persons with a chronic disability (N = 220; including N = 151 with spinal cord disorder) trained 5 months and participated in the time trial. The IC Questionnaire measured helplessness, acceptance, perceived benefits and was assessed before training (T1), after training (T2), and four months after the event (T3). Age, sex, body mass index (BMI), time since injury (TSI), disability characteristics, self-efficacy, mental health (MH) and musculoskeletal pain were obtained at T1. Multilevel regression analyses showed that helplessness decreased (from 11.96 to 11.28, p < 0.01) and perceived benefits increased (from 16.91 to 17.58, p < 0.01) from T1 to T2. For helplessness this decrease persisted during follow-up (11.16 at T3). Changes in helplessness were associated with self-efficacy (p = 0.02), MH (p = 0.02) and lesion completeness (p = 0.02), and were independent of disability type (p = 0.66), lesion level (p = 0.30) and demographics such as sex (p = 0.29) and age (p = 0.67). Training with peers may improve helplessness and perceived benefits in individuals with a chronic disability. Especially individuals with MH problems might benefit from training for an athletic challenge with peers to improve illness cognitions, and ultimately, quality of life.

Association between upper-limb isometric strength and handcycling performance in elite athletes.

This study investigated the association among isometric upper-limb strength of handcyclists and sport-specific performance outcomes. At two international events, 62 athletes were tested on upper-limb strength, measured with an isometric-strength setup and with Manual Muscle Test (MMT). Horizontal force (Fz), effectiveness, rate of development, variability, and asymmetries were calculated for upper-limb pull and push. Performance measures were mean (POmean) and peak (POpeak) 20-s sprint power output and average time-trial velocity (TTvelocity). Regression models were conducted to investigate which pull and push strength variables associated strongest with performance measures. Additional regression analyses were conducted with an MMT sum score as predictor. Push and pull Fz showed the strongest associations with all outcomes. Combined push and pull Fz explained (p < .001) 80-81% of variance of POmean and POpeak. For TTvelocity, only push Fz was included in the model explaining 29% of the variance (p < .001). MMT models revealed weaker associations with sprint PO (R2 = .38-.40, p < .001) and TTvelocity (R2 = .18, p = 0.001). The findings confirmed the relevance of upper-limb strength on handcycling performance and the significance of ratio-scaled strength measures. Isometric strength outcomes are adequate sport-specific indicators of impairment in handcycling classification, but future research should corroborate this notion and its potential to discriminate between sports classes.

Low drop-out rates in the HandbikeBattle free-living training study: understanding the reasons for dropping out.

STUDY DESIGN: Longitudinal observational study. OBJECTIVES: During the five-month free-living training period for the HandbikeBattle event several participants dropped out. The aim of this study was to clarify the numbers and reasons for drop out, and to characterize the differences between study participants who did (dropouts) and did not (competitors) drop out during the training period for the HandbikeBattle event. SETTING: Former participants of the HandbikeBattle, a handcycling race on an Austrian mountain. METHODS: Participants (N = 313 (N = 209 (67%) with spinal cord injury or spina bifida)) enrolled between 2013-2018. Drop out and reasons for drop out were registered. Competitors and dropouts were compared regarding personal, disability, physical, and psychological factors, which were measured at the start of the training period. RESULTS: Forty-five participants (14%) dropped out during the training period with medical complications (49%) and motivational problems (29%) as main reasons. The only differences were that competitors participated more in sports before the study (p = 0.01) and achieved a higher peak power output (p = 0.04) compared to dropouts. CONCLUSIONS: The drop-out rate of the HandbikeBattle study was low compared to previous exercise intervention studies, which might be related to the less strictly imposed free-living training. Persons with less experience in sport and a lower fitness level might need more attention during a training intervention to prevent them from dropping out.

The Science of Handcycling: A Narrative Review.

The aim of this narrative review is to provide insight as to the history, biomechanics, and physiological characteristics of competitive handcycling. Furthermore, based upon the limited evidence available, this paper aims to provide practical training suggestions by which to develop competitive handcycling performance. Handbike configuration, individual physiological characteristics, and training history all play a significant role in determining competitive handcycling performance. Optimal handcycling technique is highly dependent upon handbike configuration. As such, seat positioning, crank height, crank fore-aft position, crank length, and handgrip position must all be individually configured. In regard to physiological determinants, power output at a fixed blood lactate concentration of 4 mmol·L-1, relative oxygen consumption, peak aerobic power output, relative upper body strength, and maximal anaerobic power output have all been demonstrated to impact upon handcycling performance capabilities. Therefore, it is suggested that that an emphasis be placed upon the development and frequent monitoring of these parameters. Finally, linked to handcycling training, it is suggested that handcyclists should consider adopting a concurrent strength and endurance training approach, based upon a block periodization model that employs a mixture of endurance, threshold, interval, and strength training sessions. Despite our findings, it is clear that several gaps in our scientific knowledge of handcycling remain and that further research is necessary in order to improve our understanding of factors that determine optimal performance of competitive handcyclists. Finally, further longitudinal research is required across all classifications to study the effects of different training programs upon handcycling performance.

Training for the HandbikeBattle: an explorative analysis of training load and handcycling physical capacity in recreationally active wheelchair users.

PURPOSE: (1) to analyze training characteristics of recreationally active wheelchair users during handcycle training, and (2) to examine the associations between training load and change in physical capacity. METHODS: Former rehabilitation patients (N = 60) with health conditions such as spinal cord injury or amputation were included. Participants trained for five months. A handcycling/arm crank graded exercise test was performed before and after the training period. Outcomes: peak power output per kg (POpeak/kg) and peak oxygen uptake per kg (VO2peak/kg). Training load was defined as Training Impulse (TRIMP), which is rating of perceived exertion (sRPE) multiplied by duration of the session, in arbitrary units (AU). Training intensity distribution (TID) was also determined (time in zone 1, RPE ≤4; zone 2, RPE 5-6; zone 3, RPE ≥7). RESULTS: Multilevel regression analyses showed that TRIMPsRPE was not significantly associated with change in physical capacity. Time in zone 2 (RPE 5-6) was significantly associated with ΔVO2peak, %ΔVO2peak, ΔVO2peak/kg and %ΔVO2peak/kg. CONCLUSION: Training at RPE 5-6 was the only determinant that was significantly associated with improvement in physical capacity. Additional controlled studies are necessary to demonstrate causality and gather more information about its usefulness, and optimal handcycle training regimes for recreationally active wheelchair users.IMPLICATIONS FOR REHABILITATIONMonitoring of handcycle training load is important to structure the training effort and intensity over time and to eventually optimize performance capacity. This is especially important for relatively untrained wheelchair users, who have a low physical capacity and a high risk of overuse injuries and shoulder pain.Training load can be easily calculated by multiplying the intensity of the training (RPE 0-10) with the duration of the training in minutes.Results on handcycle training at RPE 5-6 intensity in recreationally active wheelchair users suggests to be promising and should be further investigated with controlled studies.

Effects of trunk muscle activation on trunk stability, arm power, blood pressure and performance in wheelchair rugby players with a spinal cord injury.

Objective: In wheelchair rugby (WR) athletes with tetraplegia, wheelchair performance may be impaired due to (partial) loss of innervation of upper extremity and trunk muscles, and low blood pressure (BP). The objective was to assess the effects of electrical stimulation (ES)-induced co-contraction of trunk muscles on trunk stability, arm force/power, BP, and WR performance.Design: Cross-sectional study.Setting: Rehabilitation research laboratory and WR court.Participants: Eleven WR athletes with tetraplegia.Interventions: ES was applied to the rectus abdominis, obliquus externus abdominis and erector spinae muscles. For every test, the ES condition was compared to the non-ES condition.Outcome measures: Stability was assessed with reaching tasks, arm force/power with an isokinetic test on a dynamometer, BP during an ES protocol and WR skill performance with the USA Wheelchair Rugby Skill Assessment.Results: Overall reaching distance (ES 14.6 ± 7.5 cm, non-ES 13.4 ± 8.2 cm), and BP showed a significant increase with ES. Arm force (ES 154 ± 106 N, non-ES 148 ± 102 N) and power (ES 37 ± 26 W, non-ES 36 ± 25 W), and WR skills were not significantly improved.Conclusion: ES-induced trunk muscle activation positively affects trunk stability and BP, but not arm force/power. No effects were found in WR skill performance, probably due to abdominal strapping. More research is needed to assess different ES (training) protocols and longitudinal effects.

A Role for Trunk Function in Elite Recumbent Handcycling Performance?

Handcycling classification considers trunk function, but there is limited scientific evidence of trunk involvement in recumbent performance. This study investigated the association between trunk function and recumbent handcycling performance of athletes without upper-limb impairments (H3-H4 sport classes). The study was divided into two parts. First, 528 time-trial results from 81 handcyclists with spinal cord injury (SCI) were obtained between 2014 and 2020. Average time-trial velocity was used as performance measure and SCI level as trunk function determinant. Multilevel regression analysis was performed to analyse differences in performance among SCI groups while correcting for lesion completeness, sex, and age. Second, in 26 handcyclists, standardised trunk flexion strength was measured with a handheld dynamometer. Peak and mean power-output from a sprint test and time-trial average velocity were used as performance measures. Spearman correlations were conducted to investigate the association between trunk strength and performance. Results showed that the different SCI groups did not exhibit significant differences in performance. Furthermore, trunk flexion strength and performance exhibited non-significant weak to moderate correlations (for time-trial speed: rs = 0.36; p = 0.07). Results of both analyses suggest that trunk flexion strength does not seem to significantly impact recumbent handcycling performance in athletes without upper-limb impairments.

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.

Good association between sprint power and aerobic peak power during asynchronuous arm-crank exercise in people with spinal cord injury.

PURPOSE: To (1) investigate the association between sprint power and aerobic power output (POpeakGXT) during a graded peak exercise test (GXT); and (2) validate the prediction models of POpeakGXT based on sprint power and personal and lesion characteristics. MATERIALS AND METHODS: Wheelchair users with tetraplegia (N = 35) and paraplegia (N = 58) performed a 30 s-Wingate test and GXT on an asynchronous arm-crank ergometer. Data were split into samples to develop and validate the model. Sprint power (POmeanWingate and POpeakWingate, respectively) and POpeakGXT were determined. Regression analyses were performed to develop POpeakGXT prediction models. Candidate independent variables included POmeanWingate or POpeakWingate, age (years), sex, body mass (kg) or BMI (kg/m2), time since injury (TSI, years) and lesion level (tetraplegia/paraplegia). The best model was validated by comparing the predicted POpeakGXT with measured POpeakGXT. RESULTS: The best model (R2 = 0.76) to predict POpeakGXT included POmeanWingate, BMI and all other independent variables. No significant difference was found between measured (68 ± 35 W) and predicted POpeakGXT (68 ± 30 W, p = 0.97). The ICC was excellent (0.89 with 95% confidence intervals: 0.75-0.95). The 95% limits of agreement for the Bland-Altman plots were wide (-30 to 31 W). CONCLUSIONS: Strong associations were found between POmeanWingate and POpeakGXT. Although relative agreement was excellent, absolute agreement was low. Implications for rehabilitation There is a strong relationship between peak aerobic power output and sprint power output, both tested on an arm-crank ergometer, in people with spinal cord injury. A prediction model for peak aerobic power output, based on sprint power output and personal and lesion characteristics, showed a high explained variance. The predictive model can give a guideline for choosing the right graded exercise test protocol but should be used with caution.

The Course of Physical Capacity in Wheelchair Users During Training for the HandbikeBattle and at 1-Yr Follow-up.

OBJECTIVE: The aims of this study were (1) to compare physical capacity at 1-yr follow-up with physical capacity before and after the training period for the HandbikeBattle event and (2) to identify determinants of the course of physical capacity during follow-up. DESIGN: This was a prospective observational study. Former rehabilitation patients (N = 33) with health conditions such as spinal cord injury or amputation were included. A handcycling/arm crank graded exercise test was performed before (January, T1) and after the training period (June, T2) and at 1-yr follow-up (June, T4). Outcomes were peak power output (W) and peak oxygen uptake (L/min). Determinants were sex (male/female); age (years); classification; physical capacity, musculoskeletal pain, exercise stage of change, and exercise self-efficacy at T1; and HandbikeBattle participation at T4. RESULTS: Multilevel regression analyses showed that peak power output and peak oxygen uptake increased during the training period and did not significantly change during follow-up (T1: 112 ± 37 W, 1.70 ± 0.48 L/min; T2: 130 ± 40 W, 2.07 ± 0.59 L/min; T4: 126 ± 42 W, 2.00 ± 0.57 L/min). Participants who competed again in the HandbikeBattle showed slight improvement in physical capacity during follow-up, whereas participants who did not compete again showed a decrease. CONCLUSION: Physical capacity showed an increase during the training period and remained stable after 1-yr follow-up. Being (repeatedly) committed to a challenge might facilitate long-term exercise maintenance.

Sport participation after the HandbikeBattle: benefits, barriers, facilitators from the event-a follow-up survey.

OBJECTIVES: To investigate sports participation among individuals in the HandbikeBattle project 1.5-5.5 years after the event, the barriers and facilitators to sport participation and benefits of participating in the event. SETTING: Former participants of the HandbikeBattle, a handcycling race on an Austrian mountain. METHODS: Handcyclists who took part in one or more HandbikeBattle events in 2013-2017 were invited to complete a survey in December 2018. Questions were asked on benefits of participating in this event, current sport participation, and experienced barriers and facilitators regarding current sport participation. RESULTS: Respondents (N = 96 (N = 59 with spinal cord injury (SCI) or Spina Bifida (SB)), response rate = 47%) reported benefits from this event regarding their fitness level (90%), personal development (81%), daily life activities (66%), and health (64%). Median current sport participation was 5 h/week (IQR: 3-8). Most frequently indicated personal barriers for sports participation were: lack of time (31%), disability (17%), and pain (15%). Most frequently mentioned environmental barriers were: transportation time to sport accommodation (19%), and lack of peers to do sports with (16%). Most important facilitators were motivation to improve health and/or fitness (92%), fun and/or relaxation (85%). The results for the subgroup with SCI were comparable with the results of the total group. CONCLUSIONS: Results highlight the role sports challenges can have in establishing a sustainable active life lifestyle among people with disabilities.

Changes in Quality of Life During Training for the HandbikeBattle and Associations With Cardiorespiratory Fitness.

OBJECTIVE: To investigate (1) changes in life satisfaction and mental health during 5 months of training for the HandbikeBattle and 4 months of follow-up; (2) associations between changes in handcycling cardiorespiratory fitness and changes in life satisfaction and mental health during the training period. DESIGN: This is a multicenter prospective cohort study with the following measurements: the start of the training (T1), after the 5-month training period, before the event (T2), and after 4 months of follow-up (T3). At T1, T2, and T3, questionnaires were filled out. At T1 and T2, a graded exercise test was performed to measure cardiorespiratory fitness (peak oxygen consumption [Vo2peak] and peak power output [POpeak]). SETTING: Ten Dutch rehabilitation centers training for the HandbikeBattle event. PARTICIPANTS: Patients with a rehabilitation history (N=136) and health conditions such as spinal cord injury, amputation, or multiple trauma history. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Life satisfaction as the sum score of 2 questions (range, 2-13) and the Mental Health subscale of the 36-item Short Form Health Survey (range, 0-100). RESULTS: Multilevel regression analyses showed that life satisfaction increased during the training period and did not significantly change during follow-up (mean ± SD, T1: 8.2±2.2; T2: 8.6±2.3; T3: 8.5±2.4). Mental health showed no change over time (T1: 77.7±14.5; T2: 77.8±14.5; T3: 75.7±16.5). An improvement in cardiorespiratory fitness was associated with an increase in life satisfaction (POpeak, ß=0.014, P=.046; Vo2peak, ß=1.068, P=.04). There were no associations between improvement in cardiorespiratory fitness and an increase in mental health (POpeak, P=.66; Vo2peak, P=.33). CONCLUSIONS: This study shows a positive course of life satisfaction during training for the HandbikeBattle. An improvement in cardiorespiratory fitness was longitudinally associated with an increase in life satisfaction. Mental health showed no changes over time.

Loss of selective wrist muscle activation in post-stroke patients.

Purpose: Loss of selective muscle activation after stroke contributes to impaired arm function, is difficult to quantify and is not systematically assessed yet. The aim of this study was to describe and validate a technique for quantification of selective muscle activation of wrist flexor and extensor muscles in a cohort of post-stroke patients. Patterns of selective muscle activation were compared to healthy volunteers and test-retest reliability was assessed.Materials and methods: Activation Ratios describe selective activation of a muscle during its expected optimal activation as agonist and antagonist. Activation Ratios were calculated from electromyography signals during an isometric maximal torque task in 31 post-stroke patients and 14 healthy volunteers. Participants with insufficient voluntary muscle activation (maximal electromyography signal <3SD higher than baseline) were excluded.Results: Activation Ratios at the wrist were reliably quantified (Intraclass correlation coefficients 0.77-0.78). Activation Ratios were significantly lower in post-stroke patients compared to healthy participants (p < 0.05).Conclusion: Activation Ratios allow for muscle-specific quantification of selective muscle activation at the wrist in post-stroke patients. Loss of selective muscle activation may be a relevant determinant in assigning and evaluating therapy to improve functional outcome.Implications for RehabilitationLoss of selective muscle activation after stroke contributes to impaired arm function, is difficult to quantify and is not systematically assessed yet.The ability for selective muscle activation is a relevant determinant in assigning and evaluating therapy to improve functional outcome, e.g., botulinum toxin.Activation Ratios allow for reliable and muscle-specific quantification of selective muscle activation in post-stroke patients.

Peak power output in handcycling of individuals with a chronic spinal cord injury: predictive modeling, validation and reference values.

Purpose: To develop and validate predictive models for peak power output to provide guidelines for individualized handcycling graded exercise test protocols for people with spinal cord injury (SCI); and to define reference values.Materials and methods: Power output was measured in 128 handcyclists with SCI during a synchronous handcycling exercise test. Eighty percent of the data was used to develop four linear regression models: two theoretical and two statistical models with peak power output (in W and W/kg) as dependent variable. The other 20% of the data was used to determine agreement between predicted versus measured power output. Reference values were based on percentiles for the whole group.Results: Lesion level, handcycling training hours and sex or body mass index were significant determinants of peak power output. Theoretical models (R2 = 42%) were superior to statistical models (R2=39% for power output in W, R2 = 30% for power output in W/kg). The intraclass correlation coefficients varied between 0.35 and 0.60, depending on the model. Absolute agreement was low.Conclusions: Both models and reference values provide insight in physical capacity of people with SCI in handcycling. However, due to the large part of unexplained variance and low absolute agreement, they should be used with caution. Implications for rehabilitationIndividualization of the graded exercise test protocol is very important to attain the true peak physical capacity in individuals with spinal cord injury.The main determinants to predict peak power output during a handcycling graded exercise test for individuals with a spinal cord injury are lesion level, handcycling training hours and sex or body mass index.The predictive models for peak power output should be used with caution and should not replace a graded exercise test.

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, VO2, 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.

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.