Prediction of peak oxygen consumption from the ratings of perceived exertion during a graded exercise test and ramp exercise test in able-bodied participants and paraplegic persons

Effect of spinal cord injury on the skin temperature of different regions of interest during a graded exercise test in a moderate temperature environment

The gradient between core and skin temperature is a relevant factor in heat exchange between the human body and the environment, but people with spinal cord injury (SCI), due to their autonomic dysfunction, have impaired mechanisms that condition skin temperature response. This study aimed to determine how SCI affects skin temperature response in different ROIs during a graded exercise test in a moderate temperature environment. 32 participants were included in the study [SCI (N = 16); Non-SCI (N = 16)]. A graded exercise test was conducted on an arm crank ergometer, with a staged duration of 3 min separated by 1 min of rest. Skin temperature was measured using infrared thermography at rest, after each interval and during recovery. Individuals with SCI exhibited lower skin temperature in the anterior leg during exercise than Non-SCI (p < 0.001). During recovery, SCI athletes experienced a lower skin temperature restoration in the anterior arm, posterior arm and anterior leg (p < 0.05). The anterior leg is an interesting region to measure during exercise in people with SCI for assessing the physiological effect of the injury, probably for the autonomic dysfunction in skin temperature regulation, but the effect observed during recovery in the arms suggests the presence of different mechanisms involved in skin temperature regulation.

Differential relationships between physical activity and pain phenotypes in individuals with spinal cord injury

BACKGROUND

Chronic pain affects 70% of individuals with spinal cord injury (SCI) and leads to declines in health and quality of life. Neuropathic and nociceptive pain are phenotypes derived from different mechanisms that contribute to pain perception. The objective of this research was to investigate differential pain responses to moderate-to-vigorous physical activity (MVPA) in two chronic pain phenotypes: neuropathic and nociceptive pain.

METHODS

Community-based physical activity levels were collected for one week in 17 individuals with SCI using a wrist-worn accelerometer, and daily pain ratings were assessed and categorized by phenotype. Physical activity levels were summarized to calculate minutes of MVPA. Correlational analyses were conducted to compare relationships between pain intensity and MVPA across individual participants and between pain phenotype groups.

RESULTS

The neuropathic pain group revealed significant negative correlation between MVPA and pain intensity. In the nociceptive pain group, there was no significant correlation between MVPA and pain intensity. Further analysis revealed two subgroups of positive (N = 4) and negative (N = 3) correlations between MVPA and pain intensity. Pain location differed between the subgroups of nociceptive pain. Individuals with negative correlation experienced neck and upper back pain, whereas individuals with positive correlation experienced unilateral upper extremity pain.

CONCLUSION

Differential relationships exist between pain phenotypes and MVPA in individuals with SCI. Pain location differed between the subgroups of nociceptive pain, which we presume may indicate the presence of nociplastic pain in some individuals. These results may contribute to the advancement of personalized pain management by targeting non-pharmacological interventions for specific pain phenotypes.Trial registration: ClinicalTrials.gov identifier: NCT05236933..

The physiological, perceptual, and thermoregulatory responses to facemask use during exercise

The use of masks in public settings and when around people has been recommended to limit the spread of Coronavirus disease 2019 (COVID-19) by major public health agencies. Several different types of masks classified as either medical- or non-medical grade are commonly used among the public. However, concerns with difficulty breathing, re-breathing exhaled carbon dioxide, a decrease in arterial oxygen saturation, and a decrease in exercise performance have been raised regarding the use of mask during exercise. We review the current knowledge related to the effect of different masks during exercise on cardiorespiratory, metabolic, thermoregulatory, and perceptual responses. As such, the current literature seems to suggest that there are minimal changes to cardiovascular, metabolic, and no changes to thermoregulatory parameters with facemask use. However, differences in ventilatory parameters have been reported with submaximal and maximal intensity exercise to volitional fatigue. Literature on perceptual responses to exercise indicate an impact on ratings of perceived exertion, dyspnea, and overall discomfort dependent on mask use as well as exercise intensity. In conclusion, data from the current literature suggests a minimal impact on physiological, perceptual, and thermoregulatory responses dependent on the type of mask used during exercise.

The Torque Referenced to a Perceived Exertion Level Is Affected by the Type of Movement in Men With Spinal Cord Injury

Objectives

To compare a standardized submaximal intensity (based on the rate of perceived exertion [RPE]) with the percentage of the average and peak torque during a familiarization session in individuals with different spinal cord injury (SCI) levels in gravity-resisted and gravity-assisted movements.

Methods

This was a cross-sectional study at a rehabilitation hospital. Thirty-six individuals stratified in tetraplegia (TP), high paraplegia (HP), and low paraplegia (LP) groups and 12 matched control participants (CG) were enrolled in the study. Participants performed a maximum strength test using isokinetic dynamometry. The familiarization consisted of 10 submaximal repetitions with a level 2 (i.e., 20% of the maximum score) in the Resistance Exercise Scale (OMNI-RES). Fisher's exact test compared the percentages of the average torque (%AT_Fam) and peak torque (%PT_Fam) of the familiarization (based on the peak torque during the maximum strength tests) to the %AT_Fam and %PT_Fam attained with 20% of RPE. The coefficient of variation (CV) was calculated to assess the torque dispersion during each familiarization set.

Results

The %AT_Fam was lower for gravity-assisted compared to gravity-resisted movements for HP, LP, and CG (p ≤ .05). The CV was significantly lower in gravity-resisted movements during familiarization for TP, LP, and CG.

Conclusion

Different RPE levels should be adopted for gravity-resisted or gravity-assisted upper limb exercises to maintain the same relative intensity during a familiarization session.

A Provider's Guide to Vascular Disease, Dyslipidemia, and Glycemic Dysregulation in Chronic Spinal Cord Injury

Individuals with chronic spinal cord injury (SCI) are predisposed to accelerated atherogenesis, dyslipidemia, and glycemic dysregulation, although not enough is known about the etiologies or clinical consequences of these secondary effects of paralysis. While guidelines for the detection and treatment of cardiometabolic disease in SCI have recently been published, there has been a historical paucity of data-driven approaches to these conditions. This article will describe what is and not known about the cardiovascular disease and glycemic dysregulation that frequently attend SCI. It will conclude with a review of both guideline-driven and informal recommendations addressing the clinical care of people living with SCI.

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.

Peak oxygen uptake measured during a perceptually-regulated exercise test is reliable in community-based manual wheelchair users

This study compares test-retest reliability and peak exercise responses from ramp-incremented (RAMP) and maximal perceptually-regulated (PRET_max) exercise tests during arm crank exercise in individuals reliant on manual wheelchair propulsion (MWP). Ten untrained participants completed four trials over 2-weeks (two RAMP (0-40 W + 5-10 W · min^-1) trials and two PRET_max. PRET_max consisted of five, 2-min stages performed at Ratings of Perceived Exertion (RPE) 11, 13, 15, 17 and 20). Participants freely changed the power output to match the required RPE. Gas exchange variables, heart rate, power output, RPE and affect were determined throughout trials. The V̇O_2peak from RAMP (14.8 ± 5.5 ml · kg^-1 · min^-1) and PRET_max (13.9 ± 5.2 ml · kg^-1 · min^-1) trials were not different (P = 0.08). Measurement error was 1.7 and 2.2 ml · kg^-1 · min^-1 and coefficient of variation 5.9% and 8.1% for measuring V̇O_2peak from RAMP and PRET_max, respectively. Affect was more positive at RPE 13 (P = 0.02), 15 (P = 0.01) and 17 (P = 0.01) during PRET_max. Findings suggest that PRET_max can be used to measure V̇O_2peak in participants reliant on MWP and leads to a more positive affective response compared to RAMP.

Robotic Rehabilitation and Spinal Cord Injury: a Narrative Review

Mobility after spinal cord injury (SCI) is among the top goals of recovery and improvement in quality of life. Those with tetraplegia rank hand function as the most important area of recovery in their lives, and those with paraplegia, walking. Without hand function, emphasis in rehabilitation is placed on accessing one's environment through technology. However, there is still much reliance on caretakers for many activities of daily living. For those with paraplegia, if incomplete, orthoses exist to augment walking function, but they require a significant amount of baseline strength and significant energy expenditure to use. Options for those with motor complete paraplegia have traditionally been limited to the wheelchair. While wheelchairs provide a modified level of independence, wheelchair users continue to face difficulties in access and mobility. In the past decade, research in SCI rehabilitation has expanded to include external motorized or robotic devices that initiate or augment movement. These robotic devices are used with 2 goals: to enhance recovery through repetitive, functional movement and increased neural plasticity and to act as a mobility aid beyond orthoses and wheelchairs. In addition, lower extremity exoskeletons have been shown to provide benefits to the secondary medical conditions after SCI such as pain, spasticity, decreased bone density, and neurogenic bowel. In this review, we discuss advances in robot-guided rehabilitation after SCI for the upper and lower extremities, as well as potential adjuncts to robotics.

Predictive factors of peak aerobic capacity using simple measurements of anthropometry and musculoskeletal fitness in paraplegic men

BACKGROUND

Protocols for evaluating cardiovascular fitness for wheelchair-dependent persons are still scarcely accessible due to the requirements such as specialized equipment and expertise in community or public healthcare settings. This study aimed to assess the potential of secondary utilization of musculoskeletal fitness components for estimating peak oxygen uptake (VO2peak) in paraplegic men.

METHODS

Thirty-three paraplegic men (T1-L3) aged 23-63 years underwent anthropometry (height, weight and calculated body mass index and body surface area) and upper-body musculoskeletal fitness tests (back-scratch, arm-curls and handgrip strength tests) and performed a graded exercise test with an arm-crank ergometer on two non-consecutive days. To determine the relationship between VO2peak and various kinanthropometric parameters and derive a regression model that predicts the VO2peak, uni- and multivariate analyses were conducted, respectively.

RESULTS

Maximal numbers of arm curls on either arm (r=0.486, P=0.004) and the back-scratch distance (r=0.426, P=0.013) were moderately correlated with VO2peak. Moreover, among the indices of handgrip strength, average handgrip strength of both hands divided by the body surface area showed a strong correlation coefficient with VO2peak (r=0.674, P<0.001). Multivariate linear regression analysis indicated that muscular endurance and strength were the main predictors for estimating VO2peak. Considering shoulder flexibility, age, and anthropometric variables, the regression model showed the highest adjusted R2 of 0.811 and lowest standard error of estimate of 3.54 mL·kg-1·min-1 (P<0.001). The Bland-Altman plots indicated good agreement between actual and estimated VO2peak. The mean absolute prediction error was 11.9%.

CONCLUSIONS

Musculoskeletal fitness and anthropometric components may be predictive factors of a new conceptual modality estimating concomitant cardiorespiratory fitness beyond their traditional health-related indications.

Methodological and clinical implications of a three-in-one Russian doll design for tracking health trajectories and improving health and function through innovative exercise treatments in adults with disability

BACKGROUND

Hybrid research designs targeting adults with neurologic disability are critical for improving the efficiency of models that can identify, track and intervene on identified health issues.

METHODS

Our Russian doll framework encompasses three study phases. Phase 1 involves prospectively following a cohort of participants with disability to examine the relationships between rates of health and functional deficits (e.g., pain, fatigue, deconditioning), functional measures (e.g., cardiorespiratory endurance, strength, balance), and environmental and sociocultural factors. In Phase 2, eligible participants with neurologic disability from Phase 1 (in our example, individuals with multiple sclerosis) are screened and randomized to a clinical exercise efficacy trial. In Phase 3, study participants are enrolled in a home-based teleexercise trial to test the feasibility and replicability of delivering the clinical exercise study in the home.

DISCUSSION

This unique three-in-one Russian doll framework serves as a foundation for informing and guiding researchers and clinicians in treating certain health and functional deficits in people with neurologic disability using exercise as a primary treatment modality in both the clinical and home settings. It offers a unique perspective for understanding the critical issues of functioning, health maintenance and quality of life for people with neurologic disability across a longitudinal framework.

TRIAL REGISTRATION

Study 2 ClinicalTrials.gov identifier NCT02533882 (retroactively registered 03/06/2015). Study 3 ClinicalTrials.gov identifier NCT03108950 (retroactively registered 04/05/2017).

Submaximal, Perceptually Regulated Exercise Testing Predicts Maximal Oxygen Uptake: A Meta-Analysis Study

BACKGROUND

Recently, several authors have proposed the use of a submaximal 'perceptually regulated exercise test' (PRET) to predict maximal oxygen uptake ([Formula: see text]). The PRET involves asking the individual to self-regulate a series of short bouts of exercise corresponding to pre-set ratings of perceived exertion (RPE). The individual linear relationship between RPE and oxygen uptake (RPE:[Formula: see text]) is then extrapolated to the [Formula: see text], which corresponds to the theoretical maximal RPE (RPE20). Studies suggest that prediction accuracy from this method may be better improved during a second PRET. Similarly, some authors have recommended an extrapolation to RPE19 rather than RPE20.

OBJECTIVES

The purpose of the meta-analysis was to examine the validity of the method of predicting [Formula: see text] from the RPE:[Formula: see text] during a PRET, and to determine the level of agreement and accuracy of predicting [Formula: see text] from an initial PRET and retest using RPE19 and RPE20.

DATA SOURCES

From a systematic search of the literature, 512 research articles were identified.

STUDY ELIGIBILITY CRITERIA

The eligible manuscripts were those which used the relationship between the RPE≤15 and [Formula: see text], and used only the Borg's RPE scale.

PARTICIPANTS AND INTERVENTIONS

Ten studies (n = 274 individuals) were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

For each study, actual and predicted [Formula: see text] from four subgroup outcomes (RPE19 in the initial test, RPE19 in the retest, RPE20 in the initial test, RPE20 in the retest) were identified, and then compared. The magnitude of the difference regardless of subgroup outcomes was examined to determine if it is better to predict [Formula: see text] from extrapolation to RPE19 or RPE20. The magnitude of differences was examined for the best PRET (test vs retest).

RESULTS

The results revealed that [Formula: see text] may be predicted from RPE:[Formula: see text] during PRET in different populations and in various PRET modalities, regardless of the subgroup outcomes. To obtain greater accuracy of predictions, extrapolation to RPE20 during a retest may be recommended.

LIMITATIONS

The included studies reported poor selection bias and data collection methods.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The [Formula: see text] may be predicted from RPE:[Formula: see text] during PRET, especially when [Formula: see text] is extrapolated to RPE20 during a second PRET.

Cross-validation of Peak Oxygen Consumption Prediction Models From OMNI Perceived Exertion

This study cross-validated statistical models for prediction of peak oxygen consumption using ratings of perceived exertion from the Adult OMNI Cycle Scale of Perceived Exertion. 74 participants (men: n=36; women: n=38) completed a graded cycle exercise test. Ratings of perceived exertion for the overall body, legs, and chest/breathing were recorded each test stage and entered into previously developed 3-stage peak oxygen consumption prediction models. There were no significant differences (p>0.05) between measured and predicted peak oxygen consumption from ratings of perceived exertion for the overall body, legs, and chest/breathing within men (mean±standard deviation: 3.16±0.52 vs. 2.92±0.33 vs. 2.90±0.29 vs. 2.90±0.26 L·min(-1)) and women (2.17±0.29 vs. 2.02±0.22 vs. 2.03±0.19 vs. 2.01±0.19 L·min(-1)) participants. Previously developed statistical models for prediction of peak oxygen consumption based on subpeak OMNI ratings of perceived exertion responses were similar to measured peak oxygen consumption in a separate group of participants. These findings provide practical implications for the use of the original statistical models in standard health-fitness settings.

Prediction of peak oxygen uptake in children using submaximal ratings of perceived exertion during treadmill exercise

Purpose

This study assessed the utility of the Children’s Effort Rating Table (CERT) and the Eston–Parfitt (EP) Scale in estimating peak oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak) in children, during cardiopulmonary exercise testing (CPET) on a treadmill.

Methods

Fifty healthy children (n = 21 boys; 9.4 ± 0.9 years) completed a continuous, incremental protocol until the attainment of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak. Oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{2}$$\end{document}V˙O2) was measured continuously, and ratings of perceived exertion (RPE) were estimated at the end of each exercise stage using the CERT and the EP Scale. Ratings up to- and including RPE 5 and 7, from both the CERT (CERT 5, CERT 7) and EP Scale (EP 5, EP 7), were linearly regressed against the corresponding \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{2}$$\end{document}V˙O2, to both maximal RPE (CERT 10, EP 10) and terminal RPE (CERT 9, EP 9).

Results

There were no differences between measured- and predicted \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak from CERT 5, CERT 7, EP 5 and EP 7 when extrapolated to either CERT 9 or EP 9 (P > 0.05). Pearson’s correlations of r = 0.64–0.86 were observed between measured- and predicted \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak, for all perceptual ranges investigated. However, only EP 7 provided a small difference when considering the standard error of estimate, suggesting that the prediction of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak from EP 7 would be within 10 % of measured \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak.

Conclusions

Although robust estimates of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak may be elicited using both the CERT and EP Scale during a single CPET with children, the most accurate estimates of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak occur when extrapolating from EP 7.

Active paraplegics are protected against exercise-induced oxidative damage through the induction of antioxidant enzymes

STUDY DESIGN

Experimental study.

OBJECTIVES

Exercise improves functional capacity in spinal cord injury (SCI). However, exhaustive exercise, especially when sporadic, is linked to the production of reactive oxygen species that may have a detrimental effect on SCI. We aimed to study the effect of a single bout of exhaustive exercise on systemic oxidative stress parameters and on the expression of antioxidant enzymes in individuals with paraplegia.

SETTING

The study was conducted in the Physical Therapy department and the Physical Education and Sports department of the University of Valencia.

METHODS

Sixteen paraplegic subjects were submitted to a graded exercise test (GET) until volitional exhaustion. They were divided into active or non-active groups. Blood samples were drawn immediately, 1 and 2 h after the GET. We determined plasma malondialdehyde (MDA) and protein carbonylation as markers of oxidative damage. Antioxidant gene expression (catalase and glutathione peroxidase-GPx) was determined in peripheral blood mononuclear cells.

RESULTS

We found a significant increase in plasma MDA and protein carbonyls immediately after the GET (P<0.05). This increment correlated significantly with the lactate levels. Active paraplegics showed lower levels of exercise-induced oxidative damage (P<0.05) and higher exercise-induced catalase (P<0.01) and GPx (P<0.05) gene expression after the GET.

CONCLUSIONS

These results suggest that exercise training may be useful in SCI patients to develop systemic antioxidant defenses that may protect them against exercise-induced oxidative damage.

Framework for Assessment of the Usability of Lower-Extremity Robotic Exoskeletal Orthoses

Persons with neurologic conditions such as spinal cord injury, stroke, and multiple sclerosis often lose the ability to stand and walk. Robotic hip-knee-ankle-foot exoskeletal orthoses have become commercially available and may allow some of these people to stand and walk again. These devices may also have applications beyond mobility, such as exercise, amelioration of secondary complications related to lack of ambulation, and the promotion of neuroplasticity. The authors present a framework for assessment of the usability of robotic exoskeletal orthoses available now or in the near future. The framework contains six modules: Functional applications, Personal factors, Device factors, External factors, Activities, and Health outcomes. Metrics and measures are suggested for each framework factor.

Time and Effort Required by Persons with Spinal Cord Injury to Learn to Use a Powered Exoskeleton for Assisted Walking

BACKGROUND

Powered exoskeletons have been demonstrated as being safe for persons with spinal cord injury (SCI), but little is known about how users learn to manage these devices.

OBJECTIVE

To quantify the time and effort required by persons with SCI to learn to use an exoskeleton for assisted walking.

METHODS

A convenience sample was enrolled to learn to use the first-generation Ekso powered exoskeleton to walk. Participants were given up to 24 weekly sessions of instruction. Data were collected on assistance level, walking distance and speed, heart rate, perceived exertion, and adverse events. Time and effort was quantified by the number of sessions required for participants to stand up, walk for 30 minutes, and sit down, initially with minimal and subsequently with contact guard assistance.

RESULTS

Of 22 enrolled participants, 9 screen-failed, and 7 had complete data. All of these 7 were men; 2 had tetraplegia and 5 had motor-complete injuries. Of these, 5 participants could stand, walk, and sit with contact guard or close supervision assistance, and 2 required minimal to moderate assistance. Walk times ranged from 28 to 94 minutes with average speeds ranging from 0.11 to 0.21 m/s. For all participants, heart rate changes and reported perceived exertion were consistent with light to moderate exercise.

CONCLUSIONS

This study provides preliminary evidence that persons with neurological weakness due to SCI can learn to walk with little or no assistance and light to somewhat hard perceived exertion using a powered exoskeleton. Persons with different severities of injury, including those with motor complete C7 tetraplegia and motor incomplete C4 tetraplegia, may be able to learn to use this device.

Wheelchair users' perceived exertion during typical mobility activities

STUDY DESIGN

Each participant performed a series of wheelchair exercises equivalent in intensity to minimal functional speed (1 m s(-1)), functional walking speed (1.3 m s(-1)), a relatively challenging speed (1.6 m s(-1)) and a self-selected speed. Each participant also completed a graded exercise test (GXT) to volitional exhaustion (VO2peak).

OBJECTIVES

The purpose of this study was (1) to assess the physical capacity of wheelchair users as they undertake typical mobility activities and (2) to investigate how closely the components of a differentiated model of perceived exertion mirror wheelchair users' own perception of exertion.

METHODS

Eleven (eight males and three females) spinal cord-injured or congenitally impaired wheelchair-dependent participants volunteered for the study. Differentiated ratings of perceived exertion (RPE_arm and RPE_respiration) and oxygen uptake (VO2) and heart rate were recorded during each exercise.

RESULTS

The mean comfortable speed at which the participants propelled their own wheelchairs on the wheelchair ergometer was 1.1±0.2 m s(-1). Speeds of 1 m s(-1) and 1.3 m s(-1) are typical of everyday functional propulsion. The corresponding RPE_respiration and RPE_arm ranged from 7 to 13 on the Borg scale; the %VO2peak measured in these trials ranged from 37 to 80% VO2peak. For propulsion intensities used in the present study-low, moderate, high and graded exercise intensity-no difference could be observed between RPE_respiration and RPE_arm. There were no significant differences between RPE_arm and RPE_respiration at the termination of the GXT.

CONCLUSION

The current study showed potential for the use of RPE to assess and monitor daily wheelchair propulsion intensity in individuals with paraplegia.

Prediction of maximal or peak oxygen uptake from ratings of perceived exertion

Maximal or peak oxygen uptake (V˙O2 max and V˙O2 peak , respectively) are commonly measured during graded exercise tests (GXTs) to assess cardiorespiratory fitness (CRF), to prescribe exercise intensity and/or to evaluate the effects of training. However, direct measurement of CRF requires a GXT to volitional exhaustion, which may not always be well accepted by athletes or which should be avoided in some clinical populations. Consequently, numerous studies have proposed various sub-maximal exercise tests to predict V˙O2 max or V˙O2 peak . Because of the strong link between ratings of perceived exertion (RPE) and oxygen uptake (V˙O2), it has been proposed that the individual relationship between RPE and V˙O2 (RPE:V˙O2) can be used to predict V˙O2 max (or V˙O2 peak) from data measured during submaximal exercise tests. To predict V˙O2 max or V˙O2 peak from these linear regressions, two procedures may be identified: an estimation procedure or a production procedure. The estimation procedure is a passive process in which the individual is typically asked to rate how hard an exercise bout feels according to the RPE scale during each stage of a submaximal GXT. The production procedure is an active process in which the individual is asked to self-regulate and maintain an exercise intensity corresponding to a prescribed RPE. This procedure is referred to as a perceptually regulated exercise test (PRET). Recently, prediction of V˙O2max or V˙O2 peak from RPE:V˙O2 measured during both GXT and PRET has received growing interest. A number of studies have tested the validity, reliability and sensitivity of predicted V˙O2 max or V˙O2 peak from RPE:V˙O2 extrapolated to the theoretical V˙O2 max at RPE20 (or RPE19). This review summarizes studies that have used this predictive method during submaximal estimation or production procedures in various populations (i.e., sedentary individuals, athletes and pathological populations). The accuracy of the methods is discussed according to the RPE:V˙O2 range used to plot the linear regression (e.g., RPE9–13 versus RPE9–15 versus RPE9–17 during PRET), as well as the perceptual endpoint used for the extrapolation (i.e., RPE19 and RPE20). The V˙O2 max or V˙O2 peak predictions from RPE:V˙O2 are also compared with heart rate-related predictive methods. This review suggests that V˙O2 max (or V˙O2 peak ) may be predicted from RPE:V˙O2 extrapolated to the theoretical V˙O2 max (or V˙O2 peak) at RPE20 (or RPE19). However, it is generally preferable to (1) extrapolate RPE:V ˙ O 2 to RPE19 (rather than RPE20); (2) use wider RPE ranges (e.g. RPE ≤ 17 or RPE9–17) in order to increase the accuracy of the predictions; and (3) use RPE ≤ 15 or RPE9–15 in order to reduce the risk of cardiovascular complications in clinical populations.

Prediction of VO2 peak using OMNI Ratings of Perceived Exertion from a submaximal cycle exercise test

The primary aim of this study was to develop statistical models to predict peak oxygen consumption (VO2 peak) using OMNI Ratings of Perceived Exertion measured during submaximal cycle ergometry. Male (M = 20.9 yr., SE = 0.4) and female (M = 21.6 yr., SE = 0.5) participants (N = 81) completed a load-incremented maximal cycle ergometer exercise test. Simultaneous multiple linear regression was used to develop separate VO2 peak statistical models using submaximal ratings of perceived exertion for the overall body, legs, and chest/breathing as predictor variables. VO2 peak (L·min(-1)) predicted for men and women from ratings of perceived exertion for the overall body (3.02 ± 0.06; 2.03 ± 0.04), legs (3.02 ± 0.06; 2.04 ± 0.04), and chest/breathing (3.02 ± 0.05; 2.03 ± 0.03) were similar to measured VO2 peak (3.02 ± 0.10; 2.03 ± 0.06, ps > .05). Statistical models based on submaximal OMNI Ratings of Perceived Exertion provide an easily administered and accurate method to predict VO2 peak.

RPE-Derived Work Rates Can Be Accurately Produced without External Feedback or Reference to the RPE Scale

Ratings of perceived exertion (RPE) are used to prescribe exercise intensity. This study assessed whether the accurate production of exercise intensity is affected when the rater cannot see the RPE scale. After completing a graded exercise test, 15 active, male participants ( M age = 34, SD = 6.7 yr.; M mass = 73.9, SD = 14.8 kg, M height = 1.74, SD = 0.08 m) completed 3 × 4 min. cycling trials at four randomised RPE-based intensities (RPEs 11, 13, 15, and 17). Participants were allocated to a Full feedback group or a No feedback group (RPEs not in view). On the third trial, No feedback conditions were imposed on the Full feedback group. No statistically significant differences between groups' mean work rates were observed. Changing from Full feedback to No feedback conditions led to a significant overestimation between the trials for power output at RPE 11. Intra-class correlations were significant at RPEs 11, 13, and 17 between all trials for both conditions. Provided adequate familiarisation, active participants can accurately produce RPE derived work rates, even when RPE is not in view.

Use of Ratings of Perceived Exertion in Sports

The rating of perceived exertion (RPE) is a recognized marker of intensity and of homeostatic disturbance during exercise. It is typically monitored during exercise tests to complement other measures of intensity. The purpose of this commentary is to highlight the remarkable value of RPE as a psychophysiological integrator in adults. It can be used in such diverse fashions as to predict exercise capacity, assess changes in training status, and explain changes in pace and pacing strategy. In addition to using RPE to self-regulate exercise, a novel application of the intensity:RPE relationship is to clamp RPE at various levels to produce self-paced bouts of exercise, which can be used to assess maximal functional capacity. Research also shows that the rate of increase in RPE during self-paced competitive events of varying distance, or constant-load tasks where the participant exercises until volitional exhaustion, is proportional to the duration that remains. These findings suggest that the brain regulates RPE and performance in an anticipatory manner based on awareness of metabolic reserves at the start of an event and certainty of the anticipated end point. Changes in pace may be explained by a continuous internal negotiation of momentary RPE compared with a preplanned “ideal rate of RPE progression” template, which takes into account the portion of distance covered and the anticipated end point. These observations have led to the development of new techniques to analyze the complex relationship of RPE and pacing. The use of techniques to assess frontal-cortex activity will lead to further advances in understanding.

A perceptually regulated, graded exercise test predicts peak oxygen uptake during treadmill exercise in active and sedentary participants

The validity of predicting peak oxygen uptake ([Formula: see text]) in sedentary participants from a perceptually regulated exercise test (PRET) is limited to two cycle ergometry studies. We assessed the validity of a treadmill-based PRET. Active (n = 49; 40.7 ± 13.8 years) and sedentary (n = 26; 33.4 ± 13.2 y) participants completed two PRETS (PRET 1 and PRET2), requiring a change in speed or incline corresponding to ratings of perceived exertion (RPE) 9, 11, 13 and 15. Extrapolation of RPE: [Formula: see text] data to RPE 19 and 20 from the RPE 9-13 and 9-15 ranges were used to estimate [Formula: see text], and compared to [Formula: see text] from a graded exercise test (GXT). The [Formula: see text] :heart rate (HR) data (≥RPE 15) from the GXT were also extrapolated to age-predicted maximal HR (HRmax(pred)) to provide further estimation of [Formula: see text]. ANOVA revealed no significant differences between [Formula: see text] predictions from the RPE 9-15 range for PRET 1 and PRET 2 when extrapolated to RPE 19 in both active (54.3 ± 7.4; 52.9 ± 8.1 ml kg(-1) min(-1)) and sedentary participants (34.1 ± 10.2; 34.2 ± 9.6 ml kg(-1) min(-1)) and no difference between the HRmax(pred) method and measured [Formula: see text] from the GXT for active (53.3 ± 10.0; 53.9 ± 7.5 ml kg(-1) min(-1), respectively) and sedentary participants (33.6 ± 8.4, 34.4 ± 7.0 ml kg(-1) min(-1), respectively). A single treadmill-based PRET using RPE 9-15 range extrapolated to RPE 19 is a valid means of predicting [Formula: see text] in young and middle to older-aged individuals of varying activity and fitness levels.