Differentiated perceived exertion and self-regulated wheelchair exercise

Intervention Design of High-Intensity Interval Training in Individuals With Spinal Cord Injury: Narrative Review and Future Perspectives

Background

Individuals with spinal cord injury (SCI) have lower levels of physical activity compared to the nondisabled population. Exercise guidelines recommend moderate or vigorous exercise to improve cardiovascular health and reduce cardiometabolic risk factors in persons with SCI. High-intensity interval training (HIIT) is a popular exercise choice and encompasses brief periods of vigorous exercise paired with intermittent periods of recovery.

Objectives

This review describes the available literature on HIIT for individuals with SCI, including differences in protocol design and suggested areas of further investigation.

Methods

Our institution's library system performed the comprehensive search. The primary keywords and phrases used to search included spinal cord injury, high-intensity interval training, tetraplegia, paraplegia, and several other related terms.

Results

Initially 62 records were screened, and 36 were deemed outside the scope of this review. Twenty-six studies published between 2001 and 2021 fulfilled the eligibility criteria and were divided among two researchers for review and analysis. All records required persons with SCI and a standardized HIIT intervention. Study design varied widely with respect to mode of exercise, prescribed intensity, duration of performance intervals, and session duration. This variability necessitates further investigation into the specifics of a HIIT prescription and the associated outcomes for persons with SCI.

Conclusion

Standardization of HIIT protocols may lead to more robust conclusions regarding its effects on cardiorespiratory fitness as well as mitigation of cardiometabolic risk factors. Meta-analyses will eventually be needed on proper dosing and session parameters to improve cardiorespiratory fitness and cardiometabolic risk factors.

Oxygen uptake and heart rate responses to 4 weeks of RPE-guided handcycle training

PURPOSE

To investigate the efficacy of using Ratings of Perceived Exertion (RPE) to prescribe and regulate a 4-week handcycle training intervention.

METHODS

Thirty active adults, untrained in upper body endurance exercise, were divided into three groups to complete a 4-week intervention: (i) RPE-guided training (n = 10; 2 female), (ii) power output (PO)-guided (n = 10; 2 female) training, or (iii) non-training control (n = 10; 4 female). Training groups performed three sessions of handcycling each week. Oxygen uptake ([Formula: see text]), heart rate (HR), and Feeling Scale (FS) rating were collected during training sessions. RPE-guided training was performed at RPE 13. PO-guided training was matched for percentage of peak PO per session, based upon that achieved by the RPE-guided training group.

RESULTS

There were no differences in percentage of peak [Formula: see text] (66 ± 13% vs 61 ± 9%, p = 0.22), peak HR (75 ± 8% vs 71 ± 6%, p = 0.11) or FS rating (1.2 ± 1.9 vs 0.8 ± 1.6, p = 0.48) between RPE- and PO-guided training, respectively. The average coefficient of variation in percentage of peak HR between consecutive training sessions was 2.8% during RPE-guided training, and 3.4% during PO-guided training.

CONCLUSION

Moderate-vigorous intensity handcycling exercise can be prescribed effectively using RPE across a chronic training intervention, suggesting utility for practitioners in a variety of rehabilitation settings.

Evaluation of a standardized test protocol to measure wheelchair-specific anaerobic and aerobic exercise capacity in healthy novices on an instrumented roller ergometer

This study aims to evaluate whether a test protocol with standardized and individualized resistance settings leads to valid wheelchair Wingate tests (WAnT) and graded exercise tests (GXT) in healthy novices. Twenty able-bodied individuals (10M/10F, age 23 ± 2 years, body mass 72 ± 11 kg) performed an isometric strength test, sprint test, WAnT and GXT on a wheelchair ergometer. Using a previously developed set of regression equations, individuals’ isometric strength outcome was used to estimate the WAnT result (P30_est), from which an effective individual WAnT resistance was derived. The subsequently measured WAnT outcome (P30_meas) was used to estimate the GXT outcome (POpeak_est) and to scale the individual GXT resistance steps. Estimated and measured outcomes were compared. The WAnT protocol was considered valid when maximal velocity did not exceed 3 m·s^-1; the GXT protocol was considered valid when test duration was 8–12 min. P30_est did not significantly differ from P30_meas, while one participant did not have a valid WanT, as maximal velocity exceeded 3 m·s^-1. POpeak_est was 10% higher than POpeak_meas, and six participants did not reach a valid GXT: five participants had a test duration under 8 min and one participant over 12 min. The isometric strength test can be used to individually scale the WAnT protocol. The WAnT outcome scaled the protocol for the GXT less accurately, resulting in mostly shorter-than-desired test durations. In conclusion, the evaluated standardized and individualized test protocol was valid for the WAnT but less valid for the GXT among a group of novices. Before implementing the standardized individual test protocol on a broader scale, e.g. among paralympic athletes, it should be evaluated among different athletic wheelchair-dependent populations.

Physiological Considerations to Support Podium Performance in Para-Athletes

The twenty-first century has seen an increase in para-sport participation and the number of research publications on para-sport and the para-athlete. Unfortunately, the majority of publications are case reports/case series or study single impairment types in isolation. Indeed, an overview of how each International Paralympic Committee classifiable impairment type impact athlete physiology, health, and performance has not been forthcoming in the literature. This can make it challenging for practitioners to appropriately support para-athletes and implement evidence-based research in their daily practice. Moreover, the lack of a cohesive publication that reviews all classifiable impairment types through a physiological lens can make it challenging for researchers new to the field to gain an understanding of unique physiological challenges facing para-athletes and to appreciate the nuances of how various impairment types differentially impact para-athlete physiology. As such, the purpose of this review is to (1) summarize how International Paralympic Committee classifiable impairments alter the normal physiological responses to exercise; (2) provide an overview of "quick win" physiological interventions targeted toward specific para-athlete populations; (3) discuss unique practical considerations for the para-sport practitioner; (4) discuss research gaps and highlight areas for future research and innovation, and (5) provide suggestions for knowledge translation and knowledge sharing strategies to advance the field of para-sport research and its application by para-sport practitioners.

Validity of Session-Rate of Perceived Exertion to Quantify Training Loads in Paralympic Swimmers

ABSTRACT

Sinnott-O'Connor, C, Comyns, TM, and Warrington, GD. Validity of session-RPE to quantify training loads in Paralympic swimmers. J Strength Cond Res 35(9): 2611-2615, 2021-Multiple measures may be used by coaches to quantify training load (TL). The application of heart rate (HR) has limitations in swimming and in Paralympic swimmers, and it may not always be a suitable measure. Therefore, the aim of this study was to determine the validity and reliability of the session-rate of perceived exertion (sRPE) method for quantifying internal TL in Paralympic swimmers. A further aim was to examine the relationship between athlete and coach perceptions of sRPE TL. Four international Paralympic swimmers selected to compete in Rio 2016 Paralympic Games participated in this study. Heart rate, RPE, and session duration were recorded for 30 training sessions of varied intensities across a 6-week home training period to quantify TL. Significant high to very high positive correlations were observed between sRPE and 3 HR-based measures-Banister's, Edwards, and Lucia's TRIMP (r = 0.68, 0.66, 0.74, p < 0.01, respectively). Moderate correlations were observed between sRPE and distance measures (r = 0.53, p < 0.05) but were lower than those observed with HR-based measures. A 2-way analysis of variance identified significant differences in the sRPE ratings between coaches and athletes (F(2, 108) = 170.4, p < 0.01, η2 = 0.75). The results of this study suggest that the sRPE method may be an appropriate monitoring tool for quantifying TL during water-based training using a single measure in Paralympic swimmers.

The ability of heart rate or perceived exertion to predict oxygen uptake varies across exercise modes in persons with tetraplegia

STUDY DESIGN

Descriptive study.

OBJECTIVES

To examine grouped and intra-individual relationships between 1) exercise intensity and heart rate (EI-HR); 2) EI and oxygen uptake (EI-VO₂); 3) VO₂ and HR (VO₂-HR); and 4) perceived exertion and VO₂ (PE-VO₂) in persons with tetraplegia (C4/5-C8) during different modes of exercise.

SETTING

Community in Winnipeg, Canada.

METHODS

Participants exercised at 3 graded intensities during arm ergometry (ERG), wheeling indoors on cement (MWC), or hand-cycling outdoors (HC). EI (Watts, km/hr) and VO₂, HR and PE were recorded.

RESULTS

22 persons completed ERG, 14/22 also completed MWC and 5/22 completed ERG, MWC and HC. Regression analysis of grouped data showed a significant relationship between EI-VO₂ but not for EI-HR or HR-VO₂. Intra-individual analyses showed a strong correlation (r or ρ > 0.7) for VO₂-HR for 16/22 during ERG. In the participants completing multiple exercise modes, a strong VO₂-HR relationship was present in 12/14 in ERG, but in only 6/14 in MWC. The 5 persons exercising with all 3 modes had a strong HR-VO₂ relationship in 5/5 for ERG, 2/5 in MWC and 1/5 in HC. A strong relationship for PE-VO₂ was observed in a higher proportion of participants (versus HR-VO₂) during MWC (9/14) and HC (2/4).

CONCLUSION

Within the same individual, the HR-VO₂ relationship varies across modes, despite exercising over similar ranges of steady-state VO₂. HR appears less able to predict VO₂ compared to PE. Based on these new findings, systematic investigation of the HR-VO₂ relationship across modes of exercise in tetraplegia is warranted.

Perceived exertion responses to wheelchair propulsion differ between novice able-bodied and trained wheelchair sportspeople

OBJECTIVES

To investigate peripheral (RPE_P) and central (RPE_C) Ratings of Perceived Exertion during wheelchair propulsion in untrained able-bodied (AB) participants, and trained wheelchair rugby athletes with and without cervical spinal cord injury (CSCI).

DESIGN

Cross-sectional study.

METHODS

38 participants (AB: n=20; wheelchair rugby athletes with CSCI: n=9; without CSCI: n=9) completed an incremental wheelchair propulsion test to exhaustion on a motorised treadmill. Gas exchange measures and heart rate (HR) were collected throughout. RPE_P and RPE_C on the Category Ratio-10 were verbally recorded each minute. Blood lactate concentration ([BLa]) was determined post-test.

RESULTS

Between 50-100% peak oxygen uptake (V̇O_2peak), RPE_P was greater than RPE_C in AB (p<0.05), but not in athletes with (p=0.07) or without (p=0.16) CSCI. RPE_P was greater in AB compared to players with CSCI (Effect sizes: 1.24-1.62), as were respiratory exchange ratio (1.02±0.10 vs 0.82±0.11, p<0.05) and [BLa]_peak (7.98±2.53 vs 4.66±1.57mmol·L^-1). RPE_C was greater in athletes without CSCI compared to those with CSCI (Effect sizes: 0.70-1.38), as were HR (166±20 vs 104±15 beats·min^-1, p<0.05) and ventilation (59.2±28.8 vs 35.1±16.6L·min^-1, p=0.01).

CONCLUSIONS

RPE_P was dominant over RPE_C during wheelchair propulsion for untrained AB participants. For athletes with CSCI, lower RPE_P and RPE_C were reported at the same %V̇O_2peak compared to those without CSCI. The mechanism for this remains to be fully elucidated.

Modality-specific training adaptations - do they lead to a dampened acute inflammatory response to exercise?

While adaptations to a short-term training program can dampen the acute inflammatory response to exercise, less is known about the influence of chronic modality-specific adaptations to training. This study compares the acute inflammatory response to upper- and lower-body interval exercise in individuals chronically trained in these respective modalities. Ninety minutes of interval exercise matched for relative power output on an arm-crank (ARM) and cycle ergometer (LEG) was performed by 8 trained paddlers and 8 trained cyclists. Blood samples were taken before and after exercise. Interleukin-6 (IL-6) concentrations were analysed in plasma, while the expression of intracellular heat shock protein 72 (iHsp72) was assessed in monocytes. IL-6 was increased following both modalities (fold change - ARM: 7.23 ± 3.56, p < 0.001; LEG: 9.03 ± 4.82, p < 0.001), in both groups (cyclists, p < 0.001; paddlers, p < 0.001), but the increase was smaller in ARM compared with LEG (time × modality, p < 0.001). ARM induced a smaller iHsp72 response compared with LEG (fold change - ARM: 1.07 ± 0.14, p = 0.102; LEG: 1.18 ± 0.14, p < 0.001; time × modality, p = 0.039). Following ARM, iHsp72 expression was increased in the cyclists only (fold change cyclists: 1.12 ± 0.11, p = 0.018; paddlers: 1.03 ± 0.17, p = 0.647), while iHsp72 expression following LEG was increased in both groups (fold change cyclists: 1.14 ± 0.15, p = 0.027; paddlers: 1.22 ± 0.13, p < 0.001). Taken together, the acute inflammatory response to lower-body interval exercise was larger compared with work-matched upper-body interval exercise. Moreover, adaptations to upper-body exercise training dampened the iHsp72 response to this modality. Therefore, exercise may be less effective in reducing chronic low-grade inflammation in individuals relying on their upper body, such as wheelchair users.

Load Monitoring Variables in Training and Competition Situations: A Systematic Review Applied to Wheelchair Sports

The aim of this review was to identify the main variables for load monitoring in training and competition situations in wheelchair sports. Studies were identified from a systematic search of three databases (PubMed, Web of Science, and SportDiscuss), with search phrases constructed from MeSH terms, alone or in combination, limited to English-language literature, and published up to January 2016. Our main findings were that variables related to external load (distance, speed, and duration) are used to monitor load in competition. In training situations, researchers have used variables related to internal load (heart rate and VO₂); in both training and competition situations, researchers used internal load measurements (training impulse and ratings of perceived exertion). We conclude that the main variables for load monitoring in competitive situations were distance, speed, and duration, whereas the variables for training situations were heart rate, VO₂, training impulse, and ratings of perceived exertion.

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.

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.

Plasma cytokine and exertional responses in relation to exercise intensity and volume of exercising muscle mass during arm-crank ergometry

This original study investigated the effect of submaximal exercise intensity and volume of contracting muscle mass on plasma inflammation-mediating cytokine and perceived exertional responses to acute arm-crank ergometry (ACE). Twelve recreationally active but upper limb untrained males performed 30 min of (i) low-intensity (40% peak oxygen uptake) ACE (LOW); (ii) moderate-intensity (60% peak oxygen uptake) ACE (MOD); and (iii) concurrent low-intensity (40% peak oxygen uptake) ACE plus lower limb cycle ergometry to match total power output in MOD (HYB). Plasma concentrations of interleukin (IL)-6, IL-10, IL-1ra, adrenaline, and cortisol were determined at rest, immediately postexercise, and 1 h and 2 h postexercise. Heart rate (HR) and differentiated ratings of perceived exertion (RPE) were also recorded. Plasma IL-6 concentrations were elevated (p < 0.05) immediately postexercise and 1 h postexercise (∼ 2.5-fold) in all trials and 2 h postexercise in MOD (3-fold). Plasma IL-1ra concentrations were elevated (p < 0.05) 2 h postexercise in MOD only (2-fold). No plasma IL-10, cortisol, and adrenaline responses were observed. HR and differentiated RPE were significantly higher during MOD than HYB and LOW. Peripheral RPE were significantly higher than central and overall RPE in each trial. Thirty minutes of moderate intensity ACE initiated a plasma cytokine response associated with the protective effect of regular exercise against cardiovascular and metabolic disease risk. Further work is required to establish an optimal intensity and duration of upper limb exercise to maximise the anti-inflammatory potential whilst managing the risk of over-use injury.

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.

Validity of a Wheelchair Perceived Exertion Scale (Wheel Scale) for Arm Ergometry Exercise in People with Spina Bifida

This study assessed the concurrent and construct validity of the Borg 6–20 Scale and WHEEL Scale during arm ergometry exercise stress testing in ( n = 24) adolescents and adults with spina bifida. Significant, moderate, positive correlations were observed between power output and relative heart rate and power output to relative VO2peak. Further, a moderate, significant correlation between physiologic criterion variables and the rating of perceived exertion derived from the Borg Scale and the WHEEL Scale was found. Concurrent validity was supported by the following findings: (1) relative heart rate was significantly correlated with the Borg (Kendall's τ = .41) and WHEEL Scales (τ = .44), and relative VO2 was significantly correlated with the Borg (τ = .46) and WHEEL Scales (τ = .47); (2) content validity was supported by the finding that the Borg and WHEEL Scales shared significant variance (τ = .70), demonstrating internal consistency. The WHEEL Scale shows strong potential for use in this cohort subsequent to further testing and validation.

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.