Perceived Exertion: Recent Advances and Novel Applications in Children and Adults

Since 2008, there have been significant advances to assess the efficacy of the ratings of perceived exertion (RPE) to predict maximal oxygen uptake or estimate the time to volitional exhaustion in adults. The principle of using the relationship of submaximal RPE values with the performance criterion of interest has also been applied successfully to estimate maximal strength in adults and children. This short note describes how these studies have further confirmed the predictive efficacy of the RPE. Potential studies which may enhance our understanding of perceived exertion in children are also described

Maximal Fat Oxidation during Incremental Upper and Lower Body Exercise in Healthy Young Males

The aim of this study is to determine the magnitude of maximal fat oxidation (MFO) during incremental upper and lower body exercise. Thirteen non-specifically trained male participants (19.3 ± 0.5 y, 78.1 ± 9.1 kg body mass) volunteered for this repeated-measures study, which had received university ethics committee approval. Participants undertook two incremental arm crank (ACE) and cycle ergometry (CE) exercise tests to volitional exhaustion. The first test for each mode served as habituation. The second test was an individualised protocol, beginning at 40% of the peak power output (POpeak) achieved in the first test, with increases of 10% POpeak until volitional exhaustion. Expired gases were recorded at the end of each incremental stage, from which fat and carbohydrate oxidation rates were calculated. MFO was taken as the greatest fat oxidation value during incremental exercise and expressed relative to peak oxygen uptake (%V˙O2peak). MFO was lower during ACE (0.44 ± 0.24 g·min−1) than CE (0.77 ± 0.31 g·min−1; respectively, p < 0.01) and occurred at a lower exercise intensity (53 ± 21 vs. 67 ± 18%V˙O2peak; respectively, p < 0.01). Inter-participant variability for MFO was greatest during ACE. These results suggest that weight loss programs involving the upper body should occur at lower exercise intensities than for the lower body

Prefrontal cortex haemodynamics and affective responses during exercise: a multi-channel near infrared spectroscopy study

The dose-response effects of the intensity of exercise upon the potential regulation (through top-down processes) of affective (pleasure-displeasure) responses in the prefrontal cortex during an incremental exercise protocol have not been explored. This study examined the functional capacity of the prefrontal cortex (reflected by haemodynamics using near infrared spectroscopy) and affective responses during exercise at different intensities. Participants completed an incremental cycling exercise test to exhaustion. Changes (Δ) in oxygenation (O2Hb), deoxygenation (HHb), blood volume (tHb) and haemoglobin difference (HbDiff) were measured from bilateral dorsal and ventral prefrontal areas. Affective responses were measured every minute during exercise. Data were extracted at intensities standardised to: below ventilatory threshold, at ventilatory threshold, respiratory compensation point and the end of exercise. During exercise at intensities from ventilatory threshold to respiratory compensation point, ΔO2Hb, ΔHbDiff and ΔtHb were greater in mostly ventral than dorsal regions. From the respiratory compensation point to the end of exercise, ΔO2Hb remained stable and ΔHbDiff declined in dorsal regions. As the intensity increased above the ventilatory threshold, inverse associations between affective responses and oxygenation in (a) all regions of the left hemisphere and (b) lateral (dorsal and ventral) regions followed by the midline (ventral) region in the right hemisphere were observed. Differential activation patterns occur within the prefrontal cortex and are associated with affective responses during cycling exercise

A security proof of continuous-variable QKD using three coherent states

We introduce a ternary quantum key distribution (QKD) protocol and asymptotic security proof based on three coherent states and homodyne detection. Previous work had considered the binary case of two coherent states and here we nontrivially extend this to three. Our motivation is to leverage the practical benefits of both discrete and continuous (Gaussian) encoding schemes creating a best-of-both-worlds approach; namely, the postprocessing of discrete encodings and the hardware benefits of continuous ones. We present a thorough and detailed security proof in the limit of infinite signal states which allows us to lower bound the secret key rate. We calculate this is in the context of collective eavesdropping attacks and reverse reconciliation postprocessing. Finally, we compare the ternary coherent state protocol to other well-known QKD schemes (and fundamental repeaterless limits) in terms of secret key rates and loss.Comment: Close to the published versio

Effort Perception

Research addressing children's perceptions of exercise effort (their ‘perceived exertion’) has appeared steadily in the scientific literature over the last 30 years. Accepting that the established Borg adult rating of perceived exertion (RPE) scale was not appropriate for children, investigators set about developing child-specific scales which employed numbers, words and/or images that were more familiar and understandable. Numerous studies have examined the validity and reliability of such scales as the CERT, PCERT and OMNI amongst children aged 5 to 16, across different modes of exercise (cycling, running, stepping, resistance exercise), protocols (intermittent vs. continuous, incremental vs. non-incremental) and paradigms (estimation vs. production). Such laboratory-based research has enabled the general conclusion that children can, especially with practice, use effort perception scales to differentiate between exercise intensity levels, and to self-regulate their exercise output to match various levels indicated on them. However, inconsistencies in the methodological approaches adopted diminish the certainty of some of the interpretations made by researchers. In addition, though often mentioned, the would-be application of effort perception in physical education and activity/health promotion contexts has been relatively ignored. Accordingly, the scope for research in this applied domain is now considerable

Differentiated perceived exertion and self-regulated wheelchair exercise

OBJECTIVE. To investigate the utility of the differentiated rating of perceived exertion (RPE) for the self-regulation of submaximal wheelchair propulsion in novice users. DESIGN. Each participant completed a submaximal incremental test and a graded test to exhaustion to determine peak oxygen consumption (Vo2peak) on a wheelchair ergometer. On a separate day, two 12-minute intermittent bouts consisting of three 4-minute stages were completed at individualized imposed power outputs equating to light (40% Vo 2peak) and moderate (60% Vo2peak) intensity exercise. On a third occasion, participants were assigned to either the overall group or the peripheral group and were required to self-regulate 12-minute intermittent exercise according to either overall RPE or peripheral RPE reported during the corresponding imposed intensity trial. SETTING. Laboratory facilities at a university. PARTICIPANTS. Preliminary population of able-bodied participants with no prior experience of wheelchair propulsion (N=18). INTERVENTIONS. Not applicable. MAIN OUTCOME MEASURES. Differences in oxygen consumption (V̇o2), heart rate, blood lactate concentration, and power output between the imposed and self-regulated exercise trials. RESULTS. No difference was found in physiological responses between the moderate-intensity imposed and RPE-regulated trials in the peripheral group, whereas a significant (P<.05) underproduction in V̇o2 (1.76±.31 vs 1.59±.25L/min) and blood lactate concentration (2.8±0.90 vs 2.21±.83mmol/L) was seen in the overall group. In contrast, a significant (P<.05) overproduction was seen in the peripheral group at a light exercise intensity, whereas no difference was found between all variables during the light-intensity imposed and RPE-regulated trials in the overall group. CONCLUSIONS. Peripheral RPE enabled a more precise self-regulation during moderate-intensity wheelchair exercise in novice users. In contrast, overall RPE provided a more accurate stimulus when performing light-intensity propulsion

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

This study aimed to compare test-retest reliability and peak exercise responses from ramp-incremented (RAMP) and maximal perceptually-regulated (PRETmax) exercise tests during arm crank exercise in individuals reliant on manual wheelchair propulsion (MWP). Ten untrained participants (9 male) completed four trials over a 2-week period, performing two RAMP (0-40 W + 5-10 W·min-1) trials one week followed by two PRETmax trials the next, or vice versa. PRETmax 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 V̇ O2peak from RAMP (14.8 ± 5.5 ml·kg-1 ·min-1 ) and PRETmax (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 V̇ O2peak from RAMP and PRETmax, respectively. Affect was more positive at RPE 13 (P = 0.02), 15 (P = 0.01) and 17 (P = 0.01) during PRETmax. This study shows the PRETmax can be used to measure V̇ O2peak in participants reliant on MWP and leads to a more positive affective response compared to RAMP

Knee joint neuromuscular activation performance during muscle damage and superimposed fatigue

This study examined the concurrent effects of exercise-induced muscle damage and superimposed acute fatigue on the neuromuscular activation performance of the knee flexors of nine males (age: 26.7 ± 6.1yrs; height 1.81 ± 0.05m; body mass 81.2 ± 11.7kg [mean ± SD]). Measures were obtained during three experimental conditions: (i) FAT-EEVID, involving acute fatiguing exercise performed on each assessment occasion plus a single episode of eccentric exercise performed on the first occasion and after the fatigue trial; (ii) FAT, involving the fatiguing exercise only and; (iii) CON consisting of no exercise. Assessments were performed prior to (pre) and at lh, 24h, 48h, 72h, and 168h relative to the eccentric exercise. Repeated-measures ANOVAs showed that muscle damage within the FAT-EEVID condition elicited reductions of up to 38%, 24%) and 65%> in volitional peak force, electromechanical delay and rate of force development compared to baseline and controls, respectively (F[io, 80] = 2.3 to 4.6; p to 30.7%>) following acute fatigue (Fp; i6] = 4.3 to 9.1; p ; Fp, iq = 3.9; p <0.05). The safeguarding of evoked muscle activation capability despite compromised volitional performance might reveal aspects of capabilities for emergency and protective responses during episodes of fatigue and antecedent muscle damaging exercise

Validation of the GENEA accelerometer

Purpose: The study aims were: 1) to assess the technical reliability and validity of the GENEA using a mechanical shaker; 2) to perform a GENEA value calibration to develop thresholds for sedentary and light-, moderate-, and vigorous-intensity physical activity; and 3) to compare the intensity classification of the GENEA with two widely used accelerometers. Methods: A total of 47 GENEA accelerometers were attached to a shaker and vertically accelerated, generating 15 conditions of varying acceleration and/or frequency. Reliability was calculated using SD and intrainstrument and interinstrument coefficients of variation, whereas validity was assessed using Pearson correlation with the shaker acceleration as the criterion. Next, 60 adults wore a GENEA on each wrist and on the waist (alongside an ActiGraph and RT3 accelerometer) while completing 10-12 activity tasks. A portable metabolic gas analyzer provided the criterion measure of physical activity. Analyses involved the use of Pearson correlations to establish criterion and concurrent validity and receiver operating characteristic curves to establish intensity cut points. Results: The GENEA demonstrated excellent technical reliability (CVintra = 1.4%, CVinter = 2.1%) and validity (r = 0.98, P < 0.001) using the mechanical shaker. The GENEA demonstrated excellent criterion validity using V̇O as the criterion (left wrist, r = 0.86; right wrist, r = 0.83; waist, r = 0.87), on par with the waist-worn ActiGraph and RT3. The GENEA demonstrated excellent concurrent validity compared with the ActiGraph (r = 0.92) and the RT3 (r = 0.97). The waist-worn GENEA had the greatest classification accuracy (area under the receiver operating characteristic curve (AUC) = 0.95), followed by the left (AUC = 0.93) and then the right wrist (AUC = 0.90). The accuracy of the waist-worn GENEA was virtually identical with that of the ActiGraph (AUC = 0.94) and RT3 (AUC = 0.95). CONCLUSION:: The GENEA is a reliable and valid measurement tool capable of classifying the intensity of physical activity in adults. © 2011 by the American College of Sports Medicine

Misperception: No evidence to dismiss RPE as regulator of moderate-intensity exercise

This document is the Accepted Manuscript version of a published work that appeared in final form in Medicine and Science in Sport and Exercise. To access the final edited and published work see https://doi.org/10.1249/MSS.0000000000000748.Dear Editor-in-Chief, Shaykevich et al. (7) demonstrate the efficacy of auditory feedback anchored at 75% of age-predicted HRmax to regulate intensity (claimed as ‘‘moderate’’) during several 20-min bouts of cycling. Their technical approach is novel, but 76% HRmax is the upper limit of moderate intensity, so given the large error in age-predicted HRmax, it is unlikely that their exercise bandwidth was ‘‘moderate’’ for all participants. This is not our major concern, but it reveals one among other inaccuracies: the most serious include training, interpretation, and inferences relating to the RPE