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

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

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

Comparison of a countermovement jump test and submaximal run test to quantify the sensitivity for detecting practically important changes within high-performance Australian rules football

Purpose: The purpose of this study was to determine the typical variation of variables from a countermovement jump (CMJ) test and a submaximal run test (SRT), along with comparing the sensitivity of each test for the detection of practically important changes within high-performance Australian rules football (ARF) players. Methods: 23 professional and semi-professional ARF players, performed six CMJs and three, eight-second 50-meter runs every 30 s (SRT), seven days apart. Absolute and trial-to-trial reliability was represented as a coefficient of variation (CV) +/- 90% confidence intervals (CI). Test-retest reliability was examined using the magnitude of the difference (effect size (ES) ± 90% CI) from week 1 to week 2. The smallest worthwhile change (SWC) was calculated as 0.25 x SD. Results: Good reliability (CVs = 6.6 – 9.3%) was determined for all variables except eccentric displacement (CV = 12.8%), with no clear changes observed in any variables between week 1 and week 2. All variables from the SRT possessed a CV < SWC, indicating an ability to detect practically important changes in performance. Only peak velocity from the CMJ test possessed a CV < SWC, exhibiting a limitation of this test in detecting practically meaningful changes within this environment. Conclusions: The results suggest that while all variables possess acceptable reliability, a SRT might offer to be a more sensitive monitoring tool than a CMJ test within high-performance ARF, due to its greater ability for detecting practically important changes in performance

A novel method of assessment for monitoring neuromuscular fatigue within Australian rules football players

Purpose: To compare the sensitivity of a submaximal run test (SRT) with a countermovement-jump test (CMJ) to provide an alternative method of measuring neuromuscular fatigue (NMF) in high-performance sport. Methods: A total of 23 professional and semiprofessional Australian rules football players performed an SRT and CMJ test prematch and 48 and 96 h postmatch. Variables from accelerometers recorded during the SRT were player load 1D up (vertical vector), player load 1D side (mediolateral vector), and player load 1D forward (anteroposterior vector). Meaningful difference was examined through magnitude-based inferences (effect size [ES]), with reliability assessed as typical error of measurements expressed as coefficient of variance. Results: A small decrease in CMJ height, ES −0.43 ± 0.39 (likely), was observed 48 h postmatch before returning to baseline 96 h postmatch. This was accompanied by corresponding moderate decreases in the SRT variables player load 1D up, ES −0.60 ± 0.51 (likely), and player load 1D side, ES −0.74 ± 0.57 (likely), 48 h postmatch before also returning to prematch baseline. Conclusion: The results suggest that in the presence of NMF, players use an alternative running profile to produce the same external output (ie, time). This indicates that changes in accelerometer variables during an SRT can be used as an alternative method of measuring NMF in high-performance Australian rules football and provides a flexible option for monitoring changes in the recovery phase postmatch

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