Comparison of distance covered, physiological cost, and perceived exertion in four six-minute walk test protocols.

Objective: There is evidence that indicates that the Walked Distance (WD) in the 6-Minute Walk Test (6MWT) would be sensitive to the type of track and encouragement. The aim of study was compared the impact of track type and verbal encouragement provided in the 6MWT on WD, physiological cost, perceived exertion, and gait efficiency in healthy young adults unfamiliar with the test. Method: WD, heart rate, subjective sensation of dyspnea (SSD), and fatigue (SSF) were measured in four 6MWT protocols: i) 30 m linear track and protocolized encouragement (LT + PE), ii) 30 m linear track and constant encouragement (LT + CE), iii) 81 m elliptical track and protocolized encouragement (ET + PE), and iv) 81 m elliptical track and constant encouragement (ET + CE). In addition, the Gait Efficiency Index (GIE) associated with physiological cost, dyspnea and fatigue was calculated and compared between the different protocols. Results: The WD was significantly higher in the ET + CE protocol. The percentage of the heart rate reserve used (%HRRu) at minute 6 was higher in the ET + CE protocol. The SSD and SSD had difference in startup time between the protocols. The GEI was higher in %HRRu, SSD, and SSF for the ET + CE protocol. Conclusion: The ET + CE protocol showed a significant increase in WD during the 6MWT in healthy young adults. Although it obtained the highest physiological cost, it did not present perceptual differences when entering cardiopulmonary assessment windows relevant to a more efficient test for the participant. It is advisable to discuss, based on the findings, the fundamental objective of the 6MWT and national and international recommendations to achieve a result as close as possible to the real maximal effort.

The Use of a Just Noticeable Difference Approach to Improve Perceptual Acuity Ability in Male Runners.

We were interested in micro-variations in an athlete's psychophysical state that separate peak exertion from physiological collapse. Thus, we measured perceptual acuity in runners using a classic psychophysical approach, the just noticeable difference (JND) on two standard stimuli runs at treadmill speed corresponding to 70%VO2max and 80%VO2max. Thirty-four male runners (M age = 35.26, SD = 7.33 years) first performed a maximal treadmill test to determine the speed of a standard exercise bout for the JND trials. The JND trials consisted of four 5-minute running bouts on a treadmill with 5-minute rests between bouts. For bouts 1 and 3, participants ran at the standard stimuli pace, but for bouts 2 and 4, they adjusted their speeds to achieve a level of exertion at a JND above/below the SS. They achieved differences in the final 30 seconds of the VO2 between each JND bout and the previous standard stimuli at just above (JND-A) and just below (JND-B) the JND perceived exertions. We used a Generalized Linear Model analysis to compare the JND-A and JND-B within and between ventilatory threshold groups (lower/higher) in absolute and relative VO2 and in terms of the total JND magnitude. The magnitude of JND-A was greater than that of JND-B at 70%VO2max and 80%VO2max in absolute units (70%VO2 Δ = 2.62; SE = 0.37; p < .001; 80%VO2 Δ = 1.67; SE = 0.44; p = .002) and in relative units (70%VO2max Δ = 4.70; SE = 0.66; p < .001; 80%VO2max Δ = 2.96; SE = 0.80; p = .002). The total magnitude was greater in the 70%VO2max trial than 80%VO2max in absolute units (70%VO2 M = 3.78, SE = 0.31 mL·kg-1·min-1; 80%VO2 M = 2.62, SE = 0.37 mL·kg-1·min-1; p = .020) and in relative units (70%VO2max M = 6.57, SE = 0.53%VO2max; 80%VO2max M = 4.71, SE = 0.64%VO2max; p = .030). The JND range narrowed when physiologic demand increased, for both physical (speed) and psychological (RPE) variables.

Performance of soccer players under acute physical fatigue: An approach based on cognitive, tactical and physical aspects.

This study aimed to verify whether peripheral perception, tactical behaviour, and physical performance are influenced by acute physical fatigue in soccer players. The study included 24 trained soccer players (18.6 ± 1.5 years) from two Brazilian clubs. The TSAFT90 test was used to induce acute physical fatigue. The results showed that physical fatigue did not affect peripheral perception (p = 0.360). Regarding tactical behaviour, improved efficiency was observed for the principles of offensive coverage (p = 0.029), width and length with the ball (p = 0.044), and concentration (p = 0.008). On the other hand, a reduction was observed in the number of tactical actions of offensive coverage (p = 0.020) and recovery balance (p = 0.042). Also, improved accuracy in the principles of defensive balance (p = 0.009), recovery balance (p = 0.021) and defensive unity (p = 0.003) occurred under physical fatigue. A reduction in the physical performance outcomes total distance covered (p < 0.001), average speed (p < 0.001), sprints (p = 0.029), number of accelerations (p = 0.008) and decelerations (p = 0.008) were also detected. The internal (p < 0.01) and external (p < 0.01) workload was higher under physical fatigue. Overall, acute physical fatigue did not influence peripheral perception. However, physical performance was reduced under fatigue, the perceived effort increased, and tactical behaviours were affected by decreasing tactical actions performed near the ball, increasing errors in defensive movements in the lateral corridors and the last defensive line, and improving offensive tactical actions performance.

Fatigue and Performance Rates as Decision-Making Criteria in Pacing Control During CrossFit®.

We investigated fatigue and performance rates as decision-making criteria in pacing control during CrossFit®. Thirteen male regional-level competitors completed conditions of all-out (maximum physical work from beginning to end) and controlled-split (controlled physical work in the first two rounds but maximum work in the third round) pacing throughout the Fight Gone Bad workout separated by one week. We assessed benchmarks, countermovement jumps and ratings of fatigue after each round. Benchmarks were lower in round 1 (99 vs. 114, p < .001) but higher in rounds 2 (98 vs. 80, p < .001) and 3 (97 vs. 80, p < .001) for controlled-split compared with all-out pacing. Reductions in countermovement jumps were higher after rounds 1 (-12.6% vs. 1.6%, p < .001) and 2 (-12.7% vs. -4.0%, p = .014) but similar after round 3 (-13.2% vs. -11.3%, p = .571) for all-out compared with controlled-split pacing. Ratings of fatigue were higher after rounds 1 (7 vs. 5 a.u., p < .001) and 2 (8 vs. 7 a.u, p = .023) but similar after round 3 (9 vs. 9 a.u., p = .737) for all-out compared with controlled-split pacing. During all-out pacing, countermovement jump reductions after round 2 correlated with benchmark drops across rounds 1 and 2 (r = .78, p = .002) and rounds 1 and 3 (r = -.77, p = .002) and with benchmark workout changes between pacing strategies (r = -.58, p = .036), suggesting that the larger the countermovement jump reductions the higher the benchmark drops across rounds and workouts. Therefore, benchmarks, countermovement jumps and ratings of fatigue may assess exercise-induced fatigue as decision-making criteria to improve pacing strategy during workouts performed for as many repetitions as possible.

Effect of Menstrual Cycle Phase on Perceived Exertion During Aerobic Exercise in Eumenorrheic Women: A Systematic Review and Meta-analysis.

Background: The rating of perceived exertion (RPE) is a readily available and practical tool widely used in exercise science to monitor exercise load, but a rigorous review of the effect of menstrual cycle (MC) phases on RPE within continuous aerobic exercise has not yet been completed. Objective: This study investigated the effects of the MC phase on RPE during aerobic exercise. Study Design: This was a systematic review and meta-analysis. Methods: The search strategy was carried out using the 5 most common scientific databases. While qualitative analyses were performed in all included studies, random effects to standard mean difference were calculated and meta-analysis was performed where possible. This study addresses comparison for RPE at the beginning, middle, and end of the exercise adopting 2 mains analysis. The first adopted early cycle (first session of the cycle) as control compared with the subsequent phases, and the second adopted days 1 to 5 (early follicular) as control compared with the subsequent phases. Results: A total of 17 studies (n = 160) were included in the qualitative synthesis. The meta-analysis showed that MC phases did not impact RPE (P > .05). Conclusions: The current meta-analysis showed that MC does not impact RPE. Although acute RPE is not impacted by MC phases, future studies and practitioners should pay attention to the impact of RPE session by session throughout the MC.

Exercise-induced potentiation of the acute hypoxic ventilatory response: Neural mechanisms and implications for cerebral blood flow.

A given dose of hypoxia causes a greater increase in pulmonary ventilation during physical exercise than during rest, representing an exercise-induced potentiation of the acute hypoxic ventilatory response (HVR). This phenomenon occurs independently from hypoxic blood entering the contracting skeletal muscle circulation or metabolic byproducts leaving skeletal muscles, supporting the contention that neural mechanisms per se can mediate the HVR when humoral mechanisms are not at play. However, multiple neural mechanisms might be interacting intricately. First, we discuss the neural mechanisms involved in the ventilatory response to hypoxic exercise and their potential interactions. Current evidence does not support an interaction between the carotid chemoreflex and central command. In contrast, findings from some studies support synergistic interactions between the carotid chemoreflex and the muscle mechano- and metaboreflexes. Second, we propose hypotheses about potential mechanisms underlying neural interactions, including spatial and temporal summation of afferent signals into the medulla, short-term potentiation and sympathetically induced activation of the carotid chemoreceptors. Lastly, we ponder how exercise-induced potentiation of the HVR results in hyperventilation-induced hypocapnia, which influences cerebral blood flow regulation, with multifaceted potential consequences, including deleterious (increased central fatigue and impaired cognitive performance), inert (unchanged exercise) and beneficial effects (protection against excessive cerebral perfusion).

Effect of High-Intensity Interval Exercise versus Continuous Low-Intensity Aerobic Exercise with Blood Flow Restriction on Psychophysiological Responses: A Randomized Crossover Study.

This study compared the effect of continuous low-intensity aerobic exercise with blood flow restriction (LI-AE-BFR) versus high-intensity interval exercise (HIIE), matching total external mechanical work between conditions, on perceptual (exertion, pain, affective and pleasure) and physiological responses (heart rate [HR], blood lactate [BL] and muscle fatigue). Ten healthy untrained men (25.6 ± 3.78 years old; 75.02 ± 12.02 kg; 172.2 ± 6.76 cm; 24.95 ± 3.16 kg/m²) completed three visits to the laboratory. In visit 1, anthropometry, blood pressure and peak running velocity on the treadmill were measured. In visits 2 and 3, participants were randomly assigned to HIIE or LI-AE-BFR, both in treadmill. HIIE consisted of 10 one-minute stimuli at 80% of peak running velocity interspersed with one-minute of passive recovery. LI-AE-BFR consisted of 20-minutes of continuous walking at 40% of peak running velocity with bilateral cuffs inflated to 50% of arterial occlusion pressure. BL and maximum isometric voluntary contraction (MIVC - fatigue measure) were measured pre- and immediately post-exercise. HR, rating of perceived exertion (RPE), and rating of perceived pain (RPP) were recorded after each stimulus in HIIE and every two minutes in LI-AE-BFR. Affective response to the session, pleasure, and future intention to exercise (FIE) were assessed 10 minutes after the intervention ended. Increases in BL concentrations were greater in HIIE (p = 0.028; r = 0.51). No effects time or condition were reported for MIVC. HR was higher in HIIE at all analyzed time points (p < 0.001; d = 3.1 to 5.2). RPE did not differ between conditions (p > 0.05), while average session RPP was higher in LI-AE-BFR (p = 0.036; r = 0.46). Affective positive response (p = 0.019; d = 0.9) and FIE (p = 0.013; d = 0.97) were significantly higher in HIIE. Therefore, HIIE elicited higher physiological stress, positive affective response, and intention to engage in future exercise bouts compared to LI-AE-BFR.

Guarana (Paullinia cupana) but Not Low-Dose Caffeine Improves Cycling Time-Trial Performance Versus Placebo.

Guarana (GUA) seed extract, containing caffeine (CAF) and additional bioactive compounds, may positively affect mental performance, but evidence regarding exercise is limited. This investigation assessed acute GUA ingestion compared with CAF on endurance performance. Eleven endurance-trained noncyclists and cyclists (V˙O2peak = 49.7 ± 5.9, 60.4 ± 4.6 ml·kg·min-1) completed a double-blind, crossover experiment after ingesting (a) 100 mg CAF, (b) 500 mg GUA (containing 130 mg CAF), or (c) placebo (P) prior to 60-min fixed cycling workload (FIX) + 15-min time trial. Oxygen uptake, heart rate, respiratory exchange ratio, blood glucose, and lactate were not different (p ≥ .052) during FIX. A significant interaction (p = .042) for perceived exertion was observed at 50-min FIX with lower rating (p = .023) for GUA versus CAF but not compared with P. Work accumulated over 15-min time trial was greater (p = .038) for GUA versus P due to higher early (1-11 min) work outputs. Work performance favored (effect size = 0.18; 95% confidence interval [0.003, 0.355], p = .046) GUA (241.4 ± 39.9 kJ) versus P (232.1 ± 46.6 kJ), but CAF (232.3 ± 43.9) was not different from GUA (effect size = 0.19; 95% confidence interval [-0.022, 0.410], p = .079) or P. Postexercise strength loss was not attenuated with GUA (-5.6 ± 8.5%) or CAF (-8.3 ± 9.4%) versus P (-10.3 ± 5.1%). Acute GUA ingestion improved work performance relative to P, but effects were trivial to small and unrelated to altered substrate oxidation or muscular strength. Ergogenicity may involve central mechanisms reducing perceived effort with GUA (containing 130 mg caffeine). Due to issues related to identical matching of dosage, whether GUA confers additional benefits beyond its CAF content cannot be determined at present.

Validity and reliability of SEIS-3: An instrument for subjective measuring of strength in older adults.

The use of rating of perceived exertion (RPE) has grown substantially, providing a valuable alternative for exercise intensity monitoring, especially for older adults. However, some challenges, such as cross-cultural validity, age-related differences, and reliability issues, necessitate the development of a concise and user-friendly RPE instrument, particularly for strength training in this population. This study aimed to validate the Subjective Effort Induction Scale (SEIS-3), a simplified tool for measuring effort during strength training. SEIS-3 is a graded instrument with three exertion levels: 1) Light effort, 2) Moderate effort, and 3) Strong effort. Twenty seniors, aged 71±7 years, of both genders participated in the study (CEP/Unimontes 2,741,071/2018). We collected maximal isometric voluntary contraction (MIVC) data using a digital dynamometer. Subsequently, participants underwent the initial test, following the three SEIS-3 categories in a randomly assigned order of induced subjective effort. SEIS-3 instrument was evaluated by the approaches:•Linear regression analysis: employed to assess the validity of the instrument.•Intraclass Correlation Coefficient (ICC): employed to assess the reliability of the instrument.SEIS-3 effort categories correlated with MIVC in both hands (R2=0.80, F = 25.596, df=3, p < 0.01 for right hand; R2=0.56, F = 9.132, p < 0.01 for left hand). Test-retest reliability for grip strength across effort categories was excellent (ICC > 0.9). SEIS-3 is a valid and reliable user-friendly tool for accurately assessing and regulating exercise intensity in older adults during strength tasks, benefiting their health, functional capacity, and overall quality of life. This low-cost instrument can help health professionals in their activities.

Cross-cultural adaptation and concurrent validity of the children's OMNI scale of perceived exertion for Arm-Crank activity in Spina Bifida.

PURPOSE: To perform a cross-cultural adaptation of the OMNI verbal descriptors to Brazilian-Portuguese and examine the validity of the Brazilian version for arm-crank activity. MATERIALS AND METHODS: Cross-cultural adaptation stages were: permission, translation, synthesis, back translation, expert committee review, pretesting, and submission and appraisal. For the concurrent validity, a Brazilian OMNI-Wheel scale was used to obtain rating of perceived exertion for the overall body (RPEOverall) and arms (RPEArms) in participants (n = 9, 10-17 years) with spina bifida. Cardiopulmonary exercise test was used to measure heart rate (HR) and oxygen uptake (VO2). Repeated Measures Correlation (rrm) was used to examine the scale validity. RESULTS: The cross-cultural adaptation produced equivalence between English and Brazilian-Portuguese verbal descriptors based on successful translation and pretesting. The Brazilian OMNI-wheel was validated based on strong associations of RPEOverall with VO2 (rrm (35) = 0.86, 95% CI [0.93, 0.73], p < 0.001) and HR (rrm (35) = 0.89, 95% CI [0.94, 0.79], p < 0.001) and RPEArms with VO2 (rrm (33) = 0.82, 95% CI [0.91, 0.66], p < 0.001) and HR (rrm (33) = 0.82, 95% CI [0.91, 0.66], p < 0.001). CONCLUSIONS: The OMNI scale was cross-culturally adapted to Brazilian-Portuguese. The Brazilian OMNI-Wheel was validated based on strong associations of RPE with HR and VO2. Implications For RehabilitationThe original English OMNI was cross-culturally adapted to Brazilian-Portuguese.A Brazilian wheelchair OMNI was concurrently validated for Arm-Crank Activity in adolescents with spina bifida.This OMNI scale version may aid health providers in monitoring perceived exertion in Brazil.

Association between internal training load and muscle injuries in Brazilian professional soccer players.

The training load is associated with injury risk in a variety of sports. This study aimed to evaluate the association between the internal training load and injury risk in Brazilian professional soccer players. The data were collected from 32 soccer players across two full seasons (2017 and 2018). The rating of perceived exertion (RPE) for every training/match session was used as an internal load variable. The cumulative training load from 3 and 4 weeks (C3 and C4) and the acute:chronic workload ratio (ACWR) were calculated. A generalized estimating equation analysis was applied to examine associations of non-contact muscle injuries with C3, C4 and ACWR. A total of 33 injuries were recorded across the two full seasons. A significant association was found between cumulative training load for three (C3, p = 0.003) and four weeks (C4, p = 0.023) and the occurrence of injuries. Players in the "high load" group presented greater injury risk in relation to the "moderate load" group (C4: OR = 4.5; IC 95% 1.5-13.3; C3: OR = 3.7; IC 95% 1.7-8.1). There was no association between ACWR and injury occurrence. The athletes exposed to a high cumulative load in a period of 3 to 4 weeks presented higher injury risk in comparison to those who had moderate cumulative training loads. Besides that, there was no association between ACWR and injury occurrence.

Heated environment offsets the cardiovascular responses to prolonged rowing exercise in competitive athletes.

Prolonged rowing exercise sessions are often prescribed considering competitive training schedules, and under hostile environments (e.g., heated ambient). The study aimed to investigate the effect of heat stress (HS) on physical performance, Lactate concentration ([Lac]), and cardiorespiratory responses during prolonged exercise sessions in competitive rowers. Twelve rowers performed preliminary exercise tests (2-km test and five-step incremental lactate test) to assess the target workload intensity corresponding to a 2.5 mmol.L-1 of [Lac]. On two separate days, participants were enrolled in two exercise sessions of 12 km in a rowing machine under HS (∼30 °C) and thermal comfort (TC 22 °C) conditions. Heart rate (HR), stroke volume (SV), cardiac output (CO), oxygen uptake (VO2), [Lac], and the rating of perceptual exertion (RPE) were obtained. From baseline, HS increased the maximum temperature of the face compared to TC. Workload and VO2 reduced while RPE increased at 9- and 12-km of rowing exercise under HS compared to TC. From baseline to the last stage of exercise, HS shifted SV downwards and HR upwards compared to TC. Consequently, CO did not change between thermal conditions (TC vs. HS). Therefore, HS provokes a cardiovascular drift during prolonged rowing in comparison to TC. The last stages of prolonged rowing sessions under HS seem to be critical to physical performance and relative perceptual of effort in rowers.

Drop-Set Resistance Training versus Pyramidal and Traditional Sets Elicits Greater Psychophysiological Responses in Men.

We compared the effects of resistance training (ResisT) to pyramidal and traditional weightlifting sets on men's psychophysiological responses. In a randomized crossover design, 24 resistance-trained males performed drop-set, descending pyramid, and traditional ResisT in the barbell back squat, 45° leg press, and seated knee extension. We assessed participants' rating of perceived exertion (RPE) and feelings of pleasure/displeasure (FPD) at the end of each set and at 10, 15, 20, and 30 minutes post-session. No differences were detected across ResisT Methods in total training volume (p = 0.180). Post hoc comparisons revealed that drop-set training elicited higher RPE (M 8.8 SD 0.7 arbitrary units) and lower FPD (M -1.4 SD 1.5 arbitrary units) values compared to descending pyramid (M Set RPE 8.0 SD 0.9 arbitrary units and M Set FPD 0.4 SD 1.6 arbitrary units) and traditional set (M Set RPE 7.5 SD 1.1 arbitrary units and M Set FPD 1.3 SD 1.2 arbitrary units) schemes (p < 0.05). In addition, drop-set training elicited higher session RPE (M 8.1 SD 0.8 arbitrary units) and lower session FPD (M 0.2 SD 1.4 arbitrary units) values than descending pyramid and traditional ResisT (p < 0.001). Similarly, descending pyramid training elicited higher session RPE (M 6.6 SD 0.9 arbitrary units) and lower session FPD (M 1.2 SD 1.4 arbitrary units) than traditional set (M Session RPE 5.9 SD 0.8 arbitrary units and M Session FPD 1.5 SD 1.2 arbitrary units) training (p = 0.015). No differences were found in the temporality of post-session metrics, suggesting that testing 10 and 15 minutes post-ResisT was sufficient to assess session RPE (p = 0.480) and session FPD (p = 0.855), respectively. In conclusion, even with similar total training volume, drop-set training elicited more pronounced psychophysiological responses than either pyramidal or traditional ResisT in resistance-trained males.

Cardiovascular and Perceptual Responses to Resistance Training with Practical Blood Flow Restriction Induced by a Non-Elastic Band vs. Pneumatic Cuff: A Crossover Randomized Study.

Our purpose in this study was to analyze perceptual and cardiovascular responses in low-load resistance training (RT) sessions associated with a fixed non-elastic band compressed to the proximal region of the arms (p-BFR) versus a pneumatic cuff inflated to a pressure of 150 mmHg (t-BFR). Participants (16 healthy trained men) were randomly assigned to two conditions of low-load RT (20% one repetition maximum [1RM]) with BFR (p-BFR or t-BFR). In both conditions, the participants performed five exercises (4 sets/30-15-15-15) for the upper-limbs, but in one of the conditions, the exercises were performed with a p-BFR induced by a non-elastic band, while in the other, the exercises were performed with a t-BFR using a device with similar width. The devices used to generate the BFR had similar widths (5 cm). Brachial blood pressure (bBP) and heart rate (HR) were measured before, after each exercise and after the experimental session (5-, 10-, 15-, and 20 min post-session). Rating of perceived exertion (RPE) and rating of pain perception (RPP) were reported after each exercise and 15 minutes post-session. HR increased during the training session in both conditions, with no differences between p-BFR and t-BFR. Neither intervention increased diastolic BP (DBP) during training, but there was a significant post-session reduction in DBP in the p-BFR, with no differences observed between conditions. There were no significant differences in RPE and RPP in the two training conditions, with both conditions associated with higher RPE and RPP at the end versus beginning of the experimental session. We conclude that when BFR device width and material are similar, low-load training with t-BFR and p-BFR promotes similar acute perceptual and cardiovascular responses in healthy trained men.

Is There a Dose-Response Relationship between High-Intensity Interval Exercise (HIIE) Intensity and Affective Valence? Analysis of Three HIIE Sessions Performed with Different Amplitudes.

The inverse relationship between exercise intensity and affective valence is well established for continuous exercise but not for high-intensity interval exercise (HIIE). The objective was to verify the dose-response relationship between exercise intensity and affective valence in HIIE sessions. Eleven young men underwent a vigorous-intensity continuous exercise (VICE) and three HIIE sessions at the same average intensity (70% of peak power-WPeak) and duration (20 min) but with different amplitudes: 10 × [1 min at 90% WPeak/1 min at 50% WPeak]-HIIE-90/50; 10 × [1 min at 100% WPeak/1 min at 40% WPeak]-HIIE-100/40; 10 × [1 min at 110% WPeak/1 min at 30% WPeak]-HIIE-110/30. During the exercise sessions, psychophysiological variables were recorded (VO2, VCO2, heart rate, perceived exertion CR10, and Feeling Scale (FS)). Higher correlations were found between CR10 and FS for all conditions (VICE = -0.987; HIIE-90/50 = -0.873; HIIE-100/40 = -0.908; HIIE-110/30 = -0.948). Regarding the physiological variables, the %HRMax presented moderate inverse correlations with FS for all exercise conditions (VICE = -0.867; HIIE-90/50 = -0.818; HIIE-100/40 = -0.837; HIIE-110/30 = -0.828) while the respiratory variables (%VO2Peak and %VCO2Peak) presented low-to-moderate correlations only for VICE, HIIE-90/50, and HIIE-100/40 (ranging from -0.523 to -0.805). Poor correlations were observed between the %VO2Peak (r = -0.293) and %VCO2Peak (r = -0.020) with FS. The results indicated that perceived exertion is more sensible than physiological variables to explain the intensity-affective valence relationship in HIIE sessions. RPE should be used for HIIE prescription with a focus on affect.

Influence of Cluster Sets on Mechanical and Perceptual Variables in Adolescent Athletes.

Cluster sets (CS) are effective in maintaining performance and reducing perceived effort compared to traditional sets (TRD). However, little is known about these effects on adolescent athletes. The purpose of this study was to compare the effect of CS on the performance of mechanical and perceptual variables in young athletes. Eleven subjects [4 boys (age = 15.5 ± 0.8 years; body mass = 54.3 ± 7.0 kg; body height = 1.67 ± 0.04 m; Back Squat 1RM/body mass: 1.62 ± 0.19 kg; years from peak height velocity [PHV]: 0.94 ± 0.50) and 7 girls (age = 17.2 ± 1.4 years; body mass = 54.7 ± 6.3 kg; body height = 1.63 ± 0.08 m; Back Squat 1RM/body mass: 1.22 ± 0.16 kg; years from PHV: 3.33 ± 1.00)] participated in a randomized crossover design with one traditional (TRD: 3 × 8, no intra-set and 225 s interest rest) and two clusters (CS1: 3 × 2 × 4, one 30 s intra-set and 180 s inter-set rest; and CS2: 3 × 4 × 2, three 30 s intra-set and 90 s inter-set rest) protocols. The subjects were assessed for a Back Squat 1RM for the first meet, then performed the three protocols on three different days, with at least 48 h between them. During experimental sessions, a back squat exercise was performed, and mean propulsive velocity (MPV), power (MPP), and force (MPF) were collected to analyze performance between protocols, together with measures of countermovement jump (CMJ) and perceptual responses through Rating of Perceived Exertion for each set (RPE-Set) and the overall session (S-RPE), and Muscle Soreness (DOMS). The results showed that velocity and power decline (MVD and MPD) were favorable for CS2 (MVD: -5.61 ± 14.84%; MPD: -5.63 ± 14.91%) against TRD (MVD: -21.10 ± 11.88%; MPD: -20.98 ± 11.85%) (p < 0.01) and CS1 (MVD: -21.44 ± 12.13%; MPD: -21.50 ± 12.20%) (p < 0.05). For RPE-Set, the scores were smaller for CS2 (RPE8: 3.23 ± 0.61; RPE16: 4.32 ± 1.42; RPE24: 4.46 ± 1.51) compared to TRD (RPE8: 4.73 ± 1.33; RPE16: 5.46 ± 1.62; RPE24: 6.23 ± 1.97) (p = 0.008), as well as for Session RPE (CS2: 4.32 ± 1.59; TRD: 5.68 ± 1.75) (p = 0.015). There were no changes for jump height (CMJ: p = 0.985), and the difference between time points in CMJ (ΔCMJ: p = 0.213) and muscle soreness (DOMS: p = 0.437) were identified. Our findings suggest that using CS with a greater number of intra-set rests is more efficient even with the total rest interval equalized, presenting lower decreases in mechanical performance and lower perceptual effort responses.

Systemic exertion intolerance disease associated to neuroendocrine dysfunction and cortical atrophy: a case report.

BACKGROUND: Scarce evidence about the organic and functional abnormalities of systemic exertion intolerance disease (SEID) is found in literature and the pathophysiology is still unclear. METHODS: Following the CARE Guidelines, this case report describes a patient with a 5-year history of nonspecific symptoms, lately recognized as SEID. RESULTS: Low serum thyroid- and adrenocorticotropic stimulating hormone levels, and 24-h urinary cortisol excretion almost twice the upper limit were detected. Computed tomography scan found significant cortical atrophy. Low-dose modafinil improved the clinical outcome, added to nonpharmacologic approach. CONCLUSION: To ascertain an accurate SEID diagnosis and treatment are a challenge in daily clinical practice, that must be engaged based in clear methods and good practice recommendations. Thus, family practitioners should be aware of this diagnosis.

Acute Effect of Resistance Training With Blood Flow Restriction on Perceptual Responses: A Systematic Review and Meta-Analysis.

CONTEXT: Several studies have compared perceptual responses between resistance exercise with blood flow restriction and traditional resistance exercise (non-BFR). However, the results were contradictory. OBJECTIVES: To analyze the effect of RE+BFR versus non-BFR resistance exercise [low-load resistance exercise (LL-RE) or high-load resistance exercise (HL-RE)] on perceptual responses. DATA SOURCES: CINAHL, Cochrane Library, PubMed®, Scopus, SPORTDiscus, and Web of Science were searched through August 28, 2021, and again on August 25, 2022. STUDY SELECTION: Studies comparing the effect of RE+BFR versus non-BFR resistance exercise on rate of perceived exertion (RPE) and muscle pain/discomfort were considered. Meta-analyses were conducted using the random effects model. STUDY DESIGN: Systematic review and meta-analysis. LEVEL OF EVIDENCE: Level 2. DATA EXTRACTION: All data were reviewed and extracted independently by 2 reviewers. Disagreements were resolved by a third reviewer. RESULTS: Thirty studies were included in this review. In a fixed repetition scheme, the RPE [standardized mean difference (SMD) = 1.04; P < 0.01] and discomfort (SMD = 1.10; P < 0.01) were higher in RE+BFR than in non-BFR LL-RE, but similar in sets to voluntary failure. There were no significant differences in RPE in the comparisons between RE+BFR and non-BFR HL-RE; after sensitivity analyses, it was found that the RPE was higher in non-BFR HL-RE in a fixed repetition scheme. In sets to voluntary failure, discomfort was higher in RE+BFR versus non-BFR HL-RE (SMD = 0.95; P < 0. 01); however, in a fixed scheme, the results were similar. CONCLUSION: In sets to voluntary failure, RPE is similar between RE+BFR and non-BFR exercise. In fixed repetition schemes, RE+BFR seems to promote higher RPE than non-BFR LL-RE and less than HL-RE. In sets to failure, discomfort appears to be similar between LL-RE with and without BFR; however, RE+BFR appears to promote greater discomfort than HL-RE. In fixed repetition schemes, the discomfort appears to be no different between RE+BFR and HL-RE, but is lower in non-BFR LL-RE.

Efeitos do Treinamento Intervalado de Alta Intensidade e do Treinamento Contínuo na Capacidade de Exercício, Variabilidade da Frequência Cardíaca e em Corações Isolados em Ratos Diabéticos / Effects of High-Intensity Interval Training and Continuous Training on Exercise Capacity, Heart Rate Variability and Isolated Hearts in Diabetic Rats

Resumo Fundamento O treinamento intervalado de alta intensidade (HIIT) tem sido sugerido como alternativa ao treinamento contínuo (TC) em indivíduos com diabetes mellitus (DM) devido à sua curta duração e potencial para melhorar a adesão ao exercício. No entanto, dados sobre seu impacto sobre a variabilidade da frequência cardíaca (VFC) são escassos. Objetivos Avaliar e comparar os efeitos do HIIT e TC sobre a capacidade no exercício, VFC e corações isolados em ratos diabéticos. Métodos Animais diabéticos (estreptozotocina intravenosa, 45 mg.kg -1 ) e controles (C) realizaram 20 sessões de TC (5 dias/semana, 50 min, por quatro semanas) em esteira (70% da capacidade máxima de exercício) ou HIIT (ciclos de 1:1min a 50% e 90% da capacidade máxima de exercício). A VFC foi avaliada por eletrocardiograma contínuo, e a função cardíaca foi avaliada em corações isolados perfundidos. Para a análise dos dados, utilizamos a matriz do modelo linear generalizado de covariância multivariada ou o teste one-way ANOVA seguido pelo teste de Tukey, considerando um valor de p<0,05 como significativo. Resultados A capacidade de exercício (m/min) foi maior no grupo submetido ao HIIT [DM-HIIT: 36,5 (IIQ 30,0-41,3); C-HIIT: 41,5 (37,8-44,5), ambos n=10) em comparação ao grupo submetido ao TC [DM-TC: 29,0 (23,8-33,0); C-TC: 32,0 (29,5-37,0), ambos n=10) (p<0,001). A frequência cardíaca (bpm) foi mais baixa no grupo DM em comparação aos controles (p<0,001) tanto in vivo (DM-HIIT: 348±51, C-HIIT:441±66, DM-TC:361±70, C-TC:437±38) como nos corações isolados. Não houve diferenças na VFC entre os grupos. Os valores máximos e mínimos de dP/dt foram reduzidos no DM, com exceção da +dP/dt no grupo DM-HIIT vs. C-HIIT (diferença média: 595,5±250,3, p=0,190). Conclusão O HIIT de curto prazo promoveu melhora superior no desempenho no exercício em comparação ao TC, sem causar mudanças significativas na variabilidade da frequência cardíaca.

Abstract Background High-intensity interval training (HIIT) has been suggested as an alternative for continuous training (CT) in people with diabetes mellitus (DM) due to its short duration and potential to improve adherence to exercise. However, data on its impact on heart rate variability (HRV) are scarce. Objectives To assess and compare the effects of HIIT and CT on exercise capacity, HRV and isolated hearts in diabetic rats. Methods DM (intravenous streptozotocin, 45 mg.kg -1 ) and control (C) animals performed 20 sessions (5 days/week, 50 min, for 4 weeks) of CT on a treadmill (70% of maximal exercise capacity) or HIIT (cycles of 1:1min at 50% and 90% of maximal exercise capacity). HRV was assessed by continuous electrocardiogram, and cardiac function assessed in isolated perfused hearts. For data analysis, we used the framework of the multivariate covariance generalized linear model or one-way ANOVA followed by Tukey's test, considering p<0.05 as significant. Results Higher exercise capacity (m/min) was achieved in HIIT (DM-HIIT: 36.5 [IQR 30.0-41.3]; C-HIIT: 41.5 [37.8-44.5], both n=10) compared to CT (DM-CT: 29.0 [23.8-33.0]; C-CT: 32.0 [29.5-37.0], both n=10) (p<0.001). Heart rate (bpm) was lower in DM compared to controls (p<0.001) both in vivo (DM-HIIT:348±51, C-HIIT:441±66, DM-CT:361±70, C-CT:437±38) and in isolated hearts. There were no differences in HRV between the groups. Maximum and minimal dP/dt were reduced in DM, except +dP/dt in DM-HIIT vs. C-HIIT (mean difference: 595.5±250.3, p=0.190). Conclusion Short-term HIIT promotes greater improvement in exercise performance compared to CT, including in DM, without causing significant changes in HRV.

O Uso da Escala de Borg na Percepção do Esforço em Manobras de Reanimação Cardiopulmonar / The Use of the Borg Rating of Perceived Exertion Scale in Cardiopulmonary Resuscitation

Resumo Fundamento A parada cardiorrespiratória é um evento crítico cuja taxa de sobrevivência é relacionada à qualidade das manobras de reanimação, aliada à tecnologia. É importante compreender a percepção do cansaço durante esse procedimento visando a efetividade das compressões e o aumento das chances na sobrevida. Objetivo Aplicar a Escala de Borg para analisar o esforço percebido por enfermeiros durante as manobras de reanimação cardiopulmonar com dispositivo de feedback. Método Estudo experimental com distribuição randomizada de enfermeiros em hospital de ensino, simulando parada cardiorrespiratória, para avaliação da percepção do esforço utilizando a escala de Borg durante a reanimação cardiopulmonar com/sem dispositivo de feedback. Foi adotado nível de significância estatística 5%. Resultados Foram incluídos 69 enfermeiros atuantes em unidades críticas e não críticas de atendimento ao adulto. A percepção de esforço e a frequência cardíaca foi menor no grupo intervenção (p<0,001), influenciadas pelo dispositivo de feedback, sem diferença significativa quanto às unidades de atuação. Conclusão A escala de Borg mostrou-se adequada para os objetivos propostos. O dispositivo de feedback contribuiu no menor esforço e redução da frequência cardíaca durante as manobras de reanimação. O baixo custo e a facilidade de aplicação favorecem o uso em treinamentos e atendimentos em tempo real para avaliar o desempenho durante a reanimação, utilizando dispositivo de feedback por reduzir os esforços e a percepção do cansaço. Também permite a reflexão sobre os fatores intervenientes e recursos que podem influenciar na qualidade da assistência e nas chances de sobrevivência.

Abstract Background A cardiopulmonary arrest is a critical event whose survival rate is related to the quality of resuscitation maneuvers combined with the use of technology. It is important to understand the perception of fatigue during this procedure, aiming to improve the effectiveness of compressions to increase the chances of survival. Objectives To apply the Borg rating of perceived exertion scale (Borg scale) to analyze the exertion perceived by nurses during cardiopulmonary resuscitation maneuvers using a feedback device. Methods Experimental study with a randomized distribution of nurses in a teaching hospital. Perceived exertion during simulated cardiopulmonary resuscitation with/without a feedback device was assessed using the Borg scale. The statistical significance level of 5% was adopted. Results 69 nurses working in critical and non-critical adult care units were included. Perceived exertion and heart rate were lower in the intervention group (p<0.001), influenced by the feedback device, with no significant difference between critical and non-critical units. Conclusions The Borg scale proved to be adequate for the proposed objectives. The feedback device contributed to lower exertion and heart rate reduction during resuscitation maneuvers. The low cost and ease of application favor its use during training and real-time resuscitation attempts to assess performance using a feedback device to reduce exertion and perception of fatigue. It allows reflection on the intervening factors and resources that can influence the quality of resuscitation attempts and the chances of survival.