Does a broad-spectrum cannabidiol supplement improve performance in a 10-min cycle ergometer performance-test?

Cannabidiol (CBD) is a non-intoxicating phytocannabinoid which has been proposed to possess anti-inflammatory and analgesic properties. Given the potential for perceptions of pain to limit exercise performance, the aim of the present study was to investigate if 3 weeks of daily CBD supplementation (150 mg day-1) improved performance in a 10-min performance-trial on a cycle ergometer. In a randomized, double-blind and placebo-controlled study, 22 healthy participants (n = 11 male and n = 11 female) completed two 10-min performance trials on a WattBike cycle ergometer interspersed with a 3-week supplementation period. Supplementation involved either 150 mg day-1 oral CBD or 150 mg day-1 of a visually identical placebo (PLA). During trials, ratings of perceived exertion (RPE [6-20]), heart rate (HR) and blood lactate (BLa) were collected every 2 min. Mean power (W) was also taken throughout the exercise at each time point. All data were analyzed using two-way ANOVAs. There were no significant differences (P > 0.05) between CBD or PLA groups for mean power (W) during the 10-min performance trial. There were also no significant differences (P > 0.05) in any of the physiological or perceptual parameters (HR, BLa and RPE) between conditions. Three weeks supplementation of a broad-spectrum CBD supplement did not improve performance via any change in RPE during a 10-min time trial on a cycle ergometer, and as such, this evidence does not support the claim that broad-spectrum CBD supplements could be performance-enhancing in this exercise modality.

The Influence of the Playing Surface on Workload Response in Spanish Professional Male Soccer Players.

This study aimed to quantify the influence of the playing surface on workload-related variables (i.e., external load, Rate of perceived exertion (RPE), and mental load) in training sessions with a Spanish professional soccer team. Twenty professional male players from the same soccer team were involved. A total of thirty training sessions related to the preseason period were included. All the players completed training sessions on three playing surfaces: natural turf of poor quality, natural turf of high quality, and third-generation artificial turf. Monitoring during sessions involved assessing internal load (i.e., RPE and mental load) via self-reported questionnaires, and external load using Global Positioning System devices. Linear mixed models showed that RPE was significantly higher on natural turf of high quality than on natural turf of poor quality (p < 0.001). Total distance, relative total distance, the number of accelerations, decelerations, and high metabolic load distance were significantly lower on third-generation artificial turf compared to natural turf of poor quality (p < 0.001) and high quality (p < 0.001). In addition, high-speed running, sprint running distances, and the number of sprints reached higher values on third-generation artificial turf compared to the other two playing surfaces. These findings highlight the need for coaches to consider the type of training surface in soccer to optimize training load planning and prevent injuries.

How Do Young Soccer Players Train? A 5-Year Analysis of Weekly Training Load and its Variability Between Age Groups in an Elite Youth Academy.

ABSTRACT: Connolly, DR, Stolp, S, Gualtieri, A, Ferrari Bravo, D, Sassi, R, Rampinini, E, and Coutts, AJ. How do young soccer players train? A 5-year analysis of weekly training load and its variability between age groups in an elite youth academy. J Strength Cond Res 38(8): e423-e429, 2024-The aim of this study was to quantify the session rating of perceived exertion (sRPE), duration, and training load accrued across typical training weeks undertaken by youth soccer players. Differences between starters, nonstarters, and variations in training load variables were also investigated. Data were collected from 230 elite youth players in 4 age groups (U15, U16, U17, and U19) during 5 competitive seasons. Mixed models were used to describe variation between age groups and compare starters with nonstarters, with season as a fixed covariate effect. Week-to-week variation in training load was expressed as the percentage coefficient of variation. The main findings may be used to highlight a significant effect of age and playing status on training intensity, duration, and internal training load. Weekly training load increased progressively from the U15 to U17, with significant differences between each age group (p < 0.03). Lower mean weekly perceived intensity (sRPE) was noted in U15 when compared with the older age groups (4.2 vs. 4.6-4.9 arbitrary unit for U16 to U19, p < 0.001). Low weekly training load variation was observed across the different phases of the season in each age group, with the preseason exhibiting the greatest variance (3.6-6.2%). Differences in the training load are likely more attributable to changes in training duration rather than sRPE. Control of session duration seems to play an important role when aiming to control load in the academy environment, and practitioners should closely monitor the differences in duration and load being recorded between starters and nonstarters.

Comparison of Force, Neuromuscular, and Metabolic Responses During Sustained, Isometric Handgrip Holds to Failure Anchored to Low and High Perceptual Intensities in Men: An Exploratory Study.

ABSTRACT: Kwak, M, Succi, PJ, Benitez, B, Mitchinson, C, Samaan, MA, Abel, MG, and Bergstrom, HC. Comparison of force, neuromuscular, and metabolic responses during sustained, isometric handgrip holds to failure anchored to low and high perceptual intensities in men: An exploratory study. J Strength Cond Res 38(8): e405-e416, 2024-This study examined the responses of force alterations, relative to critical force (CF), neuromuscular parameters, and muscle oxygenation (SmO2) for isometric handgrip holds to failure (HTF) anchored to ratings of perceived exertion (RPE) of 3 and 7. Twelve men completed pre-maximal voluntary isometric contractions (pre-MVIC), submaximal HTF at 4 percentages of pre-MVIC, HTF at RPE = 3 and 7, and post-MVIC. Mechanomyograpic (MMG) signals and SmO2 were recorded during the RPE HTF. Analyses included paired-samples t-tests and repeated-measures ANOVAs at an alpha level of p ≤ 0.05. Time to task failure was not different between RPE 3 (478.7 ± 196.6 s) and RPE 7 (495.8 ± 173.8 s). Performance fatigability (PF) and MMG amplitude (AMP) were greater for RPE 7 (PF: 37.9 ± 12.9%; MMG AMP: 15.7 ± 7.4% MVIC) than RPE 3 (PF: 30.0 ± 14.5%; MMG AMP: 10.2 ± 6.5% MVIC), but MMG mean power frequency (MPF) was greater for RPE 3 (146.2 ± 31.1% MVIC) than RPE 7 (128.8 ± 23.0% MVIC). There were RPE-dependent decreases in force (p ≤ 0.01) across 3 discernable phases during the HTF. There were decreases in MMG AMP across time for both RPEs, but there were no significant changes in MMG MPF or SmO2. There were overall similar motor unit control strategies and local metabolic demand between RPEs. The majority of the HTF performed below CF at RPE 3 and 7 indicated CF did not reflect the highest sustainable force. When prescribing isometric exercise anchored to RPE, practitioners should be aware of the magnitude of force loss and relative intensity of the task to be sure desired training loads are met.

Evaluating Airflow Sensor Methods: Precision in Indirect Calorimetry.

This study assesses the impact of three volumetric gas flow measurement methods-turbine (fT); pneumotachograph (fP), and Venturi (fV)-on predictive accuracy and precision of expired gas analysis indirect calorimetry (EGAIC) across varying exercise intensities. Six males (Age: 38 ± 8 year; Height: 178.8 ± 4.2 cm; V ̇ O 2 peak $$ \dot{V}{\mathrm{O}}_2\mathrm{peak} $$ : 42 ± 2.8 mL O2 kg-1 min-1) and 14 females (Age = 44.6 ± 9.6 year; Height = 164.6 ± 6.9 cm; V ̇ O 2 peak $$ \dot{V}{\mathrm{O}}_2\mathrm{peak} $$ = 45 ± 8.6 mL O2 kg-1 min-1) were recruited. Participants completed physical exertion on a stationary cycle ergometer for simultaneous pulmonary minute ventilation ( V ̇ $$ \dot{V} $$ ) measurements and EGAIC computations. Exercise protocols and subsequent conditions involved a 5-min cycling warm-up at 25 W min-1, incremental exercise to exhaustion ( V ̇ O 2 $$ \dot{V}{\mathrm{O}}_2 $$ ramp test), then a steady-state exercise bout induced by a constant Watt load equivalent to 80% ventilatory threshold (80% VT). A linear mixed model revealed that exercise intensity significantly affected V ̇ O 2 $$ \dot{V}{\mathrm{O}}_2 $$ measurements (p < 0.0001), whereas airflow sensor method (p = 0.97) and its interaction with exercise intensity (p = 0.91) did not. Group analysis of precision yielded a V ̇ O 2 $$ \dot{V}{\mathrm{O}}_2 $$ CV % = 21%; SEM = 5 mL O2 kg-1 min-1. Intra- and interindividual analysis of precision via Bland-Altman revealed a 95% confidence interval (CI) precision benchmark of 3-5 mL kg-1 min-1. Agreement among methods decreased at power outputs eliciting V ̇ $$ \dot{V} $$ up to 150 L min-1, indicating a decrease in precision and highlighting potential challenges in interpreting biological variability, training response heterogeneity, and test-retest comparisons. These findings suggest careful consideration of airflow sensor method variance across metabolic cart configurations.

No Effect of Interset Palm Cooling on Acute Bench Press Performance, Neuromuscular or Metabolic Responses, Following Moderate-Intensity Resistance Exercise.

ABSTRACT: McMahon, G. No effect of interset palm cooling on acute bench press performance, neuromuscular or metabolic responses, following moderate-intensity resistance exercise. J Strength Cond Res 38(7): 1213-1220, 2024-Despite the growing literature in high-intensity exercise regarding palm cooling, the acute effects of palm cooling on exercise performance indices, neuromuscular and metabolic responses, have not been described during moderate-intensity resistance exercise. Nine (age, 22 ± 1 year; mass, 80.8 ± 16.2 kg; height, 1.80 ± 0.11 m) healthy, male (n = 7) and female (n = 2) resistance-trained subjects performed 4 sets of bench press to failure at 60% 1 repetition maximum with 3-minute passive recovery. Subjects were randomly allocated to either the cooling (COL; 2 minutes of cooling at 10 °C) or the control (passive rest; CON) condition separated by 1 week between the conditions. Exercise performance (volume load, repetitions, barbell velocity), muscle activation, blood lactate, and rate of perceived exertion were assessed. Despite changes across the variables during the resistance exercise sessions, there were no statistical differences (p > 0.05) in any of the performance, neuromuscular or physiological responses, between the 2 experimental conditions, despite palm temperature being significantly (p < 0.001) reduced in the cooling condition compared with control throughout. Therefore, based on the results of this study, palm cooling does not enhance acute moderate-intensity resistance exercise.

Neuromechanical Differences between Pronated and Supinated Forearm Positions during Upper-Body Wingate Tests.

Arm-cycling is a versatile exercise modality with applications in both athletic enhancement and rehabilitation, yet the influence of forearm orientation remains understudied. Thus, this study aimed to investigate the impact of forearm position on upper-body arm-cycling Wingate tests. Fourteen adult males (27.3 ± 5.8 years) underwent bilateral assessments of handgrip strength in standing and seated positions, followed by pronated and supinated forward arm-cycling Wingate tests. Electromyography (EMG) was recorded from five upper-extremity muscles, including anterior deltoid, triceps brachii lateral head, biceps brachii, latissimus dorsi, and brachioradialis. Simultaneously, bilateral normal and propulsion forces were measured at the pedal-crank interface. Rate of perceived exertion (RPE), power output, and fatigue index were recorded post-test. The results showed that a pronated forearm position provided significantly (p < 0.05) higher normal and propulsion forces and triceps brachii muscle activation patterns during arm-cycling. No significant difference in RPE was observed between forearm positions (p = 0.17). A positive correlation was found between seated handgrip strength and peak power output during the Wingate test while pronated (dominant: p = 0.01, r = 0.55; non-dominant: p = 0.03, r = 0.49) and supinated (dominant: p = 0.03, r = 0.51; don-dominant: p = 0.04, r = 0.47). Fatigue changed the force and EMG profile during the Wingate test. In conclusion, this study enhances our understanding of forearm position's impact on upper-body Wingate tests. These findings have implications for optimizing training and performance strategies in individuals using arm-cycling for athletic enhancement and rehabilitation.

Lateral Shuffle-Induced Fatigue Effects on Ankle Proprioception and Countermovement Jump Performance.

To determine how lateral shuffling/lateral shuffle (LS) -induced fatigue affects ankle proprioception and countermovement jump (CMJ) performance. Eighteen male college athletes performed 6 modes of a repeated LS protocol with 2 distances (2.5 and 5 m) and 3 speeds (1.6, 1.8, and 2.0 m/s). After LS, ankle inversion proprioception (AIP) was measured using the active movement extent discrimination apparatus (AMEDA). CMJ, blood lactate (BLa), heart rate (HR) and rating of perceived exertion (RPE) were measured before and after LS. The number of changes of direction (CODs) in each protocol was recorded. LS-induced fatigue was evident in BLa, HR and RPE (all p < 0.05), increasing with shorter shuffle distance and faster speed. RM-ANOVA showed a significant distance main effect on both AIP (p < 0.01) and CMJ (p < 0.05), but the speed main effect was only significant for CMJ (p ≤ 0.001), not AIP (p = 0.87). CMJ performance was correlated with BLa, HR and RPE (r values range from -0.62 to -0.32, all p ≤ 0.001). AIP was only correlated with CODs (r = -0.251, p < 0.01). These results suggested that in LS, shorter distance, regardless of speed, was associated with worse AIP, whereas subsequent CMJ performance was affected by both LS distance and speed. Hence, AIP performance was not related to physiological fatigue, but CMJ performance was. Results imply that LS affects processing proprioceptive input and producing muscular output differently, and that these two aspects of neuromuscular control are affected by physiological fatigue to varying degrees. These findings have implications for injury prevention and performance enhancement.

Force and Neuromuscular Responses During a Handgrip Hold to Failure Anchored to a Moderate Perceptual Intensity in Males.

OBJECTIVES: The current study investigated performance fatigability (PF) and time course of changes in force, electromyographic amplitude (EMG AMP) and frequency (EMG MPF), and neuromuscular efficiency (NME) during a sustained, isometric, handgrip hold to failure (HTF) using the rating of perceived exertion (RPE)-Clamp Model. METHODS: Twelve males performed a handgrip HTF anchored to RPE=5. The time to task failure (Tlim), force (N), EMG AMP and MPF, and NME (normalized force/ normalized EMG AMP) were recorded. Analyses included a paired samples t-test for PF at an alpha of p<0.05, 1-way repeated measures ANOVA across time and post-hoc t-tests (p<0.0025) for force, EMG AMP and MPF, and NME responses. RESULTS: The PF (pre- to post- maximal force % decline) was 38.2±11.5%. There were decreases in responses, relative to 0% Tlim, from 40% to 100% Tlim (force), at 30%, 60%, and 100% Tlim (EMG AMP), from 10% to 100% Tlim(EMP MPF), and from 50% to 65%, and 80% to 100% Tlim (NME) (p<0.0025). CONCLUSIONS: The RPE-Clamp Model in this study demonstrated that pacing strategies may be influenced by the integration of anticipatory, feedforward, and feedback mechanisms, and provided insights into the relationship between neuromuscular and perceptual responses, and actual force generating capacity.

ACE gene polymorphisms (rs4340) II and DI are more responsive to the ergogenic effect of caffeine than DD on aerobic power, heart rate, and perceived exertion in a homogeneous Brazilian group of adolescent athletes.

The purpose of this study was to verify the association between angiotensin-converting enzyme (ACE) genotypes DD, DI, and II and caffeine (CAF) ingestion on endurance performance, heart rate, ratio of perceived exertion (RPE), and habitual caffeine intake (HCI) of adolescent athletes. Seventy-four male adolescent athletes (age: DD=16±1.7; DI=16±2.0; II=15±1.7 years) ingested CAF (6 mg/kg) or placebo (PLA) one hour before performing the Yo-Yo Intermittent Recovery level 1 (Yo-Yo IR1) test. No difference was found among groups for HCI. However, CAF increased the maximal distance covered and VO2max in DI and II genotype carriers compared to PLA (DD: Δ=31 m and 0.3 mL·kg-1·min-1; DI: Δ=286 m and 1.1 mL·kg-1·min-1; II: Δ=160 m and 1.4 mL·kg-1·min-1). Heart rate of DI and II genotype carriers increased with CAF compared to PLA, while RPE was higher in the II and lower in the DD genotypes. The correlations between HCI and maximal distance covered or VO2max were significant in the II genotype carriers with CAF. CAF increased endurance capacity, heart rate, and RPE in adolescent athletes with allele I, while endurance performance and aerobic power had a positive correlation to HCI in the II genotype group. These findings suggested that DD genotype were less responsive to CAF and that genetic variations should be taken into account when using CAF supplementation to enhance exercise performance.

The influence of physical fitness qualities, individual characteristics and contextual factors on youth basketball players' perceived exertion and recovery responses to official games.

BACKGROUND: This study examined the influence of physical fitness qualities, individual characteristics, and contextual factors on perceived exertion and recovery responses to official games in youth basketball players. METHODS: Twenty-six males (age: 15.8±1.2 years; 12 guards, 9 forwards, and 5 centers) and 7 females (age: 16.1±0.9 years; 3 guards, 4 forwards) were monitored for an entire basketball season (N.=635 observations). Yo-Yo Intermittent Recovery (level 1) and countermovement jump (CMJ) tests were administered, with players categorized as high and low Yo-Yo and CMJ groups according to test results. Ratings of perceived exertion (RPE) were collected after each official game. Before the game and the day after, the Total Quality of Recovery (scores) were collected, and the difference between post- and pregame TQR was calculated (TQRΔ). Separate linear mixed models evaluated the effects of sex (M; F), fitness qualities (high Yo-Yo; low Yo-Yo) (high CMJ; low CMJ), playing position (guard; forward; center), game outcome (won; loss) and game location (home; away). RESULTS: Male players reported higher RPE (7.0±0.3) than females (5.5±0.4) (P=0.003, effect size [ES]: moderate). Players with high Yo-Yo performance also reported higher RPE (6.7±0.4) than low Yo-Yo (5.8±0.3) (P=0.049, ES: small). TQRΔ was higher in guards (-1.3±0.2) than forwards (-0.8±0.2) (P=0.041, ES: trivial), and lower after lost games (-0.8±0.2) compared to won games (-1.2±0.2) (P=0.002, ES: small). CONCLUSIONS: In youth basketball, postgame perceived exertion and recovery responses are influenced by players' sex, intermittent endurance capacity, and game outcome. Current findings can help youth basketball practitioners to better understand their players' performances and perceptual responses.

Decision-making accuracy of soccer referees in relation to markers of internal and external load.

This study examined the relationships between the decision-making performances of soccer referees and markers of physiological load. Following baseline measurements and habituation procedures, 13 national-level male referees completed a novel Soccer Referee Simulation whilst simultaneously adjudicating on a series of video-based decision-making clips. The correctness of each decision was assessed in relation to the mean heart rate (HR), respiratory rate (RR), minute ventilation (VE), perceptions of breathlessness (RPE-B) and local muscular (RPE-M) exertion and running speeds recorded in the 10-s and 60-s preceding decisions. There was a significant association between decision-making accuracy and the mean HR (p = 0.042; VC = 0.272) and RR (p = 0.024, VC = 0.239) in the 10-s preceding decisions, with significantly more errors observed when HR ≥ 90% of HRmax (OR, 5.39) and RR ≥ 80% of RRpeak (OR, 3.34). Decision-making accuracy was also significantly associated with the mean running speeds performed in the 10-s (p = 0.003; VC = 0.320) and 60-s (p = 0.016; VC = 0.253) preceding decisions, with workloads of ≥250 m·min-1 associated with an increased occurrence of decisional errors (OR, 3.84). Finally, there was a significant association between decision-making accuracy and RPE-B (p = 0.021; VC = 0.287), with a disproportionate number of errors occurring when RPE-B was rated as "very strong" to "maximal" (OR, 7.19). Collectively, the current data offer novel insights into the detrimental effects that high workloads may have upon the decision-making performances of soccer referees. Such information may be useful in designing combined physical and decision-making training programmes that prepare soccer referees for the periods of match play that prove most problematic to their decision-making.

Can mental fatigue affect perception of barbell velocity in resistance training?

Perception of Velocity (PV) is the ability to estimate single repetition velocity during resistance training (RT) exercises. The main purpose of the study was to evaluate the effects of Mental Fatigue (MF) on the accuracy of barbell PV. The secondary aims were to evaluate whether MF affected RT performance and ratings of perceived exertion (RPE; OMNI-RES) in the back squat. Twenty-four (14 Females, 10 Males) resistance-trained participants underwent 2 familiarization sessions and 1RM test for the back squat. In two separate sessions, PV was tested for light, medium, and heavy loads in 2 conditions in random order: at rest (REST) and in MF condition (POST-MF) induced by previous incongruent Stroop color-word task. MF and Motivation were assessed through visual analog scales (VAS; 0-100) before and after the Stroop task. For each load subjects performed 2 repetitions and reported the RPE value. Mean propulsive velocity (Vr) of the barbell was recorded with a linear encoder, while the perceived velocity (Vp) of the subjects was self-reported using the Squat-PV scale. The PV accuracy was calculated through the delta score (ds: Vp-Vr). Following the Stroop task MF increased significantly (p < 0.001; F (1, 23) = 52.572), while motivation decreased (p < 0.05; F (1, 23) = 7.401). Ds, Vr, and RPE did not show significant differences between conditions (p > 0.05) for the three loads analyzed. MF induced by previous demanding cognitive task did not affect PV accuracy. Furthermore, subjects maintained unchanged both RT performance and RPE values associated with each load, even when mentally fatigued.

Active ischemic pre-conditioning does not additively improve short-term high-intensity cycling performance when combined with caffeine ingestion in trained young men.

We investigated the effect of ischemic preconditioning (IPC) with and without caffeine supplementation on mean power output (MPO) during a 4-min cycling time-trial (TT). In a double-blinded, randomized, crossover-design, 11 trained men performed a TT on 4 days separated by ∼1 week. One hour before TT, participants ingested either caffeine (3 mg kg bw-1) or placebo pills, after which femoral blood-flow was either restricted with occlusion cuffs inflated to ∼180 mmHg (IPC), or sham-restricted (0-10 mmHg; Sham) during 3 × 2-min low-intensity cycling (10% of incremental peak power output). Then, participants performed a standardized warm-up followed by the TT. Plasma lactate and K+ concentrations and ratings of perceived exertion (RPE) were measured throughout trials. TT MPO was 382 ± 17 W in Placebo + Sham and not different from Placebo + IPC (-1 W; 95% CI: -9 to 7; p = 0.848; d: 0.06), whereas MPO was higher with Caffeine + Sham (+6W; 95% CI: -2 to 14; p = 0.115; d: 0.49) and Caffeine + IPC (+8 W; 95% CI: 2-13; p = 0.019; d: 0.79) versus Placebo + Sham. MPO differences were attributed to caffeine (caffeine main-effect: +7 W; 95% CI: 2-13; p = 0.015; d: 0.54. IPC main-effect: 0 W; 95% CI: -6 to 7; p = 0.891; d: 0.03; caffeine × IPC interaction-effect: p = 0.580; d: 0.17). TT RPE and plasma variables were not different between treatments. In conlcusion, IPC with co-ingestion of placebo does not improve short-term high-intensity performance in trained men versus a double-placebo control (Placebo + Sham) and does not additively enhance performance with caffeine. These data do not support IPC as a useful strategy for athletes prior to competition but confirms caffeine's performance-enhancing effect.

Quantitative Proteomics Provided Insights into the Protective Effects of Heat Acclimation on the Rat Hypothalamus after Exertional Heatstroke.

BACKGROUND: The effects of heat acclimation (HA) on the hypothalamus after exertional heatstroke (EHS) and the specific mechanism have not been fully elucidated, and this study aimed to address these questions. METHODS: In the present study, rats were randomly assigned to the control, EHS, HA, or HA + EHS groups (n = 9). Hematoxylin and eosin (H&E) staining was used to examine pathology. Tandem mass tag (TMT)-based proteomic analysis was utilized to explore the impact of HA on the protein expression profile of the hypothalamus after EHS. Bioinformatics analysis was used to predict the functions of the differentially expressed proteins. The differential proteins were validated by western blotting. An enzyme-linked immunosorbent assay was used to measure the expression levels of inflammatory cytokines in the serum. RESULTS: The H&E staining (n = 5) results revealed that there were less structural changes in hypothalamus in the HA + EHS group compared with the EHS group. Proteomic analysis (n = 4) revealed that proinflammatory proteins such as argininosuccinate synthetase (ASS1), high mobility group protein B2 (HMGB2) and vimentin were evidently downregulated in the HA + EHS group. The levels of interleukin (IL)-1ß, IL-1, and IL-8 were decreased in the serum samples (n = 3) from HA + EHS rats. CONCLUSIONS: HA may alleviate hypothalamic damage caused by heat attack by inhibiting inflammatory activities, and ASS1, HMGB2 and vimentin could be candidate factors involved in the exact mechanism.

Relationship Between External Training Load and Session Rating of Perceived Exertion Training Impulse in Elite Sprinters.

PURPOSE: To quantify the change in session rating of perceived exertion training impulse (RPE-TRIMP) that may occur in response to increased running distance at 3 running velocity ranges in elite sprinters. METHODS: We monitored training load in elite sprinters (women: n = 7; men: n = 11) using wearable Global Positioning System technology and RPE-TRIMP for a total of 681 individual training sessions during a 22-week competition-preparation period. Internal training load was operationalized by RPE-TRIMP, and external training load was operationalized by distance covered in 3 velocity ranges. A linear mixed-effects model with athlete as a random effect was fit to RPE-TRIMP with total distance covered at ≤69.99% (low-velocity running [LVR]), 70% to 84.99% (high-velocity running [HVR]), and 85% to 100% (very-high-velocity running [VHVR]) of individual maximum velocity. RESULTS: Increased running distance in all 3 velocity ranges (LVR, HVR, and VHVR) resulted in a significant (P < .001) increase in RPE-TRIMP. Coefficients (95% CIs) were .10 (.08-.11) for LVR, .23 (.18-.28) for HVR, and .44 (.35-.53) for VHVR. A 50-m increase in running distance covered in the LVR, HVR, and VHVR velocity ranges was associated with increases in RPE-TRIMP of 5, 11.5, and 22 arbitrary units, respectively. CONCLUSIONS: Internal training load, calculated as RPE-TRIMP, increased with increases in total distance covered in the LVR, HVR, and VHVR velocity ranges (P < .001). RPE-TRIMP can be a practical solution for monitoring global training-session load in elite sprinters.

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.

Perceived exertion can be lower when exercising in field versus indoors.

PURPOSE: Studies indicate that the rated perceived exertion (RPE) during physical exercise can be lower in field environments than indoors. The environmental conditions of those studies are explored. Furthermore, we study if the same phenomenon is valid when cycling indoors versus in cycle commuting environments with high levels of stimuli from both traffic and suburban-urban elements. METHODS: Twenty commuter cyclists underwent measurements of heart rate (HR) and oxygen uptake ([Formula: see text]O2) and RPE assessments for breathing and legs, respectively, while cycling in both laboratory and field conditions. A validated mobile metabolic system was used in the field to measure [Formula: see text]O2. Three submaximal cycle ergometer workloads in the laboratory were used to establish linear regression equations between RPE and % of HR reserve (%HRR) and %[Formula: see text]O2max, separately. Based on these equations, RPE from the laboratory was predicted and compared with RPE levels at the participants' individual cycle commutes at equal intensities. The same approach was used to predict field intensities and for comparisons with corresponding measured intensities at equal RPE levels. RESULTS: The predicted RPE levels based on the laboratory cycling were significantly higher than the RPE levels in cycle commuting at equal intensities (67% of HRR; 65% of [Formula: see text]O2max). For breathing, the mean RPE levels were; 14.0-14.2 in the laboratory and 12.6 in the field. The corresponding levels for legs were; 14.0-14.2 and 11.5. The range of predicted field intensities in terms of %HRR and %[Formula: see text]O2max was 46-56%, which corresponded to median differences of 19-30% compared to the measured intensities in field at equal RPE. CONCLUSION: The cycle commuters perceived a lower exertion during their cycle commutes compared to ergometer cycling in a laboratory at equal exercise intensities. This may be due to a higher degree of external stimuli in field, although influences from other possible causes cannot be ruled out.

The relationship between prescribed ratings of perceived exertion and force production in repeated isometric contractions.

Ratings of perceived exertion (RPE) are frequently used to monitor and prescribe exercise intensity. However, studies examining the shape and robustness of how feelings of effort map onto objective outputs are limited and report inconsistent results. To address this, we investigated whether (1) producing isometric forces according to RPE levels reliably leads to differences in force output, (2) if feelings of effort map linearly or non-linearly onto force output, and (3) if this mapping is robust when visual feedback and social facilitation are present. In a counterbalanced repeated measures design, N = 26 participants performed isometric handgrip contractions prescribed by ten levels of the Borg CR-10 scale. They did so either with or without the availability of concurrent visual feedback regarding their force production, and in the presence or absence of another person performing the same task simultaneously. We found that subjects reliably produced different force outputs that corresponded to each RPE level. Furthermore, concurrent visual feedback led to a linearization of force output, while in the absence of feedback, the produced forces could also be described by quadratic and cubic functions. Exploratory post-hoc analyses revealed that participants perceived moderate RPE levels to be more challenging to produce. By shedding light on the dynamic nature of the mapping between RPE and objective performance, our findings provide helpful insights regarding the utility of RPE scales.