Perceptual Responses Research Articles

Physiological, perceptual and neuromuscular responses to 15 vs. 30 s work durations during short high intensity interval training

High intensity interval training (HIIT) is an extremely potent stimulus for physiological adaptation offering a low volume training approach that can be easily accommodated into an individual’s training schedule. A key feature that drives physiological adaptation is the time the individual spends at or around their individual V̇O2max during HIIT. This can be influenced by several variables, including the work bout duration (Buchheit & Laursen, 2013, Sports Med, 43, 318-338). The use of short duration HIIT intervals (i.e., < 60 s) are popular due to their ability to facilitate a high oxygen uptake while minimising fatigue (Buchheit & Laursen, 2013, Sports Med, 43, 318-338). However, the physiological response to different short duration HIIT formats has not yet been investigated. The aim of this study was to measure the physiological, perceptual and neuromuscular responses to two traditional short duration (i.e., 15 and 30 s) HIIT formats in trained athletes. With ethics approval, 10 well-trained male and female team sport players (mean + SD; age: 22 ± 1 years; body mass: 78 ± 6 kg; stature: 176 ± 4 cm) were recruited to the study and visited the laboratory on three separate occasions. After an incremental test to exhaustion on a cycle ergometer to establish V̇O2max (52.3 ± 5.7 ml·kg-1·min-1) and peak power output at V̇O2max (pV̇O2max; 313 ± 21 W), two HIIT sessions (15 s effort: 15 s passive recovery and 30 s effort: 30 s passive recovery) were completed in a randomised order. HIIT interventions comprised 15 s or 30 s at 120% pV̇O2max followed by 15 or 30 s passive recovery, repeated for 2 × 6 min with 5 min active recovery at 40% pV̇O2max. V̇O2, time >90% V̇O2max, heart rate, and RPE were measured during the HIIT session and blood lactate concentration recorded 5 minutes afterwards. Measures of knee extensor maximal voluntary contraction (MVC) were measured immediately before and after each HIIT session.

Seasonal variation of physical, perceptual, and cognitive function measures in professional academy soccer players

Soccer match play and training have been documented to significantly impair players' physical function and affect their perceptual wellness, indicating the necessity of evaluating the response to mixed-content training across a soccer season (Deely et al., 2022, Front Physiol, 13, 911009; Brownstein et al., 2017, Front Physiol, 8, 831; Thomas et al., 2017, Med Sci Sports Exer, 49, 955-964). This study aimed to assess seasonal variation in physical, perceptual, and cognitive functions in response to training among professional academy soccer players, to identify whether players develop increased physical robustness or encounter greater physiological and psychological impairments due to the demanding training and match schedule. Ethical approval was granted for sixteen academy players (age: 18 ± 1 years) to undergo a range of tests at three seasonal points - early, mid, and late - at baseline, immediately post-strenuous training, and at 24, 48, and 72 h. The testing regime encompassed physical performance (countermovement jump [CMJ], ten-to-five repeated jump test [10/5 RJT]), cognitive function (Stroop task, Four-Choice Reaction Time [FCRT] test, Corsi Block Test), and perceptual responses via an adapted Short Questionnaire of Fatigue (SQF). Linear mixed modelling (LMM) was employed to analyse the impact of season phase and testing time-points on training response, incorporating testing measures as dependent variables. Jump performance varied across time-points, with performance maintained immediately post-training, although displaying decrements at 24 h (P < 0.001), 48 h (P < 0.01), and remained unresolved at 72 h (P < 0.05). Season phase exerted a fixed effect on physical function, with vertical jumps decreasing from both early- (P = 0.033, CMJ; P < 0.001, 10/5 RJT) and mid-season (P < 0.001, CMJ; P < 0.001, 10/5 RJT) to late-season. Perceptual measures—soreness, fatigue, and readiness to train—varied across the week, with immediate post-session impairments recovering by 48 and 72 hours. Cognitive function remained relatively stable across the training week, with only a decline in Corsi Block performance noted immediately post-session. An improvement in FCRT from early to mid-season was observed, though accuracy decreased from early to late-season. No interaction between season phase and training week time-points was found across any variable, indicating a consistent training response throughout the season, despite substantial impairments in physical function and declines in perceptual wellness observed post-training. The decrease in physical function during the late-season phase underscores the need for enhanced recovery focus and training load monitoring as the season progresses.

Influence of head-mounted virtual reality (VR) on psychological and physiological responses in the heat

Evidence suggests that vision may play a role in the perception of temperature in humans (Mayes et al., 2023, J Therm Bio, 112, 103488). Virtual reality (VR) has garnered attention for its potential applications in various domains, including sports training and rehabilitation. However, the psychophysiological effects of using VR in hot environments remain relatively unexplored. The present study tested the hypothesis that a ‘cold’ visual environment would decrease thermal perception when compared to a ‘hot’ visual environment during passive heat exposure. Twelve healthy participants (2 females) [mean ± SD, age: 24 ± 5 years; stature: 174 ± 9 cm; mass: 72 ± 8 kg] provided their written informed consent to participate in this study. Ethical approval was obtained from the Faculty of Science and Health’s Ethics Committee at The University of Portsmouth. In a within-participant, randomised, controlled crossover design participants completed a familiarisation visit followed by three experimental sessions in 40°C (50% r.h.). The three conditions were: no virtual reality (NoVR), virtual reality displaying an arid landscape (HotVR), and virtual reality displaying a snow-covered landscape (ColdVR). Thermal sensation, thermal comfort, skin wetness, heart rate, rectal temperature, and four-site skin temperature were recorded. Mean skin temperature and mean body temperature were subsequently calculated. Data were analysed using a 3 (Condition [NoVR, VRHot, VRCold]) × 7 (Time [Pre, 5-, 10-, 15-, 20-, 25-, 30-min post-VR exposure]) repeated measures ANOVA. The main effects of condition, time, and their interaction were explored, with statistical significance accepted at P < 0.05. The use of VR in the heat resulted in increased thermal sensation, skin wetness, mean skin temperature, mean body temperature, and heart rate over time (all P < 0.05). However, the manipulation of the visual environment did not alter perceptual or physiological variables (all P > 0.05). Significant interaction effects were observed for mean skin temperature and mean body temperature; however, these minimal differences were considered not meaningful. In conclusion, these novel data indicate that using VR to manipulate the virtual environment in the heat does not meaningfully alter perceptual or physiological responses. These findings also suggest that VR may be used within settings such as the military and elite-sport without any deleterious effects. Future work should look to examine the effects of using VR whilst exercising on perceptual and physiological measures.

Effects of food bar chewing duration on the physiologic, metabolic, and perceptual responses to moderate-intensity running

PurposeChewing duration can affect food particle size, gastric processing, and postprandial glycemia, but these effects have not been investigated with exercise. This study examined how the chewing duration of a food bar impacts glycemic and metabolic responses, gastrointestinal (GI) symptoms, psychological affect, and performance during endurance running.MethodsThis randomized, unblinded, crossover study had 15 males (35.2 ± 7.4 years, VO2peak: 56.1 ± 5.2 ml/kg/min) attend three laboratory visits. Visit 1 required a VO2peak test, 10 min familiarization run at 60% VO2peak, and familiarization time-to-exhaustion (TTE) test (10 min at 90% VO2peak, followed by TTE at 100% VO2peak). Visits 2 and 3 consisted of a 60 min run at 60% VO2peak, followed by TTE testing. Participants were fed 45 g of a bar (180 kcal, 4 g fat, 33 g carbohydrate, 3 g protein, 1 g fiber) in 9 g servings 30 min before running, and 27 g of bar in 9 g servings at three timepoints during the 60 min run. Participants consumed the servings in 20 (20CHEW) or 40 (40CHEW) masticatory cycles, at 1 chew/second. Outcomes included blood glucose, substrate use, GI symptoms, perceived exertion (RPE), overall feeling, and TTE.ResultsPost-prandial blood glucose, GI symptoms, and RPE increased over time, but there were no significant between-condition or condition-by-time effects. TTE showed no significant between-condition effect (20CHEW: 288 ± 133 s; 40CHEW: 335 ± 299 s; p = 0.240). Overall feeling demonstrated a time-by-condition effect (p = 0.006), suggesting possible better maintenance over time with 40CHEW.ConclusionCumulatively, the results suggest that extended chewing minimally impacts physiology, perceptions, and performance during 60 min moderate-intensity running.

An examination of acute physiological and perceptual responses following blood flow restriction exercise using a traditional research device or novel, automated system

Objective. To compare the acute physiological and perceptual responses to blood flow restriction (BFR) exercise using a traditional research device or novel, automated system. Methods. Forty-four resistance trained individuals performed four sets of unilateral elbow flexion exercise (30% one-repetition maximum) to volitional failure using two distinct restrictive devices [SmartCuffs PRO BFR Model (SMARTCUFF), Hokanson E20 Rapid Inflation device (HOKANSON)] and with two levels of BFR [40% limb occlusion pressure (LOP), 80% LOP]. Blood pressure (BP), muscle thickness (MT), and isometric strength (ISO) were assessed prior to and following exercise. Perceptual responses [ratings of perceived exertion (RPE), discomfort] were assessed prior to exercise and following each exercise set. Main results. Data are displayed as means (SD). Immediately following exercise with 40% LOP, there were no statistical differences between devices for BP, MT, and ISO. However, only following Set 1 of exercise, RPE was greater with SMARTCUFF compared to HOKANSON (p < 0.05). In addition, only following Set 2 of exercise, discomfort was greater with HOKANSON compared to SMARTCUFF (p < 0.001). Immediately following exercise with 80% LOP, there were no statistical differences between devices for BP, MT, and ISO. However, only following Set 4 of exercise, RPE was greater with HOKANSON compared to SMARTCUFF (p < 0.05). In addition, following all exercise sets, discomfort was greater with HOKANSON compared to SMARTCUFF (p < 0.001). For repetitions completed with 40% LOP there were no statistical differences between SMARTCUFF and HOKANSON across any exercise sets. For repetitions completed with 80% LOP there were no statistical differences between SMARTCUFF and HOKANSON across Set 1 of exercise (p = 0.34), however, for Sets 2–4 of exercise, significantly greater number of repetitions were completed during SMARTCUFF than HOKANSON. Significance. The present study provides valuable insight into the efficacy of a novel, automated BFR system (SMARTCUFF) eliciting comparable acute physiological responses to BFR exercise and in some cases favorable perceptual responses when compared to a traditional research device (HOKANSON).

Low-load Resistance Exercise with Perceptually Primed Practical Blood Flow Restriction Induces Similar Motor Performance Fatigue, Physiological Changes, and Perceptual Responses Compared to Traditional Blood Flow Restriction in Males and Females.

In the recent past, practical blood flow restriction (pBFR) using non-pneumatic, usually elastic cuffs has been established as a cost-effective alternative to traditional blood flow restriction (BFR) using pneumatic cuffs, especially for training in large groups. This study investigated whether low-load resistance exercise with perceptually primed pBFR using an elastic knee wrap is suitable to induce similar motor performance fatigue as well as physiological and perceptual responses compared to traditional BFR using a pneumatic nylon cuff in males and females. In a randomized, counterbalanced cross-over study, 30 healthy subjects performed 4 sets (30-15-15-15 repetitions) of unilateral knee extensions at 20% of their one-repetition-maximum. In the pBFR condition, each individual was perceptually primed to a BFR pressure corresponding to 60% of their arterial occlusion pressure. Before and after exercise, maximal voluntary torque, maximal muscle activity, and cuff pressure-induced discomfort were assessed. Moreover, physiological (i.e., muscle activity, muscle oxygenation) and perceptual responses (i.e., effort and exercise-induced leg muscle pain) were recorded during exercise. Moderate correlations with no differences between pBFR and BFR were found regarding the decline in maximal voluntary torque and maximal muscle activity. Furthermore, no to very strong correlations between conditions, with no differences, were observed for muscle activity, muscle oxygenation, and perceptual responses during exercise sets. However, cuff pressure-induced discomfort was lower in the pBFR compared to the BFR condition. These results indicate that low-load resistance exercise combined with perceptually primed pBFR is a convenient and less discomfort inducing alternative to traditional BFR. This is especially relevant for BFR training with people who have a low cuff-induced discomfort tolerance.

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

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. 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). 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). 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.

Exploring perceptions, cognitive factors, and motivations: A study on green structures on residential rooftops

Urban greenhouse and green roof cultivation propose a nature-based solution to current socio-ecological challenges in urban ecosystems, as it offers several socio-ecological solutions and benefits. The interdisciplinary techniques for scientific explorations of cognition and perception towards urban green structures could not get the attention of the researchers across varying scientific disciplines, especially in the developing world. Addressing the personal factors involved in human cognition and its subsequent impact on perceptions will lay the foundation for the studies of the field. The study included questions about socio-demographic characteristics and socio-environmental motivations, as well as a set of images depicting potential future of green structures. The study was accomplished in Tabriz city of Iran with 375 participants. The findings showed that individuals prioritize certain types of rooftop green structures based on their personal characteristics and motivations. Additionally, cognitive differences were observed among individuals based on age, gender, and marital status, leading to perceptual differences towards green structures. Socio-environmental motivations activate perceptual responses within individuals, influencing their preferences for specific types of rooftop greenhouses. Understanding the response of individuals towards green structure types is crucial for effective planning and design. This knowledge can enhance the overall success and satisfaction of rooftop green structures projects, leading to greater wellness and a positive impact on the environment.

The influence of empathy on the perceptual response to visual art.

The influence of empathy on the perceptual response to visual art.

No Sex Differences in Perceptual Responses to High-Intensity Interval Training or Sprint Interval Training.

Coe, LN and Astorino, TA. No sex differences in perceptual responses to high-intensity interval training or sprint interval training. J Strength Cond Res 36(6): 1025-1032, 2024-High-intensity interval training (HIIT) elicits similar and, in some cases, superior benefits vs. moderate-intensity continuous training (MICT). However, HIIT is typically more aversive than MICT because of the higher intensity and in turn, greater blood lactate accumulation (BLa). This study explored potential sex differences in perceptual responses to acute HIIT and sprint interval training. Fifteen men (age and V̇O2max = 29 ± 8 years and 39 ± 3 ml·kg-1·min-1) and 13 women (age and V̇O2max = 22 ± 2 years and 38 ± 5 ml·kg-1·min-1) who are healthy and recreationally active initially underwent testing of maximal oxygen uptake (V̇O2max) on a cycle ergometer. In randomized order on 3 separate occasions, they performed the 10 × 1-minute protocol at 85% of peak power output, 4 × 4-minute protocol at 85-95% maximal heart rate (%HRmax), or reduced exertion high intensity interval training consisting of 2 "all-out" 20-second sprints at a load equal to 5% body mass. Before and throughout each protocol, rating of perceived exertion (rating of perceived exertion [RPE] 6-20 scale), affective valence (+5 to -5 of the Feeling Scale), and BLa were assessed. Five minutes postexercise, enjoyment was measured using the Physical Activity Enjoyment scale survey. Results showed no difference in RPE (p = 0.17), affective valence (0.27), or enjoyment (p = 0.52) between men and women. Blood lactate accumulation increased in response to all protocols (p < 0.001), and men showed higher BLa than women (p = 0.03). Previous research suggests that interval exercise protocols are not interchangeable between men and women, yet our data reveal that men and women having similar V̇O2max exhibit no differences in perceptual responses to interval exercise.

The Effects of Post-Exercise Cold Water Immersion on Neuromuscular Control of Knee.

To date, most studies examined the effects of cold water immersion (CWI) on neuromuscular control following exercise solely on measuring proprioception, no study explores changes in the brain and muscles. The aim of this study was to investigate the effects of CWI following exercise on knee neuromuscular control capacity, and physiological and perceptual responses. In a crossover control design, fifteen participants performed an exhaustion exercise. Subsequently, they underwent a 10 min recovery intervention, either in the form of passively seated rest (CON) or CWI at 15 °C. The knee proprioception, oxygenated cerebral hemoglobin concentrations (Δ[HbO]), and muscle activation during the proprioception test, physiological and perceptual responses were measured. CWI did not have a significant effect on proprioception at the post-intervention but attenuated the reductions in Δ[HbO] in the primary sensory cortex and posterior parietal cortex (p < 0.05). The root mean square of vastus medialis was higher in the CWI compared to the CON. CWI effectively reduced core temperature and mean skin temperature and improved the rating of perceived exertion and thermal sensation. These results indicated that 10 min of CWI at 15 °C post-exercise had no negative effect on the neuromuscular control of the knee joint but could improve subjective perception and decrease body temperature.

Physiological, Perceptual, and Neuromuscular Responses to V˙O2-Clamp Cycle Ergometry Exercise

Physiological, Perceptual, and Neuromuscular Responses to V˙O2-Clamp Cycle Ergometry Exercise

Introduction to the assessment and management of persistent postural-perceptual dizziness.

Persistent postural-perceptual dizziness classifies patients with chronic dizziness, often triggered by an acute episode of vestibular dysfunction or threat to balance. Unsteadiness and spatial disorientation vary in intensity but persist for over three months, exacerbated by complex visual environments. Literature suggests diagnosis relies on a clinical history of persistent subjective dizziness and normal vestibular and neurological examination findings. Behavioural diagnostic biomarkers have been proposed, to facilitate diagnosis. Research has focused on understanding the neural mechanisms that underpin this perceptual disorder, with imaging data supporting altered connectivity between neural brain networks that process vision, motion and emotion. Behavioural research identified the perceptual and motor responses to a heightened perception of imbalance. Management utilises head and body motion detection, and downregulation of visual motion excitability, reducing postural hypervigilance and anxiety. Combinations of physical and cognitive therapies, with antidepressant medications, help if the condition is associated with mood disorder.

EFFECTS OF FACE MASKS ON CARDIORESPIRATORY PARAMETERS DURING EXERCISE VELOERGOMETRY TEST

The COVID-19 pandemic has sparked ongoing scientific discussions about the adverse effects of wearing face masks on cardiorespiratory indicators, and the subjective response to exertion. Many researchers have investigated the impact of wearing face masks on different physiological factors through various exercise routines, such as a progressive cycling test, the 6-minute walk test, and treadmill walking at a constant pace, yielding inconsistent findings. This study aimed to examine the physiological and perceptual responses of wearing surgical face masks during and after the veloegometry test. Fifteen healthy young adults (mean age, 26.8±4.4 years, 5 males and 10 females) conducted the Astrand-Rhyming veloegometry protocol twice (with and without masks). Physiological outcomes (heart rate, maximal oxygen uptake, and oxygen saturation level), perceived exertion, and discomfort feeling by modified Borg scale were assessed. No significant differences were observed in physiological outcomes with or without masks during increasing load intensities (p &gt; 0.05) except for the last minute of testing and the minute after testing (p ≤ 0.005). Participants wearing masks reported the tendency of higher exertion level (3.8±1.08 vs 4.4±0.9) but statistical analysis can't definitively confirm it. While exercising with a face mask may not adversely affect cardiorespiratory factors, it can elevate perceived exertion levels and discomfort, particularly when exercise intensity exceeds a certain threshold.

An evaluation of the effects of localised skin cooling on microvascular, inflammatory, structural, and perceptual responses to sustained mechanical loading of the sacrum: A study protocol.

This study protocol aims to investigate how localised cooling influences the skin's microvascular, inflammatory, structural, and perceptual tolerance to sustained mechanical loading at the sacrum, evaluating factors such as morphology, physiology, and perceptual responses. The protocol will be tested on individuals of different age, sex, skin tone and clinical status, using a repeated-measure design with three participants cohorts: i) young healthy (n = 35); ii) older healthy (n = 35); iii) spinal cord injured (SCI, n = 35). Participants will complete three testing sessions during which their sacrum will be mechanically loaded (60 mmHg; 45 min) and unloaded (20 min) with a custom-built thermal probe, causing pressure-induced ischemia and post-occlusive reactive hyperaemia. Testing sessions will differ by the probe's temperature, which will be set to either 38°C (no cooling), 24°C (mild cooling), or 16°C (strong cooling). We will measure skin blood flow (via Laser Doppler Flowmetry; 40 Hz); pro- and anti-inflammatory biomarkers in skin sebum (Sebutape); structural skin properties (Optical Coherence Tomography); and ratings of thermal sensation, comfort, and acceptance (Likert Scales); throughout the loading and unloading phases. Changes in post-occlusive reactive hyperaemia will be considered as the primary outcome and data will be analysed for the independent and interactive effects of stimuli's temperature and of participant group on within- and between-subject mean differences (and 95% Confidence Intervals) in peak hyperaemia, by means of a 2-way mixed model ANOVA (or Friedman). Regression models will also be developed to assess the relationship between absolute cooling temperatures and peak hyperaemia. Secondary outcomes will be within- and between-subject mean changes in biomarkers' expression, skin structural and perceptual responses. This analysis will help identifying physiological and perceptual thresholds for the protective effects of cooling from mechanically induced damage underlying the development of pressure ulcers in individuals varying in age and clinical status.

Effects of Different Weekly Set Volumes on Strength and Perceptual Responses in Athletes.

This study investigated the effects of different resistance training (RT) volumes quantified by weekly sets at high intensity (load and effort) on dynamic strength adaptations and psychophysiological responses in trained individuals. Twenty-four athletes were randomly allocated to three groups that performed three (3 S, n=8), six (6 S, n=8), and nine (9 S, n=8) weekly sets, respectively, three times a week on the barbell back squat and bench press during an 8-week period. While all groups showcased strength gains (p<0.05), post hoc comparisons revealed that 6 S and 9 S elicited greater strength adaptations than 3 S in barbell back squat (p=0.027 and p=0.004, respectively) and bench press (p=0.001 and p=0.044, respectively). There were no differences between 6 S and 9 S conditions for back squat (p=0.999) and bench press (p=0.378). Although a time effect was observed for Session-RPE (p=0.014) and Total Quality Recovery scale (p=0.020), psychophysiological responses were similar among groups. Our findings suggest that performing six and nine weekly sets at high intensities led to greater strength gains compared to three weekly sets in strength-trained individuals, despite similar psychophysiological responses.

Physiological and Perceptual Demands During a Simulated “The Hundred” Batting Work-Bout in Female Cricketers

Abstract Purpose No research has investigated the physiological and perceptual demands of female cricket players at any level or for any format, making this study unique. This is despite the growth in popularity and professionalism of the women’s game. Therefore, the purpose of this study was to determine the physiological (heart rate, oxygen consumption) and perceptual (ratings of perceived exertion, body discomfort) demands of female cricketers during a simulated “The Hundred” protocol. Methods Twenty female cricketers (age: 19 ± 4.53 years, stature: 167.90 ± 7.28 cm; mass: 67.30 ± 13.51 kg) currently playing for a first-class county cricket club were recruited. The protocol consisted of six sets and was designed to mimic the nonpowerplay phase of a women’s “Hundred” match. Throughout the protocol selected physiological and perceptual responses were recorded. Results Heart rate responses increased significantly (P &lt; 0.05) from the first set (149 ± 14 beats/min) until the end of the third set (167 ± 10 beats/min). A further significant decrease (P &lt; 0.05) was observed between set three (167 ± 10 beats/min) and set six (165 ± 12 beats/min). Oxygen uptake responses increased significantly (P &lt; 0.05) from set one (22.06 ± 7.82 mL/kg/min) until set three (26.30 ± 7.58 mL/kg/min). A significant difference (P &lt; 0.05) was also observed between set three and all the other sets. Central ratings of perceived exertion increased significantly (P &lt; 0.05) throughout the protocol (9 ± 1.83–13 ± 3.17). Body discomfort, results indicated that the quadriceps and calves were the areas that felt the most discomfort during the protocol. Conclusion In conclusion, the design of training programs should mimic the demandsof the women?s format of the game and focus on individualised exercise preparation.

Disrupted Rotational Perception During Simultaneous Stimulation of Rotation and Inertia.

Two vestibular signals, rotational and inertial cues, converge for the perception of complex motion. However, how vestibular perception is built on neuronal behaviors and decision-making processes, especially during the simultaneous presentation of rotational and inertial cues, has yet to be elucidated in humans. In this study, we analyzed the perceptual responses of 20 participants after pairwise rotational experiments, comprised of four control and four test sessions. In both control and test sessions, participants underwent clockwise and counterclockwise rotations in head-down and head-up positions. The difference between the control and test sessions was the head re-orientation relative to gravity after rotations, thereby providing only rotational cues in the control sessions and both rotational and inertial cues in the test sessions. The accuracy of perceptual responses was calculated by comparing the direction of rotational and inertial cues acquired from participants with that predicted by the velocity-storage model. The results showed that the accuracy of rotational perception ranged from 80 to 95% in the four control sessions but significantly decreased to 35 to 75% in the four test sessions. The accuracy of inertial perception in the test sessions ranged from 50 to 70%. The accuracy of rotational perception improved with repetitive exposure to the simultaneous presentation of both rotational and inertial cues, while the accuracy of inertial perception remained steady. The results suggested a significant interaction between rotational and inertial perception and implied that vestibular perception acquired in patients with vestibular disorders are potentially inaccurate.

A Dose-Response Study to Examine Paraxanthine’s Impact on Energy Expenditure, Hunger, Appetite, and Lipolysis

This study investigated if paraxanthine (PX) impacts energy expenditure, lipolysis and perceptual responses. In a randomized, double-blind, placebo-controlled, crossover fashion, 21 adults (13 M, 8 F; 26.0 ± 6.4 years, 174.9 ± 11.5 cm, 81.0 ± 15.7 kg body mass, 26.3 ± 3.4 kg/m2) consumed a placebo (PLA), 100 mg (PX100), 200 mg (PX200), and 300 mg of PX (PX300, enfinity®, Ingenious Ingredients, L.P. Lewisville, TX, USA). Venous blood was collected 0, 30, 60, 90, 120 and 180 min (min) after ingestion and analyzed for glycerol and free fatty acids. Resting hemodynamics, metabolic rate and perceptual indicators of hunger, appetite and anxiety were evaluated. Mixed factorial analysis of variance were used to evaluate changes time within and between groups. Heart rate decreased in PX100 compared to PLA 60 (p = .022) and 180 min (p = .001). Blood pressure did not change. Hunger ratings in PLA increased 30 (p = .05), 60 (p = .04), 90 (p = .02), and 180 min (p = .05) after ingestion when compared to PX200. PX200 increased energy expenditure (all p < .05) when compared to PLA. Rates of fat oxidation tended to increase 90 (p = .056) and 120 min (p = .066) in PX200 compared to PLA. Free fatty acids increased in PX300 compared to PLA (p = .002). Glycerol did not change. Ingestion of PX200 augmented energy expenditure and hunger ratings when compared to PLA without impacting hemodynamics or lipolysis.

Cold Habituation Does Not Alter Thermal Responses or Manual Dexterity During Prolonged Cold Air Exposure

Background: Habituation is a pattern of cold acclimatization characterized by attenuated cold defense responses, including a reduction in peripheral vasoconstriction and subsequent increase in skin temperature (TSk) as well as a decrease in shivering thermogenesis. Habituation is achieved through repeated reductions in TSk, rather than deep body core temperature (TC), via exposure to prolonged cold air or brief cold-water immersion. Due to improvements in TSk, enhanced manual dexterity and peripheral cold injury risk reduction are purported benefits of cold habituation. Warfighters frequently operate in cold climates and experience decrements in manual dexterity and strength. These functional losses can negatively impact mission critical tasks and training exercises; however, the effectiveness of cold habituation as a potential countermeasure to alleviate the deleterious effects of prolonged cold exposure on peripheral temperatures, thermal comfort, and hand function is unclear. Purpose: To evaluate the influence of eight consecutive cold air exposures on the thermal (TC and TSk), perceptual (thermal comfort and sensation), and functional (manual dexterity and strength) responses to cold air. We hypothesized that TSk would be higher and perceptual responses and manual dexterity improved, following repeated cold exposure. Methods: Eight young adults (6 M/1 F/1 FTM; 21 ± 2 years; %BF 24.5 ± 7.0) underwent a 2-h cold air exposure (8 °C, ~50% RH) on 8 consecutive days wearing minimal clothing. On Day 0 (baseline exposure ~1 week prior) and Days 1 and 8 of repeated exposure, TC was recorded continuously via a telemetry pill used as a rectal suppository. Extremity (Thand and Tfinger) and mean weighted TSk (MWTSk) from 8 skin sites were recorded continuously. Thermal comfort (TC) and thermal sensation (TS) were recorded at 20 min intervals. Expired gases were collected at 20 min intervals and used to calculate metabolic heat production (MHP). Manual dexterity was assessed using the Purdue Pegboard and Minnesota Manual Dexterity Test (MMDT), and hand strength were measured before and at the end of cold exposure. Results: TC changed across time ( p &lt; 0.05) but did not differ between days ( p &gt; 0.05). MWTSk, Thand, and Tfinger decreased across time ( p &lt; 0.05) but also did not differ between days ( p &gt; 0.05). Mean and minimum whole-body TS and TC were not different between days ( p &gt; 0.05). MHP increased across time ( p &lt; 0.05) but did not differ between days ( p &gt; 0.05). Purdue Pegboard, MMDT task performance, and hand strength did not differ between days ( p &gt; 0.05). Conclusion: Eight consecutive days of cold air exposure does not augment extremity skin temperature, thermal comfort, or manual performance during prolonged cold conditions. Supported by U.S. Army Medical Research and Development Command, Military Operational Medicine Research Program; author views not offcial US Army or DoD policy. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.