Journal of applied physiology最新文献

{"title":"The Extraction Of Neural Strategies From The Surface Emg: 2004-2024.","authors":"Dario Farina, Roberto Merletti, Roger M Enoka","doi":"10.1152/japplphysiol.00453.2024","DOIUrl":"https://doi.org/10.1152/japplphysiol.00453.2024","url":null,"abstract":"<p><p>This review follows two previous papers (Farina <i>et al</i>., 2004, 2014) in which we reflected on the use of surface EMG in the study of the neural control of movement. This series of papers began with an analysis of the indirect approaches of EMG processing to infer the neural control strategies and then closely followed the progress in EMG technology. In this third paper, we focus on three main areas: surface EMG modelling; surface EMG processing, with an emphasis on decomposition; and interfacing applications of surface EMG recordings. We highlight the latest advances in EMG models that allow fast generation of simulated signals from realistic volume conductors, with applications ranging from validation of algorithms to identification of non-measurable parameters by inverse modelling. Surface EMG decomposition is currently an established state-of-the-art tool for physiological investigations of motor units. It is now possible to identify large samples of motor units, to track motor units over multiple sessions, to partially compensate for the non-stationarities in dynamic contractions, and to decompose signals in real-time. The latter achievement has facilitated advances in myocontrol, by using the online decoded neural drive as a control signal, such as in the interfacing of prostheses. Looking back over the 20 years since our first review, we conclude that the recording and analysis of surface EMG signals has seen breakthrough advances in this period. Although challenges in its application and interpretation remain, surface EMG is now a solid and unique tool for the study of the neural control of movement.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142687153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying the Time-course of Changes in Maximal Skin Wettedness with 7 days of Heat Acclimation.","authors":"Grant P Lynch, Yorgi Mavros, Ollie Jay","doi":"10.1152/japplphysiol.00919.2023","DOIUrl":"10.1152/japplphysiol.00919.2023","url":null,"abstract":"<p><p>The aim of the present study was to quantify the time-course of changes in maximum skin wettedness (ω_max) - i.e., the proportion of skin surface area covered in sweat at the point of uncompensable heat stress, throughout 7 consecutive days of heat acclimation. Nine adults (6M, 3F) completed a humidity-ramp protocol (RAMP) on days 1, 3, 5 and 7 of seven consecutive days of heat acclimation. In each RAMP trial, participants cycled continuously at 275 W·m^-2 for 120 min at 37°C: 60-min at a vapour pressure of 2.05 kPa followed by 60-min with vapour pressure increased by 0.045 kPa·min^-1. An upward inflection in esophageal temperature (T_eso) signaled a transition to uncompensable heat stress with the critical water vapour pressure at that point used to calculate ω_max. In days between RAMP assessments participants cycled for 90-min at 75% HRmax at 37°C, 60% RH. T_eso, whole-body sweat rate (WBSR), local sweat rate (LSR_back, LSR_arm) and activated sweat gland density (AGSD) were measured throughout. ω_max was progressively and significantly greater from Day 1 (0.68±0.10) to Day 3 (0.75±0.10;P=0.002), to Day 5 (0.79±0.10;P=0.004), to Day 7 (0.87±0.06;P=0.009). WBSR was higher on Day 5 (1.11±0.30 L·h^-1;P=0.01) and Day 7 (1.12±0.19 L·h^-1;P<0.001) compared to Day 1 (0.94±0.21 L·h^-1). ASGD was higher on Day 5 (78±15 glands·cm^-2;P<0.001), and Day 7 (81±17 glands·cm^-2;P=0.001) compared to Day 1 (65±12 glands·cm^-2). There were no observed differences in sweat gland output (P=0.21). In conclusion, ω_max significantly increased throughout 7 days of heat acclimation. These progressive increases in ω_max were predominantly mediated by an increase in the number of active sweat glands, not the output per gland.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142667989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Greater lactate accumulation does not alter peripheral concentrations of key appetite-regulating neuropeptides.","authors":"Seth F McCarthy, Derek P D Bornath, Jessica A L Tucker, Tamara R Cohen, Philip J Medeiros, Tom J Hazell","doi":"10.1152/japplphysiol.00559.2024","DOIUrl":"10.1152/japplphysiol.00559.2024","url":null,"abstract":"<p><p>The potential mechanisms involved in lactate's role in exercise-induced appetite suppression require further examination. We used sodium bicarbonate (NaHCO₃) supplementation in a double-blind, placebo-controlled, randomized crossover design to explore lactate's role on neuropeptide Y (NPY), agouti-related peptide (AgRP), and alpha-melanocyte-stimulating hormone (α-MSH) concentrations. Twelve adults (7 males; 24.2 ± 3.4 kg·m^-2; 42.18 ± 8.56 mL·kg^-1·min^-1) completed two identical high-intensity interval training sessions following ingestion of NaHCO₃ (BICARB) or sodium chloride (PLACEBO) pre-exercise. Blood lactate, acylated ghrelin, NPY, AgRP, α-MSH, and appetite perceptions were measured pre-exercise, 0-, 30-, 60-, and 90-min postexercise. Free-living energy intake (electronic food diaries) was measured the day before, of, and after each experimental session. In BICARB, blood lactate was greater postexercise (<i>P</i> < 0.002, <i>d</i> > 0.70), though acylated ghrelin was similar (<i>P</i> = 0.075, [Formula: see text] = 0.206) at all time points postexercise (<i>P</i> > 0.034, <i>d</i> < 0.22). NPY (<i>P</i> = 0.006, [Formula: see text] > 0.509) and AgRP (<i>P</i> < 0.001, [Formula: see text] > 0.488) had main effects of time increasing following exercise and returning to baseline, with no differences between sessions (NPY: <i>P</i> = 0.0.192, [Formula: see text] = 0.149; AgRP: <i>P</i> = 0.422, [Formula: see text] = 0.060). α-MSH had no main effect of time (<i>P</i> = 0.573, [Formula: see text] = 0.063) or session (<i>P</i> = 0.269, [Formula: see text] = 0.110). Appetite perceptions were similar during BICARB and PLACEBO (<i>P</i> = 0.007, <i>d</i> = 0.28), increasing in both sessions postexercise (<i>P</i> < 0.088, <i>d</i> > 0.57). Energy intake had a main effect of day (<i>P</i> = 0.025, [Formula: see text] = 0.825), where the experimental session day was greater than the day before (<i>P</i> = 0.010, <i>d</i> = 0.59) with no other differences between days (<i>P</i> > 0.260, <i>d</i> < 0.38). The lower accumulation of lactate than our previous work did not generate exercise-induced appetite suppression as there were no differences in acylated ghrelin, appetite perceptions, or peripheral concentrations of neuropeptides.<b>NEW & NOTEWORTHY</b> Current evidence supports lactate's role in exercise-induced appetite suppression. Here, we demonstrate a smaller degree of lactate accumulation with sodium bicarbonate ingestion and HIIT than our previous work and no subsequent suppression of acylated ghrelin concentrations, subjective appetite perceptions, or peripheral concentrations of neuropeptides. These results suggest either changes in central appetite-regulating neuropeptides are not reflected peripherally or the smaller magnitude of lactate accumulation did not generate exercise-induced appetite suppression as seen previously.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1397-1408"},"PeriodicalIF":3.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142365351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Skin heating during simulated hemorrhage lowers arterial blood pressure but not tolerance following exercise in a cold environment.","authors":"Phillip Tracy, Joel Hill, Jai Liester, Kevin Sullivan, James Pearson","doi":"10.1152/japplphysiol.00560.2024","DOIUrl":"10.1152/japplphysiol.00560.2024","url":null,"abstract":"<p><p>Skin heating helps avoid hypothermia in trauma victims but may influence the systolic (SBP) and mean arterial blood pressures (MAP) helping to guide resuscitation. We examined the effect of skin heating on tolerance and arterial blood pressure during lower body negative pressure (LBNP) across four trials. Nine participants completed 15 exercise intervals [60 s 88% peak power output (PPO) and 60 s 10% PPO] in a cold environment (0°C, 70% RH) lowering mean skin temperature (Tsk) before undergoing LBNP to pre syncope where Tsk remained low (Cold Trial: 27.6 ± 1.1°C) or was increased via a water-perfused suit 60 s into LBNP to 32.3 ± 0.7°C (Normothermic Trial), 34.8 ± 0.4°C (Warm Trial), or 36.1 ± 0.8°C (Hot Trial). Tsk was different between trials (<i>P</i> = 0.001). Core temperature was not different between trials, increasing with exercise (36.9 ± 0.3°C to 37.9 ± 0.4°C) and remaining elevated during LBNP (37.7 ± 0.4°C). During LBNP, MAP was greatest in the Cold Trial (88 ± 7 mmHg) and relatively lowered in the Normothermic (83 ± 5 mmHg), Warm (82 ± 5 mmHg), and Hot Trials (79 ± 7 mmHg; all <i>P</i> ≤ 0.017 vs. Cold). SBP was greatest in the Cold (111 ± 9 mmHg) and Normothermic Trials (110 ± 10 mmHg) and relatively lowered in the Warm (105 ± 7 mmHg) and Hot Trials (103 ± 11 mmHg; both <i>P</i> ≤ 0.037). LBNP tolerance was not different between trials (<i>P</i> = 0.746). Following exercise in a cold environment, skin heating during simulated hemorrhage lowers arterial blood pressures and has implications for prehospital care of trauma victims.<b>NEW & NOTEWORTHY</b> Skin heating helps avoid hypothermia in trauma victims but may influence arterial blood pressures, thus helping to guide resuscitation depending on the type of injury. Following exercise in a cold environment, arterial blood pressure was elevated during LBNP with cold skin but lowered with skin heating without changing LBNP tolerance. These findings are important for understanding the effect of skin heating on arterial blood pressure control in the prehospital and combat casualty care of trauma victims.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1313-1323"},"PeriodicalIF":3.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142287958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Breakfast skipping suppresses the vascular endothelial function of the brachial artery after lunch.","authors":"Hideaki Kashima, Natsuki Seo, Masako Yamaoka Endo, Masako Kanda, Kohei Miura, Naomi Kashima, Akira Miura, Yoshiyuki Fukuba","doi":"10.1152/japplphysiol.00681.2023","DOIUrl":"10.1152/japplphysiol.00681.2023","url":null,"abstract":"<p><p>Breakfast skipping has been suggested to be associated with cardiovascular diseases. However, whether breakfast skipping affects vascular endothelial function (VEF), a marker of cardiovascular diseases, remains unclear. This study aimed to investigate the impact of breakfast consumption (Eating trial) and skipping (Skipping trial) on brachial artery (BA) VEF in healthy breakfast eaters. A total of nine healthy individuals (4 females and 5 males) either had breakfast between 830 and 900 or skipped it and had lunch between 1200 and 1230, followed by a 3-h rest period until 1530. For BA VEF evaluation, flow-mediated dilation (FMD) was measured by ultrasound before and after breakfast and lunch. FMD was calculated as the percent change in BA diameter normalized to the shear rate area under the curve (FMD/SR_AUC). Blood glucose, plasma insulin, and plasma free fatty acid levels in capillaries were measured before and after breakfast and lunch. At 1530, the Eating trial, but not the Skipping trial, significantly increased FMD/SR_AUC from baseline (<i>P</i> = 0.006). The Skipping trial showed significantly lower changes in FMD/SR_AUC from 830 than the Eating trial at 1530 (<i>P</i> < 0.001). We found a significant inverse correlation between changes in FMD/SR_AUC between 830 and 1530 and peak glucose levels after lunch (<i>r</i> = -0.882, <i>P</i> < 0.001) and with an incremental area under the curve for glucose between 830 and 1530 (<i>r</i> = -0.668, <i>P</i> < 0.001). These results suggest that a single bout of breakfast skipping can suppress BA VEF in the afternoon because of postlunch hyperglycemia.<b>NEW & NOTEWORTHY</b> Skipping breakfast does not affect vascular endothelial function (VEF) before lunch. However, after lunch on normal meals (i.e., not oral glucose tolerance test), VEF was found to be lower in those who skipped breakfast than those who ate breakfast. Such reduced postlunch VEF after skipping breakfast was associated with postprandial hyperglycemia. These results provide important insight into the impact of eating breakfast on VEF and glycemic control in healthy adults.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1267-1278"},"PeriodicalIF":3.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142287938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exogenous ketosis attenuates acute mountain sickness and mitigates normobaric high-altitude hypoxemia.","authors":"Myrthe Stalmans, Domen Tominec, Wout Lauriks, Ruben Robberechts, Tadej Debevec, Chiel Poffé","doi":"10.1152/japplphysiol.00190.2024","DOIUrl":"10.1152/japplphysiol.00190.2024","url":null,"abstract":"<p><p>Acute mountain sickness (AMS) represents a considerable issue for individuals sojourning to high altitudes with systemic hypoxemia known to be intimately involved in its development. Based on recent evidence that ketone ester (KE) intake attenuates hypoxemia, we investigated whether exogenous ketosis might mitigate AMS development and identified underlying physiological mechanisms. Fourteen healthy, male participants were enrolled in two 29-h protocols (simulated altitude of 4,000-4,500 m) receiving either KE or a placebo (CON) at regular timepoints throughout the protocol in a randomized, crossover manner. Physiological responses were characterized after 15 min and 4 h in hypoxia, and the protocol was terminated prematurely upon development of severe AMS (Lake Louise Score ≥ 10). KE ingestion induced a consistent diurnal ketosis (d-β-hydroxybutyrate, [βHB] of ∼3 mM), whereas blood [βHB] remained low (<0.6 mM) in CON. Each participant tolerated the protocol equally long or longer (<i>n</i> = 6 or <i>n</i> = 8, respectively) in KE. Protocol duration increased by 32% on average with KE, and doubled upon KE for severe AMS-developing participants (<i>n</i> = 9). Relative to CON, KE induced a mild metabolic acidosis, hyperventilation, and relative sympathetic dominance. KE also inhibited the progressive hypoxemia that was observed between 15 min and 4 h in hypoxia in CON, while concomitantly increasing cerebral oxygenation and capillary Po₂ within this timeframe despite a KE-induced reduction in cerebral oxygen supply. These data indicate that exogenous ketosis attenuates AMS development. The key underlying mechanisms include improved arterial and cerebral oxygenation, in combination with lowered cerebral blood flow and oxygen delivery, and increased sympathetic dominance.<b>NEW & NOTEWORTHY</b> Ketone ester intake attenuated the development of acute mountain sickness at a simulated altitude of 4,000-4,500 m. This likely resulted from a mitigation of arterial and cerebral hypoxemia, reduced cerebral blood flow, and increased sympathetic drive.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1301-1312"},"PeriodicalIF":3.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142347217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbon monoxide supplementation: evaluating its potential to enhance altitude training effects and cycling performance in elite athletes.","authors":"Tomas Urianstad, Simone Villanova, Ingvill Odden, Joar Hansen, Knut S Mølmen, Simone Porcelli, Bent R Rønnestad, Daniele A Cardinale","doi":"10.1152/japplphysiol.00469.2024","DOIUrl":"10.1152/japplphysiol.00469.2024","url":null,"abstract":"<p><p>Altitude training is a cornerstone for endurance athletes for improving blood variables and performance, with optimal effects observed at ∼2,300-2,500 meters above sea level (m.a.s.l.). However, elite cyclists face challenges such as limited access to such altitudes, inadequate training facilities, and high expenses. To address these issues, a novel method involving daily exposure to carbon monoxide (CO) has been proposed to amplify altitude training adaptations at suboptimal altitudes. Thirty-one male cyclists were assigned to three groups: Live-High Train-High with CO inhalation (LHTH_CO), Live-High Train-High (LHTH), and Live-Low Train-Low (LLTL). The LHTH_CO group underwent CO inhalation twice daily in the afternoon/evening to elevate carboxyhemoglobin concentration to ∼10%. Hematological variables, in vivo muscle oxidative capacity, and physiological indicators of cycling performance were assessed before and after a 3-week altitude training camp at 2,100 m.a.s.l. LHTH_CO demonstrated a larger increase in hemoglobin mass (Hb_mass) compared to both LHTH and LLTL. Although there were no statistical differences between LHTH_CO and LHTH in submaximal and maximal performance measures, LHTH_CO displayed greater improvements in 1-min maximal power output during incremental testing (W_max), power output at lactate threshold, and maximal oxygen consumption (V̇o_2max) compared to LLTL. LHTH demonstrated a larger improvement than LLTL in W_max and V̇o_2max, with no group differences in Hb_mass or submaximal measures. Muscle oxidative capacity did not differ between groups. These findings suggest that combining moderate-altitude training with daily CO inhalation promotes hematological adaptations more effectively than moderate altitude alone and enhances cycling performance metrics in cyclists more than sea-level training.<b>NEW & NOTEWORTHY</b> Three weeks of training at moderate altitude with exposure to low doses of CO can significantly enhance hematological adaptations in elite cyclists compared to moderate-altitude training alone. Cycling performance determinants improved more with CO inhalation at moderate altitude compared to sea-level training, whereas there were no differences in submaximal and maximal performance measures compared to moderate-altitude training alone. This study highlights the potential of CO supplementation as an effective adjunct to altitude training regimens.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1092-1105"},"PeriodicalIF":3.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142140196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differences in cardiorespiratory fitness by gonadotropin-releasing hormone agonist treatment before and after testosterone in transgender adolescents.","authors":"Natalie J Nokoff, Travis Nemkov, Samantha Bothwell, Melanie G Cree, Kelly N Z Fuller, Amy C Keller, Megan M Kelsey, Kristen J Nadeau, Kerrie L Moreau","doi":"10.1152/japplphysiol.00629.2024","DOIUrl":"10.1152/japplphysiol.00629.2024","url":null,"abstract":"<p><p>There are known sex differences in cardiorespiratory fitness (CRF). Little is known about the impact of pubertal blockade with a gonadotropin-releasing hormone agonist (GnRHa) followed by hormone therapy on CRF for transgender adolescents. We aimed to <i>1</i>) determine the effect of GnRHa monotherapy on CRF and mitochondrial function and associations with metabolomic profiles and <i>2</i>) evaluate changes after 1 and 12 mo of testosterone therapy among transgender adolescents. Participants assigned female at birth (<i>n</i> = 19, baseline age of 15.0 ± 1.0 yr) from two groups: GnRHa⁺ (<i>n</i> = 8) and GnRHa^- (<i>n</i> = 11) were examined at baseline and 1- and 12-mo post-testosterone therapy in a longitudinal observational study to assess cardiorespiratory fitness, mitochondrial respiration, and metabolic profile. Fasted morning labs included assessment of metabolomics and peripheral blood mononuclear cell mitochondrial respiration and degree of mitochondrial coupling (respiratory control ratio, RCR). A graded cycle ergometer test was performed. Baseline differences were evaluated between groups. Changes were compared with mixed linear regression models evaluating time (baseline, 1 mo, and 12 mo), group (GnRHa treatment yes/no), and their interaction. At baseline GnRHa⁺ individuals had higher relative V̇o_2peak (30.1 ± 4.83 vs. 25.24 ± 4.47 mL/kg/min, <i>P</i> = 0.042) than GnRHa^- individuals. In regression models, GnRHa⁺ individuals had a significant increase in peak watts (<i>P</i> = 0.011) and total exercise time (<i>P</i> = 0.005) after 12 mo of testosterone (<i>P</i> = 0.012) but not GnRHa^- individuals. GnRHa⁺ individuals have significantly higher RCR under carbohydrate (<i>P</i> = 0.0007) and lipid (<i>P</i> = 0.0002) conditions than GnRHa⁺ individuals. Pretreatment with GnRHa positively influences peak CRF and mitochondrial respiration in adolescent transgender males undergoing testosterone therapy.<b>NEW & NOTEWORTHY</b> This study demonstrates differences in exercise capacity and mitochondrial respiration at baseline based on whether or not individuals had feminizing puberty blocked. Individuals who had puberty blocked had greater improvements in cardiopulmonary exercise testing parameters after 12 mo of testosterone than those who went through feminizing puberty.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1470-1483"},"PeriodicalIF":3.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11573275/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142466232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ankle torque variance is a better indicator of balance control performance than plantar perceptual sensitivity threshold.","authors":"Frederic J F Viseux, Maxime Billot, Grant Handrigan, Martin Simoneau","doi":"10.1152/japplphysiol.00091.2024","DOIUrl":"10.1152/japplphysiol.00091.2024","url":null,"abstract":"<p><p>We explored whether ankle torque variability or plantar perceptual threshold explains human balance control more effectively. We hypothesized that ankle torque variance is a better indicator of center of pressure (COP) velocity variance than plantar perceptual sensitivity. Two conditions were tested: loaded (23-kg vest added) and unloaded, as loading should diminish plantar sensitivity and increase COP velocity variability. We created a linear feedback model to assess the noise change in the sensorimotor loop induced by loading. Plantar sensitivity was quantified using a psychophysical approach while participants stood barefoot. A linear motor applied a force impulse on the participant's heel. A \"yes-no\" method of limits was selected to identify plantar sole sensory thresholds in both conditions. We observed reduced plantar sensitivity in loaded compared with unloaded conditions. In the loaded condition, participants exhibited greater COP velocity variance, with significant positive Pearson's correlations confirming a substantial association between ankle torque and COP velocity variances for both loaded [variance accounted for (VAF): <i>r</i>² = 44.56%, <i>P</i> = 0.018] and unloaded conditions (VAF: <i>r</i>² = 58.83%, <i>P</i> = 0.004). No significant correlation existed between COP velocity variance and plantar sensitivity threshold for both loaded (VAF: <i>r</i>² = 0.002%, <i>P</i> = 0.99) and unloaded conditions (VAF: <i>r</i>² = 21.81%, <i>P</i> = 0.35). The model confirmed an ∼88% rise in sensorimotor loop noise in the loaded condition. Ankle torque variance assesses the precision of nonperceptual and perceptual detection mechanisms in evaluating whole body motions and the accuracy in converting sensory cues into ankle torque.<b>NEW & NOTEWORTHY</b> Plantar cutaneous information contributes to balance control by modulating motor commands, but plantar perceptual sensitivity is a suboptimal indicator of balance performance. Multiple sensory cues encode whole body dynamics, guiding sensorimotor mechanisms to minimize body sway variability. Ankle torque variance is proposed as a superior measure for explaining balance control performance and evaluating the sensorimotor loop's functioning in balance control.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1082-1091"},"PeriodicalIF":3.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142140195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Implementing the cold pressor test in cardiovascular research: Does limb choice matter?","authors":"Yasmine Coovadia, Charlotte W Usselman","doi":"10.1152/japplphysiol.00658.2024","DOIUrl":"10.1152/japplphysiol.00658.2024","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1194-1195"},"PeriodicalIF":3.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142347218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}