Journal of applied physiology最新文献

{"title":"Exercise during artificial gravity preserves cardiorespiratory fitness but not orthostatic tolerance following 60 days of head-down bed rest (BRACE).","authors":"Eric T Hedge, Carol G Bryans, Carmelo J Mastrandrea, Christoph Siebenmann, Alan R Hargens, Lars L Karlsson, Richard L Hughson, Dag Linnarsson","doi":"10.1152/japplphysiol.00224.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00224.2025","url":null,"abstract":"<p><p>Exercise is a critical countermeasure to prevent cardiovascular deconditioning during spaceflight; however, exercise does not protect astronauts from post-flight orthostatic intolerance. Artificial gravity (AG) by short-arm centrifugation can attenuate reductions in orthostatic tolerance following prolonged head-down bed rest (HDBR), but AG does not protect cardiorespiratory fitness. The European Space Agency hypothesized that exercise and AG countermeasures could be applied simultaneously to protect both cardiorespiratory fitness and orthostatic tolerance following prolonged HDBR. Twenty-four healthy men (age: 29±6 yr, peak oxygen uptake: 47.5±6.0 mL·min^-1·kg^-1) completed 60 days of HDBR and were randomized into either sedentary control (n=8), exercise (n=8), or exercise + AG (n=8) groups. Exercise participants performed 30 min of high-intensity interval cycling on 49 of 60 days during HDBR. The exercise + AG group performed the same 30-min exercise program while spinning supine in a short-arm centrifuge to generate a head-to-foot acceleration. Peak oxygen uptake (HDBR×group: <i>p</i><0.001) was reduced in the control group following HDBR (Δ=-24±5 %) but was protected by the exercise (Δ=0±6 %) and exercise + AG (Δ=4±6 %) countermeasures. Time to pre-syncope was reduced in all groups (control: Δ=-9.0±3.4 min, exercise: Δ=-12.4±5.2 min, exercise + AG: Δ=-4.5±8.8 min) following HDBR (main effect: <i>p</i><0.001). Activation of the muscle pump during exercise likely minimized the redistribution of blood volume into the legs and consequently, the simulated orthostatic stress experienced during centrifugation, preventing benefits of exercise + AG on orthostatic tolerance following HDBR. Therefore, AG by short-arm centrifugation should be implemented at rest or post-exercise to protect orthostatic tolerance.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145069633","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":"Central Command: The Navigator in the Storm of Autonomic Reflexes During Simulated Diving.","authors":"Alvaro Reischak-Oliveira","doi":"10.1152/japplphysiol.00733.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00733.2025","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145053561","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":"Agreement Between Mean Weighted Skin Temperature Formulas During Exercise.","authors":"Nathan E Bartman, Nicole E Moyen, Stephen S Cheung, Naoto Fujii, Tatsuro Amano, Toby Mündel","doi":"10.1152/japplphysiol.00445.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00445.2025","url":null,"abstract":"<p><p>There are many formulas to calculate mean weighted skin temperature (T_mws) with little evidence for their agreement with each other. This investigation assessed the agreement of five common T_mws formulas (≤7 sites) with a 12-site formula (Hardy-DuBois 12-site, HDB12). It was hypothesized that a formula with more measurement sites (Hardy-Dubois 7-site, HDB7) would have more agreement during steady-state exercise in moderate (20°C) and warm (30°C) conditions. Ten well-trained male participants (age: 37±12y, height: 178±7 cm, mass: 76±9 kg, body fat: 8±2%, VO2peak: 66±10 mL/kg/min) cycled at 55% of peak oxygen uptake for 60 minutes. The T_mws were calculated for HDB12, HDB7, Palmes/Park 6-site (PP6), Teichner 6-site (TEI6), Ramanathan 4-site (RAM4), and Burton 3-site (BTN3) formulas. Good agreement was determined when mean bias, mean absolute error (MAE), or root mean squared error (RMSE) was ≤0.5°C or limits of agreement (LOA) was ≤1.0°C. The T_mws formulas were in better agreement with HDB12 in warm compared to moderate conditions. The best performing formulas were RAM4, BRT3, and TEI6; mean bias was low in RAM4 (moderate: 0.2°C; warm: 0.1°C) and BRT3 (moderate: 0.1°C; warm:0.0°C) and RMSE was low in TEI6 (moderate: 0.6°C; warm: 0.4°C) compared to the others. The large deviation in torso skin temperature for HDB7 (moderate: -2.0°C; warm: -1.6°C) resulted in consistent underestimation of HDB12 (mean bias, moderate: -0.8°C; warm: -0.5°C). Due to its popularity the four-site RAM4 is acceptable for cycling in 20°C and 30°C conditions, when a 12-site formula is not feasible.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145053488","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":"Hypoxic ventilatory decline in young healthy adults persists during moderate-intensity exercise in isocapnic hypoxia.","authors":"Antonia N Berdeklis, Benjamin P Thompson, Paolo B Dominelli","doi":"10.1152/japplphysiol.00053.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00053.2025","url":null,"abstract":"<p><p>Hypoxic ventilatory decline (HVD) is part of the mammalian ventilatory response to hypoxia and is characterized by a decline in ventilation that begins after 3-5 mins of sustained, moderate hypoxia. Exercise is a powerful ventilatory stimulus that increases ventilation and chemosensor sensitivity. The extent to which these opposing ventilatory stimuli interact is not fully characterized. We compared the ventilatory response to moderate exercise during two conditions: during pre-established HVD and shortly after the onset of hypoxia but prior to the establishment of HVD. Eleven (N=6 males) young, healthy participants completed 3 testing visits. Day 1 was a maximal exercise test and Days 2 & 3 were randomized experimental visits separated by > 48 hrs. Each experimental visit began with a 5 minute normoxic baseline followed by 15 mins of rest and 15 mins of exercise at 30% of peak power. The experimental visits differed in that, during the 'sustained hypoxia' protocol (oxyhemoglobin saturation ~80%), hypoxia began at the start of rest, whereas in the 'acute hypoxia' protocol, hypoxia began 1 min before exercise. At the onset of exercise, ventilation was significantly lower in the sustained hypoxia protocol (-5.1 L min^-1) suggesting a persistent blunting of ventilation. At end exercise, ventilation was not different between protocols (51.2±11.6 vs 50.5±7.3 L min^-1, for sustained and acute hypoxia, respectively). The percent decline in ventilation (HVD) was greater during the sustained hypoxia (-23±13 vs. -14±9%, p=0.04). We conclude that HVD persists when acute exercise is imposed on sustained isocapnic hypoxia.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145053538","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":"Dietary nitrate supplementation suppresses sympathetic neural responses to mechanoreflex activation during static handgrip exercise in postmenopausal women.","authors":"Kazumasa Manabe, Jeung-Ki Yoo, Ryosuke Takeda, Takuro Washio, Qi Fu","doi":"10.1152/japplphysiol.00108.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00108.2025","url":null,"abstract":"<p><p>We investigated the impact of short-term dietary nitrate supplementation on sympathetic neural responses to isometric exercise in postmenopausal women. Ten healthy women aged 64±2 (SD) years participated in this randomized, placebo-controlled, double-blind, crossover study. All participants underwent two-week beetroot juice (BRJ: 800 mg nitrate/day) and placebo (nitrate-depleted BRJ) interventions with ≥14 days of wash-out. Before and after each intervention, participants performed static handgrip (SHG) at 40% of maximum voluntary contraction until fatigue, followed by 2-min post-exercise circulatory occlusion (PECO) with an upper-arm cuff inflated to 250 mmHg to isolate metaboreflex activation. Heart rate (HR; electrocardiogram), blood pressure (BP; finger photoplethysmography), and muscle sympathetic nerve activity (MSNA; microneurography) were continuously measured. BRJ increased the time to fatigue more than placebo (79±67 vs. 9±74 sec, p=0.03), which was correlated with decreases in MSNA burst frequency, total activity, and burst incidence at the first 30-sec of SHG when predominately mechanoreflex activation occurs (r=-0.65, -0.62, and -0.68, respectively, all p<0.05). However, BRJ did not alter MSNA responses to peak SHG and PECO. Subsequently, we added 4 postmenopausal women who finished the BRJ intervention only, and categorized all participants into early (n=6) and normal menopause (n=8). The early, but not normal, menopause group showed decreases in MSNA burst frequency and incidence at the first 30-sec of SHG after the BRJ intervention (both p<0.05). Collectively, nitrate supplementation prolonged the time to fatigue during SHG, and this prolongation was likely associated with attenuated sympathetic neural responses to mechanoreflex activation in postmenopausal women, especially those with early menopause.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145033293","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":"Vasoconstrictor responsiveness in resting and contracting skeletal muscle following an acute bout of exercise: Impact of aging.","authors":"DongNyeuck Seo, Jack E Shelley, Erika Iwamoto, Darren P Casey","doi":"10.1152/japplphysiol.00549.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00549.2025","url":null,"abstract":"<p><p>Long-term exercise training can attenuate sympathetic vasoconstriction in both resting and contracting skeletal muscle; however, the impact of an acute bout of exercise on vasoconstrictor responsiveness and the influence of aging is unknown. Therefore, we tested the hypothesis that an acute bout of exercise will blunt sympathetic-mediated vasoconstriction in resting and contracting skeletal muscle of young and older adults. Twenty-one adults (10 Young: 23±5 yr and 11 Older: 65±8 yr) performed a rest and a rhythmic handgrip exercise trial before and after either 30 minutes of cycling exercise (60-65% HRmax) or a time control period (seated rest). Lower body negative pressure (- 30mmHg) was applied during each trial to induce sympathetic-mediated vasoconstriction. Forearm blood flow (FBF; ml/min) was assessed via Doppler ultrasound and forearm vascular conductance (FVC; ml·min^-1·100 mmHg^-1) was calculated as the quotient of FBF and mean arterial pressure (mmHg). The acute bout of cycling exercise did not change vasoconstrictor responsiveness (% change FVC) in resting skeletal muscle in either age group (P>0.05). However, vasoconstrictor responsiveness was attenuated in contracting skeletal muscle following the acute bout cycling exercise in the group (-11.0 ± 5.7 to -8.2 ± 5.1%, P<0.001), as well as separated by age (Young: -6.7 ± 3.2 to -5.0 ± 4.0%, Older: -14.9 ± 4.6 to -11.0 ± 4.2%, P<0.01 for both). Our data indicate that an acute bout of exercise does not change vasoconstrictor responsiveness in resting skeletal muscle but enhances functional sympatholysis in young and older adults.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145029913","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":"Lung Volume Modulation of Sternohyoid Muscle Function: An Anesthetised Rat Model.","authors":"Charith Horadagoda, Christopher Lambeth, Kristina Kairaitis, Terence Amis","doi":"10.1152/japplphysiol.00280.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00280.2025","url":null,"abstract":"<p><p>Lung volume change modifies pharyngeal airway patency by altering breathing-related passive force transmission between lower and upper airways (via tracheal and other connections). We hypothesise that such force transmission may also impact active upper airway dilator muscle function by altering resting muscle length. The aim of this study was to determine the relationship between end expiratory lung volume (EELV) and ability of sternohyoid muscle (SH) contraction to alter pharyngeal airway patency. Eleven supine, anesthetized, spontaneously breathing Wistar rats with sealed snout mask to monitor airflow (<i>̇</i>) and mask pressure (P_M) were positioned in head-out plethysmograph (P_BOX). Graded changes in P_BOX (±8cmH₂O) were applied, tracheal pressure (P_tr), SH length (SHL) and tension (SHT_P) were monitored. Change in EELV (ΔEELV) and upper-airway resistance (R_UA-Passive) (%baseline) were calculated. Electrical stimulation of SH at each P_BOX was performed, and changes in SH tension (SHT_A) and R_UA (ΔR_UA= R_UA-Passive - R_UA-Active) calculated. Data were analysed using mixed-effects models. Increasing EELV increased SHL by 0.062 mm/ml (0.037 - 0.086) [mean(95%CI)], increased SHT_P by 5.42 mN/ml (3.96 - 6.87), and decreased R_UA-Passive by 4%/ml (1.1 - 7.4), while decreasing EELV decreased SHL by 0.31 mm/ml (0.14 - 0.49), SHT_P by 17.8 mN/ml (11.7 - 23.9), and increased R_UA-Passive by 132%/ml (95.6 - 168.3). Increasing EELV decreased SHT_A by 19.7%/ml (10.6 - 28.8) and ΔR_UA by 60.1%/ml (27.1 - 93.1), while decreasing EELV also decreased both SHT_A, by 57.5%/ml (31.4 - 84.2) and ΔR_UA by 139.0%/ml (46.8 - 231.2), (all p<0.05). Maximal SHT_A and ΔR_UA occurred at baseline EELV. We conclude that while shifts in EELV impact passive upper airway function, they also negatively impact active SH pharyngeal dilator function, potentially via generation of a sub-optimal resting SHL.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145029904","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":"Impact of intravenous iron or exogenous erythropoietin on hemoglobin mass, exercise performance, and acute mountain sickness during altitude acclimatization.","authors":"Karleigh E Bradbury, Elizabeth A Gideon, Marissa N Baranauskas, Aaron W Betts, Kyle A Davis, Kaitlyn G DiMarco, Colin D Hubbard, Tyler Kelly, Michael Thomas Miller, Morgan B Pendleton, Wade E Quilter, Jamie A Rhodine, Michael R Stephens, David J Lore, Joseph W Duke, Robert C Roach, Andrew W Subudhi","doi":"10.1152/japplphysiol.00076.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00076.2025","url":null,"abstract":"<p><p>Chronic exposure to high altitude leads to increases in hemoglobin mass (Hbmass), which may improve exercise performance and decrease acute mountain sickness (AMS) symptoms. We evaluated the influence of intravenous iron or erythropoietin (EPO) treatment on Hbmass, exercise performance, and AMS during a 14-day exposure to 3094 m. Thirty-nine participants (12F) completed the study conducted in Eugene, Oregon (sea level (SL), 130 m) and Leadville, Colorado (3094 m). Participants were dosed with either a placebo (saline; n = 13), iron (Fe(III)- hydroxide sucrose 200mg 2x; n = 14), or EPO (epoetin alpha 50 IU/kg 3x per week; n = 12) at SL for 4 weeks. Hbmass, exercise performance, and AMS symptoms were measured at SL prior to treatment and on days 1, 2, 7, 13 and 14 at altitude. Absolute Hbmass (g) increased from SL and day 1 to day 13 (p < 0.0001) with no differences between treatment groups (p = 0.3868). 5 km run times were slower at altitude compared to SL (p < 0.0001) and did not improve over the 14-day period at altitude for any group (p > 0.05). Hike times improved with acclimatization from day 2 to day 14 (p = 0.0018) in all groups, independent of treatment. The incidence and severity of AMS remained low across all participants and time points, regardless of treatment. In the current study and dosing, intravenous iron and EPO did not lead to improvements in Hbmass, exercise performance, or AMS with rapid ascent and residence at 3100 m.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145006122","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":"Muscle metaboreflex activation via post-exercise ischemia increases intercostal muscle blood flow index without evidence of local vasoconstriction in humans.","authors":"Masashi Ichinose, Mikie Nakabayashi, Yumie Ono","doi":"10.1152/japplphysiol.00577.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00577.2025","url":null,"abstract":"<p><p>Muscle metaboreflex is activated in limb skeletal muscles during high-intensity exercise that increases respiratory demand, but its effects on respiratory muscle blood flow remain unknown. Therefore, we investigated whether metaboreflex activation in the forearm alters blood flow in the intercostal muscles. Sixteen healthy young male subjects performed isometric handgrip at 30% of maximal voluntary contraction for 2 minutes, followed by either post-exercise muscle ischemia (PEMI; metaboreflex activation condition) or a control recovery. Respiratory variables were controlled post-exercise to match baseline levels. Microvascular blood flow index (BFI) in the left intercostal muscles was monitored using diffuse correlation spectroscopy (DCS), and cardiovascular variables were recorded. To reduce respiratory motion artifacts, BFI and vascular resistance index (VRI) were analyzed during breath-holding periods. During PEMI, both mean arterial pressure (MAP) and BFI were significantly elevated compared to rest [medians (IQRs), MAP: 92.1 (84.4-94.4) vs. 110.2 (102.4-116.4) mmHg, p < 0.001; BFI: 3.5 (2.8-4.9) vs. 4.2 (3.8-6.4) ×10⁻⁹ cm²·s⁻¹, p = 0.002] and higher than in the control condition [MAP: 91.0 (89.4- 101.7) vs. 110.2 (102.4-116.4) mmHg, p < 0.001; BFI: 3.3 (2.5-4.5) vs. 4.2 (3.8-6.4) ×10⁻⁹ cm²·s⁻¹, p < 0.001], whereas VRI remained unchanged [23.4 (19.0-29.9) vs. 23.2 (17.4-30.4) mmHg·(×10⁻⁹ cm²·s⁻¹)⁻¹, p = 0.375]. These findings suggest that muscle metaboreflex activation enhances intercostal muscle BFI via a pressor response without evidence of significant local vasoconstriction. This study demonstrates reflex-mediated increases in intercostal muscle BFI and highlights the role of the metaboreflex in supporting ventilation.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145006163","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":"The sense and control of standing balance in the presence of motor noise.","authors":"Lucas Mensink, Amin M Nasrabadi, Brandon G Rasman, Jean-Sébastien Blouin, Patrick A Forbes","doi":"10.1152/japplphysiol.00325.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00325.2025","url":null,"abstract":"<p><p>This study aimed to characterize motor noise in human standing balance and uncover mechanisms that enable the nervous system to robustly sense and control upright posture despite this variability. We conducted three experiments using a robotic balance simulator. First, we quantified the natural variability of ankle torques, revealing that torque variability was stable within preferred postures and increased only at more extreme orientations. The range of constant variability may be explained by passive mechanisms that contribute to plantarflexion torque along with the bilinear scaling of motor noise with torque. Together, these factors help maintain stable motor variability, despite the substantial increase (6% of <i>mgL</i>) in gravitational torque load. Second, we investigated perceptual thresholds for detecting the sensory consequences of artificially imposed torque noise, designed to replicate and amplify the variability of ankle torque during quiet standing. Participants detected the consequences of imposed torque when it exceeded ~50% of baseline torque variability, which was accompanied by a two-fold increase in whole-body angular velocity variability. Third, we assessed the impact of artificially imposed torque noise on the vestibular control of balance. We found that the threshold for generating corrective responses remained unchanged, as increased variability in balance-correcting responses was accompanied by proportional increases in vestibulomotor gain. Collectively, these findings reveal that the nervous system accommodates motor noise by leveraging passive stiffness and the minimal scaling of motor noise at ankle torques near preferred postures, while also engaging robust error correction mechanisms - such as increased vestibulomotor gain - that operate outside conscious awareness.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145000605","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}