Journal of applied physiology最新文献

{"title":"Propulsion without penalty: greater soleus force with stiffer footwear does not necessarily increase estimated soleus metabolic cost across walking speeds.","authors":"Daniel J Davis, Samuel F Ray, Jason R Franz, Kota Z Takahashi","doi":"10.1152/japplphysiol.00045.2025","DOIUrl":"10.1152/japplphysiol.00045.2025","url":null,"abstract":"<p><p>Numerous assistive devices have been designed to improve mobility by improving propulsion and reducing the metabolic cost of walking. Stiff carbon fiber insoles integrated into footwear have emerged as a potentially viable option by increasing longitudinal bending stiffness, providing additional leverage for the ankle joint musculature, and increasing soleus force output. However, it remains unknown whether this increased leverage comes with a metabolic penalty at the individual muscle level, which would create a translational barrier for prescribing carbon fiber insoles as targeted interventions. We incorporated motion capture, cine B-mode ultrasound, and electromyography data (<i>n</i> = 14) into a bioenergetic model to estimate soleus metabolic cost. Participants walked on an instrumented treadmill at 1.25, 1.75, and 2.0 m/s wearing standardized shoes containing either no carbon fiber insole (low stiffness), a 1.6-mm-thick insole (medium stiffness), or a 3.2-mm-thick insole (high stiffness). We found a significant main effect (<i>P</i> < 0.001) of walking speed, but not stiffness, for estimated soleus average metabolic power. These results indicate that increases in soleus force output while walking due to increased footwear bending stiffness do not statistically significantly alter muscle-specific metabolic cost, likely due to concomitant reductions in fascicle shortening velocity. As such, carbon fiber insoles may be a particularly useful assistive device for walking in those with ankle plantarflexion deficits.<b>NEW & NOTEWORTHY</b> Increasing footwear bending stiffness via carbon fiber insoles has been shown to reduce soleus fascicle shortening velocity and increase force output. Here, we used a bioenergetic model to estimate the metabolic energy consumed by the soleus muscle with increasing footwear stiffness across walking speeds. Footwear stiffness did not statistically significantly alter estimated soleus muscle energy consumption at any speed, highlighting carbon fiber insoles' capacity to increase muscle force without a clear metabolic penalty.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"509-516"},"PeriodicalIF":3.3,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12396604/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144659324","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":"Learning lessons from the world's best middle-distance runner.","authors":"Mark Burnley","doi":"10.1152/japplphysiol.00395.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00395.2025","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":"139 1","pages":"254"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144608422","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":"Effects of analgesic doses of opioids on cardiorespiratory responses and survival to hemorrhage and trauma in rats.","authors":"Stephanie M Marshall-Lipiec, Kathy L Ryan, Mariam L Calderon, Cassandra M Rodriguez, Brian S Connor, Carmen Hinojosa-Laborde, Harold G Klemcke","doi":"10.1152/japplphysiol.00708.2024","DOIUrl":"10.1152/japplphysiol.00708.2024","url":null,"abstract":"<p><p>Opioids are used for analgesia, but questions persist about their safety after traumatic hemorrhage. We investigated analgesic doses of three opioids (morphine, fentanyl, and sufentanil) on cardiorespiratory responses and survival to moderate or severe (37% or 50% blood volume) hemorrhage after trauma. A conscious hemorrhage model with extremity trauma (fibular fracture + soft tissue injury) was used; mean arterial pressure (MAP) and heart rate (HR) were measured by telemetry, whereas minute volume (MV) was determined by whole body plethysmography. Male rats (<i>n</i> = 10/group) received saline, morphine (2 mg/kg), fentanyl (10 µg/kg), or sufentanil (1 µg/kg) after traumatic hemorrhage. Neither survival times (for 37% hemorrhage: <i>P</i> = 0.209; for 50% hemorrhage: <i>P</i> = 0.88) nor survival percentages (for 37% hemorrhage: <i>P</i> = 0.357; for 50% hemorrhage: <i>P</i> = 1.0) differed among groups. For 37% hemorrhage, MAP of all opioid groups was higher than that in the saline-treated group 10 min post injection. By 75 min post injection, MAP after sufentanil was higher than saline; MAP for other opioids did not differ from saline. HR did not differ across treatments. Opioid injection decreased MV within 10 min but did not vary by treatment subsequently. For 50% hemorrhage, opioid injection did not immediately alter MAP but morphine and sufentanil were lower than saline at ≥75 min post injection, with no treatment effects on HR. Fentanyl produced an immediate (5 min) decrease in MV with no treatment effects thereafter. Opioid effects on cardiorespiratory function were therefore modest and did not alter survival during a 4-h observation period, supporting the judicious use of analgesic doses after traumatic hemorrhage.<b>NEW & NOTEWORTHY</b> Administration of an analgesic dose of either morphine, fentanyl, or sufentanil produced only modest and transient effects on cardiorespiratory function after either moderate (37% blood volume) or severe (50%) hemorrhage in conscious rats with extremity trauma. Under the conditions of these experiments, analgesic doses of these commonly used opioids also did not alter survival after traumatic hemorrhage.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"145-161"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143648592","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":"Corrigendum for Ortiz de Zevallos et al., volume 137, 2024, p. 1649-1658.","authors":"","doi":"10.1152/japplphysiol.00321.2024_COR","DOIUrl":"https://doi.org/10.1152/japplphysiol.00321.2024_COR","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":"139 1","pages":"164-166"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144528128","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":"Human skeletal muscle-specific hypertrophy with exercise training and aging: a comprehensive review.","authors":"Caroline S Vincenty, Gilhyeon Yoon, Kaitlyn Rogers, Masatoshi Naruse, Scott Trappe, Todd A Trappe","doi":"10.1152/japplphysiol.00892.2024","DOIUrl":"10.1152/japplphysiol.00892.2024","url":null,"abstract":"<p><p>Age-related skeletal muscle atrophy is a muscle group-specific process. Therefore, we were interested in understanding exercise-induced hypertrophy across different muscles in older individuals. This review provides a comprehensive summary of the available information on muscle-specific hypertrophy responses to exercise training with aging (≥60 yr). In total, 6,018 peer-reviewed publications were reviewed for inclusion [e.g., supervised resistance (RE) or aerobic (AE) exercise training; MRI, CT, or ultrasound-determined muscle size], resulting in 1,417 individuals from 68 studies (RE: <i>n</i> = 1,254; AE: <i>n</i> = 163). Data were divided across age (60-69, 70-79, 80-89, and ≥90 yr) and duration (≤9, 10-14, 15-19, 20-24, and ≥25 wk), with the majority coming from the sexa- and septuagenarians (<i>n</i> = 1,335, 94%) and 10-14 wk of training (<i>n</i> = 806, 57%). The number of muscle groups (RE: 7, AE: 8) and subcomponent muscles (RE: 10, AE: 16) was a low representation of the whole body musculature, with 79% of the data (<i>n</i> = 1,113) coming from the quadriceps. The 10-14 wk responses showed a range of unique muscle-specific hypertrophy and atrophy (RE: 60-69 yr: 2%-14% across 6 muscles; 70-79 yr: 1%-12% across 9 muscles; AE: 70-79 yr: -6% to +9% across 22 muscles). The large quadriceps-only resistance exercise training dataset (60-79 yr) showed that no additional hypertrophy was observed with increased training repetitions (i.e., dose) and that men and women elicited an equivalent hypertrophic training response. The optimal exercise training mode(s) and dose(s) for all of the skeletal muscles of sexa-, septa-, octo-, and nonagenarian women and men are far from being elucidated based on the current scientific literature.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"58-69"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12188863/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144127740","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":"Durability, Fatigability, Repeatability and Resilience in Endurance Sports: Definitions, Distinctions, and Implications.","authors":"Benedikt Meixner, Michael J Joyner, Billy Sperlich","doi":"10.1152/japplphysiol.00343.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00343.2025","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144540272","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":"Effects of exercise on peripheral hypercapnic chemosensitivity during high altitude acclimatization.","authors":"Jou-Chung Chang, Leah M Mann, Katherine M Taylor, Benjamin P Thompson, Scott T Thrall, Megan L Lance, Richard J A Wilson, Trevor A Day, Glen E Foster, Paolo B Dominelli","doi":"10.1152/japplphysiol.00283.2025","DOIUrl":"10.1152/japplphysiol.00283.2025","url":null,"abstract":"<p><p>Hypercapnic sensitivity of the peripheral chemoreceptors can be enhanced by sustained exposure to high altitude (HA), leading to a greater ventilatory response to hypercapnic stimulus. Exercise is known to also increase peripheral hypercapnic chemosensitivity (PHC) in an intensity-independent manner. We sought to determine how sustained exposure to hypobaric hypoxia influences exercise-induced potentiation of PHC. Twenty-one healthy participants were recruited to complete a maximal and submaximal exercise test at both low altitude (LA; Calgary, Canada, 1,100 m) and high altitude (HA; La Paz, Bolivia, 3,500 m). Both tests were conducted on a cycle ergometer with submaximal tests following 2-5 days after arrival at LA and 6-10 days after arrival at HA. The PHC was assessed at rest and throughout two 10-min submaximal exercise bouts by giving two breaths of a hypercapnic inspirate (10% CO₂, 21% O₂) and was repeated five times each separated by 40-60 s. The PHC response was quantified as the quotient of the change in ventilation (V̇_I) over the change in end-tidal PCO₂ ([Formula: see text]) following each hypercapnic stimulus. At HA, compared with LA, there was a greater resting V̇_I (15 ± 3 vs. 12 ± 2 L·min^-1, <i>P</i> = 0.0016) and lower resting [Formula: see text] (27 ± 3 vs. 37 ± 4 mmHg, <i>P</i> < 0.0001). Resting PHC at HA was greater than LA (1.8 ± 0.7 vs. 0.9 ± 0.4 L·min^-1·mmHg^-1, <i>P</i> < 0.0001). The increase in PHC induced by exercise was not different between LA and HA (+38 ± 60% vs. +24 ± 51%, <i>P</i> = 0.18). Sustained high-altitude exposure increases resting PHC, and exercise at HA sensitizes the peripheral chemoreceptors to a similar extent as LA.<b>NEW & NOTEWORTHY</b> Temporary residence at 3,500 m resulted in a greater resting peripheral hypercapnic chemosensitivity than at 1,100 m. Exercise increases hypercapnic sensitivity of the peripheral chemoreceptors from rest at both 1,100 m and 3,500 m, but the magnitude of increase from rest was not different between altitudes. The mechanism for the increased peripheral hypercapnic chemosensitivity induced by exercise is likely unaffected by altitude exposure.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"91-97"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144199224","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":"Models of cerebrovascular reactivity in BOLD-fMRI and transcranial Doppler ultrasound.","authors":"Genevieve Hayes, Sierra Sparks, Daniel P Bulte, Joana Pinto","doi":"10.1152/japplphysiol.00107.2025","DOIUrl":"10.1152/japplphysiol.00107.2025","url":null,"abstract":"<p><p>The ability of cerebrovasculature to respond to meet tissue demands is vital for normal brain function and health. Cerebrovascular reactivity (CVR), a measure of the responsiveness of cerebrovasculature to vasoactive stimuli, is a valuable tool for evaluating cerebrovascular health. Although CVR is commonly assessed using transcranial Doppler ultrasound (TCD), which measures blood velocity, or magnetic resonance imaging (MRI)-based techniques such as blood-oxygen-level-dependent (BOLD) imaging, which reflect changes in blood oxygenation, direct comparisons between these modalities remain limited, particularly with stimuli that induce a large dynamic range. Because both methods capture hypercapnia-induced vascular changes, we hypothesized that their CVR metrics may be correlated. This study evaluates intermodality correlations of CVR using TCD and BOLD-functional MRI (fMRI) extracted from the middle cerebral artery territory (parietal lobe) during a ramped hypercapnic protocol and different modeling strategies. Linear correlations across broad end-tidal partial pressure of carbon dioxide ([Formula: see text]) ranges validated the utility of linear CVR modeling in capturing repeatable metrics using TCD and MRI. A four-parameter sigmoid model revealed significant intermodality variability in span and bound parameters, improved by fixing these parameters and focusing on slope and inflection point, which enhanced the correlations between modalities. These results support the reliability of linear CVR modeling within narrow vasoactive response ranges in healthy subjects and propose a simplified two-parameter sigmoid model as an effective framework for characterizing nonlinear CVR dynamics. This work adds to the sparse literature on intermodality CVR comparisons and indicates which CVR metrics are comparable between TCD and BOLD-fMRI, emphasizing CVR as a useful tool for assessing cerebrovascular health in research and clinical contexts.<b>NEW & NOTEWORTHY</b> This study compares cerebrovascular reactivity (CVR) between transcranial Doppler ultrasound (TCD) and BOLD-fMRI using a hypercapnia protocol. Linear intermodality correlations across [Formula: see text] ranges validate linear CVR modeling. Significant variability in a four-parameter sigmoid model was mitigated by fixing span and bound parameters, supporting a two-parameter model for improved agreement but reducing sensitivity to diminished reserve. These findings clarify which CVR metrics are consistent between TCD and BOLD-fMRI, advancing multimodal integration for cerebrovascular health assessment.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"219-230"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144293824","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":"Beyond physiology: the role of footwear technology in the women's sub-4 min mile.","authors":"Víctor Rodrigo-Carranza, Wouter Hoogkamer","doi":"10.1152/japplphysiol.00423.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00423.2025","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":"139 1","pages":"257-258"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144608417","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":"Breaking 4: what it takes for a woman to run a sub-4-minute mile.","authors":"Alejandro Alda-Blanco, Fernando González-Mohíno","doi":"10.1152/japplphysiol.00415.2025","DOIUrl":"https://doi.org/10.1152/japplphysiol.00415.2025","url":null,"abstract":"","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":"139 1","pages":"255"},"PeriodicalIF":3.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144608418","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}