Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme最新文献

Different doses of theacrine do not improve 4-km cycling time trial performance.

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-03-06 DOI: 10.1139/apnm-2024-0442

Victor Henrique VIeira Cavalcante, Julio Cezar Schamne, Felippi Gonçalves, Romulo Bertuzzi, Anna Paola Tr Pierucci, Daniel Boari, Adriano Eduardo Lima-Silva, Renata Gonçalves Silva

{"title":"Different doses of theacrine do not improve 4-km cycling time trial performance.","authors":"Victor Henrique VIeira Cavalcante, Julio Cezar Schamne, Felippi Gonçalves, Romulo Bertuzzi, Anna Paola Tr Pierucci, Daniel Boari, Adriano Eduardo Lima-Silva, Renata Gonçalves Silva","doi":"10.1139/apnm-2024-0442","DOIUrl":"https://doi.org/10.1139/apnm-2024-0442","url":null,"abstract":"The aim of the present study was to test the effects of different doses of anhydrous theacrine (3 and 6 mg.kg-1 of body mass) on 4-km cycling time trial performance. Nineteen (11 men and 8 women) cyclists (30.8 ± 10.0 years, 71.7 ± 11.8 kg, 170.1 ± 9.0 cm, and 17.0 ± 6.2 % of body fat) completed three 4-km cycling time trials after ingesting either placebo, or 3 mg.kg-1 or 6 mg.kg-1 of body mass of theacrine. No significant differences (p < 0.05) were observed in time to cover the 4-km cycling time trial between the placebo, 3 mg.kg-1 of theacrine, and 6 mg.kg-1 of theacrine conditions. However, the intake of theacrine at the dose of 6 mg.kg-1 increased resting systolic and diastolic blood pressure (p < 0.05). Some side effects, such as gastrointestinal discomfort, perception of tachycardia, dizziness, headache, head pressure, hand tremor, and lack of disposition were reported after the ingestion of either 3 or 6 mg.kg-1 of body mass of theacrine. In conclusion, theacrine supplementation does not improve endurance performance and provokes side effects that might restrict its use as a supplement.","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143574902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of Brief Ambient Cooling on Serum Stress Biomarkers in Older Adults During a Daylong Heat Exposure: A Laboratory-Based Heat Wave Simulation.

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-03-04 DOI: 10.1139/apnm-2024-0476

Ben Lee, Robert D Meade, Sarah L Davey, Charles D Thake, James J McCormick, Kelli E King, Glen P Kenny

引用次数: 0

Effects of pedestal-mounted electric fans on self-reported symptoms and mood-state in older adults exposed to indoor overheating during a simulated heatwave: an exploratory analysis.

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-02-28 DOI: 10.1139/apnm-2024-0461

Fergus O'Connor, Gregory W McGarr, Roberto C Harris-Mostert, Pierre Boulay, Ronald J Sigal, Robert D Meade, Glen P Kenny

{"title":"Effects of pedestal-mounted electric fans on self-reported symptoms and mood-state in older adults exposed to indoor overheating during a simulated heatwave: an exploratory analysis.","authors":"Fergus O'Connor, Gregory W McGarr, Roberto C Harris-Mostert, Pierre Boulay, Ronald J Sigal, Robert D Meade, Glen P Kenny","doi":"10.1139/apnm-2024-0461","DOIUrl":"https://doi.org/10.1139/apnm-2024-0461","url":null,"abstract":"Recent evidence from modelling and laboratory-based studies showed that electric fans are ineffective at lowering core temperature in older adults at air temperatures of 36°C. However, their influence on self-reported environmental symptoms and mood-state during daylong use in hot indoor environments remains unclear. Eighteen older adults (8 females, median [interquartile range]; 72 [67-76 years]) completed three randomized 8-hour heat exposures (36°C, 45% relative humidity) with a fan generating air speeds of 0 (no fan, Control), 2, or 4 m/s at the front of the body positioned 1-m away. Participants were seated throughout, except for 4 x 10-min periods of simulated activities of daily living (stepping [~2.25 METs]). Core temperature, mean skin temperature, and heart rate areas under the curve (AUC, hours 0-8) were calculated to assess cumulative physiological strain. Total symptom scores (68-item environmental symptoms questionnaire) as well as total mood disturbance and energy index (40-item profile of mood states questionnaire) were evaluated at end-heating (adjusted for pre-exposure). Core temperature, mean skin temperatures, and heart rate AUCs were not different between conditions (all P≥0.087). Total symptom scores were 0.89-fold [0.81,0.97] lower with fan use (combined across speeds) compared to no fan (P=0.009). Energy index scores were 2.4 points [0.8,4.0] higher with fan use compared to no fan (P=0.004). However, mood disturbance was not significantly different between conditions (P=0.345). Our exploratory analysis show that fans can reduce self-reported symptoms and increase perceived energy levels in older adults in overheated indoor environments, despite no meaningful attenuation of physiological strain.","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of eccentric versus stretching exercise training on cognitive function of older women. 偏心与拉伸运动训练对老年妇女认知功能的影响。

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-02-26 DOI: 10.1139/apnm-2024-0390

Min-Jyue Huang, Favil Singh, Dennis Taaffe, Trevor C Chen, Kazunori Nosaka

{"title":"Effects of eccentric versus stretching exercise training on cognitive function of older women.","authors":"Min-Jyue Huang, Favil Singh, Dennis Taaffe, Trevor C Chen, Kazunori Nosaka","doi":"10.1139/apnm-2024-0390","DOIUrl":"https://doi.org/10.1139/apnm-2024-0390","url":null,"abstract":"Exercises focusing on eccentric contractions may stimulate the brain better, improving cognitive function. We tested the hypothesis that executive function and attention would improve more after eccentric resistance exercise (ECC) than stretching exercise (STRETCH) training. Healthy older women (65-75y) underwent either ECC (n=14) or STRETCH (n=14) intervention for 8 weeks. ECC consisted of 7 exercises emphasizing eccentric contractions while STRETCH performed 12 stretching exercises, with supervised sessions undertaken twice weekly accompanied by a home-based program. Executive function and attention were assessed using the Stroop test of color naming (STCN) and conflicting color words, symbol digit modalities test, digit span test (DST), and trail making tests (TMT-A, TMT-B), and 6 physical function tests were undertaken before and after the 8-week training period. Fasting blood samples were obtained before and after the training. A significant (p<0.05) group x time interaction effect was evident for STCN, DST and TMT-A, with only ECC showing improvements (DST:14.7±27% and TMT-A:10.2±12%) from pre- to post-training. No significant changes in other cognitive function tests were found for either group. All physical function tests except one-leg balance test showed greater improvement (p<0.05) for ECC than STRETCH. No significant changes in blood lipid profile and brain-derived neurotrophic factor were found, but serum glucose concentration and glycosylated hemoglobin decreased (p<0.05) in ECC. These results suggest that a short-term eccentric exercise intervention was effective in enhancing components of cognitive and physical function of older women and may prove a useful strategy in combating age-related decline in cognitive and physical function.","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143517666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An exploration of physical literacy in Masters Athletes.

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-02-24 DOI: 10.1139/apnm-2024-0373

Garry McCracken, Elijah M K Haynes, Jennifer M Jakobi

{"title":"An exploration of physical literacy in Masters Athletes.","authors":"Garry McCracken, Elijah M K Haynes, Jennifer M Jakobi","doi":"10.1139/apnm-2024-0373","DOIUrl":"https://doi.org/10.1139/apnm-2024-0373","url":null,"abstract":"Sport participation among older adults, is increasing, but many still fall short of meeting physical activity (PA) guidelines. Master athletes, who engage in PA through systematic training, and competition, offer unique insights into PA practices in later life. This study explored whether master athletes embody the principles of physical literacy and how their experiences could inform strategies to promote PA among older adults. An electronic survey completed by 35 master athletes (55-75 years, 20 female) and follow-up interviews with eight participants revealed that most were unfamiliar with the term \"physical literacy,\" yet they intuitively practiced its principles. Master athletes identified parallels between their behaviors and physical literacy but viewed existing models as primarily youth-focused and less applicable to older adults. Additionally, lifelong sport participation was not universal; nine participants, predominantly women, began competitive sports later in life. A key finding was the importance of social connectedness, which emerged as a critical motivator and enabler for sustained PA among master athletes. This element, largely absent from current physical literacy frameworks, may be vital for engaging older adults in PA. Integrating social connection into physical literacy models could address barriers unique to this demographic, enhancing participation and promoting healthier aging.","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dose-response Relationship between Leisure-time Physical Activity and Metabolic Syndrome in Short Sleep US Adults: Evidence from a Nationwide Investigation.

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-02-24 DOI: 10.1139/apnm-2024-0347

Yanwei You, Hao Ding, Meihua Tang, Weizhao Wang, Ning Yan, Leizi Min, Yuquan Chen, Xindong Ma

{"title":"Dose-response Relationship between Leisure-time Physical Activity and Metabolic Syndrome in Short Sleep US Adults: Evidence from a Nationwide Investigation.","authors":"Yanwei You, Hao Ding, Meihua Tang, Weizhao Wang, Ning Yan, Leizi Min, Yuquan Chen, Xindong Ma","doi":"10.1139/apnm-2024-0347","DOIUrl":"https://doi.org/10.1139/apnm-2024-0347","url":null,"abstract":"Metabolic syndrome (MetS) and short sleep are prevalent health concerns in the United States, yet the relationship between leisure-time physical activity (LTPA) and MetS among individuals with short sleep duration remains unclear. This cross-sectional study analyzed data from 8999 US adults aged 20 years and older in the National Health and Nutrition Examination Survey (NHANES). Short sleep duration was defined as less than 7 hours per night, and MetS was diagnosed based on criteria from the American Endocrine Society and the American Society of Clinical Endocrinology. Weighted regression analyses revealed a significant inverse association between LTPA and MetS, with higher LTPA levels linked to lower MetS [OR (95% CI): 0.990 (0.984, 0.997), p = 0.003]. Participants who achieved the World Health Organization's recommended LTPA levels had a substantially lower MetS compared to those with no LTPA [OR (95% CI): 0.624 (0.527, 0.738), p = 0.001]. Stratified analyses showed that this protective effect varied across demographic subgroups, and a threshold effect was observed at 2000 MET-minutes per week, beyond which further LTPA did not significantly enhance protection against MetS. These findings highlight the importance of regular LTPA is negatively associated with MetS among individuals with inadequate sleep, emphasizing the need for targeted health promotion efforts in this population.","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Carnosine-enriched functional food enhances micro- and macrovascular endothelium-independent vasodilation in competitive athletes - a randomized study.

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-02-21 DOI: 10.1139/apnm-2024-0458

Leon Perić, Ines Drenjancevic, Ivana Jukić, Alina Boris, Petar Šušnjara, Nikolina Kolobarić, Zrinka Mihaljević, Zlata Kralik, Gordana Kralik, Manuela Košević, Olivera Galović, Ana Stupin

{"title":"Carnosine-enriched functional food enhances micro- and macrovascular endothelium-independent vasodilation in competitive athletes - a randomized study.","authors":"Leon Perić, Ines Drenjancevic, Ivana Jukić, Alina Boris, Petar Šušnjara, Nikolina Kolobarić, Zrinka Mihaljević, Zlata Kralik, Gordana Kralik, Manuela Košević, Olivera Galović, Ana Stupin","doi":"10.1139/apnm-2024-0458","DOIUrl":"https://doi.org/10.1139/apnm-2024-0458","url":null,"abstract":"This randomized interventional study aimed to investigate the effect of carnosine-enriched chicken meat consumption on systemic endothelium-dependent and -independent micro- and macrovascular reactivity in thirty-five healthy competitive male athletes. Both forearm skin micro- and macrovascular endothelium-independent vasodilation were increased, and diastolic and mean arterial blood pressure (BP) were decreased in Carnosine group (n=19) following the 3-week dietary protocol. Microvascular endothelium-dependent response (PORH) was increased in the Carnosine group and significantly associated with decreased mean arterial BP level. Following dietary protocol, Controls (n =16) had substantially higher urate (but still normal) levels than the Carnosine group. Carnosine supplementation in the form of functional food enhances endothelium-dependent and vascular smooth muscle-dependent vasodilation in peripheral micro- and microcirculation. Carnosine's effect on vascular endothelium could be attributed to its blood pressure-lowering effect. Results suggest that carnosine has the potential to resist hyperuricemia in healthy individuals. (NCT05723939).","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143473263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Are post-exercise plasma glucose elevations involved in exercise-induced appetite suppression?

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-02-21 DOI: 10.1139/apnm-2024-0331

Derek P D Bornath, Seth F McCarthy, Jessica A L Tucker, Tamara R Cohen, Philip J Medeiros, Tom J Hazell

{"title":"Are post-exercise plasma glucose elevations involved in exercise-induced appetite suppression?","authors":"Derek P D Bornath, Seth F McCarthy, Jessica A L Tucker, Tamara R Cohen, Philip J Medeiros, Tom J Hazell","doi":"10.1139/apnm-2024-0331","DOIUrl":"https://doi.org/10.1139/apnm-2024-0331","url":null,"abstract":"Changes in glucose and insulin are potentially involved in the appetite-regulatory effects of exercise considering their role post-prandially.Purpose: To examine if glucose and insulin play a role in post-exercise appetite regulation.Methods: 12 participants (M=8; 26±5 y) completed 3 experimental sessions in a systematically rotated randomized crossover design: 1) no-exercise control (CTRL); 2) moderate-intensity continuous training (MICT; 30-min, 70% maximal oxygen consumption (V̇O2max)); and 3) sprint interval training (SIT; 4 x 30-s \"all-out\" sprints, interspersed with 4-min rest). Plasma glucose, insulin, acylated ghrelin, active peptide tyrosine tyrosine (PYY), active glucagon-like peptide-1 (GLP-1), and overall appetite perceptions were measured pre-exercise, 0-, 30-, 60-, and 120-min post-exercise. Energy intake was recorded the day before, of, and after experimental sessions.Results: Glucose was elevated 0-min post-exercise (p<0.097, d>0.52) compared to CTRL with no differences between exercise bouts. Acylated ghrelin was suppressed by MICT (60-, 120-min) and SIT (0-, 30-, 60-, 120-min; p<0.080, d> 0.56) compared to CTRL, while also suppressed in SIT compared to MICT at 30-, 60-, 120-min (p<0.026, d>0.74). GLP-1 was elevated following MICT (0-, 30-, 60-min) and SIT (60-min; p<0.094, d>0.53) compared to CTRL and following MICT compared to SIT (0-min; p=0.005, d=1.03). Overall appetite was suppressed by SIT post-exercise (p<0.058, d>0.61) compared to CTRL and MICT, and by MICT 0-min post-exercise compared to CTRL (p=0.036, d=0.71). There were no exercise effects on insulin, PYY, or free-living energy intake (p>0.217, ηp2<0.130).Conclusion: Glucose and insulin do not appear to play a role in exercise-induced appetite suppression.","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143473261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Brain-derived neurotrophic factor response to daylong exposure to extreme heat in young and older adults: A secondary analysis.

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-02-19 DOI: 10.1139/apnm-2024-0289

Nathalie V Kirby, Robert D Meade, James J McCormick, Kelli E King, Glen P Kenny

{"title":"Brain-derived neurotrophic factor response to daylong exposure to extreme heat in young and older adults: A secondary analysis.","authors":"Nathalie V Kirby, Robert D Meade, James J McCormick, Kelli E King, Glen P Kenny","doi":"10.1139/apnm-2024-0289","DOIUrl":"https://doi.org/10.1139/apnm-2024-0289","url":null,"abstract":"Brain-derived neurotrophic factor (BDNF) is a growth factor with a range of neurological, cardioprotective, and metabolic health benefits. While passive heat stress has been observed to increase circulating BDNF, the BDNF response to a given stressor may be attenuated with increasing age. To investigate the influence of age on the BDNF response to heat stress, we compared BDNF responses to daylong (9-hours) exposure to hot ambient conditions (40°C, 9% relative humidity) between 19 young (range: 19-31 years; 9 female) and 37 older adults (61-78 years; 12 female). We also explored whether cumulative thermal strain (area under the curve of rectal and mean body temperatures) impacted comparisons. Serum BDNF concentrations were assessed at pre- and end-exposure using enzyme-linked immunosorbent assays. Circulating BDNF concentrations increased from baseline in both groups (P<0.001), but end-exposure concentrations were 2594 [1555, 3633] pg/mL lower in older than young adults (P<0.001). This age-related difference persisted, albeit to a lesser magnitude, after accounting for the lower pre-exposure BDNF levels in older adults (baseline-adjusted between-group difference: 1648 [667, 2630] pg/mL; P<0.001). Additionally, the BDNF response was not related to indices of thermal strain (P≥0.562), and baseline-adjusted between-group differences were not appreciably altered by adjusting for area under the curve of rectal (1769 [714, 2825] pg/mL; P=0.002) or mean body temperatures (1745 [727, 2763] pg/mL; P=0.001). Our study is the first to demonstrate an age-related reduction in the BDNF response to prolonged passive heat exposure, which informs our wider understanding of how environmental stressors influence BDNF responses in older adults.","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143461042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

REDUCED H-REFLEX GAIN IN SOLEUS DURING ISOMETRIC PLANTAR FLEXOR AND DORSIFLEXOR MUSCLE CONTRACTIONS IN OLD ADULTS.

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme Pub Date : 2025-02-19 DOI: 10.1139/apnm-2024-0369

Mélanie Henry, Anastasia Theodosiadou, Stéphane Baudry

{"title":"REDUCED H-REFLEX GAIN IN SOLEUS DURING ISOMETRIC PLANTAR FLEXOR AND DORSIFLEXOR MUSCLE CONTRACTIONS IN OLD ADULTS.","authors":"Mélanie Henry, Anastasia Theodosiadou, Stéphane Baudry","doi":"10.1139/apnm-2024-0369","DOIUrl":"https://doi.org/10.1139/apnm-2024-0369","url":null,"abstract":"The modulation of the Hoffmann (H) reflex amplitude during agonist and antagonist muscle contractions provides relevant information on the neural control of leg muscles but remains largely unknown in older adults. This study investigated the H-reflex gain in the soleus muscle at rest and during plantar flexor (PF) and dorsiflexor (DF) muscle contractions performed at 10%, 20% and 30% of the maximal electromyographic activity (EMGMVC) in 12 young (23-35yrs) and 12 old adults (61-76yrs). The reflex gain was measured as the slope of the relation between H-reflex amplitude and background EMG activity. The stimulation intensity was set to evoke at rest an H reflex in the ascending phase of its recruitment curve preceded by an M wave (5 and 10% of its maximal amplitude; Mmax). During PF contractions, the H-reflex amplitude increased with the increase in contraction intensity in both groups with a greater reflex gain (p=0.024) in young [1.2 (0.5)% Mmax/% EMGMVC] than old adults [0.7 (0.4)% Mmax/% EMGMVC]. During DF contractions, the H-reflex amplitude decreased in both groups, with a more negative reflex gain (p=0.009) in young [-6.8 (2.8)% Mmax/% EMGMVC] than old adults [-2.7 (4.0)% Mmax/% EMGMVC]. Furthermore, the decrease in H-reflex amplitude was linearly associated with the increase in tibialis anterior EMG in both groups. The present study showed a smaller reflex gain in old adults in soleus during submaximal PF and DF contractions, suggesting a decreased ability to adjust the excitatory afferent inputs during PF contractions, and to modulate reciprocal inhibition during DF contractions.","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143461044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0