Medicine and Science in Sports and Exercise最新文献

{"title":"Blunted Exercise Pressor Response to Isometric Knee Extension and Post-Exercise Ischemia in Individuals with Down Syndrome.","authors":"Sara R Sherman, Ronald Jackson, Natalia S Lima, Brooks A Hibner, B O Fernhall, Tracy Baynard","doi":"10.1249/MSS.0000000000003619","DOIUrl":"10.1249/MSS.0000000000003619","url":null,"abstract":"<p><strong>Introduction: </strong>Individuals with Down syndrome (DS) exhibit autonomic dysfunction, which contributes to reduced work capacity. The metaboreflex produces exercise-induced sympathoexcitation and can be assessed via post-exercise muscle ischemia (PEMI). Blunted sympathoexcitation is common in individuals with DS and contributes to the physiological basis for reduced work capacity observed this population, but the influence of the metaboreflex is unknown. Using unilateral isometric knee extension exercise with PEMI, we hypothesized that individuals with DS would demonstrate a reduced metaboreflex compared with individuals without DS.</p><p><strong>Methods: </strong>Twenty-four individuals with DS (M/F: 13/11; 24 ± 5 yr; 30.3 ± 6.2 kg·m -2 ) and without DS (M/F: 13/11; 25 ± 4 yr; 26.5 ± 4.5 kg·m -2 ) performed a unilateral isometric knee extension at 30% of their maximal voluntary contraction on a leg dynamometer. Following 2 min of contraction, a thigh cuff was rapidly inflated to 220 mm Hg on the exercised leg for 3 min to isolate the activation of the muscle metaboreflex via PEMI. Beat-to-beat mean arterial pressure (MAP) and systolic blood pressure (SBP) were assessed using finger photoplethysmography. Heart rate (HR) was collected via three-lead electrocardiogram.</p><p><strong>Results: </strong>Despite similar baseline values of all variables in both groups, individuals with DS demonstrated a blunted pressor response to unilateral isometric knee extension compared with individuals without DS (MAP; DS: 103 ± 14 vs non-DS: 125 ± 19 mm Hg), and the blunted MAP response was maintained with PEMI (MAP; DS: 95 ± 13 vs non-DS: 106 ± 18 mm Hg; group-time interaction, P < 0.001). Individuals with DS also exhibited reduced HR 2 min into contraction compared with individuals without DS (HR; DS: 90 ± 16 vs non-DS: 114 ± 22 bpm; group-time interaction, P < 0.001).</p><p><strong>Conclusions: </strong>Individuals with DS demonstrated a diminished metaboreflex response compared with their peers without DS, during a task known to induce sympathoexcitation. Our findings suggest that reduced influence of the metaboreflex contributes to the reduced exercise pressor response in individuals with DS. Such exercise-specific peripheral autonomic alterations extend beyond our previous cardiac autonomic findings demonstrating blunted sympathoexcitatory perturbations in individuals with DS, which may contribute to reduced work capacity observed in this population.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"876-883"},"PeriodicalIF":4.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142770494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effect of Perceived Groove in Music on Effective Brain Connectivity during Cycling: An fNIRS Study.","authors":"Jiangang Chen, Gaoquan Zhou, Junbo Han, Pei Su, Hongli Zhang, Donghui Tang","doi":"10.1249/MSS.0000000000003609","DOIUrl":"10.1249/MSS.0000000000003609","url":null,"abstract":"<p><strong>Introduction: </strong>Perceived groove, a complex and integrated musical characteristic, is considered a core factor in inducing synchronization between movement and music. This study aimed to use functional near-infrared spectroscopy to explore the effective connectivity (EC) changes among brain regions during cycling activities under different perceived groove conditions.</p><p><strong>Methods: </strong>In a randomized crossover design, 18 university students performed 3-min cycling tasks under high (HG) and low (LG) perceived groove music conditions. Revolutions per minute, coefficient of variation of pedaling cadence, and sensorimotor coupling index were measured. Granger causality analyses were performed on the functional near-infrared spectroscopy data from the cycling task to obtain EC matrices at the brain region and channel (Ch) levels.</p><p><strong>Results: </strong>The revolution per minute was significantly higher, and coefficient of variation of pedaling cadence and sensorimotor coupling index were significantly lower in HG than in LG. The EC values of the Brodmann area (BA) 8→the left prefrontal cortex (lPFC), the superior portion of BA 6 (BA 6_Sup)→lPFC, and BA 1-3→lPFC were significantly higher in HG than in LG. Channel analyses indicated that the EC values of Ch 14→Ch 9, Ch 41→Ch 9, Ch 14→Ch 10, Ch 41→Ch 10, Ch 31→Ch 10, and Ch 35→Ch 23 were significantly higher in HG than in LG. Correlation analysis revealed that the EC values of the channels included in BA 6_Sup→lPFC were significantly correlated with cycling performance metrics.</p><p><strong>Conclusions: </strong>The EC changes from BA 6_Sup to lPFC may play a critical role in the process through which perceived groove affects the synchronization of cycling to music.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"857-866"},"PeriodicalIF":4.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142984100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Running Distance and Biomechanical Risk Factors for Plantar Fasciitis: A 1-yr Prospective 4HAIE Cohort Study.","authors":"Jan Plesek, Joseph Hamill, Michal Burda, Steriani Elavsky, Jiri Skypala, Jan Urbaczka, Julia Freedman-Silvernail, David Zahradnik, Jaroslav Uchytil, Daniel Jandacka","doi":"10.1249/MSS.0000000000003617","DOIUrl":"10.1249/MSS.0000000000003617","url":null,"abstract":"<p><strong>Introduction: </strong>Plantar fasciitis (PF) is one of the most common running-related injuries.</p><p><strong>Purpose: </strong>The aim of this prospective study was to determine the incidence of PF and identify potential risk or protective factors for PF in runners and non-runners.</p><p><strong>Methods: </strong>Data from 1206 participants from the 4HAIE cohort study (563 females/643 males; 715 runners/491 non-runners; 18-65 yr of age) were included in the analysis. We collected biomechanical data during overground running using a three-dimensional motion capture system at the baseline and running distance data via retrospective questionnaires and followed the participants for 12 months following the baseline data collection. Participants were asked weekly about any sports-related injury (including PF). A binary logistic regression was performed to reveal potential associations between running distance and biomechanical risk factors and PF while controlling for running distance, sex, and age.</p><p><strong>Results: </strong>The total incidence of PF was 2.3% (28 PF from 1206 participants), 2.5% in runners and 2.0% in non-runners ( P = 0.248). Runners who ran more than 40 km·wk -1 had six times higher odds of suffering PF than individuals who ran 6-20 km·wk -1 ( P = 0.009). There was a significant association between maximal ankle adduction and PF; that is, runners with a lower abduction angle during the stance period had higher risk of PF ( P = 0.024). No other biomechanical variables indicated significant associations with PF.</p><p><strong>Conclusions: </strong>Regular running with a moderate weekly volume and more toeing out of the foot relative to the shank may reduce the risk against PF in runners, which may be useful for researchers, runners, coaches, and health professionals to minimize PF injury risk.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"756-766"},"PeriodicalIF":4.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11878588/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142770496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the Influence of Limb Blood Flow on Contraction-Induced Muscle Growth and the Impact of That Growth on Changes in Maximal Strength.","authors":"Vickie Wong, Robert W Spitz, John P Bentley, Jun Seob Song, Yujiro Yamada, Ryo Kataoka, William B Hammert, Aldo Seffrin, Zachary W Bell, Jeremy P Loenneke","doi":"10.1249/MSS.0000000000003613","DOIUrl":"10.1249/MSS.0000000000003613","url":null,"abstract":"<p><strong>Purpose: </strong>To determine 1) whether the relationship between isometric training and muscle growth depends on baseline blood flow or is mediated by a change in blood flow, and 2) whether muscle growth mediates changes in maximal isometric strength.</p><p><strong>Methods: </strong>A total of 179 participants were randomized into low-intensity isometric handgrip exercise (LI), low-intensity isometric handgrip exercise with blood flow restriction (LI-BFR), maximal handgrip exercise (MAX), and a non-exercise control (CONTROL). Muscle thickness, strength, and resting limb blood flow were measured before and after the 6-wk intervention.</p><p><strong>Results: </strong>Baseline blood flow did not moderate training effects on muscle thickness changes (MTHchg) ( P = 0.666), and moderated mediation tests were nonsignificant. Although the LI-BFR group showed a significant effect on MTHchg ( P = 0.018), MTHchg was not significantly related to handgrip strength change (HGchg) ( P = 0.281), suggesting no mediation of the training-to-strength effect by MTHchg. Both the LI-BFR ( P = 0.004) and MAX ( P < 0.001) groups exhibited positive direct effects on HGchg compared with CONTROL. Furthermore, there were no differences between training groups and CONTROL on blood flow change (BFchg), BFchg and MTHchg were not significantly related, and neither BFchg nor MTHchg predicted HGchg, providing no evidence for mediated pathways.</p><p><strong>Conclusions: </strong>Muscle growth may not have occurred to an extent that would require vascular adaptation. Training maximally induced the greatest strength adaptations but was seemingly not driven by muscle growth.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"867-875"},"PeriodicalIF":4.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142739892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationships between Patient-Reported Outcomes and Predictors of Second ACL Injuries during Unanticipated Jump Landings.","authors":"Scott M Monfort, Fatemeh Aflatounian, Patrick D Fischer, James N Becker, Keith A Hutchison, Janet E Simon, Dustin R Grooms","doi":"10.1249/MSS.0000000000003603","DOIUrl":"10.1249/MSS.0000000000003603","url":null,"abstract":"<p><strong>Background: </strong>Reactive and external visual-cognitive demands are prevalent in sport and likely contribute to anterior cruciate ligament (ACL) injury scenarios. However, these demands are absent in common return-to-sport assessments. This disconnect leaves a blind spot for determining when an athlete can return to sport with mitigated re-injury risk.</p><p><strong>Purpose: </strong>To characterize relationships between patient-reported outcome measures (PROMs) and cognitive-task interference (i.e., cognitive demands exacerbating neuromuscular impairments) for biomechanical predictors of second ACL injuries during jump landings that involved rapid unanticipated decision making.</p><p><strong>Methods: </strong>Thirty-six persons following primary ACL reconstruction (ACLR; 26 females/10 males, 19.8 ± 1.8 yr; 1.71 ± 0.1 m; 69.6 ± 12.8 kg, 1.5 ± 0.6 yr post-ACLR; Tegner: 6.8 ± 1.8) participated. PROMs of ACL-RSI and the Forgotten Joint Score-12 Knee (FJS-12) were selected to assess altered psychological state (e.g., confidence, attention toward knee). Jumping tasks under anticipated and unanticipated secondary jump directions were performed. Biomechanical variables were dual-task changes (unanticipated - anticipated) in 1) uninvolved limb hip rotator impulse (DTC_Uni-HRot_Imp), 2) asymmetry of knee extensor moment at initial contact (DTC_KEM_Asym), and 3) range of involved knee abduction angle (DTC_KAbA_Range). Regression models tested for relationships between PROMs and the dual-task change in biomechanical variables.</p><p><strong>Results: </strong>ACL-RSI (DTC_Uni-HRot_Imp ( P < 0.001)) and FJS-12 (DTC_KAbA_Range ( P = 0.001)) had significant relationships with dual-task change in the opposite direction as expected (worse PROM ➔ less dual-task change). A follow-up analysis indicated that dual-task change was inversely correlated with the baseline estimates for kinetic biomechanical variables (less risky single-task biomechanics ➔ greater dual-task change for Uni-HRot_Imp and KEM_Asym).</p><p><strong>Conclusions: </strong>The collective results are consistent with higher functioning participants (better PROMs) who also demonstrate desirable biomechanics during single-task conditions being prone to demonstrating the greatest risk-associated DTC in unanticipated scenarios.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"840-848"},"PeriodicalIF":4.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142984077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theta-Burst Stimulation Modulates Exercise Performance by Influencing Central Fatigue and Corticospinal Excitability.","authors":"Camilla Martignon, Chiara Barbi, Gianluca Vernillo, Simranjit K Sidhu, Mehran Emadi Andani, Federico Schena, Massimo Venturelli","doi":"10.1249/MSS.0000000000003611","DOIUrl":"10.1249/MSS.0000000000003611","url":null,"abstract":"<p><strong>Purpose: </strong>Theta-burst stimulation (TBS) over the primary motor cortex modulates activity of the underlying neural tissue, but little is known about its consequence on neuromuscular fatigue and its neural correlates. This study aimed to compare the effects of facilitatory versus inhibitory TBS on the neuromuscular fatigue and excitability/inhibition of the corticospinal pathway in an unfatigued/fatigued muscle.</p><p><strong>Methods: </strong>The effects of three TBS protocols (facilitatory/intermittent: iTBS; inhibitory/continuous: cTBS, and sham: sTBS) were tested on exercise performance, neuromuscular function, and corticospinal excitability and inhibition in 20 young healthy participants. Transcranial magnetic and peripheral electrical stimulations were used at baseline, following TBS (unfatigued state), and after a fatiguing sustained contraction (fatigued state) at 35% of the maximal voluntary isometric contraction (MVIC) of the elbow flexors.</p><p><strong>Results: </strong>Time-to-task failure was shorter for cTBS (142 ± 51 s) and longer for iTBS (214 ± 68 s) compared with sTBS (173 ± 65 s) ( P < 0.05). In an unfatigued state, cTBS reduced MVIC and voluntary activation (VA), increased motor-evoked potential, and silent period ( P < 0.05), whereas iTBS did not cause any change. In a fatigued state, MVIC and VA decreased in all TBS sessions ( P < 0.05). However, the reduction in VA was larger after cTBS (Δ -18 ± 18%) compared with iTBS (Δ-3 ± 5%), and sTBS (Δ-9 ± 9%) ( P < 0.001). Furthermore, the increase in motor-evoked potential and silent period were greater for cTBS ( P < 0.05), compared with iTBS and sTBS ( P < 0.05).</p><p><strong>Conclusions: </strong>Facilitatory TBS augments exercise performance that is independent of central parameters and corticospinal mechanisms, whereas inhibitory TBS attenuates exercise performance through an exacerbation in the development of central fatigue and possibly intracortical inhibition.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"716-726"},"PeriodicalIF":4.1,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142687362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Vivo Biomechanical Interactions Between Bones, Patellar Tendon, and Cartilage Surfaces at the Knee During Cycling.","authors":"Tung-Wu Lu, Kuan-Hsien Wu, Mei-Ying Kuo, Jia-Da Li, Hsuan-Yu Lu, Horng-Chaung Hsu","doi":"10.1249/MSS.0000000000003713","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003713","url":null,"abstract":"<p><strong>Abstract: </strong>Purpose: Stationary cycling is essential in rehabilitation programs for various patient groups, such as knee osteoarthritis and cruciate ligament injuries and reconstruction. The study aimed to measure in vivo the 3D rigid-body and articular surface kinematics of the knee and the patellar tendon orientations during stationary cycling and isolated flexion-extension exercise in healthy young adults using a model-based tracking approach with dual-plane fluoroscopy. Methods: Ten healthy left knees were imaged by CT and MRI to reconstruct subject-specific volumetric bone-cartilage models. The 3D rigid-body and articular surface kinematics and patellar tendon angles during stationary cycling and isolated knee flexion-extension exercise were measured in vivo using a dual-plane fluoroscopy with a voxel-based registration method, compared between tasks and between power and recovery phases. Results: Significant differences in the rigid-body and surface kinematics and patellar tendon orientations were found between the power and recovery phases and between the power phase and isolated knee extension. Compared to the recovery phase, the power phase showed significantly greater external rotations, adductions, and posterior translations for flexions greater than 45° (p < 0.05) with significantly more posterior medial and lateral contact positions for flexion angles less than 45° (p < 0.05) and more vertical patellar tendon orientations for flexion angles lesser than 60° (p < 0.05). Conclusions: The contact locations and loads on the posterior half of the tibial articular surface during the first half of the power phase indicate that stationary cycling as a daily and rehabilitative exercise is safe for people with anterior medial knee OA. Key Words: FLUOROSCOPY, IMAGE REGISTRATION, KNEE JOINT, KINEMATICS, SURFACE KINEMATICS.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143772682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Voluntary Exercise Attenuates Tumor Growth in a Preclinical Model of Castration-Resistant Prostate Cancer.","authors":"Nicolas Berger, Benjamin Kugler, Dong Han, Muqing Li, Paul Nguyen, Meaghan Anderson, Susan Patalano-Salsman, Songqi Zhang, Jill Macoska, Changmeng Cai, Kai Zou","doi":"10.1249/MSS.0000000000003712","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003712","url":null,"abstract":"<p><strong>Purpose: </strong>To examine the effects of voluntary wheel running on tumor growth and explore potential intratumoral molecular pathways responsible for the beneficial effects of voluntary wheel running on tumor formation and progression in a mouse model of Castration-Resistant Prostate Cancer (CRPC).</p><p><strong>Methods: </strong>Male immunodeficient mice (SCID) were castrated and subcutaneously inoculated with human CWR-22RV1 cancer cells to construct CRPC xenograft model before assigned to either voluntary wheel running (VWR) or sedentary (SED) group (n = 6/group). Tumor size was measured and calculated throughout the study. After three weeks, tumor tissues were collected. mRNA expression of markers of DNA replication, Androgen Receptor (AR) signaling, and mitochondrial dynamics was determined by RT-PCR. Protein expression of mitochondrial dynamics was determined by western blotting. Finally, transcriptomics analysis was performed using the tumor tissues.</p><p><strong>Results: </strong>Voluntary wheel running resulted in smaller tumor volume at the initial stage and attenuated tumor progression throughout the time course (P < 0.05). The reduction of tumor volume in the VWR group coincided with lower mRNA expression of DNA replication markers (MCM2, MCM6, and MCM7), AR signaling (ELOVL5 and FKBP5) and regulatory proteins of mitochondrial fission (Drp1 and Fis1) and fusion (MFN1 and OPA1) when compared to the SED group (P < 0.05). RNA sequencing data further revealed that pathways related to angiogenesis, extracellular matrix formation and endothelial cell proliferation were downregulated.</p><p><strong>Conclusions: </strong>Three weeks of voluntary wheel running was effective in delaying tumor formation and progression, which coincided with reduced transcription of DNA replication, AR signaling targets and mitochondrial dynamics. We further identified a downregulation in molecular pathways related to angiogenesis that may be responsible for the delayed tumor formation and progression by voluntary wheel running.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143772743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physiological Determinants of V̇O2max Increase with Endurance Training in a Group Including Older and Young Adults.","authors":"Robin Faricier, Donald H Paterson, Juan M Murias","doi":"10.1249/MSS.0000000000003707","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003707","url":null,"abstract":"<p><strong>Purpose: </strong>To examine central and peripheral physiological adaptations contributing to increases in maximal oxygen uptake (V̇O2max) following a 12-week of vigorous endurance exercise program in healthy, older and young adults.</p><p><strong>Methods: </strong>Fourteen participants (7 older: 68 ± 7 years and 7 young: 26 ± 7 years; 9 males and 5 females) engaged in a cycling training program 3 times/week for 45 min at ~70%V̇O2max. Changes in V̇O2max, cardiac function, O2 extraction, muscle capillarization, and mitochondrial content from pre- to post-training were examined.</p><p><strong>Results: </strong>The increase in V̇O2max from pre- to post-training for all participants (20 ± 8%) was accompanied by increases in maximal cardiac output (Q̇max: 15 ± 11%), maximal stroke volume (SVmax: 14 ± 12%), muscle fiber cross-sectional area (CSA: 17 ± 21%) and perimeter (P: 7 ± 9%), citrate synthase activity (CS: 144 ± 175%), individual capillary-to-fiber ratio (C:Fi: 32 ± 17%), capillary-to-fiber perimeter exchange index (CPFE: 30 ± 15%), capillary contact (CC: 38 ± 20%), capillary density (CD: 22 ± 17%), and arteriovenous O2 difference (a-vO2diff: 4 ± 6%) (p < 0.05 for all). No training-related variation existed for maximal heart rate (HRmax: -1 ± 4%; p = 0.448). Changes in V̇O2max were positively correlated with Q̇max (r = 0.830: p < 0.001), SVmax (r = 0.655; p = 0.011), CD (r = 0.546; p = 0.043), and CS activity (r = 0.630; p = 0.021). No significant correlations were found for changes in V̇O2max and changes in HRmax, a-vO2diff, muscle fiber CSA and P, CC, C:Fi and CPFE (p > 0.05 for all).</p><p><strong>Conclusions: </strong>Cardiorespiratory fitness improvements were primarily determined by enhancement in central (i.e., cardiac function) and peripheral (i.e., vascularization) adaptations within the O2 transport system as well as the upregulation of mitochondrial aerobic enzymatic activity (i.e., CS activity) at the intracellular level.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143772741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Moderate-Intensity Interval Training Block Improves Endurance Performance in Well-Trained Cyclists.","authors":"Knut Sindre Mølmen, Ingvill Odden, Margit Dahl Sørensen, Anne Mette Rustaden, Daniel Hammarström, Joar Hansen, Håvard Nygaard, Håvard Hamarsland, Bent R Rønnestad","doi":"10.1249/MSS.0000000000003706","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003706","url":null,"abstract":"<p><strong>Purpose: </strong>This study compared the physiological effects of a moderate-intensity interval training (MIT) microcycle followed by an active recovery period (collectively termed MITblock) with a time-matched regular training period (REG) during the general preparation phase in well-trained cyclists.</p><p><strong>Methods: </strong>Using a randomized crossover design, 30 well-trained male cyclists (maximal oxygen consumption (VO2max), 70.5 (4.6) mL·min-1·kg-1) completed both MITblock and REG. The MIT microcycle involved six interval sessions over seven days with 5-7 × 10-14 min work intervals at a perceived exertion (RPE) of 14-15 on the Borg 6-20 scale. A six-day active recovery period followed before physiological testing. During REG, cyclists performed their regular preparatory-phase training routine, which primarily involved low-intensity exercise. Specific guidelines included completing either two MIT sessions or one MIT session and one high-intensity interval session per week. Endurance performance indicators assessed included changes in 15 min maximal average power output (PO15min), power output at 4 mmol·L-1 [blood lactate] (PO4mmol), 1 min peak power output during incremental testing (POVO2max), and VO2max.</p><p><strong>Results: </strong>Although the Training Impulse (TRIMP) score was not different between MITblock and REG (1944 (436) vs. 1800 (232), respectively; p = 0.27), MITblock resulted in significantly greater improvements than REG in PO4mmol (4.0 (4.4)% vs. -1.3 (3.7)%, p < 0.01), POVO2max (2.5 (4.5)% vs. -0.7 (3.9)%, p < 0.01) and VO2max (2.0 (3.9)% vs. 0.0 (3.5)%, p = 0.05). Changes in PO15min were not statistically different between MITblock and REG (3.9 (8.3)% vs. 0.2 (6.8)%, p = 0.14). During MIT intervals, RPE was 14.4 (0.3), corresponding to 66 (5)% of POVO2max, 85 (3)% of maximal heart rate, and 2.8 (1.1) mmol·L-1 [blood lactate].</p><p><strong>Conclusions: </strong>Six moderate-intensity interval sessions over seven days, followed by a six-day active recovery period, induce improvements in endurance performance indicators compared to a time-matched regular training period in well-trained cyclists.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}