Medicine and Science in Sports and Exercise最新文献

{"title":"BEETter AGING: Short-Term Dietary Nitrate Supplementation Enhances Muscle Contractile Properties in Older But Not in Young Adults.","authors":"Letizia Rasica, Marta Colosio, Alessandra Ferri, Giovanni Baldassarre, Chris Easton, Mia Burleigh, Gianluca Vernillo, Roberto Bottinelli, Mauro Marzorati, Simone Porcelli","doi":"10.1249/MSS.0000000000003708","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003708","url":null,"abstract":"<p><strong>Purpose: </strong>Dietary nitrate (NO3-) supplementation has been shown to improve skeletal muscle contractile function and reduce fatigue, potentially due to alterations in skeletal muscle Ca2+ handling/sensitivity. Since aging muscle can have impaired Ca2+ handling, the aim of the study was to evaluate the effects of dietary NO3- supplementation on muscle contractile properties in young and older adults.</p><p><strong>Methods: </strong>Eleven older (69 ± 4 yrs, O) and 11 young (26 ± 2 yrs, YG) adults consumed either NO3--rich beetroot juice (BR) or placebo (PLA), for 7 days. After supplementations, plantar flexors of dominant leg were evaluated as follow: a) maximal voluntary isometric contraction (MVIC); b) potentiated single twitches (Twpot) and double twitches electrical stimulations at the frequency of 100 Hz (Db100) on the tibial posterior nerve; c) a fatigue isometric (70% of MVIC) test until exhaustion. The force-frequency relationship was assessed with trains of electrical pulses across a wide range of frequencies on the muscle belly of the non-dominant leg.</p><p><strong>Results: </strong>BR supplementation increased plasma [NO3-] and nitrite [NO2-] in both O and YG compared to PLA (more than 7-fold; all P ≤ 0.02). No changes were observed in MVC, Twpot, and Db100 force after BR compared to PLA in both YG and O. Only in O, Db100 area under the curve (-7 ± 6 N·s change from PLA) and half relaxation time (-0.05 ± 0.06 s change from PLA) were significantly reduced. and time to exhaustion (+32 ± 43 s change from PLA) was significantly longer (all P < 0.02) after BR. In O, BR also significantly increased submaximal force produced by trains of electrical pulses (P < 0.001).</p><p><strong>Conclusions: </strong>NO3- supplementation positively affects muscle contractile proprieties, submaximal electrically evoked force production and fatigue resistance in older adults while these positive results were not found in young.</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":"143649423","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":"Effects of Intense Physical Training on Left Ventricular Hemodynamic Forces in Endurance Athletes: A Feature-Tracking Cardiac Magnetic Resonance Study.","authors":"Yeltay Rakhmanov, Dinara Jumadilova, Bauyrzhan Toktarbay, Zaukiya Kamitova, Aizhan Zankorazhova, Nurmakhan Zholshybek, Nail Khissamutdinov, Makhabbat Bekbossynova, Tairkhan Dautov, Alessandro Salustri","doi":"10.1249/MSS.0000000000003703","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003703","url":null,"abstract":"<p><strong>Purpose: </strong>We sought to evaluate the effect of intensive physical training on left ventricular (LV) hemodynamic forces (HDF) in athletes.</p><p><strong>Methods: </strong>Forty professional endurance athletes were evaluated at the beginning of their training cycle (off-season) and after a period of aerobic isotonic dynamic exercise (peak training period) using cardiac magnetic resonance (CMR). Images were analyzed off-line using dedicated software. LV HDF for the whole cardiac cycle and the different cardiac phases were measured. Standard statistics were used to compare off-season and peak training period values.</p><p><strong>Results: </strong>The average sport experience was 11 ± 7 years. There were no differences in LV volumes, stroke volume, LVEF and LV mass between off-season and peak training CMR. Similarly, there were no changes induced by physical training in the strain parameters. Physical training induced a significant increase of the longitudinal HDF (18.7 vs 21.2, p = 0.023) and an increase of the transverse HDF (3.4 vs 4.0, p = 0.048) throughout the entire heartbeat. After physical training, the peak values and the hemodynamic work (expressed as AUC) of the first part of the systole were significantly higher compared to off-season values (63.9 vs 53.9, p = 0.034; 4.67 vs 3.79, p = 0.015, respectively). The difference in the elastic rebound between off-season and peak training (-0.22 vs -0.37) did not reach statistical significance (p = 0.056).</p><p><strong>Conclusions: </strong>Intense physical training induces an increase in LV HDF of the first part of the systole and of the elastic rebound phase, independent from geometric cardiac remodeling.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143630605","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":"Hamstrings Muscle Architecture and Morphology Following 6 Weeks of an Eccentrically-Biased Romanian Deadlift or Nordic Hamstring Exercise Intervention.","authors":"Scott K Crawford, Caleb Sandberg, Jessica Vlisides, Quinlan Thompson, Samuel J Mosiman, Bryan C Heiderscheit, Jack T Hickey","doi":"10.1249/MSS.0000000000003701","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003701","url":null,"abstract":"<p><strong>Purpose: </strong>This study investigated the effects of a 6-week eccentrically-biased training intervention between Romanian deadlift (RDL) and Nordic hamstring exercises (NHE) on regional hamstring muscle architecture and morphology.</p><p><strong>Methods: </strong>Participants were randomly allocated to an RDL or NHE intervention group and trained twice per week for 6 weeks followed by a 2-week detraining period. Biceps femoris long head (BFlh) architecture (fascicle length [FL] and pennation angle [PA]) and muscle thickness (MT) were measured using extended-field-of-view ultrasound. Anatomical cross-sectional areas (ACSA) of BFlh, semimembranosus, and semitendinosus were also assessed via ultrasound. Muscle architecture and morphology were measured proximally, in the middle, and distally along the thigh. Separate linear mixed effects models were run for each outcome.</p><p><strong>Results: </strong>Thirty-two healthy participants (15 females, 17 males) aged 20.8 (0.9) years were enrolled and allocated to RDL (n = 16) or NHE (n = 16) groups. Following the intervention, BFlh FL increased (0.80 [0.6, 1.0] cm (9%), p < 0.001), while PA decreased uniformly across all regions (-1.2° [-1.5, -0.9] (10%), p < 0.001) and MT did not change (p = 0.29). Both BFlh FL and PA returned to baseline after detraining. No differences were observed between groups for changes in FL (p = 0.55), PA (p = 0.74), or MT (p = 0.48). Hamstrings ACSA increased after the intervention (0.78 cm2 [0.45, 1.11] (10%), p < 0.001) and remained elevated after detraining. There were no significant differences in ACSA between groups after the intervention (p = 0.60).</p><p><strong>Conclusions: </strong>Changes in FL, PA, and ACSA are consistent between an eccentrically-biased RDL and NHE intervention. These findings provide practitioners choice in exercise selection for eliciting adaptations relevant to hamstring injury prevention.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143630608","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":"Cardiometabolic Benefit of Replacing Sedentary Time with Light-Intensity Physical Activity: Compositional Data Analysis of the Nijmegen Exercise Study.","authors":"Koen M van der Sluijs, Janneke I A Vloet, Dick H J Thijssen, Thijs M H Eijsvogels, Esmée A Bakker","doi":"10.1249/MSS.0000000000003705","DOIUrl":"10.1249/MSS.0000000000003705","url":null,"abstract":"<p><strong>Purpose: </strong>The cardiometabolic benefits of replacing sedentary time with light-intensity physical activity (LIPA) are unclear. We studied the associations of hypothetically reallocating sedentary time towards LIPA with changes in cardiometabolic risk factors using thigh-worn accelerometery. We also explored whether reallocation effects differed across subgroups with low, moderate, and high sedentary time and compared proportionally similar reallocations to either LIPA or moderate-to-vigorous physical activity (MVPA).</p><p><strong>Methods: </strong>We assessed physical behaviours across eight consecutive days using thigh-worn accelerometers among adults from the Nijmegen Exercise Study. Multiple cardiometabolic risk factors were assessed and categorised as: 1) anthropometrics, 2) cardiovascular biomarkers, and 3) glucose metabolism. Reallocation effects were estimated for each cardiometabolic risk factor using compositional isotemporal substitution models adjusted for confounders. Analyses were repeated in sedentary time subgroups, i.e. <8.5, 8.5-10, and > 10 hours/day.</p><p><strong>Results: </strong>We included 1,041 participants (64 (standard deviation 11) years; 39.5% female). Reallocating sedentary time towards LIPA was associated with improvements in anthropometrics, some cardiovascular biomarkers, and glucose metabolism; e.g., replacing 60 minutes/day of sedentary time with LIPA was associated with improvements in BMI (-0.28 (-0.42, -0.13) kg/m 2 ), eGFR (0.68 (0.15, 1.20) mL/min/1.73m 2 ), and glucose (-0.05 (-0.08, -0.03) mmol/L). Trends suggested that reallocation benefits were strongest in those with >8.5 hours/day of sedentary time. Proportionally similar replacements of sedentary time with either LIPA or MVPA were associated with similar cardiometabolic benefits.</p><p><strong>Conclusions: </strong>Reallocation of sedentary time to LIPA was associated with improvements in cardiometabolic risk factors, predominantly in anthropometrics and glucose metabolism, with greater benefits in the most sedentary individuals. Time reallocation from sedentary time to LIPA may be an effective and arguably feasible strategy to improve population-wide cardiometabolic health.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143630603","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":"Trends, Characteristics and Mortality of U.S. Adults Unable To Do Aerobic Leisure-Time Physical Activity: The U.S. National Health Interview Survey 1998-2018.","authors":"Salud Pintos-Carrillo, Miguel Angelo Duarte, Rosario Ortolá, Fernando Rodríguez-Artalejo, Rocío Izquierdo-Gomez, Verónica Cabanas-Sánchez, David Martínez-Gómez","doi":"10.1249/MSS.0000000000003699","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003699","url":null,"abstract":"","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143575779","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":"Effects of Tai Chi on Multiple Brain Networks Structure-Function Couplings in Individuals with Subthreshold Depression: A Randomized Controlled Trial.","authors":"Jingsong Wu, Zhihan Liu, Baoru Zhao, Youze He, Jian Song, Yudie Hu, Tiecheng Wu","doi":"10.1249/MSS.0000000000003688","DOIUrl":"10.1249/MSS.0000000000003688","url":null,"abstract":"<p><strong>Introduction: </strong>Subthreshold depression represents a prodromal stage of major depressive disorder and may be associated with abnormalities in brain structural and functional networks. While studies have shown that mind-body exercises such as Tai Chi can alleviate subthreshold depression, the underlying mechanisms remain unclear. Purpose: This study aimed to explore the potential mechanisms of Tai Chi for improving subthreshold depression from the perspective of structure-function coupling of brain networks.</p><p><strong>Methods: </strong>This randomized controlled trial enrolled 112 individuals with subthreshold depression, randomly assigning them to either the Tai Chi group or a waitlist control group. Participants in the Tai Chi group received three 60-minute training sessions per week for 12 weeks. Outcome measures included assessments of negative mood symptoms, such as depression and stress, as well as structural and functional brain imaging.</p><p><strong>Results: </strong>After accounting for the dropout of nine participants, a total of 103 individuals were included in the final statistical analysis. Compared to the control group, participants in the Tai Chi group exhibited significant reductions in depression, stress, and anxiety scores. Network analyses revealed a decrease in structure-function coupling and characteristic path length within the frontoparietal network following Tai Chi practice. Further nodal analyses indicated a significant reduction in nodal degree and efficiency in the left prefrontal cortex and posterior cingulate gyrus, while increases were observed in the right lateral prefrontal cortex. Partial correlation analysis demonstrated a significant negative correlation between right prefrontal efficiency and anxiety scores.</p><p><strong>Conclusions: </strong>The benefits of Tai Chi on subthreshold depression may be related to modulating the structure-function coupling of the frontoparietal network and increasing nodal efficiency.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143537241","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":"Peripheral and Central Hemodynamic Responses to Rhythmic Handgrip Exercise in Young, Healthy Black Women.","authors":"Ruby Ama Nyarko, Randy Liu, Justo Perez, Ashlesha Dilip Dalve, Jasdeep Kaur","doi":"10.1249/MSS.0000000000003698","DOIUrl":"10.1249/MSS.0000000000003698","url":null,"abstract":"<p><strong>Purpose: </strong>Non-Hispanic Black (NHB) women in the United States exhibit higher prevalence and mortality rates from cardiovascular diseases compared to non-Hispanic White (NHW) women. Previous studies in NHB men have demonstrated impaired vascular function at rest and during exercise; however, to date, no studies have investigated the hyperemic responses during exercise in NHB women. Therefore, we tested the hypothesis that, compared with NHW women, NHB women would present an attenuated increase in forearm blood flow (FBF) and forearm vascular conductance (FVC) during steady-state rhythmic handgrip exercise.</p><p><strong>Methods: </strong>FBF (duplex Doppler ultrasound) and central hemodynamics including mean arterial pressure (MAP; finger photoplethysmography) were measured in healthy young NHW (n = 16) and NHB (n = 14) women during rhythmic handgrip exercise performed at 15%, 30% and 45% of maximal voluntary contraction (MVC).</p><p><strong>Results: </strong>FVC (calculated as FBF/MAP), FBF, and MAP were not different between groups at rest (FVC: 52 ± 13 ml/min/100 mmHg in NHW women vs. 56 ± 14 ml/min/100 mmHg in NHB women; P = 0.43). There was an intensity-dependent increase in FBF and FVC during exercise in both groups, but there was no difference between the groups (e.g., FVC at 45% MVC; NHW: 304 ± 55 ml/min/100 mmHg, NHB: 351 ± 121 ml/min/100 mmHg, interaction P = 0.257). MAP responses during exercise were also not different between groups (e.g., ΔMAP at 45% MVC; NHW: 7 ± 6 mmHg, NHB:8 ± 6 mmHg, P = 0.553). Additionally, all central hemodynamics during exercise, and flow-mediated dilation were comparable between the groups.</p><p><strong>Conclusions: </strong>Collectively, these findings indicate that the hyperemic responses to rhythmic handgrip exercise are not different between young, healthy NHB and NHW women.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143567514","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":"Changes in V̇O2max after 6 Weeks of Intensity Domain-Specific Training: Role of Central and Peripheral Adaptations.","authors":"Erin Calaine Inglis, Letizia Rasica, Danilo Iannetta, Mary Z Mackie, Felipe Mattioni Maturana, Daniel A Keir, Martin J MacInnis, Juan M Murias","doi":"10.1249/MSS.0000000000003697","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003697","url":null,"abstract":"<p><strong>Purpose: </strong>This study characterized central and peripheral adaptations to domain-specific endurance exercise training.</p><p><strong>Methods: </strong>Eighty-four young healthy participants were randomly assigned to age- and sex-matched groups of: continuous cycling in the 1) moderate (MOD)-, 2) lower heavy (HVY1)-, and 3) upper heavy-intensity (HVY2)- domain; interval cycling in the 4) severe-intensity domain (i.e., high-intensity interval training (HIIT), or 5) extreme-intensity domain (i.e., sprint-interval training (SIT)); or 6) control (CON). Two 3-week phases of training (three sessions per week) were performed. All training protocols, except SIT, were work-matched.</p><p><strong>Results: </strong>Maximal oxygen uptake (V̇O2max), maximal cardiac output (Q̇max), derived maximal arterial-venous oxygen difference (a-vO2diff), blood volume (BV), plasma volume (PV), and near-infrared spectroscopy (NIRS)-derived muscle oxidative capacity (τOxCap) were measured and compared at PRE and POST. The largest change in V̇O2max occurred in HIIT (0.43 ± 0.20 L·min-1), which was greater than CON (0.02 ± 0.08 L·min-1), MOD (0.11 ± 0.19 L·min-1), HVY1 (0.24 ± 0.18 L·min-1) and SIT (0.28 ± 0.21 L·min-1) (p < 0.05) but not HVY2 (0.36 ± 0.14 L·min-1) (p > 0.05). Changes in Q̇max were observed in HVY1 (1.6 ± 0.5 L·min-1), HVY2 (3.0 ± 0.6 L·min-1), HIIT (2.9 ± 1.2 L·min-1) and SIT (1.8 ± 1.4 L·min-1) (p < 0.05) but not in MOD (1.2 ± 0.3 L·min-1) and CON (0.1 ± -0.5 L·min-1) (p > 0.05). HVY2 and HIIT produced significant changes in BV ((438 ± 101 mL, and 302 ± 38 mL) and PV (198 ± 92 mL, and 158 ± 51 mL), respectively (p < 0.05) whereas other groups did not.</p><p><strong>Conclusions: </strong>No significant peripheral adaptations (i.e., τOxCap and a-vO2diff) were observed in any group (p > 0.05). The results indicate that higher training intensities (i.e., HVY2 and HIIT) produces larger changes in V̇O2max which is supported predominantly by central adaptations. Additionally, results suggest that, despite non-significant changes, the contribution of peripheral components to changes in V̇O2max should not be dismissed.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143567511","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":"Oxygen Uptake Dynamics Conform to Acute Changes in Muscle Excitation and Total Hemoglobin Concentration during Constant-Work Rate Exercise.","authors":"Gabriele Marinari, Robin Trama, Alessandro M Zagatto, Danilo Iannetta, Juan M Murias","doi":"10.1249/MSS.0000000000003700","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003700","url":null,"abstract":"<p><strong>Purpose: </strong>to investigate whether muscle excitation during constant-work rate (WR) cycling is connected with total[Hb + Mb] and interact with oxygen uptake (V̇O2) dynamics.</p><p><strong>Methods: </strong>Experiment 1: ten participants performed a 21-min constant-WR (CWR) within the heavy-intensity domain (i.e., 75% of the difference between the gas exchange threshold and the maximal metabolic steady state), and a ramp-to-constant-WR (rCWR) to the same WR. CWR and rCWR were repeated twice and allocated in random order. Experiment 2: nine participants performed a double-constant-WR (dCWR) consisting of a 21-min exercise bout, a short 20-sec break, and a second bout of 21 min within the heavy domain. V̇O2, EMG root mean square (EMGRMS), total[Hb + Mb] and deoxygenated hemoglobin ([HHb]) were collected from the vastus lateralis. The EMGRMS/total[Hb + Mb] and EMGRMS/[HHb] ratios were computed.</p><p><strong>Results: </strong>The EMGRMS was lower at min 1 and 7 and total[Hb + Mb] higher at min 1 during the rCWR compared to the CWR condition (all P < 0.05). EMGRMS displayed an overshoot at min 1 which was different from min 21 during the CWR condition (P < 0.05). EMGRMS did not display an overshoot following the 20 sec break during the dCWR condition. The EMGRMS/total[Hb + Mb] inverted ratio was not different from V̇O2 (%). The EMG magnitude of frequencies ranging from ~30-to-90 Hz was initially higher and decreased over time (P < 0.05).</p><p><strong>Conclusions: </strong>This study demonstrated that EMGRMS-derived muscle excitation can be reduced by exercise protocols that promote higher total[Hb + Mb]. Furthermore, the interaction between muscle excitation and total[Hb + Mb] matched with systemic V̇O2.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143567513","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":"Influence of Running Speed and Time Post-Operatively on Lower Extremity Work in Collegiate Athletes after Anterior Cruciate Ligament Reconstruction.","authors":"Keith A Knurr, Daniel G Cobian, Stephanie A Kliethermes, Mikel R Joachim, Bryan C Heiderscheit","doi":"10.1249/MSS.0000000000003695","DOIUrl":"https://doi.org/10.1249/MSS.0000000000003695","url":null,"abstract":"<p><strong>Purpose: </strong>Following anterior cruciate ligament reconstruction (ACLR), individuals present with significant and persistent deficits in surgical knee biomechanics during running. Little is known regarding the role of the hip and ankle in compensating for these knee-specific deficits. The purpose of this study was to characterize how limb (surgical and non-surgical), time post-operatively (3.5-7 months [EARLY], 8-13 months [LATE]), and running speed influence lower extremity joint-specific and total work during running post-ACLR.</p><p><strong>Methods: </strong>Fifty-six Division I collegiate athletes post-ACLR (EARLY: n = 41, LATE: n = 42, Both: n = 27) completed running analyses at 2.68, 2.95, 3.35, 3.80 and 4.47 m/s or up to their maximum comfortable speed. Linear mixed effects models assessed the influence of limb, speed, time post-ACLR, and their interactions on hip, knee, ankle, and total negative and positive work.</p><p><strong>Results: </strong>Surgical limb hip positive work was greater (0.044 J/kg [0.015, 0.074], p < 0.001) than the non-surgical limb EARLY. Surgical limb ankle negative (-0.054 J/kg [-0.093, -0.015], p = 0.003) and positive work (-0.115 J/kg [-0.168, -0.063], p < 0.001) were less than the non-surgical limb EARLY. Surgical limb knee negative (EARLY: -0.339 J/kg [-0.382, -0.296], p < 0.001; LATE: -0.222 J/kg [-0.265, -0.180], p < 0.001) and positive work (EARLY: -0.214 J/kg [-0.246, -0.182], p < 0.001; LATE: -0.142 J/kg [-0.174, -0.110], p < 0.001) were less than the non-surgical limb. Total negative and positive work followed the same pattern as the knee. Conclusions: Athletes post-ACLR exhibited greater hip positive work and lesser ankle positive and negative work during running of the surgical limb EARLY, that resolved LATE. Both knee and total negative and positive work of the surgical limb were substantially less than the non-surgical limb, which improved from EARLY to LATE, but between-limb asymmetries remained.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.1,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143567512","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}