European Journal of Applied Physiology最新文献

{"title":"Simultaneous assessment of blood flow changes in femoral artery and skeletal muscle microvasculature using pulsed-wave and power Doppler ultrasonography.","authors":"Kazuma Izumi, Kana Shiozawa, Yutaka Kano, Keisho Katayama, Noriko Tanaka, Hiroshi Akima","doi":"10.1007/s00421-025-05813-2","DOIUrl":"https://doi.org/10.1007/s00421-025-05813-2","url":null,"abstract":"<p><strong>Purpose: </strong>The purpose of this study was to evaluate blood flow changes in femoral artery and skeletal muscle microvasculature during intermittent submaximal isometric knee extension.</p><p><strong>Methods: </strong>Seventeen healthy young males (19.7 ± 1.2 years) performed intermittent (5 s on, 5 s off) isometric knee extension. Five contractions were performed at each force level of 10%, 30%, 50%, and 70% of maximal voluntary contraction (MVC) at random with a 10-min rest between sets. We measured right femoral artery blood flow by pulsed-wave Doppler ultrasonography and intramuscular blood flow in the vastus lateralis of the right mid-thigh by power Doppler ultrasonography, simultaneously. Both femoral artery and intramuscular blood flow were normalized by the peak value for each participant and represented as %Peak. Time-to-peak was defined as the time from the end of exercise to the peak.</p><p><strong>Results: </strong>%Peak of femoral artery blood flow was significantly higher than that of intramuscular blood flow at the baseline and following contractions at 10% MVC (P < 0.01). The time-to-peak during the post-exercise of intramuscular blood flow was significantly longer than that of femoral artery blood flow following contractions at 70% MVC (P < 0.01).</p><p><strong>Conclusions: </strong>These results indicate that blood flow increases appeared slowly in skeletal muscle microvasculature than in femoral artery after intermittent submaximal isometric knee extension, suggesting that differences in vascular reactivity and blood flow regulation could exist between femoral artery and skeletal muscle microvasculature in healthy young males.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144076892","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":"Physiological, perceptual and neuromuscular responses of team sport athletes to short duration high intensity interval training using cycling.","authors":"Craig Twist, Elliot Conboy, Max Davidson, Shane Price, Jamie Highton","doi":"10.1007/s00421-025-05803-4","DOIUrl":"https://doi.org/10.1007/s00421-025-05803-4","url":null,"abstract":"<p><strong>Purpose: </strong>To examine the acute physiological, perceptual and neuromuscular responses of team sport athletes to two volume-matched cycling high intensity interval training (HIIT) sessions with short work bouts (< 60 s).</p><p><strong>Methods: </strong>Using and randomised crossover design, 16 male team sport players completed 2 × 6 min (with 5 min between sets) repeated efforts of 15 s or 30 s exercising at 120% power at <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O_{2 max} (p <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O_{2 max}) followed by matched-duration passive recovery on a cycle ergometer.</p><p><strong>Results: </strong>Absolute mean <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O₂ (p = 0.0257) and relative mean <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O₂ (p = 0.0275) were higher in 15 s than 30 s HIIT. Total time at > 90% <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O_{2 max} during the HIIT was higher for 15 s compared to 30 s HIIT (p = 0.0257). Heart rate remained the same between trials (p = 0.805) as did oxygen pulse (p = 0.1161). B[La] was lower in 15 s compared to 30 s HIIT (p = 0.0257). Differences in dRPE-L (p = 0.0495), dRPE-B (p = 0.0495) and dRPE-O (p = 0.1837) suggested lower perceived exertion in 15 s compared to 30 s HIIT. Maximal isometric knee extension force revealed a greater reduction after 30 s HIIT (p = 0.0495).</p><p><strong>Conclusion: </strong>Team sport athletes using short duration cycling-based HIIT should use 15 s work intervals to elicit greater time working near <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O_{2 max} at a lower perceived exertion and with smaller reductions in peak muscle force after exercise.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143986781","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":"Mitochondrial coupling efficiency and myofiber type related to blood pressure 22 h after high-intensity exercise in premenopausal women.","authors":"Gary R Hunter, Gordon Fisher, Stephen J Carter, Douglas R Moellering","doi":"10.1007/s00421-025-05805-2","DOIUrl":"https://doi.org/10.1007/s00421-025-05805-2","url":null,"abstract":"<p><p>Previously we have shown that systolic blood pressure (SBP) increases in African American (AA) women but decreases in European American (EA) women ≈22 h after a high-intensity exercise bout, suggesting delayed recovery in the AA women. We, therefore, sought to determine whether myofiber type, systemic vascular resistance (SVR), and mitochondrial coupling efficiency may contribute to elevated blood pressure in AA women following a bout of high-intensity exercise. Premenopausal EA (9) and AA (7) women were aerobically trained for 8-16 weeks and <math> <mrow><mover><mi>V</mi> <mo>˙</mo></mover> <msub><mtext>O</mtext> <mtext>2peak</mtext></msub> </mrow> </math> was evaluated. After 2 days without exercise, participants were evaluated for myofiber type, mitochondrial respiration using high-resolution respirometry, and SVR 22 h following 1 h of high-intensity interval cycle ergometry. AAs had higher SBP and DBP and type IIx myofiber % but lower type IIa myofiber %. SBP was significantly related to SVR (0.71), RCR (0.44), type IIa myofiber type (- 0.48), and type IIx myofiber type (0.53). DBP was significantly related to SVR (0.58) and the respiratory acceptor control ratio (state 3/state 4, termed RCR, 0.69). SBP remained significantly higher in AAs even after adjusting for type IIx myofiber type, RCR, SVR, or <math> <mrow><mover><mi>V</mi> <mo>˙</mo></mover> <msub><mtext>O</mtext> <mtext>2peak</mtext></msub> </mrow> </math> adjusted for FFM, and additionally, DBP remained significantly higher after adjusting for type IIx myofiber type, RCR, or <math> <mrow><mover><mi>V</mi> <mo>˙</mo></mover> <msub><mtext>O</mtext> <mtext>2peak</mtext></msub> </mrow> </math> adjusted for FFM. These results support the premise that mitochondrial RCR, type IIx myofiber type, and SVR may contribute to increased blood pressure ≈22 h following a bout of high-intensity exercise. Still, racial differences were not explained by any of these variables.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143958117","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":"Correlation between myocardial work indices and main echocardiographic and cardiopulmonary exercise stress test parameters in Olympic endurance athletes.","authors":"Giuseppe Di Gioia, Armando Ferrera, Federica Mango, Davide Ortolina, Viviana Maestrini, Sara Monosilio, Giulia Paoletti, Erika Lemme, Maria Rosaria Squeo, Antonio Pelliccia","doi":"10.1007/s00421-025-05801-6","DOIUrl":"https://doi.org/10.1007/s00421-025-05801-6","url":null,"abstract":"<p><strong>Introduction: </strong>Myocardial works indices (MWI) are new echocardiographic parameters that innovatively assess left ventricular function. Although recent studies show correlation between these indices and traditional morpho-functional echocardiographic (TTE) and cardiopulmonary test (CPET) parameters in general population and in different pathologic conditions, data on athletes remains scarce. Aim of our study is to investigate a relationship between MWI and main TTE and CPET parameters in a large cohort of endurance athletes.</p><p><strong>Methods: </strong>We enrolled 306 endurance Olympic athletes, mean age 26.3 ± 4.3 years old, 170 (55.5%) males who underwent clinical and anthropometric evaluation, TTE and CPET. Strain rate and MWI were measured and the following parameters collected: global longitudinal strain (GLS), global myocardial work index (GWI), global constructive myocardial work (GCW), Global Wasted Work (GWW) and global cardiac work efficiency (GWE).</p><p><strong>Results: </strong>MWI showed correlation with peak systolic blood pressure at CPET (GWI, p = 0.012 and GCW, p < 0.0001) and functional TTE parameters such as EF (p = 0.016 for GWI and p = 0.017 for GCW), RV GLS% (p < 0.0001 for GWI and GCW) and LA strain (p < 0.0001 for GWI and GCW). Moreover, MWI were also correlated to echocardiographic heart remodeling parameters, such as LVEDVi (p = 0.046 for GWI) and LVEDDi (p = 0.035 for GWW and p = 0.018 for GWE). MWI correlate also with O2pulse (p = 0.005 for GWI; p = 0.010 for GCW), but not with VO2max/kg.</p><p><strong>Conclusion: </strong>In this study, MWI were associated with cardiac remodeling, but not with VO2 max. It should therefore not be considered as a surrogate marker of an athlete's training status.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143989869","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":"Self-assessment of cardiorespiratory fitness: evaluation of reliability and validity of a step test eliminating a step board.","authors":"Fumiko Murai, Rina So, Tomoaki Matsuo","doi":"10.1007/s00421-025-05786-2","DOIUrl":"https://doi.org/10.1007/s00421-025-05786-2","url":null,"abstract":"<p><strong>Purpose: </strong>Conventional assessment of cardiorespiratory fitness (CRF) requires specialized equipment and designated spaces, limiting accessibility. To address this, the modified National Institute of Occupational Safety and Health, Japan step test (mJST) was developed for self-assessment without a step board. This study evaluated the reliability and validity of the mJST.</p><p><strong>Methods: </strong>A total of 131 participants (49% female, aged 30-59) were divided into a derivation group (n = 82) to establish an estimated maximal oxygen consumption ( <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O_{2 max}) model using multiple regression, and validation group (n = 49) to test the accuracy of the model. All participants completed the mJST and a  <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O_{2 max} treadmill test. The mJST comprised whole-body exercise for 3min and 40s followed by a 2-min recovery period. Heart rates (HRs) during the mJST were self-recorded using a wrist-worn device and measured via electrocardiograph. Test-retest reliability and validity were assessed using intraclass correlation coefficients (ICCs) and Bland-Altman analysis.</p><p><strong>Results: </strong>Excellent test-retest reliability was observed with electrocardiograph HRs (ICC = 0.92); however, fair to good reliability was observed with the wrist-worn device (ICC = 0.75). Bland-Altman analysis showed that mJST overestimated  <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O_{2 max} by 1.24 mL·kg^-1·min^-1, likely owing to discrepancies in HR readings from the wrist-worn device. The correlation between estimated and measured  <math><mover><mtext>V</mtext> <mo>˙</mo></mover> </math> O_{2 max} was moderate (r = 0.68).</p><p><strong>Conclusions: </strong>Eliminating the step board in step tests may aid in regular assessments of CRF to support ongoing health management. Despite limitations in device accuracy, the mJST demonstrated sufficient reliability and validity as a practical tool.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143980585","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":"Evaluating the maximal rate of lactate accumulation and estimated maximal lactate steady state in cycling.","authors":"Mattice Sablain, Billy Sperlich, Benedikt Meixner, Kevin Caen, Kobe Vermeire, Jan Boone","doi":"10.1007/s00421-025-05751-z","DOIUrl":"https://doi.org/10.1007/s00421-025-05751-z","url":null,"abstract":"<p><p>This study examined the reliability of the maximal rate of blood lactate (BLa^-) accumulation (VLa_max) and the, thereof, derived calculated power output at maximal La^- steady state (cP-MLSS). Additionally, cP-MLSS was compared with the second La^- thresholds determined by experts (LT_2-expert), being an accurate and often used threshold concept. 13 physically active male participants (length: 182 ± 4 cm; body mass: 76.3 ± 5.8 kg) completed a step incremental protocol to determine <math> <mrow><mover><mi>V</mi> <mo>˙</mo></mover> <msub><mtext>O</mtext> <mrow><mn>2</mn> <mtext>max</mtext></mrow> </msub> </mrow> </math> (60.5 ± 5.8 mL·min^-1·kg^-1) and LT_2-expert. Additionally, a 15-s isokinetic sprint test was conducted on four separate occasions to determine VLa_max. cP-MLSS was calculated using a mathematical model based on VLa_max, <math> <mrow><mover><mi>V</mi> <mo>˙</mo></mover> <msub><mtext>O</mtext> <mrow><mn>2</mn> <mtext>max</mtext></mrow> </msub> </mrow> </math> and body mass. Intraclass correlation coefficients (ICC) and coefficients of variation (CV%) were used to assess reliability. A paired sample T test was used to compare cP-MLSS (mean value of the 4 test days) and LT_2-Expert. We found good reliability for VLa_max (ICC = 0.80) and excellent reliability for cP-MLSS (ICC = 0.99). Moreover, LT_2-expert (277 ± 41 W) and cP-MLSS (282 ± 43 W) were not significantly different. However, comparison revealed relatively wide limits of agreement (-39 to 29 W). This study concludes that VLa_max and cP-MLSS are reliable measures but need further research and refinement to be used as valid parameters in training and performance contexts.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143974081","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":"Evaluating machine learning approaches to predict the energy expenditure of cross-national preschool children: a study of preprocessing and feature effects.","authors":"Hannah J Coyle-Asbil, Mirko Brandes, Berit Brandes, Christoph Buck, Marvin N Wright, Lori Ann Vallis","doi":"10.1007/s00421-025-05800-7","DOIUrl":"https://doi.org/10.1007/s00421-025-05800-7","url":null,"abstract":"<p><strong>Purpose: </strong>This study aimed to examine the impact of preprocessing and inclusion of various features on predicting the energy expenditure (EE) of preschool children (3.0-6.99 years).</p><p><strong>Methods: </strong>The internal Canadian sample consisted of 36 children, equipped with accelerometers on their wrists (OPAL) and right hip (ActiGraph GT9X). The external German sample consisted of 41 children, equipped with accelerometers on their wrists (GENEActiv) and right hip (GENEActiv; ActiGraph GT3X +). Both datasets used portable metabolic units to record EE. The effects of filtering, rectifying, adding a time delay, frequency domain (FD) features, and participant features on EE prediction across linear regression, random forest (RF), and fully connected neural network models. The Canadian sample was split into training (2/3) and validation (1/3) sets, and the German sample served as an external validation set.</p><p><strong>Results: </strong>Consistently it was found that the RF with filtered, not rectified data with FD, participant features, and a time delay resulted in improved performance compared to approaches used previously. The models also performed similarly in the holdout sample but resulted in higher error when applied in the external validation dataset.</p><p><strong>Conclusions: </strong> Results attest that filtering, not rectifying, FD features and participant features result in improved model performance to predict the EE of preschool children.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143984562","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":"Acute neuromuscular fatigue, hormonal responses, and recovery in males during high-volume resistance exercises: Smith machine back squat vs horizontal leg press.","authors":"Johanna Kotikangas, Simon Walker, Keijo Häkkinen, Heikki Peltonen","doi":"10.1007/s00421-025-05793-3","DOIUrl":"https://doi.org/10.1007/s00421-025-05793-3","url":null,"abstract":"<p><strong>Purpose: </strong>This study compared acute neuromuscular and hormonal responses and recovery in males during resistance exercises performed in Smith machine back squat (SQ) and horizontal leg press (LP).</p><p><strong>Methods: </strong>Twelve healthy, physically active men performed SQ and LP loadings consisting of 5 sets at ten-repetition maximum. Maximal bilateral isometric force and sEMG activity of quadriceps femoris over 500 ms (MIVC_EMG) in isometric leg press, countermovement jump height, and resting twitch force were assessed before (PRE) and immediately after loadings (POST), and after recovery of 30 min (POST30), 24 h (POST24), and 48 h. Serum concentrations of cortisol (COR), growth hormone (GH), testosterone, and creatine kinase were assessed at the same time points and additionally after third set (MID). Blood lactate (BL) was measured at PRE, MID, POST, and POST30.</p><p><strong>Results: </strong>Total work performed was significantly higher during SQ than LP ( 43.0 ± 5.2 kJ vs. 29.1 ± 3.1 kJ, p < 0.001). All blood-based parameters increased significantly during both loadings (p < 0.01). COR and GH were significantly higher at MID, POST, and POST30, and BL at MID during SQ than LP (p < 0.05). Neuromuscular variables decreased significantly from PRE to POST during both loadings (p < 0.05), with an interaction observed in MIVC_EMG between SQ and LP (- 10.4 vs. 6.4%, p < 0.01). All variables had returned to baseline by POST24.</p><p><strong>Conclusion: </strong>SQ may provide a more potent stimulus for metabolic and hormonal responses during high-volume resistance exercise, at least partly due to the greater total work performed. Nevertheless, fatigue induced within the quadriceps femoris was similar between SQ and LP.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143959174","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":"Climbing performance in males: the importance of climbing-specific finger strength.","authors":"B F Buraas, M F Brobakken, E Wang","doi":"10.1007/s00421-025-05802-5","DOIUrl":"https://doi.org/10.1007/s00421-025-05802-5","url":null,"abstract":"<p><strong>Purpose: </strong>Climbing is one of the fastest growing sports worldwide and with recent inclusion in the Olympic Games, and mounting number of indoor climbing gyms, its popularity is augmented. However, which physiological factors that predominantly determine climbing performance is unclear. Surprisingly, evidence of the importance of climbing-specific finger strength, intuitively the most obvious physiological component for climbing performance, is limited. This study sought to examine the relationship between distal finger digits isometric strength, assessed hanging from a 22 mm edge, and redpoint climbing and bouldering performance. Moreover, the aim was to contrast the results to less climbing-specific forearm flexor (handgrip) strength and multi-joint upper extremities (pullup) strength.</p><p><strong>Methods: </strong>Nineteen males (26 ± 3 years; 181 ± 7 cm; 75.2 ± 7.7 kg) with a previous redpoint level from 6b + to 8c (French grading scale) participated in the study.</p><p><strong>Results: </strong>Very strong and strong associations, respectively, were shown between climbing-specific finger strength and bouldering (r = 0.89) and redpoint (r = 0.67, both p < 0.01) climbing performance. It also exhibited a strong correlation with campus boarding (r = 0.82, p < 0.01). Handgrip strength was moderately associated with redpoint (r = 0.54) and campus board (r = 0.47, both p < 0.05), but not bouldering performance (p > 0.05). Pullup-strength exhibited a moderate association with bouldering (r = 0.55) and campus boarding (r = 0.57, both p < 0.05), but not redpoint performance. Body weight associated moderately with bouldering (r = - 0.49) and campus boarding (r = - 0.51, both p < 0.05), whereas height did not (all p > 0.05).</p><p><strong>Conclusion: </strong>Isometric distal finger strength appears to be the physiological factor most strongly related to bouldering and redpoint performance in males. However, it should be assessed in a climbing-specific exercise.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144004567","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 knee and hip flexion angle on region-specific and longitudinal compartmental muscle stiffness of the rectus femoris using shear wave elastography in male bodybuilders.","authors":"Hiroku Mitsuya, Koichi Nakazato, Takashi Okada","doi":"10.1007/s00421-025-05807-0","DOIUrl":"https://doi.org/10.1007/s00421-025-05807-0","url":null,"abstract":"<p><strong>Purpose: </strong>To investigate the effects of different knee and hip flexion angles (KFA and HFA) on region-specific and longitudinal compartmental muscle stiffness of the rectus femoris (RF) using shear wave elastography (SWE). As muscle mechanical tension is a key indicator of activation, measurements of muscle stiffness offer new insights into muscle contractile dynamics.</p><p><strong>Methods: </strong>Isometric knee extension (KE) was performed by nine male bodybuilders at maximum voluntary contraction (MVC) using a dynamometer under combined conditions of KFA at 30°, 60°, and 90° and HFA at 0°, 40°, and 80°. Muscle stiffness during KE was measured in the RF, vastus lateralis (VL), and vastus medialis (VM) using SWE. The RF and VL were divided into proximal, middle, and distal regions, and the VL, VM, and RF were compared across joint angle conditions and regions. Additionally, muscle activity during the KE was assessed in the proximal, middle, and distal RF using multichannel electromyography (EMG).</p><p><strong>Results: </strong>Muscle stiffness in the proximal RF was higher at HFA 0° and 40° compared to HFA 80° under KFA 30° conditions (p < 0.05). The stiffness in the middle RF was higher than that in the middle VL at HFA 0° and 40° under a KFA 30° (p < 0.01). EMG revealed no differences across regions or joint angles.</p><p><strong>Conclusion: </strong>Performing KE with the hip in an extended position enhanced the stiffness of the RF, particularly in the proximal region, compared to the VL. While region-specific muscle activity was observed using SWE, these differences were not detected using EMG.</p>","PeriodicalId":12005,"journal":{"name":"European Journal of Applied Physiology","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143993358","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}