Scandinavian Journal of Medicine & Science in Sports最新文献

{"title":"Number of Sprint Repetitions in a Sprint Interval Training Session Does Not Moderate Improvements in V̇O2max With Training: A Systematic Review and Meta-Analysis.","authors":"M Hutchinson,D J Kinghorn,E C R Hall,R S Metcalfe,D R Paval,I J Gallagher,N B J Vollaard","doi":"10.1111/sms.70347","DOIUrl":"https://doi.org/10.1111/sms.70347","url":null,"abstract":"Sprint interval training (SIT) is promoted as a time-efficient method for improving maximal aerobic capacity (V̇O2max); however, the \"classic\" protocol (4-6 × 30-s all-out sprints) is less time-efficient than claimed, may be poorly tolerated, and is expected to lead to low adherence. The present study examined the effect of the number of sprint repetitions per session on training-induced changes in V̇O2max through meta-analysis of the available literature. PubMed and Web of Science were searched (May 2016-September 2024) for eligible studies involving ≥ 2 weeks of training involving repeated all-out cycling with pre- and post-training V̇O2max data. Forty-four eligible studies were combined with 34 studies from a previous meta-analysis, totalling 93 trials across 78 studies (n = 1188). A hierarchical random-effects meta-regression model was used to assess the influence of key moderators on the change in V̇O2max. SIT produced an 8.3% increase in V̇O2max (95% CrI: 7.0 to 9.5%). Increasing sprint repetitions showed a trivial association with changes in V̇O2max (-0.04% per additional sprint, 95% CrI: -0.32 to 0.24%). Increasing intervention duration was associated with the largest improvements in V̇O2max (0.7% per additional week; 95% CrI: 0.3 to 1.0%). The present study confirms that increasing sprint repetitions does not meaningfully enhance V̇O2max improvements in untrained populations. As performing fewer sprint repetitions increases time-efficiency and attenuates reductions in affect, future research into interventions for improving general health in physically inactive populations should focus on low-volume SIT protocols. Trial Registration: PROSPERO database (registration number CRD42022349104).","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"67 1","pages":"e70347"},"PeriodicalIF":4.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148521962","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":"Rapid Torque Production of the Knee Extensors: An Integrative Analysis of Neuromuscular and Muscle-Tendon Determinants.","authors":"Francesco Salvaggio,Baptiste Bizet,Samuel D Emanuele,Michele Trinchi,Tommaso Berbenni,Alberto Rainoldi,Federico Schena,Cantor Tarperi,Andrea Monte,Gennaro Boccia","doi":"10.1111/sms.70328","DOIUrl":"https://doi.org/10.1111/sms.70328","url":null,"abstract":"The physiological determinants of explosive strength are usually investigated separately. We aimed to quantify the relative contributions of muscle excitation, structural, and mechanical determinants of rapid torque production in the knee extensors in a multi-domain framework. Twenty-four young adults performed ballistic isometric knee extensions. High-density surface electromyographic (HD-sEMG) signals were recorded from vasti lateralis and medialis muscles. Patellar tendon stiffness and muscle architecture were assessed via ultrasound. Impulse and RTDpeak were outcomes. The predictors were from four domains: muscle excitation, muscle thickness, fascicle shortening velocity, and tendon stiffness. Linear regressions and LMG were used to quantify the weight of each predictor. The models explained substantial variance in impulse: R2 = 0.62 (0-50 ms), 0.76 (0-75 ms), 0.74 (0-100 ms), 0.61 (0-125 ms), 0.70 (0-150 ms). Early impulse (50 and 75 ms) was mainly explained by tendon stiffness and muscle excitation; mid-phase impulse (100 ms) by fascicle velocity and tendon stiffness; late impulse (125 and 150 ms) by fascicle shortening velocity and muscle thickness. RTDpeak was explained (R2 = 0.70) by patellar tendon stiffness (~32% of impulse variance), fascicle velocity (~18%), muscle thickness (~12%), and muscle excitation (~8%). Four predictors across different neuromechanical domains explained up to 76% of the variance in rapid torque production. Interestingly, the determinants shift over time: tendon stiffness and muscle excitation dominate earlier, while fascicle dynamics and muscle size become more important later. RTDpeak was largely determined by tendon stiffness and a balanced contribution of muscular predictors.","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"60 1","pages":"e70328"},"PeriodicalIF":4.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148365489","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 Relationship Between Vision and Performance in Swimming Under Simulated Vision Impairment: Establishing an Empirically Driven Minimum Impairment Criteria for Para Swimming.","authors":"Daniel Fortin-Guichard,H J C Rianne Ravensbergen,Kai Krabben,Lieske de Wit,Inger Wouters,David L Mann","doi":"10.1111/sms.70340","DOIUrl":"https://doi.org/10.1111/sms.70340","url":null,"abstract":"Paralympic sport provides tremendous opportunities for individuals with impairment, including vision impairment, but there is controversy about the fairness of competition. Particularly, it remains unclear how much impairment should be necessary to compete. Swimming for athletes with vision impairment presently requires athletes to have a visual acuity of at least 1.0 logMAR to qualify (20/200 or 6/60), though this cut-off is based on the legal definition of low vision, with no evidence to suggest it decreases swimming performance. Accordingly, swimming might currently include individuals without a disadvantage, or exclude those who do have a disadvantage. The aim of this study was to establish the level of visual acuity loss that decreases performance in swimming. Twenty-one national-level swimmers without vision impairment swam 100 m freestyle maximal effort time trials in each of four different levels of vision impairment simulated using plus lenses (plano, +4.00, +6.00, +8.00). Visual acuities ranged from -0.3 to +1.6 logMAR (an acuity of 0.0 logMAR would typically be considered to represent \"normal\" vision, a negative value better than \"normal\", and a positive value worse. For reference, under the existing system of classification for VI swimming, an acuity of 1.0 logMAR would qualify an individual to compete in the S13 class, an acuity of 1.5 logMAR in the S12 class, and an acuity worse than 2.6 logMAR for the S11 class). ROC analysis and repeated-measure decision tree were used to establish the level of visual acuity that brought performance below what would be expected by normal variation. Results revealed that a cut-off of at least 1.1 logMAR provided the optimal classification of performance as below-expected performance. In general, performance was not impacted by lesser amounts of vision impairment. The findings suggest that the existing minimum level of impairment required to compete in swimming is close to being appropriate, but that the current threshold may be slightly too low. The results are expected to contribute to the introduction of evidence-based classification rules to be used for swimming in the future Paralympic Games.","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"31 1","pages":"e70340"},"PeriodicalIF":4.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148432904","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 Continuous and Cluster-Set Configurations Performed to Failure on Performance and Physiological Responses in the Bench Press and Half Squat.","authors":"Athanasios Tsoukos,Anastasios Ververis,Gregory C Bogdanis","doi":"10.1111/sms.70337","DOIUrl":"https://doi.org/10.1111/sms.70337","url":null,"abstract":"This study compared the acute effects of continuous execution (CON) and two cluster-set configurations performed to momentary failure with high loads (~85% one-repetition maximum) on mechanical and physiological responses during the bench press and half squat. Twelve recreationally trained men completed three randomized, counterbalanced conditions: two using cluster sets of three repetitions with either 10 s (CS10) or 20 s (CS20) intra-set rest, and a control (CON) condition. In the bench press, CS10 did not significantly increase the number of repetitions compared with CON, while CS20 increased repetitions from 6.8 ± 1.6 to 11.4 ± 2.9 (p = 0.044). In the half-squat, the effect of cluster sets on repetitions was evident in both CS10 and CS20 compared with CON (18.3 ± 4.0 and 42.1 ± 7.7 vs. 10.6 ± 3.2 repetitions, respectively, p < 0.001). Set duration increased progressively with longer intra-set rest, particularly in the half squat, reaching in CS20, 90.7 ± 26.2 s and 344.6 ± 65.3 s (p < 0.001) in the bench press and half squat exercises, respectively. Mean heart rate (HR) in CS20 was higher in the half squat than the bench press (87.2% ± 4.9% vs. 70.4% ± 6.5% of max HR, p < 0.001), while blood lactate responses were also greater in half-squat compared with bench press (~8.5 vs. 5.5 mmol L-1, p < 0.001), with values in CS20 reaching 10.8 ± 4.5 mmol L-1. In summary, when sets are performed to momentary failure with high loads, CS10 provides only modest performance benefits, whereas CS20 markedly increases training volume, particularly in the half squat. The elevated cardiovascular and metabolic stress observed under CS20 reflects the substantially greater total work performed rather than an inherent effect of the cluster configuration.","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"37 1","pages":"e70337"},"PeriodicalIF":4.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148388566","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":"24-h Movement Behaviors and Incident Hypertension Among Adolescents: A Prospective Study From the ABCD Study.","authors":"Augusto César F De Moraes,Ethan T Hunt,Jacob Szeszulski,Gabrielli T De Mello,Marcus V Nascimento-Ferreira,Pamela A Madden","doi":"10.1111/sms.70346","DOIUrl":"https://doi.org/10.1111/sms.70346","url":null,"abstract":"Hypertension during adolescence is a growing public health concern with long-term cardiovascular implications. This study examined whether adherence to 24-h movement behavior guidelines-physical activity, screen time, and sleep-was associated with the prevalence and incidence of hypertension among U.S. adolescents, and whether these associations varied by social determinants of health (SDoH). We analyzed data from 2067 participants in the Adolescent Brain Cognitive Development (ABCD) Study, followed across 21 U.S. cities from 2018-2020 (T0) to 2020-2022 (T1). Movement behaviors were dichotomized using international recommendations, and SDoH was measured using the Child Opportunity Index. Hypertension was defined as systolic or diastolic blood pressure ≥ 95th percentile for age, sex, and height. Adolescents with screen time > 2 h/day had higher hypertension prevalence (1.9%) and incidence (4.0%) than those within recommended limits. In crude analyses, adolescents meeting physical activity guidelines showed a higher incidence of hypertension than those not meeting them; however, this association was not statistically significant in adjusted models (RR = 0.87; 95% CI: 0.42-4.17), suggesting that confounding rather than a true effect may explain the crude finding. Adherence to two or more movement behavior recommendations was associated with a reduced risk of hypertension (RR = 0.31; 95% CI: 0.09-0.98), though this estimate is based on a small number of events and should be interpreted with caution. SDoH did not modify these associations. These findings underscore the importance of combined behavioral adherence in reducing hypertension risk and support the integration of lifestyle interventions for promoting cardiovascular health during adolescence.","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"8 1","pages":"e70346"},"PeriodicalIF":4.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148408506","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":"Bidirectional Influences Between Psychophysiological State and Performance in Olympic Shooting: The Role of Attention and Autonomic Function.","authors":"E Molinero-Martín,D Mon-López,M A Fernández-Del-Olmo,A Luque-Casado","doi":"10.1111/sms.70335","DOIUrl":"https://doi.org/10.1111/sms.70335","url":null,"abstract":"Olympic shooting is a precision sport where technical execution is shaped not only by motor skills but also by psychophysiological factors influencing performance. However, their interplay in relation to competition performance remains underexplored. This study aimed to: (1) examine the impact of competition's temporal dynamics on shooting performance, attentional capacity, and autonomic nervous system (ANS) function; and (2) investigate how pre-competition individual differences in attentional capacity and ANS function relate to technical shooting performance. Twenty-six intermediate-level pistol shooters were recruited to complete a simulated 60-shot competition test. Attentional capacity was assessed using a Psychomotor Vigilance Task (PVT) administered pre- and post-competition. Vagally-mediated Heart Rate Variability (vmHRV) parameters were recorded at baseline and during the competition to evaluate autonomic regulation. Competition impacted athletes' psychophysiological state, with a significant decline in attentional capacity (reaction time slowing), whereas changes in cardiac vagal modulation over time did not reach statistical significance. Exploratory analyses suggested that pre-competition psychophysiological markers may be associated with shooting performance. Greater attentional instability was associated with reduced precision hold stability, decreased aiming accuracy, and poorer trigger control, whereas lower cardiac vagal tone was linked to diminished overall shooting scores. Consistent with these preliminary observations, group comparisons based on pre-competition psychophysiological profiles revealed differences in technical shooting performance, with athletes characterized by higher cardiac vagal tone and greater attentional stability displaying more favorable execution across key parameters. Our findings highlight the potential interplay between psychophysiological state and shooting performance, suggesting that autonomic and attentional regulation may represent relevant factors to consider when preparing athletes for Olympic shooting competition and informing strategies aimed at supporting performance under competitive demands.","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"8 1","pages":"e70335"},"PeriodicalIF":4.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148388565","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":"Skeletal Muscle Mass Is Independently Associated With Water Turnover in Male Athletes","authors":"Hiroyuki Sagayama, Yoko Tanabe, Akiko Uchizawa, Suraiya Khatun, Keisuke Shiose, Rie Tomiga‐Takae, Jun Yasukata, Yasuki Higaki, Takahiro Ohnishi, Hideyuki Takahashi, Yosuke Yamada, Analiza M. Silva, Emi Kondo","doi":"10.1111/sms.70332","DOIUrl":"https://doi.org/10.1111/sms.70332","url":null,"abstract":"Fat‐free mass (FFM) is a key component of body composition that contributes moderately to water turnover (WT). However, FFM consists of multiple components, and the extent of its contribution to WT, especially in relation to skeletal muscle mass (SMM) in athletes, remains unclear. This study aimed to examine the association between WT and body composition in athletes. Thirty male participants (20 ± 2 years old) were members of college sports clubs or athletic organizations. WT was determined using the deuterium dilution method for 1 week. Total body water (TBW), intracellular water (ICW), and extracellular water (ECW) were measured using deuterium and sodium bromide dilution. Bone mineral content was measured using DXA, and four‐component models were used to calculate FFM and total body protein (TBP). MRI and MRS were used to evaluate SMM and muscle glycogen. WT was positively associated with TBW ( <jats:italic>r</jats:italic> = 0.563), ICW ( <jats:italic>r</jats:italic> = 0.549), SMM ( <jats:italic>r</jats:italic> = 0.548), and ambient temperature ( <jats:italic>r</jats:italic> = 0.519). To overcome mathematical coupling and multicollinearity, regularized regression analyses (LASSO and Elastic Net) were performed. Because TBW and TBP are algebraically dependent on the deuterium‐derived water space from which WT was calculated, they were excluded from the candidate predictors. Both models retained SMM, ICW, and ambient temperature as predictors of WT, whereas ECW, bone mineral content, muscle glycogen, and relative humidity were not retained. The modest cross‐validated performance (leave‐one‐out <jats:italic>R</jats:italic> <jats:sup>2</jats:sup> = 0.20–0.23) suggests that WT in athletes is also influenced by behavioral and unmeasured environmental factors. Functional body composition compartments, specifically SMM and ICW, were associated with WT in athletes beyond the mathematical dependency between WT and TBW; SMM, measured independently by MRI, was an independent correlate, whereas the association of ICW—derived in part from TBW—was not fully independent of the WT measurement.","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"27 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148355606","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":"Dose-Response Effects of a 4-Month FIT FIRST 10 School-Based Multisport Programme on Physical Fitness and Psychosocial Well-Being in Children Aged 7-11: A Three-Arm Cluster-Randomized Controlled Trial.","authors":"Caroline Eckert, Cecilie Thøgersen-Ntoumani, Malte Nejst Larsen, Sofie Koch, Lars Breum Christiansen, Christina Birch Meiner, Chiara Cimenti, Giampiero Tarantino, Nikos Ntoumanis, Peter Krustrup","doi":"10.1111/sms.70311","DOIUrl":"10.1111/sms.70311","url":null,"abstract":"<p><p>Low physical activity (PA) and fitness in childhood are linked to adverse health outcomes, yet many Danish children do not meet national guidelines. The FIT FIRST 10 (FF10) multisport PE programme was developed to increase PA in primary schools. To evaluate dose-response effects of a 4-month FF10 intervention on physical fitness and psychosocial well-being. Three-arm, cluster-randomized trial (1:1:1). 1357 pupils (7-11 years) from 68 classes in 27 schools were allocated to control (CON, n = 529), 1.5 FF10 sessions/week (1.5INT, n = 495), or 3 FF10 sessions/week (3INT, n = 333); 1175 provided consent. The primary outcome was cardiorespiratory fitness via the Yo-Yo Intermittent Recovery Level 1 Children's test (YYIR1C). Secondary outcomes included cardiometabolic health, muscular fitness, and psychosocial well-being. No between-group effects were observed for the primary outcome (1.5INT vs. CON: 17 m [-19, 52]; 3INT vs. CON: -8 m [-47, 31]). Among secondary outcomes, 1.5INT showed small favorable effects on body composition (body fat percentage -0.4%; fat mass -0.2 kg; fat mass index -0.1 kg/m²; BMI -0.1 kg/m²) and handgrip strength (+0.4 kg) (all p < 0.05). No intervention effects were observed for cardiovascular or psychosocial domains. Small differences favoring CON over 3INT emerged in standing long jump (-5 cm), postural balance (-0.5 s) and perceived flexibility (-0.3 AU) (all p < 0.05). In conclusion, a moderate, feasible dose of approximately 1.5 FF10 sessions per week appeared more effective than a higher-frequency implementation, highlighting the importance of feasibility and implementation fidelity in real-world school settings. ClinicalTrials.gov (NCT06180772).</p>","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"36 6","pages":"e70311"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148017197","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":"Effect of Age and Sex on Lower Extremity Power Production Capacity Throughout the Lifespan Based on 30 217 Finnish Participant Data.","authors":"Kaisa Koivunen, Eija K Laakkonen, Juha P Ahtiainen, Simon Walker","doi":"10.1111/sms.70322","DOIUrl":"10.1111/sms.70322","url":null,"abstract":"<p><p>This study examined lower-extremity power using countermovement jump (CMJ) height and estimated peak power across the lifespan with five Finnish datasets. The pooled dataset included 24 804 males and 5413 females aged 6-75 years. CMJ height (cm) was measured on a contact mat from flight time(s), and peak power (W) was estimated using equations for adults and children and expressed also relative to body mass (W/kg). Five-year age groups were formed for mean comparison. CMJ height and peak power increased throughout childhood and adolescence. From ages 11 to 15, males exhibited greater CMJ height and peak power than females. Based on mean values, CMJ height peaked at ages 16-20 and peak power at 21-25 in males, while both peaked at 21-25 in females. Males maintained their level until 26-30 years, whereas females showed a decline after the peak. Segmented regression models indicated earlier peaks for CMJ height (18 years in males, 17 in females) and slightly later peaks for peak power (21 years in males, 19 in females). Before the peaking age, annual relative increases calculated over 11-15 years were 5.6% versus 3.1% for CMJ height and 4.7%-7.6% vs. 4.0%-7.3% for peak power (males vs. females). After the peaking age, annual declines calculated over 52-58 years were 0.9% for CMJ height and 0.3%-0.7% for peak power in both sexes. The results provide insights into life-course patterns and the transitional period of late adolescence and early adulthood, when jumping performance peaks and evidence is limited.</p>","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"36 6","pages":"e70322"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13280190/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148278667","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":"Morphology-Mechanics Links of the Free Achilles Tendon Revealed by Three-Dimensional Magnetic Resonance Imaging and Ultrasound Texture Analysis.","authors":"Dongyu Deng, Yasuo Kawakami","doi":"10.1111/sms.70316","DOIUrl":"10.1111/sms.70316","url":null,"abstract":"<p><p>This study aimed to elucidate the relationship between morphological and mechanical characteristics of the free Achilles tendon (AT_Free) in vivo. The morphological features were characterized in terms of overall dimensions (length and cross-sectional area) and internal fascicular organization (longitudinal alignment and transverse structure). Their associations with AT_Free mechanical characteristics, including stiffness and elastic modulus (E-modulus), were examined under low-load passive conditions. Eighteen healthy adults participated. AT_Free length and cross-sectional area (CSA) were quantified from MRI-based three-dimensional reconstructions with the ankle positioned at 20° plantar flexion and 20° dorsiflexion. Passive ankle torque was measured to estimate AT_Free stiffness and E-modulus. B-mode ultrasound images acquired at a standardized site of the AT_Free were analyzed digitally using a two-dimensional Fourier transform-based framework, from which the mean horizontal and vertical peak spatial frequency components (PSF-H and PSF-V; reflecting fascicle longitudinal alignment and transverse structure respectively) were extracted as textural parameters. Simple linear regression revealed that AT_Free stiffness (515 ± 119 N·mm^-1) was positively predicted by CSA (β = 0.526, p = 0.025) but showed no significant association with tendon length or E-modulus. In contrast, E-modulus (485 ± 78 MPa) was negatively associated with PSF-H (β = -0.540, p = 0.021), whereas PSF-V was not predictive and exhibited minimal interindividual variation. These findings suggest two distinct morphology-mechanics links in the AT_Free under low tensile load: greater CSA is associated with higher stiffness, whereas more longitudinally aligned fascicles (reflected by lower PSF-H) correspond to a higher apparent material property (E-modulus).</p>","PeriodicalId":21466,"journal":{"name":"Scandinavian Journal of Medicine & Science in Sports","volume":"36 6","pages":"e70316"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13248229/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148205896","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}