Journal of Functional Morphology and Kinesiology

22 pages, 1837 KiB

Open AccessArticle

Anthropometric Measurements for Predicting Low Appendicular Lean Mass Index for the Diagnosis of Sarcopenia: A Machine Learning Model

by Ana M. González-Martin, Edgar Samid Limón-Villegas, Zyanya Reyes-Castillo, Francisco Esparza-Ros, Luis Alexis Hernández-Palma, Minerva Saraí Santillán-Rivera, Carlos Abraham Herrera-Amante, César Octavio Ramos-García and Nicoletta Righini

J. Funct. Morphol. Kinesiol. 2025, 10(3), 276; https://doi.org/10.3390/jfmk10030276 - 17 Jul 2025

Abstract

Background: Sarcopenia is a progressive muscle disease that compromises mobility and quality of life in older adults. Although dual-energy X-ray absorptiometry (DXA) is the standard for assessing Appendicular Lean Mass Index (ALMI), it is costly and often inaccessible. This study aims to [...] Read more.

Background: Sarcopenia is a progressive muscle disease that compromises mobility and quality of life in older adults. Although dual-energy X-ray absorptiometry (DXA) is the standard for assessing Appendicular Lean Mass Index (ALMI), it is costly and often inaccessible. This study aims to develop machine learning models using anthropometric measurements to predict low ALMI for the diagnosis of sarcopenia. Methods: A cross-sectional study was conducted on 183 Mexican adults (67.2% women and 32.8% men, ≥60 years old). ALMI was measured using DXA, and anthropometric data were collected following the International Society for the Advancement of Kinanthropometry (ISAK) protocols. Predictive models were developed using Logistic Regression (LR), Decision Trees (DTs), Random Forests (RFs), Artificial Neural Networks (ANNs), and LASSO regression. The dataset was split into training (70%) and testing (30%) sets. Model performance was evaluated using classification performance metrics and the area under the ROC curve (AUC). Results: ALMI indicated strong correlations with BMI, corrected calf girth, and arm relaxed girth. Among models, DT achieved the best performance in females (AUC = 0.84), and ANN indicated the highest AUC in males (0.92). Regarding the prediction of low ALMI, specificity values were highest in DT for females (100%), while RF performed best in males (92%). The key predictive variables varied depending on sex, with BMI and calf girth being the most relevant for females and arm girth for males. Conclusions: Anthropometry combined with machine learning provides an accurate, low-cost approach for identifying low ALMI in older adults. This method could facilitate sarcopenia screening in clinical settings with limited access to advanced diagnostic tools. Full article

(This article belongs to the Special Issue Advances in Kinanthropometry: Techniques and Applications in Sports and Health)

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17 pages, 547 KiB

Open AccessArticle

Are There Differences in Motor Coordination Among Spanish Primary School Students?

by Ricardo Fernández-Vázquez, Martín Barcala-Furelos, Javier Cachón-Zagalaz, Víctor Arufe-Giráldez, Marcos Mecías-Calvo and Rubén Navarro-Patón

J. Funct. Morphol. Kinesiol. 2025, 10(3), 275; https://doi.org/10.3390/jfmk10030275 - 17 Jul 2025

Abstract

Background: Motor coordination is a fundamental skill in childhood. Factors such as age, sex, and regular sports practice influence its development. However, there is little research that jointly analyzes the impact of these factors on the motor skills and abilities of primary school [...] Read more.

Background: Motor coordination is a fundamental skill in childhood. Factors such as age, sex, and regular sports practice influence its development. However, there is little research that jointly analyzes the impact of these factors on the motor skills and abilities of primary school children. The objective of this study was to analyze what happens to different motor skills and abilities (i.e., locomotor coordination (LC); visuomotor coordination (VC); foot object control coordination (FOCC); hand object control coordination (HOCC); global motor coordination (GMC)) in relation to regular and regulated sports practice (yes vs. no), sex (boys vs. girls), and age (6 to 11 years) in a sample of 663 primary schoolchildren (8.59 ± 1.65 years; 48.26% boys) from Galicia (Spain). Methods: The 3JS test was used to analyze motor coordination. To determine differences between the 3JS variables, a multivariate analysis of covariance (MANCOVA) was performed based on age, sex, and sports practice, including a BMI category (normal weight, overweight, or obese) as a covariate to avoid potential confounding factors. Results: Statistically significant differences were observed based on age [LC (p < 0.001); VC (p < 0.001); FOCC (p < 0.001); HOCC (p < 0.001); CMG (p < 0.001)], sex [i.e., VC (p < 0.001); FOCC (p < 0.001); HOCC (p < 0.001); CMG (p < 0.001)], and sports practice [i.e., LC (p < 0.001); VC (p = 0.008); HOCC (p < 0.001); CMG (p < 0.001)], after the application of the 3JS battery. Conclusions: Locomotor coordination in Primary Education is modulated by the interaction between age, sex, and sports practice. All of these variables increase with age, with higher scores in boys than in girls, and higher scores in children who participate in sports than in those who do not. Full article

(This article belongs to the Special Issue Tailoring Physical Activity for the Health and Development of Children and Adolescents)

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15 pages, 1472 KiB

Open AccessArticle

Determinants of 50 m Front Crawl Performance in Adolescent Non-Elite Female Swimmers: A Longitudinal Study

by Mariusz Kuberski, Agnieszka Musial, Michalina Błażkiewicz and Jacek Wąsik

J. Funct. Morphol. Kinesiol. 2025, 10(3), 274; https://doi.org/10.3390/jfmk10030274 - 17 Jul 2025

Abstract

Objectives: The aim of this study was to indicate which variables are the most important determinants of swimming results in the 50 m front crawl among non-elite pre-pubertal female swimmers. Methods: The study group consisted of 14 female swimmers (at the [...] Read more.

Objectives: The aim of this study was to indicate which variables are the most important determinants of swimming results in the 50 m front crawl among non-elite pre-pubertal female swimmers. Methods: The study group consisted of 14 female swimmers (at the time of the research commencement—biological age: 10.52 ± 0.37 years; body mass: 34.99 ± 2.77 kg; height: 146.00 ± 3.05 cm). The study was conducted over three years. The swimmers performed capacity training recommended by the British Swimming Federation. Every 6 months, in the participants the following parameters were measured: percentage of body fat; anthropometric measurements; aerobic and anaerobic capacity; and respiratory parameters: vital capacity—VC, forced expiratory volume—FEV1, and forced vital capacity—FVC. Additionally, a 50 m front crawl swim test was performed. Results: After adjusting for multicollinearity, the most influential determinants of swimming performance were anthropometric measures: shoulder width was the most influential predictor, with a regression coefficient of −0.66, followed by foot length (with a beta of −0.15) and chest depth (with a beta of 0.008). The remaining anthropometric and physical predictors did not contribute to the prediction of 50 m freestyle performance. Conclusions: These research results suggest to coaches and trainers that sports performance in sprint distances in pre-pubertal girls is not determined by aerobic and anaerobic capacity or body fat but is based on the somatic build of the swimmer. Full article

(This article belongs to the Special Issue Optimizing Performance: Training Strategies to Improve Strength, Speed, Power, and Endurance)

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14 pages, 985 KiB

Open AccessArticle

Forefoot Centre of Pressure Patterns in Black Male African Recreational Runners with Pes Planus

by Jodie Dickson, Glen James Paton and Yaasirah Mohomed Choonara

J. Funct. Morphol. Kinesiol. 2025, 10(3), 273; https://doi.org/10.3390/jfmk10030273 - 16 Jul 2025

Abstract

Background: Pes planus is a condition where the arch of the foot collapses, resulting in the entire sole contacting the ground. The biomechanical implications of pes planus on gait have been widely studied; however, research specific to Black African populations, particularly recreational runners, [...] Read more.

Background: Pes planus is a condition where the arch of the foot collapses, resulting in the entire sole contacting the ground. The biomechanical implications of pes planus on gait have been widely studied; however, research specific to Black African populations, particularly recreational runners, is scarce. Aim: This study aimed to describe the forefoot centre of pressure (CoP) trajectory during the barefoot gait cycle among Black African recreational runners with pes planus. Methods: A prospective explorative and quantitative study design was employed. Participants included Black African male recreational runners aged 18 to 45 years diagnosed with pes planus. A Freemed™ 6050 force plate was used to collect gait data. Statistical analysis included cross-tabulations to identify patterns. Results: This study included 104 male participants across seven weight categories, with the majority in the 70-to-79 kg range (34.6%, n = 36). Most participants with pes planus showed a neutral foot posture (74.0%, n = 77) on the foot posture index 6 (FPI-6) scale. Flexible pes planus (94.2%, n = 98) was much more common than rigid pes planus (5.8%, n = 6). Lateral displacement of the CoP was observed in the right forefoot (90.4%, n = 94) and left forefoot (57.7%, n = 60). Load distribution patterns differed between feet, with the right foot favouring the medial heel, arch, and metatarsal heads, while the left foot favoured the lateral heel, medial heel, and lateral arch. No statistical significance was found in the cross-tabulations, but notable lateral CoP displacement in the forefoot was observed. Conclusions: The findings challenge the traditional view of pes planus causing overpronation and highlight the need for clinicians to reconsider standard diagnostic and management approaches. Further research is needed to explore the implications of these findings for injury prevention and management in this population. Full article

(This article belongs to the Special Issue Biomechanical Analysis in Physical Activity and Sports—2nd Edition)

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13 pages, 602 KiB

Open AccessArticle

Is Cardiopulmonary Fitness Related to Attention, Concentration, and Academic Performance in Different Subjects in Schoolchildren?

by Markel Rico-González, Ricardo Martín-Moya, Jorge Carlos-Vivas, Francisco Javier Giles-Girela, Luca Paolo Ardigò and Francisco Tomás González-Fernández

J. Funct. Morphol. Kinesiol. 2025, 10(3), 272; https://doi.org/10.3390/jfmk10030272 - 16 Jul 2025

Abstract

Background: The perceived importance of physical practice and its contribution to students’ academic success have evolved considerably throughout the history of the modern educational system. Aim: The purpose of this study was to understand the relationship between physical fitness (measured as VO₂ [...] Read more.

Background: The perceived importance of physical practice and its contribution to students’ academic success have evolved considerably throughout the history of the modern educational system. Aim: The purpose of this study was to understand the relationship between physical fitness (measured as VO₂max) and cognitive abilities (attention and concentration) and academic performance in different subjects: sciences, letters, language, arts, and physical education. Method: Fifty Spanish male students who participated in extracurricular sports activities (mean age (SD): 11.59 ± 1.30; range: 9–15 years) were included in the analysis. The 6 min walk test was used to assess physical fitness (6MWT), while for selective attention and concentration, the students completed the D2 test, which is usually considered to analyse the visual ability to select the most relevant stimulus of an exercise and ignore precisely the most irrelevant stimuli. Results: Correlation the individual contribution analyses revealed no significant associations between VO₂max and academic performance in sciences (r = 0.04, p = 0.77), humanities (r = 0.00, p = 0.98), language (r = 0.03, p = 0.83), or arts (r = 0.04, p = 0.76). Similarly, no relationship was found between VO₂max and overall academic performance (r = 0.10, p = 0.46), or cognitive abilities. However, a small positive correlation was observed between VO₂max and physical education scores. Conclusions: Physical fitness showed no significant association with cognitive abilities or academic performance in most subjects, although a small positive correlation with physical education scores was observed. These findings emphasise the importance of promoting physical activity for its health and physical benefits. However, future research should explore broader cognitive outcomes and include more diverse and representative samples. Full article

(This article belongs to the Special Issue Health and Performance Through Sports at All Ages: 4th Edition)

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12 pages, 606 KiB

Open AccessArticle

High-Intensity Interval Training Improves Cardiovascular Fitness and Induces Left-Ventricular Hypertrophy During Off-Season

by Tomas Venckunas, Birute Gumauskiene, Pornpimol Muanjai, Joan Aureli Cadefau and Sigitas Kamandulis

J. Funct. Morphol. Kinesiol. 2025, 10(3), 271; https://doi.org/10.3390/jfmk10030271 - 16 Jul 2025

Abstract

Background: Well-designed endurance training leads to improved cardiovascular fitness and sports performance in prolonged exercise tasks, with the adaptations depending on multiple factors, including the training modality and the population in question. It is still disputable how the type of training affects [...] Read more.

Background: Well-designed endurance training leads to improved cardiovascular fitness and sports performance in prolonged exercise tasks, with the adaptations depending on multiple factors, including the training modality and the population in question. It is still disputable how the type of training affects myocardial remodeling, and the information on myocardial remodeling by high-intensity interval training (HIIT) is particularly scarce. Methods: The current study investigated changes in cardiac structure after volume-progressive HIIT in running mode. As part of their conditioning program, amateur athletes (mean ± SD age of 18.2 ± 1.0 years) exclusively conducted HIIT in a volume-progressive fashion over 7 weeks (a total of 21 sessions). Peak oxygen uptake as well as 200 m and 2000 m running performance were measured, and transthoracic two-dimensional echocardiography was conducted before and after the intervention. Results: Training improved running performance, increased the peak oxygen uptake and left atrium diameter (from 32.0 ± 2.5 to 33.5 ± 2.3 mm; p = 0.01), and induced ~11% thickening of the left-ventricular posterior wall (7.5 ± 0.7 to 8.2 ± 0.4 mm; p = 0.01) and interventricular septum (7.6 ± 0.7 to 8.6 ± 0.9 mm; p = 0.02), but not the dilation of left-ventricular, right-ventricular, or right atrium chambers. Conclusions: HIIT of just 127 km of running per 8.5 h during 7 weeks was sufficient to improve aerobic capacity and running performance, and induce left-ventricular wall hypertrophy and left atrium dilation, in young healthy athletes. Full article

(This article belongs to the Special Issue Optimizing Performance: Training Strategies to Improve Strength, Speed, Power, and Endurance)

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18 pages, 832 KiB

Open AccessArticle

Warm-Up Strategies at Halftime: A Pilot Randomized Controlled Trial in a Professional Women’s Soccer Team

by Marco Abreu, Fábio Y. Nakamura, Thiago Carvalho, Davi Silva, Fabrício Vasconcellos and José Afonso

J. Funct. Morphol. Kinesiol. 2025, 10(3), 270; https://doi.org/10.3390/jfmk10030270 - 16 Jul 2025

Abstract

Objectives: We compared the effects of two active re-warm-up protocols applied during halftime’s last three minutes, after a warm-up, testing, and a simulated first-half match. Methods: Twenty-two professional players from a first Portuguese division club were randomized into two re-warm-up protocols during a [...] Read more.

Objectives: We compared the effects of two active re-warm-up protocols applied during halftime’s last three minutes, after a warm-up, testing, and a simulated first-half match. Methods: Twenty-two professional players from a first Portuguese division club were randomized into two re-warm-up protocols during a simulated match interval: (i) a strength, plyometrics, and balance protocol (SPBP); and (ii) a soccer-specific protocol (SSP). Players were assessed for a 20-m linear sprint and countermovement jump (CMJ) after the warm-up and the re-warm-up. Descriptive statistics and mixed ANOVA were performed, with effect size assessed using partial eta-squared. The Acute Readiness Monitoring Scale (ARMS) questionnaire was administered after the simulated match and re-warm-up and was analyzed using a multifactorial ANOVA. Results: No significant interaction effects were observed (p > 0.05). Comparing pre-match to post-re-warm-up, there was a slight decrease in sprint (significant) and jump performance (non-significant). Additionally, there were no between-protocol differences in perceived readiness (ARMS). Conclusions: After the three-minute re-warm-up protocols, similar results were observed in the 20-m sprint performance, CMJ, and perceived readiness when comparing SPBP and SSP. These re-warm-up protocols (SPBP and SSP) are practical to implement within a 3-min time window, and, given their apparent lack of differences, players’ preferences could be considered. However, the SSP is currently subject to restrictions that limit teams’ access to the field during this period. Future research should compare active re-warm-up protocols with passive controls to more clearly assess their effectiveness. Full article

(This article belongs to the Special Issue Optimizing Post-activation Performance Enhancement)

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21 pages, 899 KiB

Open AccessArticle

Cervical Spine Range of Motion Reliability with Two Methods and Associations with Demographics, Forward Head Posture, and Respiratory Mechanics in Patients with Non-Specific Chronic Neck Pain

by Petros I. Tatsios, Eirini Grammatopoulou, Zacharias Dimitriadis, Irini Patsaki, George Gioftsos and George A. Koumantakis

J. Funct. Morphol. Kinesiol. 2025, 10(3), 269; https://doi.org/10.3390/jfmk10030269 - 16 Jul 2025

Abstract

Objectives: New smartphone-based methods for measuring cervical spine range of motion (CS-ROM) and posture are emerging. The purpose of this study was to assess the reliability and validity of three such methods in patients with non-specific chronic neck pain (NSCNP). Methods: [...] Read more.

Objectives: New smartphone-based methods for measuring cervical spine range of motion (CS-ROM) and posture are emerging. The purpose of this study was to assess the reliability and validity of three such methods in patients with non-specific chronic neck pain (NSCNP). Methods: The within-day test–retest reliability of CS-ROM and forward head posture (craniovertebral angle-CVA) was examined in 45 patients with NSCNP. CS-ROM was simultaneously measured with an accelerometer sensor (KFORCE Sens^®) and a mobile phone device (iHandy and Compass apps), testing the accuracy of each and the parallel-forms reliability between the two methods. For construct validity, correlations of CS-ROM with demographics, lifestyle, and other cervical and thoracic spine biomechanically based measures were examined in 90 patients with NSCNP. Male–female differences were also explored. Results: Both methods were reliable, with measurements concurring between the two devices in all six movement directions (intraclass correlation coefficient/ICC = 0.90–0.99, standard error of the measurement/SEM = 0.54–3.09°). Male–female differences were only noted for two CS-ROM measures and CVA. Significant associations were documented: (a) between the six CS-ROM measures (R = 0.22–0.54, p < 0.05), (b) participants’ age with five out of six CS-ROM measures (R = 0.23–0.40, p < 0.05) and CVA (R = 0.21, p < 0.05), (c) CVA with two out of six CS-ROM measures (extension R = 0.29, p = 0.005 and left-side flexion R = 0.21, p < 0.05), body mass (R = −0.39, p < 0.001), body mass index (R = −0.52, p < 0.001), and chest wall expansion (R = 0.24–0.29, p < 0.05). Significantly lower forward head posture was noted in subjects with a high level of physical activity relative to those with a low level of physical activity. Conclusions: The reliability of both CS-ROM methods was excellent. Reductions in CS-ROM and increases in CVA were age-dependent in NSCNP. The significant relationship identified between CVA and CWE possibly signifies interconnections between NSCNP and the biomechanical aspect of dysfunctional breathing. Full article

(This article belongs to the Section Kinesiology and Biomechanics)

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17 pages, 2134 KiB

Open AccessArticle

Analysis of Movement Variability During the Spike Jump Action in Young and High-Level Female Volleyball Players: Differences Between Categories and Playing Positions

by Jordi Català, Gerard Moras, Víctor Toro-Román, Carla Pérez-Chirinos Buxadé, Silvia Tuyà-Viñas and Bruno Fernández-Valdés

J. Funct. Morphol. Kinesiol. 2025, 10(3), 268; https://doi.org/10.3390/jfmk10030268 - 16 Jul 2025

Abstract

Objectives: The aim of this study was to analyze and compare movement variability (MV) during the spike jump (S) action with and without a ball in volleyball players of different categories and playing positions. Methods: A total of 48 volleyball players [...] Read more.

Objectives: The aim of this study was to analyze and compare movement variability (MV) during the spike jump (S) action with and without a ball in volleyball players of different categories and playing positions. Methods: A total of 48 volleyball players participated in this study. The players were divided according to the following categories: under-14 (U-14) (n = 12); U-16 (n = 12); U-19 (n = 12); and SENIOR (n = 12). Also, they were divided according to playing position: hitters (n = 24); liberos (n = 5); middle blockers (n = 12); and setters (n = 7). The S action with and without a ball was analyzed. Acceleration was analyzed using an IMU device. Acceleration was used to calculate MV through sample entropy (SampEn). Results: Differences were observed in all categories when comparing the S action with and without the ball (p < 0.001). SampEn was higher in the U-14 category (p < 0.001). Regarding playing positions, SampEn was lower in the hitter position compared to the middle blocker (p < 0.001) and libero (p < 0.001). There were significant inverse correlations between years of experience and SampEn (p < 0.05). Conclusions: The inclusion of a ball during the S action increases MV. MV is higher in the U-14 category compared to the rest. The hitter position showed lower MV compared to the other playing positions. Full article

(This article belongs to the Special Issue Sports-Specific Conditioning: Techniques and Applications)

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13 pages, 286 KiB

Open AccessArticle

Lack of Neuromuscular Fatigue in Singles Pickleball Tournament: A Preliminary Study

by Eric A. Martin, Steven B. Kim, George K. Beckham and James J. Annesi

J. Funct. Morphol. Kinesiol. 2025, 10(3), 267; https://doi.org/10.3390/jfmk10030267 - 16 Jul 2025

Abstract

Objectives: The objective of this study was to examine the neuromuscular fatigue response to playing in a singles pickleball tournament, as measured by performance on a countermovement jump test (CMJ). We hypothesized that players would exhibit neuromuscular fatigue after the tournament. Methods: Six [...] Read more.

Objectives: The objective of this study was to examine the neuromuscular fatigue response to playing in a singles pickleball tournament, as measured by performance on a countermovement jump test (CMJ). We hypothesized that players would exhibit neuromuscular fatigue after the tournament. Methods: Six adult pickleball players (five male and one female, M ± SD: 40.2 ± 10.1 years old, height = 178.7 ± 12.3 cm, body mass = 85.4 ± 16.7 kg) participated in a 15 game singles pickleball tournament. Prior to the tournament, everyone completed the CMJ to assess lower body strength and power on paired Hawkin Dynamics force plates. After the tournament, players repeated the CMJ. Mixed-effects regression modeling was used to examine changes in key outcomes measured from the CMJ. Results: All nine outcomes from the CMJ significantly changed from pre to post-tournament (e.g., means for net impulse increased from 2.32 ± 0.22 to 2.40 ± 0.18 N·s, p = 0.0006; RSImod increased from 0.28 ± 0.07 to 0.33 ± 0.05, p = 0.0001, and propulsive peak power increased from 41.79 ± 6.14 to 44.34 ± 4.70 W/kg, p < 0.0001). All the changes demonstrated improved performance in the CMJ test. Seven out of the nine outcomes demonstrated a large effect size by the partial-eta square statistic, with η²-partial of 0.153–0.487, and three key outcomes (RSImod, propulsive peak power, and propulsive mean power) also demonstrated large effect sizes by the F² statistic (F² of 0.4603–0.9495). Conclusions: Contrary to our hypothesis, participants did not demonstrate significant neuromuscular fatigue. In contrast, they showed significant improvements in CMJ performance. It is possible that adequate rest between games prevented neuromuscular fatigue; alternately, singles pickleball may not provide enough stimulus in the lower body musculature to induce neuromuscular fatigue. Full article

(This article belongs to the Special Issue Racket Sport Dynamics)

16 pages, 624 KiB

Open AccessArticle

Impact of a Four-Week NCAA-Compliant Pre-Season Strength and Conditioning Program on Body Composition in NCAA Division II Women’s Basketball

by Zacharias Papadakis

J. Funct. Morphol. Kinesiol. 2025, 10(3), 266; https://doi.org/10.3390/jfmk10030266 - 15 Jul 2025

Abstract

Background: Pre-season training is pivotal for optimizing athletic performance in collegiate basketball, yet the effectiveness of such programs in improving body composition (BC) under NCAA-mandated hourly restrictions remains underexplored. The aim of this study was to evaluate the impact of a four-week, NCAA [...] Read more.

Background: Pre-season training is pivotal for optimizing athletic performance in collegiate basketball, yet the effectiveness of such programs in improving body composition (BC) under NCAA-mandated hourly restrictions remains underexplored. The aim of this study was to evaluate the impact of a four-week, NCAA Division II-compliant strength and conditioning (SC) program on BC in women’s basketball. Methods: Sixteen student athletes (20.6 ± 1.8 y; 173.9 ± 6.5 cm; 76.2 ± 20.2 kg) completed an eight-hour-per-week micro-cycle incorporating functional conditioning, Olympic-lift-centric resistance, and on-court skill development. Lean body mass (LBM) and body-fat percentage (BF%) were assessed using multi-frequency bioelectrical impedance on Day 1 and Day 28. Linear mixed-effects models were used to evaluate the fixed effect of Time (Pre, Post), including random intercepts for each athlete and covariate adjustment for age and height (α = 0.05). Results The LBM significantly increased by 1.49 kg (β = +1.49 ± 0.23 kg, t = 6.52, p < 0.001; 95% CI [1.02, 1.96]; R² semi-partial = 0.55), while BF% decreased by 1.27 percentage points (β = −1.27 ± 0.58%, t = −2.20, p = 0.044; 95% CI [−2.45, −0.08]; R² = 0.24). Height positively predicted LBM (β = +1.02 kg/cm, p < 0.001), whereas age showed no association (p > 0.64). Conclusions: A time-constrained, NCAA-compliant SC program meaningfully enhances lean mass and moderately reduces adiposity in collegiate women’s basketball athletes. These findings advocate for structured, high-intensity, mixed-modality training to maximize physiological readiness within existing regulatory frameworks. Future research should validate these results in larger cohorts and integrate performance metrics to further elucidate functional outcomes. Full article

(This article belongs to the Special Issue Optimizing Performance: Training Strategies to Improve Strength, Speed, and Power)

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14 pages, 1973 KiB

Open AccessArticle

The Effects of Short-Duration Ischemic Preconditioning on Horizontal and Vertical Jump Performance in Male and Female Track and Field Jumpers

by Varvara Nektaria Gkari, Athanasios Tsoukos, Nikolaos Aspradakis and Gregory C. Bogdanis

J. Funct. Morphol. Kinesiol. 2025, 10(3), 265; https://doi.org/10.3390/jfmk10030265 - 14 Jul 2025

Abstract

Background: Ischemic preconditioning (IPC) is a non-invasive, time-efficient strategy that has been shown to acutely enhance athletic performance. The present study examined the effects of 5 min of IPC on vertical and horizontal jump performance. A secondary aim was to explore the [...] Read more.

Background: Ischemic preconditioning (IPC) is a non-invasive, time-efficient strategy that has been shown to acutely enhance athletic performance. The present study examined the effects of 5 min of IPC on vertical and horizontal jump performance. A secondary aim was to explore the associations between outcomes of the 5-Hop (5-H) test and drop jump performance, in order to provide further evidence supporting the validity of the 5-H test for assessing reactive strength characteristics in trained jumpers. Methods: Twelve trained track and field jumpers (nine males, three females, age: 23.2 ± 2.9 years; height: 1.76 ± 0.07 m; body mass: 71.5 ± 8.0 kg) completed two conditions: an IPC condition applied to one leg and a control condition applied to the contralateral leg. In the first week, one leg was assigned to IPC and the other to the control condition, while in the second week, the conditions for each leg were reversed. Vertical single-leg performance was evaluated by drop jump (DJ) height, ground contact time, and reactive strength index (RSI). Horizontal jump performance was assessed by a five-hop (5-H) test during which total distance (TD), total time (TT), and reactive hopping index (RHI) were obtained. Results: Compared to the control condition, IPC enhanced DJ height (+ 3.6%) and RSI (+ 7.8%) (p < 0.05, g = 0.16 and 0.32, respectively) and reduced contact time (−4.4% p < 0.05, g = 0.41). Also, IPC resulted in significant improvements in TD (+ 4.1%) and RHI (+ 3.9%) during the 5-H test (p < 0.05, g = 0.32 and 0.42, respectively), while TT remained unchanged. Conclusions: A single cycle of IPC acutely improved vertical and horizontal jump performance and reactive strength indices in trained jumpers. These findings support the use of IPC as a practical, time-efficient method to enhance neuromuscular performance in explosive tasks. Full article

(This article belongs to the Special Issue Optimizing Performance: Training Strategies to Improve Strength, Speed, Power, and Endurance)

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10 pages, 719 KiB

Open AccessArticle

Effects of Clenching Strength on Step Reaction Time

by Nao Sugai, Ryo Hirabayashi, Yoshiyuki Okada, Yuriko Yoshida, Takeru Okouchi, Hirotake Yokota, Tomonobu Ishigaki, Makoto Komiya and Mutsuaki Edama

J. Funct. Morphol. Kinesiol. 2025, 10(3), 264; https://doi.org/10.3390/jfmk10030264 - 13 Jul 2025

Abstract

Background: Reaction time is analyzed in various situations in sporting events and is reported to be so important that it can make the difference between victory and defeat. This study focused on teeth clenching resulting in remote muscle activation, and examined whether it [...] Read more.

Background: Reaction time is analyzed in various situations in sporting events and is reported to be so important that it can make the difference between victory and defeat. This study focused on teeth clenching resulting in remote muscle activation, and examined whether it improves performance of reaction time. This study examined the effects of clenching and clenching strength on the systemic simple reaction time. Methods: This study included 20 healthy adults with normal clenching and a right dominant foot. The task movement for the systemic simple reaction time measurement was a 30 cm forward step. The following three clenching conditions were used: no clenching without dental contact (no-bite condition), a condition in which the participants were instructed to clench with moderate strength (moderate condition), and a condition in which the participants clenching with maximum effort (max condition). The analysis items were release time, grounding time, soleus muscle (Sol) reaction time, and masseter muscle activity. Results: The max condition significantly reduced the reaction time compared with the no-bite condition. Sol reaction and grounding times showed a negative correlation between clenching strength under moderate conditions and the rate of change in reaction time under no-bite and moderate conditions. Release time exhibited no significant correlation between clenching strength under the moderate condition and the rate of change in reaction time under the no-bite and moderate conditions. The remote facilitation effect of clenching improved the systemic reaction time by producing immediate muscle activity. Conclusions: Clenching shortens the systemic simple reaction time. This finding highlights the potential importance of clenching in enhancing performance during sporting events. Full article

(This article belongs to the Section Kinesiology and Biomechanics)

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15 pages, 287 KiB

Open AccessArticle

Injury, Risk and Training Habits Among Dog Agility Handlers: A Cross-Sectional Study

by Andrea Demeco, Laura Pinotti, Alessandro de Sire, Nicola Marotta, Antonello Salerno, Teresa Iona, Antonio Frizziero, Dalila Scaturro, Giulia Letizia Mauro, Umile Giuseppe Longo, Antonio Ammendolia and Cosimo Costantino

J. Funct. Morphol. Kinesiol. 2025, 10(3), 263; https://doi.org/10.3390/jfmk10030263 - 12 Jul 2025

Abstract

Background: Dog agility is a rapidly growing sport involving a partnership between a dog and the handler, running through an obstacle course. Despite its increasing popularity and physical benefits, research on handler injuries remains limited. This study aimed to assess injury epidemiology [...] Read more.

Background: Dog agility is a rapidly growing sport involving a partnership between a dog and the handler, running through an obstacle course. Despite its increasing popularity and physical benefits, research on handler injuries remains limited. This study aimed to assess injury epidemiology of athletes practicing dog agility. Methods: This cross-sectional study was conducted using a comprehensive online survey consisting of 124 items, available in both English and Italian. The questionnaire was divided into four sections: Introduction collected demographic data and medical history; Materials and Methods focused on agility-related activities; Results explored injuries sustained in the past 12 months; Discussion examined training habits unrelated to agility. Results: Among 389 participants, the most represented age group ranged between 30 and 40 years old. Overall, 7% reported upper limb injuries, while 27% experienced at least one lower limb injury. Additionally, 20% of participants used medication, and 25% reported at least one chronic illness. On average, handlers trained twice per week and competed in two events per month. Lower limb injuries were predominantly muscular (49%) or ligamentous (14%) and most commonly occurred on grass pitches (56%). These injuries were more common in participants with a higher BMI, those using dynamic handling styles, and those competing at higher levels. Conclusions: This cross-sectional study highlighted the importance of identifying risk factors associated with dog agility handlers. Lower limb injuries were the most common, often associated with increased physical demands and handling styles involving intensive running and correlated with reduced physical fitness. Athletic conditioning, including structured warm-up and cool-down practices, might help decline injury risks. Full article

(This article belongs to the Section Kinesiology and Biomechanics)

20 pages, 1370 KiB

Open AccessArticle

Interpretable Machine Learning for Osteopenia Detection: A Proof-of-Concept Study Using Bioelectrical Impedance in Perimenopausal Women

by Dimitrios Balampanos, Christos Kokkotis, Theodoros Stampoulis, Alexandra Avloniti, Dimitrios Pantazis, Maria Protopapa, Nikolaos-Orestis Retzepis, Maria Emmanouilidou, Panagiotis Aggelakis, Nikolaos Zaras, Maria Michalopoulou and Athanasios Chatzinikolaou

J. Funct. Morphol. Kinesiol. 2025, 10(3), 262; https://doi.org/10.3390/jfmk10030262 - 11 Jul 2025

Abstract

Objectives: The early detection of low bone mineral density (BMD) is essential for preventing osteoporosis and related complications. While dual-energy X-ray absorptiometry (DXA) remains the gold standard for diagnosis, its cost and limited availability restrict its use in large-scale screening. This study investigated [...] Read more.

Objectives: The early detection of low bone mineral density (BMD) is essential for preventing osteoporosis and related complications. While dual-energy X-ray absorptiometry (DXA) remains the gold standard for diagnosis, its cost and limited availability restrict its use in large-scale screening. This study investigated whether raw bioelectrical impedance analysis (BIA) data combined with explainable machine learning (ML) models could accurately classify osteopenia in women aged 40 to 55. Methods: In a cross-sectional design, 138 women underwent same-day BIA and DXA assessments. Participants were categorized as osteopenic (T-score between −1.0 and −2.5; n = 33) or normal (T-score ≥ −1.0) based on DXA results. Overall, 24.1% of the sample were classified as osteopenic, and 32.85% were postmenopausal. Raw BIA outputs were used as input features, including impedance values, phase angles, and segmental tissue parameters. A sequential forward feature selection (SFFS) algorithm was employed to optimize input dimensionality. Four ML classifiers were trained using stratified five-fold cross-validation, and SHapley Additive exPlanations (SHAP) were applied to interpret feature contributions. Results: The neural network (NN) model achieved the highest classification accuracy (92.12%) using 34 selected features, including raw impedance measurements, derived body composition indices such as regional lean mass estimates and the edema index, as well as a limited number of categorical variables, including self-reported physical activity status. SHAP analysis identified muscle mass indices and fluid distribution metrics, features previously associated with bone health, as the most influential predictors in the current model. Other classifiers performed comparably but with lower precision or interpretability. Conclusions: ML models based on raw BIA data can classify osteopenia with high accuracy and clinical transparency. This approach provides a cost-effective and interpretable alternative for the early identification of individuals at risk for low BMD in resource-limited or primary care settings. Full article

(This article belongs to the Special Issue Applications of Machine Learning in Sports Medicine, Physical Activity, Posture, and Rehabilitation)

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19 pages, 1231 KiB

Open AccessArticle

The Development and Preliminary Validation of a Rhythmic Jumping Task for Coordination Assessment: A Task Design Based on Upper and Lower Limb Motor Congruency

by Runjie Li, Tetsuya Miyazaki, Tomoyuki Matsui, Megumi Gonno, Teruo Nomura, Toru Morihara, Hitoshi Koda and Noriyuki Kida

J. Funct. Morphol. Kinesiol. 2025, 10(3), 261; https://doi.org/10.3390/jfmk10030261 - 11 Jul 2025

Abstract

Background: The coordination between the upper and lower limbs is essential for athletic performance. However, the structural features that influence coordination difficulty remain insufficiently understood. Few studies have systematically analyzed how task components such as the directional congruence or rhythm structure affect inter-limb [...] Read more.

Background: The coordination between the upper and lower limbs is essential for athletic performance. However, the structural features that influence coordination difficulty remain insufficiently understood. Few studies have systematically analyzed how task components such as the directional congruence or rhythm structure affect inter-limb coordination. Objective: This study aimed to clarify the structural factors that influence the difficulty of upper–lower limb coordination tasks under rhythmic constraints and to explore the feasibility of applying such tasks in future coordination assessments. Methods: Eighty-six male high school baseball players performed six Rhythm Jump tasks combining fixed upper limb movements with varying lower limb patterns. The task performance was analyzed using three indices: full task success, partial success, and average successful series. One year later, a follow-up test involving 27 participants was conducted to evaluate the reproducibility and sensitivity to the performance change. Results: The task difficulty was significantly affected by structural features, including directional incongruence, upper limb static holding, and rhythmic asynchrony. The tasks that exhibited these features had lower success rates. Some tasks demonstrated moderate reproducibility and captured subtle longitudinal changes in the performance. Conclusions: The results highlight the key structural factors contributing to coordination difficulty and support the potential applicability of Rhythm Jump tasks as a basis for future assessment tools. Although further validation is necessary, this study provides foundational evidence for the development of practical methods for evaluating inter-limb coordination. Full article

(This article belongs to the Section Kinesiology and Biomechanics)

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10 pages, 248 KiB

Open AccessArticle

The Effects of Volume-Matched One-Day Versus Two-Day Eccentric Training on Physical Performance in Male Youth Soccer Players

by Raja Bouguezzi, Yassine Negra, Senda Sammoud and Helmi Chaabene

J. Funct. Morphol. Kinesiol. 2025, 10(3), 260; https://doi.org/10.3390/jfmk10030260 - 9 Jul 2025

Abstract

Objectives: This randomized controlled trial investigated the effects of an 8-week, volume-equated eccentric training program comprising Nordic hamstring and reverse Nordic exercises performed either once or twice per week on measures of physical fitness in pubertal male soccer players. Methods: A total [...] Read more.

Objectives: This randomized controlled trial investigated the effects of an 8-week, volume-equated eccentric training program comprising Nordic hamstring and reverse Nordic exercises performed either once or twice per week on measures of physical fitness in pubertal male soccer players. Methods: A total of 34 participants were randomly assigned into a 1-day (n = 16; age = 14.58 ± 0.28 years) or 2-day (n = 18; age = 14.84 ± 0.22 years) per week training group. Physical fitness was assessed using 5 m and 10 m sprints, the 505 change in direction (CiD) speed test, Y-shaped agility test, countermovement jump (CMJ), and standing long jump (SLJ). Results: Significant group-by-time interactions were observed for the 505 CiD test, agility, and CMJ performance (effect sizes [ES] = 0.80 to 1.13). However, no significant interactions were found for the 5 and 10 m sprints or for SLJ (p > 0.05). Compared to the 1-day group, the 2-day training group showed greater improvements in CiD speed (∆7.36%; p < 0.001; ES = 0.92), agility (∆7.91%; p < 0.001; ES = 1.68), and CMJ (∆7.44%; p < 0.01; ES = 0.35), while no differences were observed in 5 and 10 m linear sprints or SLJ performance. According to individual response analysis, improvements across the physical fitness parameters beyond the smallest worthwhile change (SWC_0.2) were observed in 22–83% of players in the 1-day group and 77–100% in the 2-day group. Conclusions: In summary, the findings suggest that when training volume is matched, distributing the eccentric training regimen over two days per week may lead to greater improvements in CiD speed, agility, and CMJ performance compared to a single-day approach. Full article

(This article belongs to the Special Issue Optimizing Performance: Training Strategies to Improve Strength, Speed, and Power)

18 pages, 1665 KiB

Open AccessArticle

Comprehensive Associations Between Spinal–Pelvic Alignment and Muscle Shortening in Healthy Young Men: An Analysis of Individual and Interactive Effects in the Sagittal Plane Using SHapley Additive exPlanation

by Minami Akao, Yuna Ishikura, Takuma Isshiki, Shinnosuke Tsukada, Hayato Shigetoh and Junya Miyazaki

J. Funct. Morphol. Kinesiol. 2025, 10(3), 259; https://doi.org/10.3390/jfmk10030259 - 9 Jul 2025

Abstract

Objectives: To comprehensively examine the association between spinopelvic alignment and muscle shortening in healthy young men, focusing on the individual and interactive effects of thoracic kyphosis, lumbar lordosis, and anterior pelvic tilt using SHapley Additive exPlanation (SHAP) analysis. Methods: Forty-one healthy [...] Read more.

Objectives: To comprehensively examine the association between spinopelvic alignment and muscle shortening in healthy young men, focusing on the individual and interactive effects of thoracic kyphosis, lumbar lordosis, and anterior pelvic tilt using SHapley Additive exPlanation (SHAP) analysis. Methods: Forty-one healthy young adult men participated in this cross-sectional study. Thoracic kyphosis, lumbar lordosis, and anterior pelvic tilt were measured using a flexible curve ruler and inclinometer. Muscle length indices for six muscles (iliopsoas, rectus femoris, gluteus maximus, hamstrings, back extensors, and abdominals) were assessed via standardized physical examinations and image analysis. A machine learning model was developed, and SHAP analysis applied to determine individual and interactive contributions of spinopelvic angles to each muscle length index. Results: SHAP analysis showed that hip-related muscle shortening (iliopsoas, rectus femoris, hamstrings, gluteus maximus) was influenced by both individual alignments and interactions, especially between thoracic kyphosis and lumbar lordosis. Lumbar lordosis was most associated with iliopsoas shortening (SHAP = −0.09), while anterior pelvic tilt was linked to hamstring shortening (SHAP = −0.30). Thoracic kyphosis was the key factor for rectus femoris shortening (SHAP = −0.05). Interactive effects exceeded individual contributions for the rectus femoris, gluteus maximus, and hamstrings. In contrast, spinal alignment had minimal influence on the back extensors and abdominals. Conclusions: Both individual and intersegmental spinal alignments are associated with muscle shortening, particularly in hip-related muscles. The interaction between thoracic kyphosis and lumbar lordosis plays a pivotal role. These findings underscore the importance of evaluating segmental spinal interactions when assessing muscle flexibility and posture. Full article

(This article belongs to the Special Issue Posture, Balance, and Gait: Assessment Techniques and Rehabilitation Strategies)

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15 pages, 470 KiB

Open AccessArticle

Why Motor Competence Matters: Fundamental Movement Skills and Their Role in Promoting Physical Activity and Health in Czech Children Aged 9–10 Years

by Jakub Kokstejn, Miroslav Grobar, Jindrich Vampola and Martin Musalek

J. Funct. Morphol. Kinesiol. 2025, 10(3), 258; https://doi.org/10.3390/jfmk10030258 - 8 Jul 2025

Abstract

Background: Motor competence (MC) plays a critical role in shaping children’s physical activity, health-related fitness, and weight status. However, few studies have explored these interrelationships during middle childhood. Objectives: The current study aimed to examine the relationships between MC and physical activity (PA), [...] Read more.

Background: Motor competence (MC) plays a critical role in shaping children’s physical activity, health-related fitness, and weight status. However, few studies have explored these interrelationships during middle childhood. Objectives: The current study aimed to examine the relationships between MC and physical activity (PA), health-related fitness (HRF), and weight status (WS) in children during middle childhood (9–10 years). Simultaneously, the study aimed to find possible differences in PA, HRF, and WS between children with different levels of MC. Methods: In this cross-sectional study, the TGMD-2 (MC), UNIFITTEST 6–60 (HRF), ActiGraph GT3X (PA), and anthropometry (WS) were administered to 86 children (59 boys, age range of 9–10 years and mean age of 10.1 ± 0.6 years). Results: A significant strong association was observed between MC and HRF (p < 0.01, Cramer‘s V = 0.42). Significant moderate associations were observed between MC and WS (p < 0.05, Cramer’s V = 0.34) and between MC and PA (p < 0.05, Cramer‘s V = 0.25). Children with high MC proficiency demonstrated significantly higher levels of HRF (p < 0.01; large ES) and PA (p < 0.05; moderate ES) and a healthier WS (p < 0.01; moderate ES) than those with low MC proficiency. Similarly, children with moderate MC proficiency outperformed children with low MC in terms of HRF and WS. Conclusions: The strong associations between MC and key health indicators such as PA, HRF, and WS suggest that movement proficiency in middle childhood should be viewed as a cornerstone of health promotion. Although no causal claims can be made, the results emphasize the practical importance of integrating targeted motor skill development—especially FMSs—into school-based physical education and extracurricular programs. Supporting MC at this age may be a decisive step toward fostering long-term engagement in physical activity and improving children’s overall health trajectories. Full article

(This article belongs to the Special Issue Physical Activity for Optimal Health: 2nd Edition)

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Journal of Functional Morphology and Kinesiology

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