Search Results (590)

Anterior cruciate ligament reconstruction (ACLR) results in prolonged muscle weakness, impaired neuromuscular control, and delayed return to sport. Cross-education (CE), unilateral training of the uninjured limb, has been proposed as an adjunct therapy to promote bilateral adaptations. This scoping review evaluated the functional and neuroplastic effects of CE rehabilitation post-ACLR. Following PRISMA-ScR and JBI guidelines, PubMed, Scopus, Web of Science, and PEDro were searched up to February 2025. A bibliometric analysis was also conducted to report keyword co-occurrence and identify trends in this line of research. Of 333 screened references, 14 studies (price index: 43% and low-to-moderate risk of bias) involving 721 participants (aged 17–45 years) met inclusion criteria. CE protocols (6–12 weeks; 2–5 sessions/week) incorporating isometric, concentric, and eccentric exercises demonstrated strength gains (10–31%) and strength preservation, alongside improved limb symmetry (5–14%) and dynamic balance (7–18%). There is growing interest in neuroplasticity and corticospinal excitability, although neuroplastic changes were assessed heterogeneously across studies. Findings support CE as a feasible and low-cost strategy to complement early-stage ACLR rehabilitation, especially when direct loading of the affected limb is limited. Standardized protocols for clinical intervention and neurophysiological assessment are needed. Full article

This study aimed to investigate the effects of mental fatigue on physical and cognitive performance (lower-limb power, isometric and handgrip strength, and psychomotor vigilance). Twenty-two physically active young adults (12 males, 10 females; M_age = 20.82 ± 1.47) were randomly assigned to either a Mental Fatigue (MF) or Control group (CON). The MF group showed a statistically significant (p = 0.019) reduction in non-dominant handgrip strength, declining by approximately 2.3 kg (about 5%), while no such change was observed in the CON group or in dominant handgrip strength across groups. Reaction time (RT) was significantly impaired following the mental fatigue protocol: RT increased by 117.82 ms, representing an approximate 46% longer response time in the MF group (p < 0.001), whereas the CON group showed a smaller, non-significant increase of 32.82 ms (~12% longer). No significant differences were found in squat jump performance, indicating that lower-limb explosive power may be less affected by acute mental fatigue. These findings demonstrate that mental fatigue selectively impairs fine motor strength and cognitive processing speed, particularly reaction time, while gross motor power remains resilient. Understanding these effects is critical for optimizing performance in contexts requiring fine motor control and sustained attention under cognitive load. Full article

This study aimed to compare isometric strength, range of motion (RoM), and strength ratios of shoulder internal and external rotators between female volleyball and hand ball players Twenty-five volleyball players (age = 21.8 ± 4.8 years, height = 178.5 ± 7.1 cm, mass = 69.3 ± 7.7 kg) and twenty-four handball players (age = 19.5 ± 2.9 years, height = 169.7 ± 6.4 cm, mass = 67.6 ± 8.4 kg), all competing in the Slovenian 1st national league, participated. Maximal isometric strength and passive RoM of internal and external rotation were measured bilaterally using a handheld dynamometer and goniometer, respectively. A significant group × side interaction was observed for internal rotation RoM (F = 5.41; p = 0.024; η² = 0.10), with volleyball players showing lower RoM on the dominant side (p = 0.001; d = 0.89), but this was not the case for handball players (p = 0.304). External rotation strength also showed a significant interaction (F = 9.34; p = 0.004; η² = 0.17); volleyball players were stronger in the non-dominant arm (p = 0.033), while handball players were stronger in the dominant arm (p = 0.041). The external-to-internal rotation strength ratio was significantly lower on the dominant side in volleyball players compared to handball players (p = 0.047; d = 0.59). Findings suggest sport-specific adaptations and asymmetries in shoulder function, emphasizing the need for sport-specific and individually tailored injury prevention strategies. Volleyball players, in particular, may benefit from targeted strengthening of external rotators and flexibility training to address imbalances. Full article

Background/Objectives: Platelet-rich plasma (PRP) is emerging as a safe and effective treatment for facet-mediated pain. Studies have demonstrated reductions in pain and improvements in function, both in the short (3 months) and longer term (6 and 12 months). The mechanisms underlying clinical improvements are largely unknown. It is also unclear whether reported outcomes are due to the PRP administered or concurrently applied rehabilitation. Methods: A prospective case series was conducted in a single, multidisciplinary chronic pain centre. Forty-two participants with chronic WAD and cervical facet-mediated pain who received PRP (64% female; mean age (SD) 42.8 (11.6) years; median WAD duration [IQR] 23 [18,29] mths), attended rehabilitation, and reported successful outcomes 3 months post-PRP fulfilled the inclusion criteria. Measures of pain, cervical isometric strength, and range of motion were collected at baseline and 3 months post-PRP. Mediation analyses were performed to determine how these factors influenced disability. Results: Participants demonstrated clinically significant and relevant improvements in pain, disability, and isometric strength measures (all p < 0.01). Causative mediation analyses demonstrated independent direct, but not indirect, effects of both pain and strength on disability (both p < 0.001), with no direct or indirect effects of cervical ROM on disability. Full article

Background: Expression of maximal and rapid force in the hip, knee, and plantar flexors is important for athletic performance in female soccer. This study was designed to determine the effect of relative isometric strength in the isometric mid-thigh pull (IMTP) on countermovement jump (CMJ) and rebound jump (CMJ-R) performance in female youth soccer players. Methods: Ninety-six female soccer players (age: 14.1 ± 2.3 years, height: 160.5 ± 9.7 cm, mass: 55.0 ± 10.3 kg) completed three trials of the IMTP, CMJ, and CMJ-R using force plates. Players were categorized as stronger (top quartile, n = 19) and weaker players (bottom quartile, n = 23) based on IMTP relative net peak force. One-way Bayesian independent t-tests were performed between stronger and weaker players. Results: Very large difference in lower limb strength between groups (g = 5.05). Moderate to very strong evidence to support that stronger players had greater countermovement depth and time to take-off with similar jump heights than weaker players. Strong evidence was observed for CMJ-R height, with stronger players falling from a greater height and executing similar ground contact times compared to weaker players. Conclusions: Relative strength has implications for CMJ-R, highlighting the importance of developing relative strength in hip, knee, and plantar extensors. Full article

Maximal and explosive strength—defined as the ability to rapidly generate high levels of force—are widely recognized as critical for performance in strength–power sports such as track and field throwing. However, their interrelationship remains insufficiently examined, particularly in the upper body of elite athletes. This study examined the relationship between early force production (≤250 ms, subdivided into early phase: 0–100 ms; late phase: 100–250 ms) and peak isometric upper-body push and pull force in elite Swedish track and field throwers. A total of 30 athletes (17 females, 13 males; aged 18–34 years), all competing nationally or internationally in discus, hammer, shot put, or javelin, participated in a cross-sectional assessment. Isometric force was measured during bench press (push) and supine bench row (pull) using a custom-built device. Force output was recorded at 50, 100, 150, 200, and 250 ms, along with peak force. The results showed a progressive increase in the correlation between force at early time points and peak force. Associations were weak to moderate at 50–100 ms (r = 0.07–0.55) and became strong to very strong at 150–250 ms (r = 0.64–0.92). These patterns were consistent across sexes and test types. The findings suggest that maximal strength becomes increasingly important as force production time extends beyond 100 ms. Coaches may benefit from assessing both early and peak force characteristics to inform strength profiling and guide training focus, though further research is needed to determine their impact on performance. Full article

Background and Objectives: This study aims to investigate the relationship between isokinetic knee strength and competition performance in elite male ski mountaineering sprint athletes and to identify strength parameters that predict performance and contribute to injury prevention. Materials and Methods: Thirteen male athletes participating in the Ski Mountaineering Turkey Cup final stage were included. Isokinetic knee flexion (FLX) and extension (EXT) strength of dominant (DM) and non-dominant (NDM) legs were measured at angular velocities of 60°/s and 180°/s using the DIERS-Myolin Isometric Muscle Strength Analysis System. Competition performance was evaluated using the ISMF scoring system. Data were analyzed using SPSS 26.0 with Pearson correlation and multiple regression analyses after normality, linearity, and homoscedasticity checks. Results: Strong positive correlations were found between hamstring strength at high angular velocities (180°/s) and performance (DM FLX: r = 0.809; NDM FLX: r = 0.880). Extension strength showed moderate correlations at low velocities (60°/s) (DM EXT: r = 0.677; NDM EXT: r = 0.699). Regression analysis revealed that DM FLX at 180°/s and DM EXT at 60°/s explained 49% of performance variance (Adj. R² = 0.498). For NDM legs, only 180°/s FLX was a significant predictor (β = 1.468). Conclusions: High-velocity hamstring strength plays a critical role in ski mountaineering sprint performance, particularly during sudden directional changes and dynamic balance. Quadriceps strength at low velocities contributes to prolonged climbing phases. Moreover, identifying and addressing bilateral strength asymmetries may support injury prevention strategies in elite ski mountaineering athletes. These findings provide scientific support for designing training programs targeting explosive hamstring strength, bilateral symmetry, and injury risk reduction, essential for optimizing performance in the 2026 Winter Olympics sprint discipline. Full article

The Inverted Swallow (IS) is a rare isometric upper-body skill in artistic gymnastics. Athletes use Preconditioning Strengthening Exercises (PSEs) to develop the strength necessary to hold the IS at competition rings. However, the specific muscle excitation and synergies typical of the IS and its PSEs remain unexplored. Thus, this study analyzed muscle excitations and synergies during the IS and its five common PSEs. Muscle excitation was recorded from the pectoralis major, latissimus dorsi, triceps brachii, infraspinatus, trapezius, serratus anterior, biceps brachii and posterior deltoid muscles in six elite calisthenics athletes (age: 24.5 ± 3.0 years; height: 168.6 ± 5.8 cm; body mass: 65.0 ± 4.7 kg). Non-Negative Matrix Factorization was used to extract synergies. The results showed a predominant role of the posterior deltoid and triceps brachii during the IS. Significant differences were observed in the muscle excitation of the triceps brachii between the IS and its PSEs (p ≤ 0.001; W = 0.765), and in the posterior deltoid (p = 0.002; W = 0.629). Muscle synergy patterns also differed in simultaneous muscle activation between the IS and its PSEs. These findings provide the first detailed evidence of the characteristics of the IS element, providing insights for optimizing strength training and gymnastics performance. Full article

Background/Objectives: The objective of this study was to compare muscular strength and neuromuscular activation characteristics between male gymnasts and physical education (PE) students during isometric shoulder extension and flexion tasks. Methods: Thirteen competitive male gymnasts (age: 19.59 ± 1.90 years; body mass: 66.54 ± 6.10 kg; height: 169.38 ± 6.28 cm; mean ± SD) and thirteen male physical education (PE) students (age: 20.96 ± 2.30 years; body mass: 74.00 ± 8.69 kg; height: 174.96 ± 4.93 cm) voluntarily participated in the study. Peak torque (PT), rate of torque development (RTD), RTD normalized to body mass (RTD/BM), and muscle activation assessed via surface electromyography (EMG), normalized to maximal EMG activity (EMG/EMGmax), were evaluated during bilateral isometric shoulder extension and flexion at a joint angle of 45°. Measurements were analyzed across the following time intervals: −50 to 0 ms (pre-tension), 0–30 ms, 0–50 ms, 0–100 ms, and 0–200 ms relative to contraction onset. Custom MATLAB R2024b scripts were used for data processing and visualization. One-way and two-way multivariate analyses of variance (MANOVAs) were conducted to test for group differences. Results: Gymnasts exhibit higher values of PT, PT/BM, RTD, and RTD/BM particularly within the early contraction phases (i.e., 0–50 ms and 0–100 ms) compared to PE students (p < 0.05 to <0.001; η² = 0.04–0.66). Additionally, EMG activity normalized to maximal activation (EMG/EMGmax) was significantly greater in gymnasts during both early and mid-to-late contraction phases (0–100 ms and 0–200 ms), (p < 0.05 to <0.001; η² = 0.04–0.48). Conclusions: These findings highlight gymnasts’ superior explosive neuromuscular capacity. Metrics like RTD, RTD/BM, and EMG offer valuable insights into rapid force production and neural activation, supporting performance monitoring, training optimization, and injury prevention across both athletic and general populations. Full article

Background: Sarcopenia (loss of muscle mass) and dynapenia (loss of strength) are prevalent in older adults aged 70 years and over. Both have an impact on their functional ability and quality of life, with type II muscle fibres being particularly affected. Although traditional resistance training (TRT) is effective, it presents technical difficulties and an increased risk of injury among this vulnerable population. Isometric strength training (IST) is a potentially safer, more accessible and more effective alternative. Objective: To describe the protocol of a single-arm, pre-post intervention trial designed to evaluate the efficacy and applicability of a 16-week IST programme on muscle strength, skeletal muscle mass, quality of life and applicability (safety, acceptability, perceived difficulty) in 18 older adults aged 70 years and above with a diagnosis of sarcopenia and dynapenia. The influence of genetic and environmental factors on the variability of response to IST will also be explored. Methodology: The participants, who have all been diagnosed with sarcopenia according to EWGSOP2 (European Working Group on Sarcopenia in Older People 2) criteria, will perform two IST sessions per week for 16 weeks. Each 30-min session will consist of one progressive set (total duration 45 s to 90 s) for each of the eight major muscle groups. This series will include phases at 20% and 40% of individual Maximal Voluntary Isometric Contraction (MVIC), culminating in 100% Maximal Effort (ME), using the CIEX SYSTEM machine with visual feedback. The primary outcome variables will be: change in knee extensor MVIC and change in Appendicular Skeletal Muscle Mass Index (ASMMI). Secondary variables will be measured (other components of sarcopenia, quality of life by EQ-5D-5L, use of Likert scales, posture and physiological variables), and saliva samples will be collected for exploratory genetic analyses. The main statistical analyses will be performed with t-tests for related samples or their non-parametric analogues. Discussion: This protocol details a specific IST intervention and a comprehensive evaluation plan. The results are expected to provide evidence on the feasibility and effects of IST among older adults with sarcopenia and dynapenia. Understanding individual variability in response, including genetic influence, could inform the design of more personalised and effective exercise strategies for this population in the future. Full article

Background: Interventions involving Olympic combat sports, such as Taekwondo (TKD) and Boxing (BOX), represent innovative approaches for promoting health in older people. Elastic bands training (EBT), by contrast, is a safe and cost-effective method that has demonstrated positive effects on functional physical parameters in this population. This study aimed to compare the effects of TKD and BOX interventions, relative to EBT, on body composition and physical function in Chilean older women. Methods: This randomized controlled trial comprised three parallel groups: TKD (n = 10), BOX (n = 10), and EBT (n = 10). Participants in each group underwent pre- and post-intervention assessments following two 60 min sessions per week over an eight-week period. Results: Multiple comparisons revealed significant advantages for EBT over TKD and BOX in maximal isometric handgrip strength for both the dominant (p < 0.001; d = 0.967, large effect) and non-dominant (p < 0.001; d = 0.641, moderate effect) hands. Conversely, significant improvements in Timed Up-and-Go performance were observed in the TKD and BOX groups compared to EBT (p < 0.001; d = 2.071, large effect). All groups showed significant within-group improvements in the 30 s chair stand test (p < 0.001; d = 0.095, large effect). No significant changes were found in body fat percentage, fat-free mass, back scratch test, sit-and-reach test, or 2 min step test across groups. Conclusions: Although no substantial differences were observed between groups for most variables, TKD and BOX interventions significantly reduced Timed Up-and-Go times, whereas EBT enhanced maximal isometric handgrip strength in both hands. These findings highlight the distinct functional benefits of each intervention modality for older Chilean women. Full article

Seismic waveform feature extraction is a critical task in seismic exploration, as it directly impacts reservoir prediction and geological interpretation. However, large-scale seismic data and nonlinear relationships between seismic signals and reservoir properties are challenging for traditional machine learning methods. To address these limitations, this paper proposes a novel framework combining Convolutional Neural Network (CNN) and Uniform Manifold Approximation and Projection (UMAP) for seismic waveform feature extraction and analysis. The UMAP-CNN framework leverages the strengths of manifold learning and deep learning, enabling multi-scale feature extraction and dimensionality reduction while preserving both local and global data structures. The evaluation experiments, which considered runtime, receiver operating characteristic (ROC) curves, embedding distribution maps, and other quantitative assessments, illustrated that the UMAP-CNN outperformed t-distributed stochastic neighbor embedding (t-SNE), locally linear embedding (LLE) and isometric feature mapping (Isomap). A case study in the Ordos Basin further demonstrated that UMAP-CNN offers a high degree of accuracy in predicting coal seam thickness. Furthermore, our framework exhibited superior computational efficiency and robustness in handling large-scale datasets. Full article

Wheelchair tennis (WT) is a Paralympic sport designed for athletes with physical impairments. Assessing physical fitness characteristics using appropriate field-based tests and standardized protocols is essential for individualized training, injury prevention, and performance monitoring. However, there is currently limited information on which field-based tests are most suitable and how they should be applied in WT athletes, resulting in inconsistency across studies and practical use. Establishing a standard operating procedure (SOP) enables replicable, cost-effective testing routines that improve data consistency and comparability. We conducted a scoping review to synthesize the existing evidence on field-based physical fitness assessment in WT athletes and to propose a structured SOP for these tests. A comprehensive search was conducted in three electronic databases—NLM PubMed, Web of Science, and Scopus—using predefined keywords and Boolean operators. The inclusion criteria were limited to peer-reviewed, English-language original articles focusing exclusively on field tests in WT athletes. Studies with other populations, reviews, and abstracts were excluded. Eleven studies met the eligibility criteria. This scoping review identified various field tests assessing key fitness components, including cardiorespiratory endurance, muscle strength, agility, and body composition. The most frequently employed tests were the 20 m sprint test, isometric handgrip test, spider test, Illinois Agility Test, and skinfold thickness. These findings highlight the lack of standardized fitness assessments in WT. The proposed SOP offers a practical step toward consistent, replicable, and relevant evaluation in these athletes. Full article

Climbing demands exceptional isometric finger flexor strength and neuromuscular efficiency. This study aimed to compare maximum isometric strength and muscle quality (MQ) between climbers and non-climbers and examine the influence of sex and specific grip types. Methods: 33 climbers (14 women) and 29 non-climbers (15 women) volunteered in this study. Maximum isometric strength was measured for handgrip, three-finger drag, and half-crimp grips, while forearm muscle mass was estimated using DXA. MQ was calculated as the ratio of peak isometric force to forearm muscle mass. Results: Climbers demonstrated significantly higher isometric strength in both the three-finger drag and half-crimp grips compared to non-climbers (p < 0.01); however, non-significant differences were observed in handgrip strength. Despite similar forearm muscle mass, climbers exhibited greater MQ. Notably, female non-climbers showed higher MQ than their male counterparts (p < 0.05), a sex difference that was not evident among climbers. All tests exhibited high repeatability (ICC > 0.93, CV < 5.81%) with low SEM and MDC95 values. Conclusions: The findings underscore the necessity of employing climbing-specific strength assessments to capture the unique neuromuscular adaptations induced by climbing training. Muscle quality emerges as a sex-neutral biomarker for strength performance evaluation, with potential applications in the optimization of training programs. Future research should further explore the predictive value of MQ and strive for standardized testing protocols. Full article

Background: The aim of this study was to characterise the performance, perceptual, and wellness responses to a barbell back squat overreaching training protocol. Methods: Eight trained male participants (age = 24.6 ± 2.8 years; relative to body mass back squat one repetition maximum (1-RM) = 1.9 ± 0.4; training experience = 7.0 ± 3.2 years) participated in a 5-day squat OR protocol (SqOR), followed by a 14-day taper. SqOR consisted of five sets of barbell back squats using 80% of daily adjusted 1-RM. A 40% velocity loss threshold was used to determine the set end point. For performance, isometric mid-thigh pull (IMTP) peak force (PF), and countermovement jump (CMJ) PF and jump height; for perceptual, perceived recovery scale (PRS); and for wellness, Hooper Wellness Index (HWI), were recorded at baseline, each day of SqOR, and at select intervals during the taper (POST 1 d, 2 d, 7 d, and 14 d). Follow-up back squat 1-RM testing was conducted at POST 7 d and POST 14 d to determine strength-performance changes relative to baseline. Results: Back squat 1-RM increased by 4.8% at POST 7 d and 5.2% at POST 14 d. IMTP PF increased by 10.3% at POST 7 d and 11.4% at POST 14 d relative to the baseline. CMJ PF and jump height decreased during SqOR but returned to baseline by POST 7 d. PRS and HWI worsened during SqOR, with the greatest impairment occurring on day 3 (PRS = −41.5%; HWI = 34.4%), and did not return to baseline until POST 14 d and POST 2 d, respectively. Conclusions: These findings demonstrate that a short-term period of planned OR improves muscular strength performance, but the duration of the taper influences when peak strength improvements are observed. Full article