Background: Understanding how endogenous hormonal fluctuations and exogenous hormonal modulation influence exercise-related outcomes in women is essential for developing individualized and evidence-informed training and nutritional strategies. This narrative review summarizes the endocrine physiology of the eumenorrheic menstrual cycle and hormonal contraceptive (HC) use and critically examines their implications for athletic performance, neuromuscular function, injury risk, and metabolic regulation in physically active women. Methods: A non-systematic literature search was conducted in PubMed, Scopus, and Web of Science for articles published up to January 2026. Search terms combined menstrual cycle-related, hormonal contraceptive, performance, and metabolic/nutritional keywords, and relevant studies were selected based on their relevance to the scope of this narrative review. Results: Estradiol and progesterone fluctuations may modulate substrate utilization, connective tissue properties, central fatigue regulation, and symptom expression; however, evidence indicates that performance-related effects across menstrual phases are generally small and inconsistent, reflecting both the modest magnitude of physiological effects and the methodological heterogeneity in menstrual cycle phase classification and verification across studies. Similarly, although HC use suppresses endogenous hormonal variability, current findings do not support consistent benefits for performance, injury prevention, or metabolic outcomes, and responses remain heterogeneous. From a nutritional perspective, the endocrine context may contribute to modest changes in energy expenditure, insulin sensitivity, appetite regulation, inflammation, and recovery-related processes. Importantly, symptom burden—including pain, fatigue, sleep disturbances, gastrointestinal discomfort, and fluid retention—emerges as a practical driver of day-to-day training tolerance. Conclusions: We propose an integrative framework in which sex hormones define a physiological context rather than deterministic performance regulators, while nutrition acts as a key modifiable factor influencing metabolic responses, symptom severity, and performance consistency.

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.

BACKGROUND:Patients with pancreatic cancer (PC) commonly present with reduced aerobic fitness, sarcopenia, and malnutrition, which may increase perioperative risk and compromise access to chemotherapy treatments. Although exercise-based prehabilitation can improve physical fitness, its implementation is often limited by short diagnostic-to-surgery intervals and treatment-related toxicity. METHODS:We conducted a pilot prospective pretest-posttest feasibility study in Torino, Italy. Patients with PC undergoing neoadjuvant chemotherapy prior to surgery were offered a 4-week, partially supervised, home-based bimodal exercise prehabilitation program (single-arm design) combining remotely monitored high-intensity interval training (HIIT) on a cycle ergometer with functional and resistance exercises. The primary outcome was adherence to prescribed exercise frequency, intensity, and duration, objectively assessed via remote monitoring. Secondary outcomes included cardiorespiratory fitness (CPET), muscle function, body composition, fatigue, quality of life, and circulating inflammatory markers. RESULTS:From July 2022 to February 2024, 23 patients were screened; 15 were eligible and 10 enrolled. Four participants discontinued the intervention (two due to asthenia/fatigue, one due to chemotherapy-related adverse events, and one for organizational reasons), leaving six participants who completed the program. Among completers, fatigue and quality of life did not change meaningfully. Aerobic capacity and muscle function outcomes were generally stable, with few pre-post changes exceeding the minimum clinically important difference (MCID) thresholds used. Body composition markers and the assessed circulating cytokines/chemokines remained unchanged except for IL-6 levels, which decreased significantly (p < 0.05). CONCLUSIONS:A partially supervised, home-based HIIT-based prehabilitation program is feasible for a subset of PC patients undergoing neoadjuvant therapy, but a substantial attrition rate suggests the need for more flexible symptom-adapted prescriptions and enhanced supportive strategies.

We developed the Physical Capacity Score, a set of validated and commonly used physical tests for adults, administered through a custom-built hardware and software platform that enables automated data collection and analysis. This study aimed to evaluate the platform's repeatability, examine age-related differences, and explore the relationships between different physical capacities in a sample of adults. A total of 812 participants (aged 18-68 years, 63.5% female) were recruited. Participants completed six physical tests: finger tapping, handgrip strength, single-leg stance, sit-and-reach, five-times sit-to-stand, and the YMCA 3-minute step test. Outcome data were standardized by gender (z-scores) and analyzed across age groups using ANOVA. Pearson's correlation coefficient (r) was used to assess redundancy among outcomes, and Principal Component Analysis (PCA) was conducted. In a test-retest analysis, all variables demonstrated coefficient of variation (COV) <10% and intraclass correlation coefficient (ICC) >0.90, except for CoP path length (COV = 10.5%, ICC = 0.64). Correlations among outcomes were weak (r range: 0.036-0.373). While all physical capacities declined with age (p < 0.001), effect sizes varied: from the least to the most age-sensitive outcome (η2 values), we found differences in handgrip strength (η2 = 0.035), sit-and-reach (η2 = 0.050), finger tapping (η2 = 0.059), CoP path length (η2 = 0.095), lower-limb power (η2 = 0.148), and cardiorespiratory fitness (η2 = 0.389). The average PCA component scores revealed large age-related differences (η2 = 0.301). Our findings suggest that the developed platform is a valuable tool for assessing physical function, and all physical tests captured distinct aspects of physical capacities. This highlights the necessity of employing a comprehensive battery of tests to gain a holistic understanding of an individual's physical health and detect age-related decline effectively.

This study investigated interlimb asymmetries in lower limb performance using both vertical and horizontal jump tests in elite young basketball players. Specifically, it aimed to determine whether (1) unilateral jump performance and (2) the magnitude of interlimb asymmetry differed across maturity groups, whether (3) limb dominance influences performance, and whether (4) asymmetry direction is consistent across tests. One hundred elite male basketball players (U13 to U19) were categorised into three maturational stages: Pre-PHV (n = 19), Circa-PHV (n = 29), and Post-PHV (n = 52). Each athlete performed the following unilateral tests with both the dominant and non-dominant leg: single-leg hop, triple hop for distance, 6 m timed hop, single-leg countermovement jump (SL-CMJ), and single-leg drop jump (SL-DJ) from a 30 cm box. The Bilateral Strength Asymmetry (BSA) index was computed for each test. All tests showed significant differences between Pre-PHV and Circa-PHV groups (p < 0.001), whereas only the 6 m timed hop differed between Circa-PHV and Post-PHV (p < 0.01). BSA did not differ significantly across maturation stages in any test, except for the single-leg hop. Agreement in asymmetry direction between test pairs was slight to fair (kappa ≤ 0.29). BSA values remained largely stable across maturational stages, suggesting that interlimb asymmetries are established before PHV, likely during childhood. Limb dominance did not affect jump performance, and asymmetry direction varied between tests, confirming they are not interchangeable.

This study aimed to compare changes in 9–11 years old Italian children for fitness outcomes, following a structured multicomponent intervention, The Daily Mile, and usual school physical education lessons (i.e., control group). Before and after three different 6-month weekly PAIs (2 h of structured physical workouts, with a sport science expert; 4 units of The Daily Mile + 1 h of physical activity with the generalist teacher; control group, 2 h of physical activity with the generalist teacher), 263 children were anthropometrically measured (stature, body mass), and evaluated by means of physical tests regarding sprint (20 m-sprint), endurance (shuttle-run), balance (single-leg-stance), dominant upper-limb strength (handgrip), lower-limbs muscle power (standing-long-jump), and flexibility (sit-and-reach) physical fitness qualities. To distinguish active and non-active children, participants filled the Physical Activity Questionnaire for Older Children – Italian version (PAQ-C-it) at PRE. Post-intervention outcomes were analyzed using linear mixed-effects models (with PRE values, age and PRE–POST ΔBMI as covariates). For standing long jump, the structured PAI determined higher post-intervention values than the control group (estimated difference = 18.55 ± 4.6 cm, p = 0.001, d = 1.03) and The Daily Mile group (estimated difference = 10.89 ± 3.09 cm, p = 0.008, d = 0.6). For single-leg stance with eyes open, the structured PAI group achieved higher post-intervention values than The Daily Mile group (estimated difference = 25.10 ± 8.16 s, p = 0.016, d = 0.7). No other difference emerged between PAIs. In addition, male reported better shuttle run higher post-intervention values (p = 0.008, ηp2 = 0.03) than female. No effects for sex-intervention-physical status interactions emerged. Therefore, PAI effects are limited and outcome-specific, with only structured approach able to promote some fitness enhancements, regardless from the beginning physical status of students, thus suggesting to moderately consider the association between school PAIs and substantial fitness positive post-intervention variations.

PurposeThe aim of this pilot study was to evaluate differences in vasti muscle motor unit (MU) firing between individuals with current patellofemoral pain (PFP) and asymptomatic controls during submaximal isometric knee extension contractions in both single-joint (knee extension) and multi-joint (leg press) exercises.MethodsTen individuals with PFP and ten age- and gender-matched asymptomatic controls performed submaximal isometric contractions (10-70% maximum voluntary isometric contraction; MVIC) during single-joint and multi-joint exercises. High-density surface electromyography assessed MU discharge properties of the vastus medialis (VM) and vastus lateralis (VL), while torque steadiness was quantified using the coefficient of variation of torque.ResultsNeural drive to the vasti muscles was comparable between groups across both exercises however, individuals with PFP exhibited reduced torque steadiness during single-joint compared to multi-joint exercises. This reduction in torque steadiness was accompanied by increased MU discharge rate variability at higher torque levels (50-70% MVIC), particularly for the VL muscle at 70% MVIC. For those with PFP, their pain intensity was also higher during single-joint exercises, which may have further contributed to the aforementioned neuromuscular impairments. Additionally, MU firing-torque relationships revealed neuromuscular adjustments in people with PFP, indicated by significantly lower cross-correlation values during multi-joint exercises compared to the asymptomatic controls.ConclusionPhysically active people with PFP exhibit reduced torque steadiness, increased discharge rate variability, and potentially altered MU firing-torque relationships during single-joint knee extension exercise. These MU adaptations likely reflect neuromuscular adjustments to ongoing PFP, helping to sustain force production despite impaired motor control and potentially mitigating pain during multi-joint exercises.

Background: The level of interlimb asymmetry varies significantly across outcome measures, resulting in poor agreement in categorizing participants as (a)symmetric. Several researchers have discussed the need for an individual approach to data analysis and the need to perform multiple tests. Hypothesis: Limb dominance does not consistently influence muscle function, and the direction of asymmetry may show low consistency across different muscle groups and across the various metrics applied to the same muscles. Study Design: Cross-sectional. Level of Evidence: Level 4. Methods: A total of 71 subjects visited the laboratory once to undergo assessments for knee extensors (KEs) and knee flexors (KFs) separately for the dominant and nondominant limbs. Maximal voluntary force (MVF), rate of force development (RFD) at various time intervals (50, 100, 150 ms) and at its peak (RFD peak ), and RFD-scaling factor (RFD-SF) were obtained. Approximate entropy (ApEn), coefficient of variation, and detrended fluctuation analysis (DFAα) of force signal were also calculated during sustained submaximal contractions. Analyses of variance or Wilcoxon signed-rank test assessed differences in each metric between muscle groups and limbs. Kappa coefficients (κ) were calculated to determine the level of agreement for the direction of asymmetry. Results: Except for RFD 150 (d = 0.305) and RFD-SF (r rb = 0.280) for KF, no differences between dominant and nondominant limb were observed. All κ values were null, slight or fair (all κ ≤ 0.23). Conclusion: The dominant limb is not necessarily stronger than the nondominant limb. The direction of asymmetry varies depending on the metric and muscle considered. Our findings corroborate that asymmetries are ubiquitous in physical performance with neuromuscular asymmetries observed in 75% of subjects. Clinical Relevance: These findings highlight the necessity of comprehensive assessment across a multimetrics approach, identifying imbalances and tailoring personalized programs to address performance asymmetries effectively.

This study aimed to analyse the sex differences in the rate of torque development (RTD) and torque–velocity parameters with and without normalisation for maximal voluntary torque (MVT). Right-leg knee extensors were tested in 64 healthy and active participants (31 F and 33 M). MVT and RTD were obtained under isometric conditions. Individual torque–velocity relationships were obtained using a curvilinear model on averaged torque and velocity over 80°-to-140° knee angle. Dynamic data were acquired through an incremental protocol on a leg extension machine, going from the lightest to the unmovable load despite maximal effort. Independent samples t test revealed (p < 0.001) that males possess greater RTD measured at 50 ms (d = −1.2), 100ms (d = −2.1) and 150ms (d = −2.3), peak RTD (d = −1.3) and MVT (d = 2.1). When normalised by MVT, the sex differences in RTD disappeared. Curvilinear hyperbolic TV relationship well-fitted (R2 = 0.99). In FV parameters, maximal theoretical torque (d = −1.7), maximal power (Pmax) (d = −2.0), and torque at Pmax (d = −1.7) were greater in males (p < .05), while maximal theoretical velocity (V0) and velocity at Pmax did not differ. The sex differences in explosiveness (i.e., rapid isometric and dynamic force production) were mainly due to greater maximal strength in males than in females. These findings suggest that, in non-sedentary people, males do not present higher contraction velocity capacities, i.e. higher maximal velocity until which muscles can produce force, than females in knee extension.

We investigate the contribution of isometric rate of torque development (RTD) and maximal voluntary torque (MVT) to the dynamic force production capacities of knee extensors obtained from the torque-velocity (TV) relationship, that is, the theoretical maximal velocity (V0), torque (T0), and maximal power (Pmax). Single-leg knee extensors were tested in 64 young adults (31 females). RTD and root mean square (RMS) of electromyographic signals from the knee extensors were recorded during isometric and incremental load dynamic (nonisokinetic) contractions. In the dynamic test, torque and velocity were continuously measured and averaged over 80°-140° knee angles to determine individual TV relationships. TV relationships were well fitted by hyperbolic regression (r2 from 0.983 to 0.993). Stepwise linear regressions showed that the main determinant of V0 was normalized RTD50 (R2 = 0.145, p = 0.004); the main determinant of T0 was MVT (R2 = 0.760, p < 0.001); and the main determinant of Pmax was RTD150 (R2 = 0.612, p < 0.001). V0 (when obtained from averaged values over knee extension) is partially explained by rapid torque capacity (i.e., "explosive strength"). Therefore, the capacity to produce torque at high velocity partly depends on the capacity to rise quickly the torque in the early phase of the contraction, suggesting that some underlying determinants of RFD would also affect V0.

Walking is an accessible and beneficial form of physical activity for older adults. However, when performed under perturbed conditions, it can place greater demands on both neuromuscular control and metabolic efficiency, highlighting the need to better understand the underlying adaptations. We compared stable and perturbed walking on a treadmill at three different speeds in 16 healthy older adults. Muscle synergies were extracted from electromyographic signals of eight lower limb muscles, oxygen uptake (VO2), minute ventilation, heart rate, and rate of perceived exertion (RPE) were also collected. Perturbed walking at 3 km/h increased oxygen uptake (p = 0.003; d = -0.52) and energetic cost (EC; p = 0.003; d = -1.12) compared to the stable condition. VO2 (p < 0.001; [Formula: see text] = 0.92), EC (p = 0.02; [Formula: see text] = 0.25) and RPE (χ2 = 4.45; p = 0.04) were higher at 3 km/h than at higher speeds. Four muscle synergies were required to accurately model the neuromuscular control during both conditions. Full-width at half maximum revealed that the transition from stable to perturbed walking led to statistically significant modifications in gait synergy composition (p = 0.01; [Formula: see text]= 0.04). Weight sparsity revealed no significant differences between conditions. These results suggest that the transition from an accurate to a more robust locomotor control for managing continuous perturbations may come at the expense of increased metabolic demand.

The triple jump is a demanding discipline in athletics, requiring physical capacity to cope with vertical ground reaction force peaks 8-15 times body weight when executed with a full run-up. This study investigated the potential of a specific drill executed with a shortened run up, the "specific quintuple", as a predictor of triple jump performance. A sample of 68 expert athletes participated in a total of218 testing sessions, with measurements taken during both practice sessions and competitions. Linear hierarchical regression analysis revealed a strong correlation between performance of the specific quintuple drill and the triple jump competition performance (R2 = 0.96). This correlation remained significant across different age categories and sexes. The specific quintuple drill offers a safer and more gradual approach to skill acquisition, potentially mitigating the risk of overloading and injury, particularly among youth athletes. The study provides practical insights for coaches and athletes, offering regression equations for predicting triple jump performance based on specific quintuple performance. Overall, the specific quintuple drill emerges as a valuable tool for assessing and improving triple jump performance while prioritizing athletes' safety.

ABSTRACT:Boccia, G, Serranò, S, Bonelli, B, La Torre, A, and Pavei, G. The scaling factor between jump height and ground contact time in drop jumps: A linear relationship at the individual level. J Strength Cond Res 40(2): 152-157, 2026-The extent to which jump height scales with changes in ground contact time (GCT) remains unknown. Establishing this relationship would enable more accurate comparisons of rebounds with different GCTs. Currently, to reliably compare reactive strength index (RSI) values, it is necessary to consider only those with similar contact time parameters. Elite young track and field athletes performed drop jumps from a 40 cm box under 3 distinct instructional conditions: (a) trade-off strategy-minimizing GCT while maximizing jump height; (b) maximizing jump height; (c) minimizing GCT. A hierarchical linear regression model was applied, with GCT and sex (male/female) as independent variables and jump height as the dependent variable. Compared with the trade-off condition, focusing on short GCT led to a 21-millisecond reduction in GCT ( p < 0.0001) but also a 5.9-cm decrease in jump height ( p < 0.0001). Conversely, prioritizing jump height increased jump height by 4.8 cm ( p < 0.0001) but prolonged GCT by 49 milliseconds ( p < 0.0001). However, RSI remained unaffected by instructions ( p = 0.567). A significant main effect of GCT on jump height was observed ( β = 0.154; p < 0.00001). The full model, incorporating random and fixed effects, accounted for 94% of the variance in jump height. At the individual level, our findings confirm a linear relationship between GCT and jump height. This relationship underscores the importance of considering the GCT-jump height trade-off when assessing drop jump performance and highlights the need for evaluations across various GCT ranges rather than relying solely on 1 jump strategy.

Background: Dietary advice for Paralympic athletes (PAs) with a spinal cord injury (PAs-SCI) requires particular attention and has been widely studied. However, currently, no particular attention has been addressed to nutritional guidelines for athletes with an amputation (PAs-AMP). This study aimed at filling up this gap, at least partially, and compared veteran PAs-SCI with PAs-AMP. Methods: A sample of 25 male PAs (12 with SCI and 13 with AMP), recruited during two training camps, was submitted to the following questionnaires: allergy questionnaire for athletes (AQUA), Nordic Musculoskeletal Questionnaire (NMQ), Starvation Symptom Inventory (SSI), neurogenic bowel dysfunction (NBD), orthorexia (ORTO-15/ORTO-7), alcohol use disorders identification test (AUDIT), and Mediterranean diet adherence (MDS). The PAs were also submitted to the following measurements: dietary Oxygen Radical Absorbance Capacity (ORAC) and intakes, body composition, handgrip strength (HGS), basal energy expenditure (BEE), peak oxygen uptake (VO2peak), peak power, peak heart rate (HR), post-exercise ketosis, and antioxidant response after a cardiopulmonary exercise test (CPET) to voluntary fatigue. Results: Compared to PAs-AMP, PAs-SCI had higher NBD and lower VO2peak (p < 0.05), peak power, peak HR, peak lactate, phase angle (PhA) of the dominant leg (p < 0.05), and ORTO15 (p < 0.05). The latter was related to NBD (r = −0.453), MDS (r = −0.638), and ORAC (r = −0.529), whereas ORTO7 correlated with PhA of the dominant leg (r = 0.485). Significant differences between PAs-AMP and PAs-SCI were not found in the antioxidant response, glucose, and ketone levels after CPET, nor in dietary intake, AUDIT, AQUA, NMQ, SSI, BEE, HGS, and FM%. Conclusions: The present study showed that PAs-SCI and PAs-AMP display similar characteristics in relation to lifestyle, energy intake, basal energy expenditure, and metabolic response to CPET. Based on both the similarities with PAs-SCI and the consequences of the limb deficiency impairment, PAs-AMP and PAs-SCI require personalized nutritional advice.

ABSTRACT:Grossio, L, Salvaggio, F, Brustio, PR, Rainoldi, A, Samozino, P, and Boccia, G. Both isometric and dynamic testing are essential for a comprehensive assessment of the knee extensors. J Strength Cond Res 39(10): e1226-e1232, 2025-The improvements of measurement tools and data analysis enhanced our possibilities to assess neuromuscular performance, but also created confusion regarding significance and practical applications of this available information. To simplify the strength assessment understanding, our purpose was to group force, velocity, and power metrics that could provide similar outcomes. We measured single-leg knee extensor strength under isometric and dynamic conditions on 64 young adults (33 men and 31 women). Subjects performed maximal and burst-like contractions under isometric conditions to assess maximal torque (MVT) and rate of torque development (RTD). Under dynamic conditions, a torque-velocity relationship was obtained from an incremental load test. Principal component analysis (PCA) was used to reduce the dimensionality of the data set and group variables. Principal component analysis identified 4 components: (a) "Maximal force" (composed by MVT, T 0 , RTD 100 , RTD 150 , T opt , Pmax ), (b) "Explosiveness" (composed by RTD 50 , RTD peak , RTD 50 N, RTD 100 N, RTD 150 N, RTD peak N, time to peak torque, time to RTD peak ), (c) "Force at high velocity" (composed by V 0 and V opt ), and (d) "Curvature" (C). When data were normalized by sex differences, "Explosiveness" resulted as the first component and Pmax was included in the "Force at high velocity" component. The present findings remark the importance of testing the explosiveness (i.e., early RTD and normalized RTD metrics) together with torque-velocity profiling, to have a more comprehensive assessment of neuromuscular qualities.

Background: Whole-body electromyostimulation (WB-EMS) combines full-body electrical muscle stimulation with instructor-assigned exercise. Electrical impulses are transmitted to the peripheral muscles through electrodes applied to the body. This study compared two training methodologies, WB-EMS training and traditional resistance training, to determine which approach leads to greater strength improvement in terms of 1-repetition maximum (1-RM). Methods: Twenty sedentary women participated in a 10 weeks protocol with five evaluations conducted every two weeks. The WB-EMS group trained for 20 min per week, and the resistance training group (RT) performed an average of two training sessions per week, lasting 60 min each. Both groups were evaluated using three exercises: back squat and hammer curl (1-RM), and plank exercise (time to exhaustion). Results: Both groups increased their performance in squat (WB-EMS +36%, p = 0.0001; RT +34%, p = 0.0001), curl (WB-EMS +42%, p = 0.0001; RT +33%, p = 0.0001), and plank (WB-EMS +103%, p = 0.0001; RT +65%, p = 0.0001). No significant time × training interaction was found for any exercise, indicating that the two groups improved similarly. Conclusions: Although WB-EMS did not confer greater strength improvement than traditional resistance training, it offers a time-efficient alternative, achieving similar results with reduced time commitment.

ABSTRACT:D'Emanuele, S, Boccia, G, Zardo, V, Durigon, V, Schena, F, and Tarperi, C. Strength, rate of force development, and force control evaluations to quantify upper-limbs asymmetries agreement in professional male volleyball players. J Strength Cond Res 39(4): 466-473, 2025-Asymmetries are known to vary based on the nature of the sport and differ between individuals and the tests used. We explored interlimb asymmetries in muscle function among 13 national-level male volleyball players (24 ± 3 years; 87 ± 7 kg; 194 ± 7 cm; 19 ± 2 hours training/week), aiming to determine whether these asymmetries are muscle specific and consistent across various metrics. Subjects underwent assessments for elbow extensors and flexors in both limbs, including maximal contractions to assess the maximal voluntary force (MVF), submaximal ballistic contractions measuring Rate of Force Development (RFD peak ), Scaling Factor (RFD-SF), and evaluations of Approximate Entropy (ApEn), Coefficient of Variations, and Detrended Fluctuation Analysis (DFAα) during sustained contractions. Repeated-mixed ANOVA within and between-factors assessed each metric's differences between muscle groups and limbs. Kappa coefficients (K) were calculated to determine the levels of agreement for the direction of asymmetry among muscle groups and different metrics at the individual level. Our findings revealed that asymmetries were muscle specific, with statistical significance observed only in flexors MVF (12%, p = 0.007, d = 0.68). The asymmetry direction agreement between metrics was null for all parameters except for MVF, which resulted in slight ( K = 0.022) and fair ( K = 0.308) for ApEn. The agreement between RFD peak vs MVF ( K = 0.386) was fair, slight between RFD peak vs RFD-SF ( K = 0.141), and null when comparing RFD peak with ApEn and DFAα. At the individual level, no consistent performance advantage was found for either limb, despite volleyball's partial asymmetrical nature, emphasizing the importance of creating personalized training based on the muscle/limb of interest and the parameter to be improved (i.e., maximum strength or RFD).

This study aimed to verify whether the slowing of muscle contraction quickness, typically observed in states of fatigue, may worsen force control by decreasing the rate with which force fluctuations are modulated. Therefore, we investigated the relationship between rate of force development (RFD), and force fluctuations' magnitude (Coefficient of variation, CoV) and complexity (Approximate Entropy, ApEn; Detrended fluctuation analysis, DFAα). Fourteen participants performed intermittent ballistic isometric contractions of the plantar dorsiflexors at 70

The aim of the study was to analyse individual performance trajectories of professional (PRO) Italian cyclists across their careers. It sought to compare the performance progression of successful and unsuccessful PRO cyclists, analyse the best predictors of success in PRO cyclists and explore whether the relative age effect (RAE) influences PRO success. The national ranking positions gathered in the youth (U19 and elite/U23) and the PRO categories were retrieved for every year of competition of 81 PRO Italian cyclists and retrospectively analysed. Participants were divided in successful and unsuccessful, depending on whether they reached at least once the top 400 positions in the PRO ranking or not. Successful PRO cyclists display better youth ranking positions and tend to spend less time in youth categories, transition to the PRO category at an earlier age, reach their best PRO ranking at an older age compared to unsuccessful PRO cyclists. The best youth ranking, the age of the best PRO ranking and the years spent in youth categories are all predictors of PRO success. For every additional year spent in youth categories, there are 50.8% less odds of becoming a successful PRO cyclist. RAE does not affect Italian cyclists' PRO success.