Luca Molinaro

Background: English riding requires dynamic postural control and fine modulation of muscle activation, which progressively develop with the rider’s experience. Although numerous studies have investigated these aspects using biomechanical and instrumental approaches, less attention has been paid to the rider’s subjective perception in relation to stability, movement fluidity, and balance management. Purpose: The study aimed to analyze the perception of muscle activation and perceived postural control in English riding as a function of experience level. Materials and Methods: Thirty riders were divided into three groups, according to their experience level (beginner, intermediate, expert). A structured questionnaire was administered, including multiple-choice questions and 5-point Likert-scale items aimed to assess perceived muscle fatigue, postural stability, movement fluidity, and the effect of stirrup use. Results: The results showed differences between the level of experience and perceived postural control (p<0.05). Specifically, expert riders reported greater pelvic stability and greater fluidity in following the horse’s movements, with lower perceived instability and trunk stiffness compared with beginners. Conclusions: The results suggested that the riders with different levels of experience reported different perceptions of pelvic stability, movement fluidity, and trunk stiffness. These self-reported models can provide exploratory insights for horse riding instruction; however, they need to be validated against objective biomechanical and physiological measures.

Accurate assessment of joint kinematics is fundamental to biomechanics, rehabilitation, and sports science. Although optical motion capture (OMC) remains the laboratory reference standard for biomechanical validation, its cost, infrastructure requirements, and limited applicability outside controlled environments restrict its broader use. Wearable inertial measurement units (IMUs) and vision-based markerless systems have consequently emerged as complementary alternatives, offering portability, reduced subject preparation, and applicability in ecological settings. Their rapid development, however, has not always been accompanied by an equally rigorous metrological interpretation of performance. This narrative review provides a comparative analysis of IMU- and vision-based approaches for joint kinematics estimation, focusing on biomechanical validation metrics and measurement error. Because the primary literature reports fundamentally different quantities under widely differing experimental conditions, evidence is presented stratified by outcome class, joint, plane of motion, task, and acquisition dimensionality, and values belonging to different outcome classes are not pooled. For sagittal-plane lower-limb angles during level walking in healthy adults, with careful sensor-to-segment calibration and an optoelectronic reference, IMU-based systems show the most consistent performance, with RMSE commonly between 3° and 6°. Vision-based systems achieve comparable accuracy for selected outcomes, particularly spatiotemporal gait parameters and sagittal-plane angles in controlled views, while degrading with occlusion, motion blur, and depth ambiguity. Accuracy is therefore not an intrinsic property of the sensing modality but of the entire measurement chain, including calibration, biomechanical modeling, acquisition geometry, and reporting conventions. Rather than ranking technologies by accuracy alone, the measurement requirements should be derived from the intended application.

Objectives: Volleyball playing positions are associated with different functional demands. This study compared postural control, jump performance, and upper-limb mobility across playing roles in competitive male volleyball players. Methods: Fifty male volleyball players competing in the Italian Serie C championship were equally distributed across five roles: middle blockers (MB), liberos (LIB), opposite hitters (OH), setters (SET), and outside hitters (HIT). Using a wearable inertial sensor, athletes performed bipodalic balance tasks with eyes open and closed, dominant- and non-dominant-leg single-leg balance, squat jump (SJ), countermovement jump (CMJ), and bilateral upper-limb flexion and extension tests. Results: Significant role-related differences emerged in balance and jump performance. In bipodalic balance, the eyes-open condition showed a mixed pattern, with HIT displaying the largest ellipse area and SET showing the highest path-related values, whereas in the eyes-closed condition, HIT showed the highest values across all stabilometric parameters. In the single-leg stance, OH showed the largest postural excursions on the dominant side, while LIB stood out on the non-dominant side. In jump tests, MB showed the best vertical performance in both SJ and CMJ, whereas LIB and SET generally showed the lowest outputs. Temporal differences also emerged across roles. Upper-limb mobility was similar across roles in flexion, while extension showed a role-specific pattern, with SET displaying greater ROM than LIB, HIT, and OH. Conclusions: Volleyball roles are associated with distinct functional profiles in balance, jump mechanics, and upper-limb mobility. This integrated assessment may support more specific training, monitoring, and injury-prevention strategies.

Elite karate performance depends on neuromuscular power, joint mobility, and postural stability, yet sex-specific biomechanical profiles in this population remain insufficiently characterized. This study examined differences in lower-limb explosive power, joint kinematics, and visual-dependent postural control in 28 international-level karatekas. Assessments included vertical jump tests, joint mobility tasks performed at preferred and maximum velocities, and stabilometric evaluations under eyes-open and eyes-closed conditions. Males demonstrated significantly longer flight and phase times across all jump tests (all p < 0.05), and higher maximum angular velocities during shoulder flexion and extension, while females exhibited greater hip abduction range of motion during the Wall Split test (all p < 0.05). In postural control, females showed larger Ellipse Area and Path Length under eyes-open conditions (p < 0.05), but these differences were eliminated when vision was removed. The Romberg Index indicated comparable reliance on visual input between sexes. These findings may support the development of more individualized, sex-specific conditioning strategies in elite karate.

Surface electromyography (sEMG) is a noninvasive method for monitoring muscle activity, essential in rehabilitation, prosthetics, sports, and medicine. However, current sEMG systems struggle with signal noise, unclear muscle activation detection, and limited adaptability. This study proposes a method combining signal processing and machine learning to enhance muscle activation detection. Experiments on EMG data from muscle contractions ( n = 140 per test, with 28 participants, five biceps curl repetitions, five wrist curl repetitions each) demonstrated 92.23% overall accuracy (3.83% false positives, 3.94% false negatives) for biceps tests and 91.11% overall accuracy (4.36% false positives, 4.53% false negatives) for wrist tests, and an average recall of 96% significantly outperforming traditional methods. This approach highlights potential applications in real-world biomedical settings from rehabilitation and prosthetics to sports science.

Background: Stretching is essential for maintaining overall health and is a key component of warm-up routines for well-trained individuals and athletes. The most commonly used stretching methods include static stretching (SS), dynamic stretching (DS), and ballistic stretching (BS). However, there is still an ongoing debate in the literature regarding which method is most effective, particularly with the growing interest in approaches that target myofascial chains rather than isolated muscle groups. In this context, the present study introduces a novel dynamic stretching protocol based on myofascial chains, designed to be incorporated into the warm-up routines of well-trained adults. The study aimed to evaluate the effects of this innovative protocol on mobility, balance, heart rate, lactate levels, and jumping performance. Methods: Nineteen well-trained men without sport-specific training were recruited for the experiment. The protocol consisted of three sessions, each differing in the activities performed between pre- and post-functional tests. On the first day, no activities (NA) were conducted. On the second and third days, participants were split into two groups, with one performing SS and the other following the novel DS routine. During each session, four functional tests were conducted: an incremental treadmill Run Test (RT), single-leg balance tests for both legs, repeated countermovement jumps, and joint mobility assessments. Results: The results indicated that both the innovative DS and SS protocols significantly improved joint mobility ( p -values ranging from p -values from p = 0.026), whereas SS was associated with better balance, which was not observed in DS. Conclusions: These findings support the effectiveness of the novel dynamic stretching protocol, particularly as a warm-up strategy when explosive and reactive performance is required.

Temporomandibular disorders (TMDs) refer to a group of conditions that affect the temporomandibular joint, causing pain and dysfunction in the jaw joint and related muscles. The diagnosis of TMDs typically involves clinical assessment through operator-based physical examination, a self-reported questionnaire and imaging studies. To objectivize the measurement of TMD, this study aims at investigating the feasibility of using machine-learning algorithms fed with data gathered from low-cost and portable instruments to identify the presence of TMD in adult subjects. Through this aim, the experimental protocol involved fifty participants, equally distributed between TMD and healthy subjects, acting as a control group. The diagnosis of TMD was performed by a skilled operator through the typical clinical scale. Participants underwent a baropodometric analysis by using a pressure matrix and the evaluation of the cervical mobility through inertial sensors. Nine machine-learning algorithms belonging to support vector machine, k-nearest neighbours and decision tree algorithms were compared. The k-nearest neighbours algorithm based on cosine distance was found to be the best performing, achieving performances of 0.94, 0.94 and 0.08 for the accuracy, F1-score and G-index, respectively. These findings open the possibility of using such methodology to support the diagnosis of TMDs in clinical environments.

Temporomandibular disorders (TMDs) refer to a group of conditions that affect the temporomandibular joint, causing pain and dysfunction in the jaw joint and related muscles. The diagnosis of TMDs typically involved clinical assessment through operator-based physical examination, self-reported questionnaire and imaging studies. To objectivize the measurement of TMD, this study aims at investigating on the feasibility to use machine-learning algorithms fed with data gathered from low-cost and portable instruments to discriminate the presence of TMD in adult subjects. Through this aim, the experimental protocol involved fifty participants, equally distributed between TMD and healthy subjects, acting as control group. The diagnosis of TMD has been performed by a skilled operator through the typical clinical scale. Participants underwent to a baropodometric analysis by using a pressure matrix and the evaluation of the cervical mobility through inertial sensors. Nine machine-learning algorithms belonging to support vector machine, k-nearest neighbours and decision tree were compared. The k-nearest neighbours based on cosine distance was found as the best performing, achieving performance of 0.94, 0.94 and 0.08 for the accuracy, F1-score and G-index, respectively. These findings open the possibility to use such methodology to support the diagnosis of TMDs in clinical environments.

The importance of physical activity has been widely demonstrated both in clinics and in sports. One of the new frontier training programs is high-intensity functional training (HIFT). The immediate effects of HIFT on the psychomotor and cognitive performance of well-trained people are still not clear. This paper aims to evaluate the immediate effects induced by HIFT on blood lactate levels, physical performance in terms of body stability and jump ability, and cognitive performance in terms of reaction time. Nineteen well-trained participants were enrolled in the experimental studies and asked to execute six repetitions of a circuit training. Data were gathered both in a pre-training session and after each one of the circuit repetitions. An immediate significant increase with respect to the baseline was observed during the first repetition, with a further increase after the third one. No effects on jump ability were found, whereas a deterioration in body stability was found. Positive immediate effects on cognitive performance in terms of accuracy and speed in task execution were assessed. The findings can be exploited by trainers during coaching to optimize the design of training programs.