The effect of experimentally-induced gluteal muscle paralysis on joint kinematics, reaction forces and dynamic balance performance during lunges.

Markerless motion capture is increasingly used in pediatric neurorehabilitation, yet its ability to detect patient-specific gait abnormalities in small and heterogeneous cohorts remains unclear. This study evaluated a smartphone-based markerless workflow (OpenCap integrated with OpenSim) as a clinical assessment tool to support individualized planning in the context of robot-assisted gait rehabilitation (RAGT) by characterizing individualized gait deviations in four pediatric patients with neurological gait disorders, referenced against normative data from 30 healthy individuals. Sagittal hip, knee, and ankle kinematics were extracted, normalized, and converted into gait-cycle–dependent Z-scores. Group-level comparisons using one-sample Statistical Parametric Mapping (SPM) revealed no significant deviations between patient-group means and normative trajectories (p ≥ 0.05). In contrast, individualized deviation profiling—including Z-score heatmaps, phase-wise Z-score analysis, and per-patient kinematic overlays—identified distinct, clinically meaningful abnormalities in every patient, such as excessive swing-phase hip and knee flexion, mid-stance knee extension deficits, reduced terminal-stance hip extension, and markedly diminished late-stance ankle plantarflexion and push-off. Several deviations exceeded |2–5| SD from the normative dataset, indicating substantial impairments that were obscured by group averaging. These individualized patterns were consistent with each patient’s clinical presentation and could be interpreted in relation to modifiable gait features that are commonly considered during planning and phase-specific adjustment of robot-assisted gait rehabilitation, rather than serving as direct evidence of therapeutic efficacy. Overall, the findings demonstrate that smartphone-based markerless motion capture enables sensitive, individualized gait assessment even when group-level statistics remain nonsignificant, supporting its use as an exploratory, decision-support framework rather than as an outcome measure of RAGT.

Cricket fast bowlers rely on the front leg as a mechanical lever during front foot contact, yet the underlying mechanisms that govern front leg behaviour remain unclear. This study examined front leg mechanics in 18 junior fast bowlers (17.2 ± 1.7 years) using a 14-camera 3D motion capture system and force platforms. Joint power and angular impulse analyses were performed to quantify hip and knee extension–flexion mechanics from front foot contact to ball release, enabling the classification of joint function as active (concentric), controlled (eccentric), or negligible. Power and angular impulse profiles revealed that front leg motion was dominated by controlled (eccentric) power at both the hip and knee, indicating that the regulation of knee angle occurred primarily through eccentric braking rather than concentric quadriceps extension. These findings suggest that achieving a “braced leg” position via isolated knee extensor strengthening may be ineffective. To evaluate whether kinematics and anthropometry contributed to performance, a multiple linear regression model was used. Run-up speed at back foot contact emerged as the strongest predictor of ball speed, whereas knee angle at front foot contact showed only a small and non-significant effect. Overall, the results indicate that front leg behaviour reflects coordinated whole-body dynamics, and performance interventions should prioritise momentum generation and timing across the kinetic chain rather than isolated joint actions.

Previous studies have sought to improve pitch performance and shoulder function utilizing the Muscle Energy Technique (MET) or Spencer's technique. The results of these studies have been mixed. Some found immediate, but short-lived, improvement to different planes of the range of motion (ROM) of the throwing shoulder. None found improved velocity or investigated further pitch metrics, such as spinrate. This study is the first to measure the effects of osteopathic manipulative treatment (OMT) among key points of the kinetic chain, measuring ROM of the shoulder and the hip, as well as pitch metrics beyond release velocity. Baseball pitchers from a local collegiate baseball team were offered participation in this study. Pitchers had to be medically cleared for participation as members of the team and had to be given permission by the coach to join the study. Sixteen pitchers were assessed for inclusion, and 13 of the 16 were randomized into OMT and control groups for a prospective cohort study. One dropped out of the control group upon randomization, and one member of the control broke baseline protocol, leaving six members in the experimental group, and five members in the control group. Data, including pitch metrics, active ROM, and demographics were collected at three time points with statistical analyses comparing data between groups. Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score (KJOC-SES) was collected twice. After the third time point, the control group was crossed over to receive the OMT protocol also. Data were analyzed utilizing paired t-tests and Fisher's exacttest. Six pitchers received intervention (OMT), and five pitchers received no intervention (control). Overuse injuries developed in the control group only, preventing two of the five members of the control group from throwing further pitches for data collection at 5 weeks. When analyzed by Fisher's exact test, those in the control group were 9.29times more likely to develop an injury than those receiving a single application of OMT. The only significant difference in pitch performance was an immediate 0.74 mph reduction in effective velocity in the OMT group (p=0.048), not sustained at the 5-week follow-up. Immediately posttreatment, the intervention group appreciated a 7.16° advantage in shoulder internal rotation over the control group (p=0.017). Five weeks posttreatment, the intervention group appreciated a 9.44° advantage in shoulder external rotation (p=0.047). Bilateral hip extension was immediately significantly improved in the treatment group (p<0.001). Left hip flexion was significantly improved in the treatment group when compared against the control group both immediately by 6.76° (p<0.011) and at 5-week follow-up by 12.87° (p<0.001). An advantage in right hip flexion was significant only at 5weeks by 5.89° (p<0.02). A single application of OMT is a low-risk intervention to prevent overuse injuries in the elite overhead athlete. While this study found differences in velocity, ROM, and injury risk, this study was limited by the sample size (n=11). A larger sample group is needed both for reproducibility and for assessment of other pitch parameters such as horizontal break, vertical break, and pitch extension.

Lower limbs can play a major compensating role for sagittal malalignment; however, little is known about the different types of compensation. This study aimed to identify different patterns of lower limb compensation and to determine which parameters may affect the recruitment of knee flexion versus hip extension. This study included adult spinal deformity (ASD) patients with full-body X-rays in erect position from a multicentric prospective database. All parameters were measured at baseline: demographics, clinical scores and radiographic parameters: pelvic parameters, pelvic incidence-lumbar lordosis (PI-LL) mismatch, T1 pelvic angle (TPA), sacro-femoral angle (SFA), knee flexion angle (KA), ankle dorsi-flexion angle (AA), pelvic shift (PSh), hip and knee osteoarthritis (OA) grade.A K-means cluster analysis was conducted to identify patterns of lower limb compensation based on SFA and KA. The optimal number of clusters was determined using the silhouette score. The different parameters were then compared across clusters. 871 ASD patients were included, of whom 66.9% were females. Mean age was 62.3±14.6 years, mean BMI was 27.7±5.5 kg.m-2. Four patterns of lower limb compensations were identified: "No compensators", "Recliners" (mainly hip extension), "Squatters" (mainly knee flexion) and "Mixed compensators" (both)."Mixed" and "Squatters" had significantly larger BMI. The proportion of females was the least in the "Squatters" cluster (47.0%) while it was the highest in the "Recliners" group (79.3%) (p<0.001). The proportion of patients with severe hip OA was the lowest in the "Recliners" (38.5%) while it was the highest in the "Squatters" group (71.9%). Knee OA rate was the highest in the"Squatters" group (72.7%). "Mixed compensators" had the greatest PI-LL mismatch (30.4±20.0°) and "No compensators" the lowest (5.3±21.3°). Pelvic incidence values were the highest in "Recliners" and "Mixed compensators" (59.2±13.1° and 57.0±14.1° respectively). TPA values were the highest in the "Mixed compensators" and the lowest in the "No compensators" (33.3±11.7° versus 16.1±11.5°). The "Squatters" presented the significantly poorest values for disability, frailty, and SRS score. Cluster analysis determined four types of lower limb compensation:"Recliners" using only hip extension, "Squatters" using only knee flexion,"Mixed compensators" and "No compensators". Lower limb compensatory mechanisms recruitment is multifactorial and varies with age, sex, BMI, frailty, knee and hip OA, pelvic incidence, and spinal alignment.

Background: University students are exposed to high levels of sedentary behavior (SB), which may negatively impact musculoskeletal health, including joint range of motion (ROM). However, evidence in young, healthy populations remains limited. Objective: To examine the relationship between SB and hip joint ROM in Chilean university students, with particular attention to sex differences. Methods: A cross-sectional study was conducted with 189 students (89 men, 100 women; mean age: 21.6 ± 2.4 years). SB was assessed using the short-form International Physical Activity Questionnaire, and hip ROM (flexion, extension, abduction) was measured with a digital goniometer under standardized conditions. Results: Mean SB was 691 ± 42.6 minutes/day, exceedingly commonly accepted sedentary thresholds. No significant correlations were found between SB and hip ROM. Women demonstrated significantly greater hip flexion and abduction ROM than men (p &lt; 0.05), while no sex differences were observed in hip extension. Conclusion: Despite high levels of SB in this university population, no association with hip ROM was found. The observed sex differences in joint mobility align with known anatomical and behavioral variations. These findings highlight the need for longitudinal research using objective measures to better understand SB’s impact on joint health in young adults.

IntroductionCentral diabetes insipidus is a clinical syndrome which results from loss or impaired function of ADH secreting neurons in the hypothalamus/posterior pituitary. The syndrome is characterized by hypotonic polyuria and compensatory polydipsia. It is estimated that destruction of over 90% of the vasopressinergic neurons is necessary for the clinical syndrome. Etiology of central diabetes insipidus involves trauma, autoimmunity, as well as inflammatory and infiltrative disorders.Langerhans cell histiocytosis (LCH) is a histiocytic disorder characterized by granulomatous lesions infiltrating various tissues and organs throughout the body. LCH is a rare diagnosis in adults occuring 0.07 per million annually. Pituitary may be involved in the multisystemic form of the disease and may present as diabetes insipidus. Here we present a case with polydipsia who was found out to have multisystemic LCH.Clinical CaseA 35-year-old male patient was consulted to the endocrinology department for polydipsia. The patient had been well until three months before when he began drinking about 12 liters of water a day. He had been suffering from a slight pain in the left hip for four years that remained uninvestigated. He had a smoking history of 40 pack years. His medical history was otherwise unremarkable. Physical examination showed normal findings except a limited extension and external rotation of left hip. Laboratory tests revealed a urine osmolality of 60mOsm/kg and a serum osmolality of 287mOsm/kg. Water deprivation test was consistent with complete antidiuretic hormone (ADH) deficiency; central diabetes insipidus. Pituitary MRI showed a slight increase in the stalk thickness. Further investigation was carried out to understand the underlying disease. A high-resolution thorax computerized tomography (CT) showed peribronchial thickening, cystic enlargements and irregular reticular densities involving both upper lobes and superior segments of lower lobes. These findings suggested LCH. The bone scintigraphy demonstrated increased osteoblastic activity in right frontotemporal, posteroparietal and mandibular regions and trochanteric region of left femur. Positron emission tomography with fluorodeoxycholine showed; increased uptake in both lungs, right mandible, left femur, calvarium, right iliac bone and T2 vertebra. Bone biopsy from left femur proved the diagnosis of LCH. Desmopressin nasal spray was prescribed for ADH deficiency. Cladribine was started by the department of Hematology for Langerhans cell histiocytosis.ConclusionCentral diabetes insipidus may be a sign of a multisystemic infiltrative or inflammatory disorder. Although rare, LCH should also be considered as an underlying disorder in CDI. Careful clinical and radiologic investigation is necessary for correct diagnosis and management.Figure 1:Fluoro-Deoxy Glucose- Positron Emission Tomography (FDG-PET) Table 1:Laboratory Results

Preoperative Hip Flexion and Extension Range of Motion and Global Sagittal Alignment Affect Sagittal Spino-pelvic Alignment in Patients Undergoing Total Hip Arthroplasty.

Exoskeletons have exhibited increasingly diverse designs and broader applications in rehabilitation and medical fields. To achieve optimal assistance performance, it is essential that the assistive force be synchronized with human biomechanics. However, current soft exoskeletons still face challenges in achieving natural gait synchronization and providing stable, comfortable assistance. This study proposes a biomimetic assistance method for a hip soft exoskeleton that better matches natural human gait. It explores how integrating a dual‑pretension mechanism with biomechanics‑based force modeling can enhance assistive performance, improve user comfort, and reduce metabolic energy consumption during walking. By mimicking the muscle force characteristics of hip joint extension and flexion, two sets of assistive torque curves were developed to correspond with human biomechanical motion. Additionally, to compensate for the hysteresis inherent in the exoskeleton system, a pre‑tension force was applied before and after the assistive curves to improve response time. To enhance the accuracy of gait cycle prediction and achieve better synchronization with natural gait patterns, a Gaussian-weighted moving average algorithm was employed to adaptively assign higher weights to recent gait data, thereby improving the responsiveness and adaptability of the exoskeleton. In the experiments, six subjects participated, and their net metabolic rates were compared under assisted and unassisted conditions. The results showed that the subjects' average metabolic cost decreased by 16.4% at a walking speed of 3 km/h and by 14.1% on a 4° slope. Compared with previous approaches, the proposed algorithm achieved more accurate gait‑phase adaptation and reduced metabolic expenditure, highlighting its potential for human-exoskeleton co‑adaptation.

The contribution of lower limbs to Pelvic Tilt: A baseline and postoperative full-body analysis.

Cerebral palsy (CP) is a non-progressive neurological disorder that impairs motor control and coordination due to brain injury or abnormalities before, during, or shortly after birth. Although robotic gait training can improve overall gait patterns in CP, interventions targeting the 'foot rockers' motion, essential for stable weight transfer and effective push-off, have received limited attention. In this study, five adults with CP were recruited to train on a robotic treadmill system in which controlled downward forces were applied to the pelvis during walking, promoting implicit motor learning to develop an improved foot rockers strategy. Following this, during overground walking, participants received distinct real-time auditory cues at heel strike and push-off, providing self-awareness feedback to reinforce and maintain the foot rockers pattern acquired during treadmill training. Post-training analyses reported increased Tibialis Anterior activation during early stance, enhancing dorsiflexion and heel strike, and greater Soleus and Gastrocnemius engagement in late stance for stronger push-offs (p <0.05). These functional gains were reflected in key spatiotemporal metrics: longer step length, greater toe clearance, a reduced stance percentage, and a shorter double stance time (p <0.05). Participants also exhibited increased range of motion of the foot and increased knee and hip extension throughout stance, reflecting a more upright lower limb (p <0.05). Survey responses confirmed that participants acknowledged the resistive treadmill training for strengthening their muscles and influencing their walking patterns, and reported that the auditory biofeedback enhanced their awareness of heel-to-toe contact. Participants emphasized the necessity of incorporating both interventions, highlighting its potential as a promising approach to improving foot rockers and overall gait pattern in adults with CP.

Dual-task effects on spatiotemporal, kinematic, and kinetic parameters and their variability during running.

Shoe companies produce running shoes that feature either reinforced (e.g., maximalist) or diminished (e.g., minimalist) midsole thicknesses, claiming potential benefits for injury prevention and enhanced running performance. Previous research has examined various footwear models available on the market, specifically investigating the effects of different midsole thicknesses. However, no studies have specifically focused on the biomechanical factors associated with carbon plate minimalist shoes. Therefore, the current study aims to investigate the effects of midsole thicknesses of 0mm, 6mm, and 8mm on the kinematic and kinetic parameters observed in elite runners, utilizing a standardized test shoe prototype. Method: Thirteen male participants, all habitual rearfoot strikers, were recruited from local social running clubs. A three-dimensional motion capture system (Vicon, Oxford, UK) consisting of ten cameras was employed to collect and analyze running kinematic data at a sampling frequency of 200 Hz. Ground reaction forces were recorded using a Kistler Type 9281 B force plate (Kistler Instrument AG, Winterthur, Switzerland) with a sampling frequency of 1000 Hz. One-way repeated-measures ANOVA was conducted to compare the biomechanical variables using SPSS version 25.0. We observed a significant interaction between heel drop and peak vertical ground reaction force (vGRF), foot strike angle (FSA), and propulsion force. Runners exhibited a reduced FSA when wearing DF6 and DF0 shoes compared to DF8 shoes. However, we did not observe a shift in running strike patterns. The results indicate that shoes with a higher heel drop (DF8) lead to a decrease in peak vGRF, ankle dorsiflexion moment, and knee flexion moment. Furthermore, shoes with a lower drop significantly increased peak propulsion force, ankle plantarflexion, dorsiflexion angle, knee flexion angle, and hip extension angle when compared to thicker shoes (DF8). This study primarily investigates the immediate effects of three different heel-drop running shoes on strike patterns, vertical ground reaction force (vGRF) peak force, joint angles, and joint moments during the running stance phase. The results offer insights into the mechanisms by which newly developed running shoes can enhance elite runners' performance. Furthermore, the statistical parametric mapping (SPM) findings from this study assess the differences throughout the entire stance phase, thereby improving our understanding of how variations in heel height influence running performance.

Background:A thorough understanding of posterior hip anatomy is essential for safe and effective posterior hip endoscopy. The sciatic nerve runs laterally to the ischium and hamstring origin. While sciatic nerve injury during proximal hamstring repair is uncommon, the increasing use of endoscopic techniques has led to a rise in iatrogenic injuries. This highlights the need for a structured approach to identifying and protecting the sciatic nerve.Indications:Surgical intervention is indicated for complete proximal avulsions involving all 3 hamstring tendons, partial avulsions involving ≥2 tendons and >2 cm of retraction, and partial avulsions that fail to improve after 6 months of conservative management.Technique Description:There are various safeguards to safely manage the sciatic nerve during posterior hip endoscopy. Proper patient positioning and portal creation are essential steps to minimize sciatic nerve risk. Utilization of prone positioning with strategic padding allows slight hip extension, knee flexion, and hip abduction. In turn, this will relax the nerve and increase the ischiofemoral space. Creation of the subgluteal space is critical, with meticulous resection of the subgluteal bursa to expose the proximal hamstring tendon and surrounding anatomy. A fascial veil consistently separates the tendon from the sciatic nerve and can be partially resected for nerve visualization. Tear exposure is achieved through a longitudinal split between the semimembranosus and conjoint tendon, which also serves as access for ischioplasty. The remaining tendon provides natural protection, while fluoroscopy guides safe bony resection and helps assess ischial width.Results:Endoscopic proximal hamstring repair is an effective approach leading to significant improvement in pain and function. Among endoscopic hamstring repairs, complications—such as persistent peri-incisional numbness and postoperative neuropathy—have each been reported in approximately 8% of cases. This highlights the importance of proper sciatic protection.Discussion/Conclusion:Endoscopic proximal hamstring repair and ischioplasty serve as effective, minimally invasive options for proximal hamstring pathology with careful attention to sciatic nerve safety. A thorough understanding of posterior hip anatomy, strategic patient positioning, precise portal placement, and deliberate dissection techniques is critical for minimizing iatrogenic nerve injury.Patient Consent Disclosure Statement:The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

This study applies one-dimensional statistical parametric mapping (SPM1d) to analyze the effects of exercise-induced fatigue on lower limb biomechanics during the landing phase of two high-risk backhand smash movements in female badminton players. It aims to reveal fatigue-induced changes in movement patterns and differences between the two actions, providing scientific insights for performance optimization, injury prevention, and training interventions. Thirteen female elite badminton players were recruited. A fatigue protocol based on a badminton-specific speed test was applied, and SPM1d was used to analyze kinematic and kinetic data before and after fatigue. After fatigue, significant increases were observed in hip coronal range of motion (ROM) (P = 0.024), knee valgus angle (P = 0.037), and trunk lateral tilt (P = 0.012), with significant decreases in hip abduction angle (P = 0.024) and trunk forward flexion (P = 0.048). When comparing the backward jump smash (BRJS) to the lateral jump smash (BLJS), significant differences were found in ankle (sagittal P = 0.006, horizontal P = 0.006) and hip (sagittal P &lt; 0.001, horizontal P &lt; 0.001) ROM, ankle external rotation angle (P = 0.047), knee flexion angle (P = 0.049), hip abduction angle (P = 0.002), trunk forward flexion angle (P = 0.042), ankle inversion torque (P = 0.048), internal rotation torque (P &lt; 0.001), knee inversion torque (P = 0.003), external rotation torque (P = 0.019), hip adduction torque (P = 0.003), and forward ground reaction force (GRF) (P = 0.05), all of which were significantly greater in BRJS. However, BRJS showed significantly smaller hip flexion angle (P = 0.014), hip extension torque (P = 0.019), hip internal rotation torque (P = 0.046), knee extension torque (P = 0.024), trunk lateral tilt (P = 0.004), lateral GRF (P &lt; 0.001), and vertical GRF (P = 0.003) compared to BLJS (1) The increase in knee valgus angle, trunk flexion angle, and lateral tilt angle, as well as the decrease in hip abduction angle caused by exercise-induced fatigue, increases the risk of ACL injuries in the lower limbs. (2) Both high-risk smash landings pose injury risks. In BRJS, increased ankle inversion/internal rotation torques heighten ankle sprain risk, while higher forward GRF and knee valgus torque raise ACL injury risk. In BLJS, greater medial GRF increases ankle sprain risk, whereas higher knee extension torque, trunk lateral tilt, and reduced knee/trunk flexion elevate ACL injury risk.

This review applied the two-joint link model to review the functional roles of femoral biarticular, monoarticular and lower leg muscles during walking in domestic cats, with comparative insights from dogs, horses and humans. Electromyographic (EMG) data from the right hindlimb were analyzed to characterize sequential activity switches and coactivation patterns among e-series and f-series muscles. In cats, extensive stance-phase activation of both groups including M. gluteus muscles (f1), M. biceps femoris (f3) and M. vastus muscles (e2) contrasted with humans, in whom f-series activity was minimal and the gastrocnemius (f1) was primarily active during the swing phase. Cross-species comparisons revealed consistent coactivation between two biarticular muscles (e3/f3) or between biarticular and monoarticular muscles (e3/e2), indicating functional parallels in redirecting forces at the ankle. In quadruped cats, dogs and horses, persistent M. gluteus muscle (f1) activity contributed to hip extension and hindlimb propulsion, highlighting its more prominent stance-phase role compared with humans. Mapping muscle activity onto six-sector force outputs demonstrated the model's capacity to interpret directional control of locomotion via combined muscle forces. Collectively, these findings refined the two-joint link model's applicability across tetrapods and provided a foundation for testable hypotheses regarding muscular coordination, limb segment stabilization and evolutionary adaptations in tetrapod locomotion.

Wearing high heels may adversely affect lower limb biomechanics and increase the risk of knee injury in women. This study aims to investigate gait kinematics and kinetics associated with barefoot and high-heeled walking and evaluate whether wearing high heels increases knee joint loading and alters joint stress patterns in healthy female college students. Twelve healthy female college students participated in this cross-sectional study. A Vicon motion capture system (Vicon, Oxford, UK) and AMTI force platforms (Advanced Mechanical Technology Inc., Watertown) were used to collect synchronized kinematic and kinetic data under 2 walking conditions (barefoot and high heels). Data collection was conducted between March and May 2025. Three-dimensional knee moments were calculated using inverse dynamics based on individual anthropometrics. Paired t tests were used to compare differences between conditions. Compared with barefoot walking, high heels significantly increased hip flexion and ankle plantarflexion angles, and reduced knee flexion during stance (P < .05). At toe-off, hip extension and ankle plantarflexion were also elevated. Kinetic results showed significant differences in peak flexion moment 1, adduction moments 1 and 2, and external rotation (P < .05), while peak extension moment 2 showed no difference. High heels altered the timing of adduction, internal, and external rotation peaks. Patellofemoral joint stress was significantly higher in the high-heeled condition (P < .05). High-heeled walking alters lower limb joint angles, knee moment characteristics, and increases patellofemoral joint stress in young women, suggesting a higher risk of knee injury compared with barefoot walking.

The posterior chain muscles (i.e. hamstring and gluteal) play an important role in performance and injury prevention. Posterior chain muscle injuries lead to time lost from training, competition and increased reinjury risk. Force plates enable valid and reliable assessment, current methods assessing isometric posterior chain (IPC) force production using force plates have yet to be reviewed. This review was designed to systematically review methods of single joint IPC force plate testing; establish existing reliability; and summarise descriptive data. A literature search was conducted using the following search terms: 'force plat*' AND 'isometric' AND ('hamstring*' OR 'knee flex*' OR 'posterior chain' 'hip' OR 'hip exten*'). Twenty studies were included, five test variations were used (90-90, 30-30, 90-20hands-on-wall, 90-20hands-on-chest, and isometric hip extension), the 90-90 being the most common. Peak force was the most reported metric (n = 17). Thirteen studies reported reliability. Descriptive data was predominantly on footballers. Relative peak force values ranged from 3.3-4.7N/kg and 2.9-3.4N/kg (90-90), and 3.0-3.1N/kg and 2.5N/kg (30-30) for male and female soccer players, respectively. IPC force assessment methodologies varied across studies, with clear standardisation of procedures and investigation into other team sports including sex differences recommended for future studies.

ObjectivesThe aim was to compare functional performance and isometric maximum voluntary contraction (MVC) during hip flexion, extension and abduction between patients with hip dysplasia scheduled for periacetabular osteotomy (PAO) and a group of healthy subjects.DesignCross-sectional study.MethodThe single-leg hop for distance, Y Balance Test and MVC tests in an isokinetic dynamometer were conducted using the index and contralateral leg among patients and using the right leg among healthy subjects.Results59 patients and 39 healthy subjects were included. The single-leg hop test showed a difference of 4.2 cm (95% CI: 0.3;8.0) between the index and contralateral leg for patients. Healthy subjects hopped 34.3 cm (95% CI: 23.2;45.4) longer than patients. The Y Balance Test indicated a difference in the posterolateral direction between patients hips, while healthy subjects performed better than patients in all directions. Muscle strength were similar between the patients index and contralateral hip. Hip abduction and extension were similar between the groups, but hip flexion was 149.5 Nm (95% CI: 3.9;26.4) lower for patients than healthy subjects.ConclusionsPatients with hip dysplasia had worse functional performance in single-leg hop and Y Balance Test, and notable deficit in hip flexion strength compared to healthy subjects.

Background: Video-based biomechanical running gait analysis is widely used to optimise technique, guide footwear selection, and identify orthopaedic risk factors. Despite the increasing availability of such assessments, it is often assumed—without strong empirical support—that key kinematic parameters of running gait remain stable over short periods of time. This study aimed to examine the short-term stability of key joint angles during running using a standard 2D video-based kinematic analysis. Specifically, it was investigated whether these angles change within the first 4 min of treadmill running under three defined conditions: barefoot at 12 km h−1, shoed at 12 km h−1, and shoed at 14 km h−1, in a homogeneous sample of twelve young, trained, male recreational soccer players. Methods: Participants completed three four-minute runs. Joint angles were quantified manually from 2D video recordings. Temporal variation was analysed using repeated-measures statistics, intraclass correlation coefficients (ICCs), and minimal detectable changes (MDCs). Results: Six out of nine joint angles showed statistically significant temporal changes, mainly in hip extension, knee flexion, the Duchenne angle, the Trendelenburg angle, the leg axis angle, and heel-bottom angle. Lower leg angle and Achilles tendon angle remained stable. ICCs showed moderate to excellent agreement, indicating high within-session consistency across all angles. Discussion: Under the applied study protocol, significant short-term variations were observable in several joint angles during the first four minutes of running. These findings highlight the importance of analysing multiple strides and considering measurement uncertainty when interpreting short-duration running kinematics.