Human pose estimation (HPE) is a technique used in computer vision and artificial intelligence to detect and track human body parts and poses using images or videos. Widely used in augmented reality, animation, fitness applications, and surveillance, HPE methods that employ monocular cameras are highly versatile and applicable to standard videos and CCTV footage. These methods have evolved from two-dimensional (2D) to three-dimensional (3D) pose estimation. However, in real-world environments, current 3D HPE methods trained on laboratory-based motion capture data encounter challenges, such as limited training data, depth ambiguity, left/right switching, and issues with occlusions. In this study, four 3D HPE methods were compared based on their strengths and weaknesses using real-world videos. Joint position correction techniques were proposed to eliminate and correct anomalies such as left/right inversion and false detections of joint positions in daily life motions. Joint angle trajectories were obtained for intuitive and informative human activity recognition using an optimization method based on a 3D humanoid simulator, with the joint position corrected by the proposed technique as the input. The efficacy of the proposed method was verified by applying it to three types of freehand gymnastic exercises and comparing the joint angle trajectories during motion.

This study aimed to determine the differences in the kinematic sequence and time lag of body segments for shots (pitch and lob shots) at different distances (20 and 30 m) around the green. Ten skilled female golfers participated voluntarily. A repeated-measures one-way analysis of variance was performed to assess the effect of the peak angular velocity of the shots (20-m pitch, 30-m pitch, 20-m lob, and 30-m lob shots) on the segments and the effect of the peak angular velocity and time lag of the body segments (pelvis, thorax, upper arm, forearm, and hand) on the shots. All shots taken revealed a summation effect of velocity from proximal to distal body segments, regardless of the shot type (pitch or lob shot) or distance (20 or 30 m). The peak angular velocity of the body segments demonstrated that the velocities associated with the 30-m shots were significantly higher than those associated with the 20-m shots, and the velocities associated with lob shots were significantly higher than those associated with pitch shots, irrespective of the shot distance. This study provided additional insight into the mechanism for improving performances in the shots around the green.

Maintaining lower-limb joint stability is essential for safe and efficient performance during landing and directional changes. This pilot study examined the effects of a 10-week perturbation-based Dynamic Stability Training (DST) program using an inertial water load on lower-limb joint moments during single-leg landing and a 3-s stabilization phase following a 90° cutting maneuver. Fifteen healthy young men completed DST twice weekly. Three-dimensional motion capture and force-plate data were collected at pre-, mid-, and post-training to compute hip, knee, and ankle joint moments. During landing, hip flexion and abduction moments increased, whereas knee abduction moment decreased. During the stabilization phase, hip flexion, hip rotation, and ankle abduction moments decreased, while knee abduction moment increased. These joint-specific changes suggest potential adaptations in frontal- and transverse-plane control when training with unstable inertial water loads; however, interpretations should remain cautious given the exploratory design and absence of a control group. Larger randomized controlled trials are needed to confirm these preliminary findings.

Background: Parkinson’s disease (PD) diagnosis is often delayed until signature motor symptoms manifest, at which point profound dopaminergic neuron loss has already occurred, necessitating advanced motor diagnostic biomarkers. Quantitative gait analysis is a promising tool, but phase-specific kinematic parameters remain underexplored. This study aims to identify novel, stage-divided Timed Up and Go (TUG) biomarkers not only to differentiate healthy controls (HCs) from patients with PD but also to objectively monitor and track disease progression across advancing severity stages, which are further validated against conventional clinical motor scales. Methods: A total of 81 participants (48 PD, 33 HCs) performed a 3 m TUG test using MotionCore (JEIOS Inc., Busan, Republic of Korea). The test was subdivided into three movement phases (Stage 1, sit-to-walk; Stage 2, turning; Stage 3, walk-to-sit). Results: PD patients exhibited significantly prolonged durations and altered turning metrics compared to HCs. Turning parameters including turning radius (ETR), area (EMA), and turning stability (FN) demonstrated strong correlations with disease severity and clinical scales. Notably, stage-specific analyses revealed that step counts, time, and speed metrics across Stages 1, 2, and 3 effectively differentiated disease severity, with transitional decelerating and seating metrics in Stage 3 showing the most pronounced clinical correlations. Discussion: This study confirms that the TUG test systematically deteriorates with increasing PD severity. The robust correlations with clinical scales (UPDRS, FOG-Q, BBS) validate TUG metrics as objective measures of motor and balance impairments. Utilizing novel, staging-specific indices significantly enhances the TUG test’s clinical utility for supporting diagnosis, accurate staging, and monitoring disease progression. Although the overall group comparisons demonstrated statistical significance, a data overlap remains between mild PD and HCs, underscoring the need for large-scale longitudinal studies to validate these metrics for early detection.

Background/Objectives: This study investigated the effects of dynamic stability train-ing using inertial water load on lower limb joint moments and postural control during landing and directional changes. Given the high biomechanical demands of transition-ing from the non-dominant to dominant leg, we examined whether perturbation-based training could enhance neuromuscular control and movement efficiency. Methods: Twenty-six healthy males in their 20s were randomly assigned to an experimental group (n = 13), performing water-filled bag training for 10 weeks, or a control group (n = 13) with no training. Participants completed a landing followed by a 90° cutting maneuver, with joint moments measured via a 3D motion capture system. Analyses were con-ducted for the landing and change-of-direction phases. Results: In the landing phase, group differences were observed in hip, knee, and ankle moments, particularly in the frontal and transverse planes (p < 0.05), but none remained significant after Bonferroni adjustment. The experimental group generally showed lower hip flexion/extension (Hip Moment X) and greater knee and ankle internal/external rotation moments (Knee, Ankle Moment Z). In the cutting phase, only knee abduction/adduction (Knee Moment Y) showed a significant time effect (p = 0.007), not surviving adjustment, with a trend to-ward improved frontal plane control. Conclusions: Ten weeks of water-filled inertial load training improved neuromuscular coordination, shock absorption, and postural control patterns, especially in frontal and transverse planes. Perturbation-based training may be a sport-specific strategy to enhance movement efficiency and reduce lower-limb injury risk during rapid directional changes.