Spine and lower body symmetry during treadmill walking in healthy individuals-In-vivo 3-dimensional kinematic analysis

3-Dimensional kinematics and kinetics of the snatch in elite and varsity weightlifters

Mastering the snatch lift requires physical strength as well as a deep understanding of kinematics, kinetics, and timing, making it one of the most technically demanding athletic feats. While kinematic differences across skill levels are well-documented, kinetic differences are less understood. Exploring the 3D kinetics of the snatch can reveal important insights into the movement patterns, moments, forces, and power involved in the lift, helping to enhance performance for lifters at all skill levels. This study examined the 3D kinematic and kinetic differences between elite and varsity weightlifters during the snatch lift. A total of 23 participants (10 females, 13 males), including 11 elite and 12 varsity weightlifters, were measured. Results from the SPM analysis of 3D kinematics and kinetics during the snatch lift indicate that elite athletes tend to achieve key kinematic events slightly later in the lift cycle compared to varsity athletes, particularly in knee flexion and extension. In addition, elite lifters demonstrated superior shoulder moments about adduction-abduction and internal-external rotation axes, along with increased elbow and wrist moments during most of the raising phase. Key differences indicate elite athletes showed greater hip extensor and abductor moments at the catch and rise phases, while varsity athletes exhibited higher lateral forces during the first pull and transition phases (p < 0.05). Significant differences were also found in shoulder, wrist, and ankle dynamics, with elite lifters demonstrating greater normalized power and moments across various joints (p < 0.05). These findings provide a valuable reference for improving the snatch technique of both varsity and elite lifters. Addressing variations in the mechanics and timing of the snatch lift may enhance performance and proficiency across all levels of weightlifters.

Does cranial cruciate ligament repair by tibial plateau leveling osteotomy surgery restore dog's natural kinematics? - A case series

Tibial plateau leveling osteotomy (TPLO) serves as an effective method of functional stabilization for treating cranial cruciate ligament (CrCL) deficiency. It is not clear if TPLO could restore the natural kinematics of the stifle, hip, and tarsal joints of the affected limb during walking. The hind limb motion between TPLO cases and control groups in eight adult dogs (4 French Bulldogs and 4 Pit Bull Terrier) was recorded by a motion capture system. Three-dimensional (3D) angular motions of the hip, stifle, and tarsal joints-including flexion-extension, abduction-adduction, and rotations-were computed and compared. Significant differences in joint kinematics were observed between TPLO cases and controls. In Case 1, the TPLO case in the French Bulldog showed differences in hip, stifle, and tarsal flexion-extension, abduction-adduction, and internal-external rotation. Asymmetries between affected and unaffected limbs were also detected in hip and stifle motions (up to 43° in some cases). Similar patterns of differences were found in Pit Bull Terriers Case 2 and Case 3, with significant variations in hip, stifle, and tarsal movements. Case 3 did not show hip asymmetries, but notable stifle and tarsal asymmetries were observed. The general daily activity performance for French Bulldogs and Pit Bull Terriers that underwent TPLO procedures was positive. The general daily restricted activity performance for the French Bulldog and Pit Bull Terriers that underwent TPLO procedures was positive. Our findings suggested that natural hind limb kinematics during gait was not restored in TPLO hind limb cases in both breeds.

Biomechanical analysis of the snatch technique for elite and varsity weightlifters

Understanding the importance of movement asymmetries and variations in technique proficiency across different level of weightlifters is crucial. The purpose of this study was to examine differences in joint kinematics, muscle activation, and barbell parameters between elite and varsity weightlifters during the snatch utilizing integrated 3D motion capture and EMG systems. In addition, it analyzes symmetries in joint kinematics and muscle activation in both groups. Ten female participants, comprising 5 elite and 5 varsity weightlifters, along with thirteen male participants, consisting of 6 elite and 7 varsity weightlifters during snatch were measured. Several asymmetries in posture and muscle activation were identified in both elite and varsity weightlifters. In addition, elite weightlifters exhibited significantly more flexed knees than varsity counterparts (p < 0.05) at the conclusion of the second pull and at the highest position of the barbell. Furthermore, significantly lower activity in gluteus maximus was detected in elite weightlifter at the highest point of the barbell than in the varsity groups (p < 0.05). Moreover, elite males achieved a lower maximum height for the barbell compared to varsity males (p = 0.006). Furthermore, elite females demonstrated less horizontal displacement (D2x) (p = 0.005) than varsity counterparts. Varsity women presented significantly lower horizontal velocity (p = 0.003) at the conclusion of the second pull than varsity counterparts. Despite several asymmetries detected, those may not be critical factors in achieving a successful snatch lift, given that all weightlifters successfully completed the lift. However, variations in posture and muscle activation may still be associated with improvements in technique proficiency across different levels of weightlifters.

In-vivo 3-dimensional spine and lower body gait symmetry analysis in healthy individuals

Background

Numerous research studies have delved into the biomechanics of walking, focusing on the spine and lower extremities. However, understanding the symmetry of walking in individuals without health issues poses a challenge, as those with normal mobility may exhibit uneven movement patterns due to inherent functional differences between their left and right limbs. The goal of this study is to examine the three-dimensional kinematics of gait symmetry in the spine and lower body during both typical and brisk overground walking in healthy individuals. The analysis will utilize statistical methods and symmetry index approaches. Furthermore, the research aims to investigate whether factors such as gender and walking speed influence gait symmetry.

Methods

Sixty young adults in good health, comprising 30 males and 30 females, underwent motion capture recordings while engaging in both normal and fast overground walking. The analysis focused on interlimb comparisons and corresponding assessments of side-specific spine and pelvis motions.

Results

Statistical Parametric Mapping (SPM) predominantly revealed gait symmetries between corresponding left and right motions in the spine, pelvis, hip, knee, and ankle during both normal and fast overground walking. Notably, both genders exhibited asymmetric pelvis left-right obliquity, with women and men showing an average degree of asymmetry between sides of 0.9 ± 0.1° and 1.5 ± 0.1°, respectively. Furthermore, the analysis suggested that neither sex nor walking speed appeared to exert influence on the 3D kinematic symmetry of the spine, pelvis, and lower body in healthy individuals during gait. While the maximum normalized symmetry index (SInorm) values for the lower thorax, upper lumbar, lower lumbar, pelvis, hip, knee, and ankle displayed significant differences between sexes and walking speeds for specific motions, no interaction between sex and walking speed was observed.

Significance

The findings underscore the potential disparities in data interpretations between the two approaches. While SPM discerns temporal variations in movement, these results offer valuable insights that may enhance our comprehension of gait symmetry in healthy individuals, surpassing the limitations of straightforward discrete parameters like the maximum SInorm. The information gleaned from this study could serve as reference indicators for diagnosing and evaluating abnormal gait function.

Influence of a passive exoskeleton on kinematics, joint moments, and self-reported ratings during a lifting task

It was found that the Auxivo LiftSuit reduced the load on the back and hip muscles when lifting heavy loads, but its effect on lower body kinematics, joint moments, and self-reported ratings was unclear. The purpose of this study was to assess the effect of this passive lift-exoskeleton design, on lower body kinematics, joint moments, and self-reported ratings during lifting of heavy loads. Twenty healthy subjects performed lifting of heavy loads with and without the exoskeleton under surveillance of a motion capture system. Medium and maximum level adjustments of the exoskeleton, as well as no exoskeleton use were analyzed. Our results indicate significant reduction (p <.01) in pelvis segment tilt and hip flexion ROM with the exoskeleton at maximum level adjustment in males during lifting. Lumbosacral flexion moment ranges were significantly decreased (p <.013) with the exoskeleton at maximum and medium level adjustment in males during lifting. The general user impressions were mostly positive, with participants reporting that it was easier to perform the task with the exoskeleton than without it (p <.0.001), and preferring and recommending the exoskeleton for the task. Although our findings may suggest negative effects of the Auxivo LiftSuit in males and females due to a ROM restriction and loose fit, respectively, it does not mean that the Auxivo LiftSuit is not useful for lifting tasks. Further design improvements are required to allow full range of motion of hips and pelvis, as well to provide better adjustment and level of support in female users.