Segment Angular Velocities Research Articles

A Comparison of Throwing Arm Kinetics and Ball Velocity in High School Pitchers With Overall Fast and Overall Slow Cumulative Joint and Segment Velocities

Background: Individual maximum joint and segment angular velocities have shown positive associations with throwing arm kinetics and ball velocity in baseball pitchers. Purpose: To observe how cumulative maximum joint and segment angular velocities, irrespective of sequence, affect ball velocity and throwing arm kinetics in high school pitchers. Study Design: Descriptive laboratory study. Methods: High school (n = 55) pitchers threw 8 to 12 fastball pitches while being evaluated with 3-dimensional motion capture (480 Hz). Maximum joint and segment angular velocities (lead knee extension, pelvis rotation, trunk rotation, shoulder internal rotation, and forearm pronation) were calculated for each pitcher. Pitchers were classified as overall fast, overall slow, or high velocity for each joint or segment velocity subcategory, or as population, with any pitcher eligible to be included in multiple subcategories. Kinematic and kinetic parameters were compared among the various subgroups using t tests with post hoc regressions and multivariable regression models created to predict throwing arm kinetics and ball velocity, respectively. Results: The lead knee extension and pelvis rotation velocity subgroups achieved significantly higher normalized elbow varus torque (P = .016) and elbow flexion torque (P = .018) compared with population, with equivalent ball velocity (P = .118). For every 1-SD increase in maximum pelvis rotation velocity (87 deg/s), the normalized elbow distractive force increased by 4.7% body weight (BW) (B = 0.054; β = 0.290; P = .013). The overall fast group was older (mean ± standard deviation, 16.9 ± 1.4 vs 15.4 ± 0.9 years; P = .007), had 8.9-mph faster ball velocity (32.7 ± 3.1 vs 28.7 ± 2.3 m/s; P = .002), and had significantly higher shoulder internal rotation torque (63.1 ± 17.4 vs 43.6 ± 12.0 Nm; P = .005), elbow varus torque (61.8 ± 16.4 vs 41.6 ± 11.4 Nm; P = .002), and elbow flexion torque (46.4 ± 12.0 vs 29.5 ± 6.8 Nm; P < .001) compared with the overall slow group. A multiregression model for ball velocity based on maximum joint and segment angular velocities and anthropometrics predicted 53.0% of variance. Conclusion: High school pitchers with higher maximum joint and segment velocities, irrespective of sequence, demonstrated older age and faster ball velocity at the cost of increased throwing shoulder and elbow kinetics. Clinical Relevance: Pitchers and coaching staff should consider this trade-off between faster ball velocity and increasing throwing arm kinetics, an established risk factor for elbow injury.

Effect of Torso Kinematics on Gait Phase Estimation at Different Walking Speeds.

Human gait phase estimation has been studied in the field of robotics due to its importance for controlling wearable devices (e.g., prostheses or exoskeletons) in a synchronized manner with the user. As data-driven approaches have recently risen in the field, researchers have attempted to estimate the user gait phase using a learning-based method. Thigh and torso information have been widely utilized in estimating the human gait phase for wearable devices. Torso information, however, is known to have high variability, specifically in slow walking, and its effect on gait phase estimation has not been studied. In this study, we quantified torso variability and investigated how the torso information affects the gait phase estimation result at various walking speeds. We obtained three different trained models (i.e., general, slow, and normal-fast models) using long short-term memory (LSTM). These models were compared to identify the effect of torso information at different walking speeds. In addition, the ablation study was performed to identify the isolated effect of the torso on the gait phase estimation. As a result, when the torso segment's angular velocity was used with thigh information, the accuracy of gait phase estimation was increased, while the torso segment's angular position had no apparent effect on the accuracy. This study suggests that the torso segment's angular velocity enhances human gait phase estimation when used together with the thigh information despite its known variability.

Acute and persistence of the effects of the SuperSpeed Golf™ weighted-club warm-up on golf driving performance and kinematics

ABSTRACT High-level golfers use various warm-up strategies to enhance clubhead and ball speed, including weighted equipment. We investigated the acute effects of the SuperSpeed Golf™ weighted-club warm-up on clubhead, ball, and swing kinematics, and the persistence of any acute effects in subsequent sets. Twelve competitive golfers (handicap < 3.0) completed five sets of five swings using their own drivers under two randomised warm-up conditions (Control and SuperSpeed). We compared swing, peak segment and club angular velocity, and centre of mass (COM) parameters collected using a 3D motion capture system (500 Hz) between conditions. The temporal persistence of any meaningful (Cohen’s d ≥ small) and significant (p≤ 0.05) effect detected in the first set was investigated in subsequent sets. SuperSpeed led to small significant changes in clubhead speed (2.6 mph); downswing time; peak angular velocities of the torso, lead arm, and club; and two COM variables in the initial set. There was no significant change in ball speed, resulting in a large negative change in smash factor acutely (d − 0.82, p= 0.009). Nearly all changes observed were no longer meaningful or significant in subsequent sets. Overall, golfers can expect an increase in driving clubhead speed on the first tee using the SuperSpeed Golf™ vs Control warm-up, with trivial effects from the second tee onwards.

Deformable link segment analysis for prosthetic foot-ankle components: Kinematics

Approaches in the literature for estimating prosthetic foot-ankle power typically require calculating the segment deformation velocity. This, in turn, necessitates approximating the segment angular velocity. Methods can be distinguished by the way in which a segment is defined and the assumptions used for estimating the segment angular velocity. However, isolating foot-ankle performance from overall prosthetic system performance is limited by uncertainties in the definition of angular velocity of a deformable segment. A deformable link segment (DLS) analysis is proposed that provides a means for estimating deformation velocity of a deformable segment without first approximating the angular velocity: the deformation velocity and angular velocity are solved simultaneously at each instant during the stance phase of gait. DLS analysis was compared to two approaches in the literature: the distal foot (DF) model and the unified deformable (UD) segment model during over-ground walking for three trans-tibial prosthesis users. DLS and UD segment estimates of deformation velocity were comparable when applied to the UD segment. Furthermore, DLS analysis enables modelling of deformable prosthetic foot-ankle components separately from other prosthetic componentry. The method is proposed as a rigorous approach to estimating angular velocity and deformation velocity of passive prosthetic foot-ankle components for subsequent calculation of deformation power and energy performance of these devices.

Effect of arm motion on standing lateral jumps

The role of arm swing in jumping has been examined in numerous studies of standing jumps for height and forward distance, but no prior studies have explored its effect on lateral jumping. The purpose of the present study was to investigate the effect of arm motion on standing lateral jump performance and to examine the biomechanical mechanisms that may explain differences in jump distance. Six participants executed a series of jumps for maximum lateral distance from two in-ground force platforms for two jump cases (free and restricted arms) while an eight-camera, passive-reflector, motion capture system collected 3D position data throughout the movements. Inverse kinematics and dynamics analyses were performed for all jumps using three-dimensional (3D) link models to calculate segment angular velocities, joint moments, joint powers, and joint work. Free arm motion improved standing lateral jump performance by 29% on average. This improvement was due to increased takeoff velocity and improved lateral and vertical positions of the center of gravity (CG) at takeoff and touchdown. Improved velocity and position of the CG at takeoff resulted from a 33% increase in the work done by the body. This increase in work in free arm jumps compared to restricted arm jumps was found in both upper and lower body joints with the largest improvements (>30 J) occurring at the lower back, right hip, and right shoulder.

Quantifying the velocity-dependent muscle response during gait of children with Cerebral Palsy

A new method is introduced quantifying the velocity-dependent muscle response during gait in spastic muscles of children with Cerebral Palsy. The velocity-dependent muscle activation Index is calculated during a 3-dimensional gait analysis using segment angular velocity and the Instantaneous Mean Frequency calculated from surface electromyography. Typical developed children (n = 11) and children with hemiplegia (n = 11) aging from 8 to 19 years participated in the study. The rectus femoris and the medial gastrocnemius were assessed by calculating the velocity dependent muscle activation Index and the modified Ashworth Scale. Greater velocity-dependent muscle activation Index values for both medial gastrocnemius and rectus femoris muscles were associated with greater Ashworth Scale. Post hoc analysis revealed significant lower velocity-dependent muscle activation Index means in the Typical developed group compared with Ashworth Scale scores of 1, 2, 3, and 5. In addition, velocity-dependent muscle activation Index for Ashworth Scale 0, 1, and 2 were significantly lower than for Ashworth Scale 3 and 5. The velocity dependent muscle activation Index showed negative low correlation with walking speed and cadence. Findings show that spastic muscles can be quantified during dynamic functional task such as walking. Future studies should investigate the reliability of the velocity-dependent muscle activation Index that may be used for the assessment of spasticity management such as Botulinum toxin A interventions.

Biomechanical analysis of the golf swing: methodological effect of angular velocity component on the identification of the kinematic sequence.

The golf swing is a complex whole-body motion for which a proximal-to-distal transfer of the segmental angular velocities from the pelvis to the club is believed to be optimal for maximizing the club head linear velocity. However, previous experimental results about such timing (or kinematic sequence) are contradictory. Nevertheless, methods that were used in these studies differed significantly, in particular, those regarding the component of the angular velocity vector selected for the identification of the kinematic sequence. Hence, the aim of this study was to investigate the effect of angular velocity vector component selection on the identified kinematic sequence. Thirteen golfers participated in this study and performed driver swings in a motion capture laboratory. Seven methods based on different component selection of segmental angular velocities (vector norm, component normal-to-sagittal, frontal, transversal and swing planes, segment longitudinal component and a method mixing longitudinal and swing plane components) were tested. Results showed the critical influence of the component chosen to identify the kinematic sequence with almost as many kinematic sequences as the number of tested methods for every golfer. One method seems to show the strongest correlation to performance but none of them can be assessed as a reference method for the identification of the golf swing kinematic sequence. Regarding the limited time lag between the different peak occurrences and the uncertainty sources of current materials, development of simulation studies would be more suitable to identify the optimal kinematic sequence for the golf swing.

Assessment of intersegmental coordination of rats during walking at different speeds – Application of continuous relative phase

The present study investigated the feasibility and reliability of continuous relative phase (CRP) and deviation phase (DP) to assess intersegmental hind limb coordination pattern and coordination variability in rats during walking. Twenty-six adult rats walked at 8 m/min, 12 m/min and 16 m/min while two-dimensional kinematics were recorded. Segment angles and segment angular velocities of the paw, shank and thigh on the left hind-limb were extracted from 15 strides and CRP was calculated for the paw-shank and shank-thigh coupling. The effect of walking speed on the time point average curve of the CRP (ACRP) and DP and on the mean ACRP and mean DP was established by statistical parametric mapping (SPM) and a one-way ANOVA for repeated measures. Absolute and relative reliability were assessed by measurement error and intra-class correlation coefficient. The SPM analysis revealed time dependent differences in the effect of speed. Thus, the CRP of the paw-shank coupling decreased with increasing speed during most of the gait cycle while the CRP of the shank-thigh coupling was decreased during the swing phase. The session-to-session reliability was fair to good for the coordination measure and poor for the variability measure.

Effects of cognitive task execution on stable and unstable surface balance

AbstractCompromised balance with respect to both stable and passively unstable surfaces can potentially affect performance of many occupational, recreational and daily living tasks. Many tasks that require some level of balance maintenance, however, also involve burdens on individuals’ cognitive systems. Consequently the purpose of this project was to investigate the effects of performing cognitive tasks on stable surface and passively unstable surface balance performance. Participants in this study performed balance task on a passible unstable surface, as well as on a stable surface, with and without concurrent quantitative and language based cognitive tasks. Concurrent cognitive tasks did not demonstrate statistically significant effects on stable surface balance. For unstable surface balance, concurrent cognitive tasks had significant effects on trunk and arm segment angular velocities, while significant effects on movement of the passively unstable surface were not observed. The lack of cognitive task...

Morphology and motion: hindlimb proportions and swing phase kinematics in terrestrially locomoting charadriiform birds.

Differing limb proportions in terms of length and mass, as well as differences in mass being concentrated proximally or distally, influence the limb's moment of inertia (MOI), which represents its resistance to being swung. Limb morphology - including limb segment proportions - thus probably has direct relevance for the metabolic cost of swinging the limb during locomotion. However, it remains largely unexplored how differences in limb proportions influence limb kinematics during swing phase. To test whether differences in limb proportions are associated with differences in swing phase kinematics, we collected hindlimb kinematic data from three species of charadriiform birds differing widely in their hindlimb proportions: lapwings, oystercatchers and avocets. Using these three species, we tested for differences in maximum joint flexion, maximum joint extension and range of motion (RoM), in addition to differences in maximum segment angular velocity and excursion. We found that the taxa with greater limb MOI - oystercatchers and avocets - flex their limbs more than lapwings. However, we found no consistent differences in joint extension and RoM among species. Likewise, we found no consistent differences in limb segment angular velocity and excursion, indicating that differences in limb inertia in these three avian species do not necessarily underlie the rate or extent of limb segment movements. The observed increased limb flexion among these taxa with distally heavy limbs resulted in reduced MOI of the limb when compared with a neutral pose. A trade-off between exerting force to actively flex the limb and potential savings by a reduction of MOI is skewed towards reducing the limb's MOI as a result of MOI being in part a function of the radius of gyration squared. Increased limb flexion is a likely means to lower the cost of swinging the limbs.

Swing kinematics of male and female skilled golfers following prolonged putting practice

Given that males and females respond differently to endurance-based tasks, prolonged putting practice may provide an avenue to examine gender-related differences in golf swing kinematics. The aim of this project was to determine if 40 min of putting affects thorax and pelvis kinematics during the full swing of males and females. Three-dimensional trunk kinematics were collected during the swings of 19 male (age: 26 ± 7 years, handicap: 0.6 ± 1.1) and 17 female (age: 24 ± 7 years, handicap: 1.4 ± 1.7) golfers before and after 40 min of putting. Angular displacement at address, top of backswing and ball contact for the pelvis, thorax, and pelvis–thorax interaction were calculated, in addition to the magnitude of peak angular velocity and repeatability of continuous segment angular velocities. Female golfers had less pelvis and thorax anterior–posterior tilt at address, less thorax and thorax–pelvis axial rotation at top of backswing, and less pelvis and thorax axial rotation and pelvis lateral tilt at ball contact pre- to post-putting. Analysis of peak angular velocities revealed that females had significantly lower thorax–pelvis lateral tilt velocity pre- to post-putting. In conclusion, an endurance-based putting intervention affects females’ thorax and pelvis orientation angles and velocities to a greater extent than males.

Kinematics based sensory fusion for wearable motion assessment in human walking

Measuring the kinematic parameters in unconstrained human motion is becoming crucial for providing feedback information in wearable robotics and sports monitoring. This paper presents a novel sensory fusion algorithm for assessing the orientations of human body segments in long-term human walking based on signals from wearable sensors. The basic idea of the proposed algorithm is to constantly fuse the measured segment's angular velocity and linear acceleration via known kinematic relations between segments. The wearable sensory system incorporates seven inertial measurement units attached to the human body segments and two instrumented shoe insoles. The proposed system was experimentally validated in a long-term walking on a treadmill and on a polygon with stairs simulating different activities in everyday life. The outputs were compared to the reference parameters measured by a stationary optical system. Results show accurate joint angle measurements (error median below 5°) in all evaluated walking conditions with no expressed drift over time.

Modeling and Simulating Human Arm Movement Using a 2 Dimensional 3 Segments Coupled Pendulum System

A two dimensional three segments coupled pendulum system that mathematically models human arm configuration was developed along with constructing and solving the equations of motions for this model using the energy (work) based approach of Lagrange. The equations of motion of the model were solved iteratively both as an initial value problem and as a two point boundary value problem. In the initial value problem solutions, both the initial system configuration (segment angles) and initial system velocity (segment angular velocities) were used as inputs, whereas, in the two point boundary value problem solutions initial and final configurations and time were used as inputs to solve for the trajectory of motion. The results suggest that the model solutions are sensitive to small changes in the dynamic forces applied to the system as well as to the initial and boundary conditions used. To overcome the system sensitivity a new approach is suggested.

Kinematic and kinetic energy analysis of segmental sequencing in cricket fast bowling

Although there have been many studies to quantify the segmental sequencing in other sports, there has been little such research applied to cricket bowling. In this study, 34 fast bowlers (22.3 ± 3.7 years) of premier grade level and above were tested using 3D motion analysis, their balls speed ranging from 27.0 to 35.6 m s− 1. One-way repeated measures ANOVA was used to test for within-participant differences in segmental sequencing based on the timings of maximum segmental angular velocities and kinetic energies, the data showing that bowlers exhibited a general order of proximal-to-distal sequencing. Bivariate Pearson's product-movement correlation coefficients were calculated to assess the relationships between kinematic variables and ball release speed, yielding a set of variables for entry into a stepwise multiple regression model. The multiple regression model with the sequential timing variables of thoracic linear kinetic energy (KE), upper-arm circumduction velocity and forearm rotation KE, as wel...

Mechanical factors associated with the development of high ball velocity during an instep soccer kick

The purpose of this study was to determine whether joint velocities and segmental angular velocities are significantly correlated with ball velocity during an instep soccer kick. We developed a deterministic model that related ball velocity to kicking leg and pelvis motion from the initiation of downswing until impact. Three-dimensional videography was used to collect data from 16 experienced male soccer players (age = 24.8 ± 5.5 years; height = 1.80 ± 0.07 m; mass = 76.73 ± 8.31 kg) while kicking a stationary soccer ball into a goal 12 m away with their right foot with maximal effort. We found that impact velocities of the foot center of mass (CM), the impact velocity of the foot CM relative to the knee, peak velocity of the knee relative to the hip, and the peak angular thigh velocity were significantly correlated with ball velocity. These data suggest that linear and angular velocities at and prior to impact are critical to developing high ball velocity. Since events prior to impact are critical for kick success, coordination and summation of speeds throughout the kicking motion are important factors. Segmental coordination that occurs during a maximal effort kick is critical for completing a successful kick.

Characterization of Thigh and Shank Segment Angular Velocity During Jump Landing Tasks Commonly Used to Evaluate Risk for ACL Injury

The dynamic movements associated with anterior cruciate ligament (ACL) injury during jump landing suggest that limb segment angular velocity can provide important information for understanding the conditions that lead to an injury. Angular velocity measures could provide a quick and simple method of assessing injury risk without the constraints of a laboratory. The objective of this study was to assess the inter-subject variations and the sensitivity of the thigh and shank segment angular velocity in order to determine if these measures could be used to characterize jump landing mechanisms. Additionally, this study tested the correlation between angular velocity and the knee abduction moment. Thirty-six healthy participants (18 male) performed drop jumps with bilateral and unilateral landing. Thigh and shank angular velocities were measured by a wearable inertial-based system, and external knee moments were measured using a marker-based system. Discrete parameters were extracted from the data and compared between systems. For both jumping tasks, the angular velocity curves were well defined movement patterns with high inter-subject similarity in the sagittal plane and moderate to good similarity in the coronal and transverse planes. The angular velocity parameters were also able to detect differences between the two jumping tasks that were consistent across subjects. Furthermore, the coronal angular velocities were significantly correlated with the knee abduction moment (R of 0.28-0.51), which is a strong indicator of ACL injury risk. This study suggested that the thigh and shank angular velocities, which describe the angular dynamics of the movement, should be considered in future studies about ACL injury mechanisms.

External Sensors for Detecting the Activation and Deactivation Times of the Major Muscles Used in Walking

Functional electrical stimulation (FES) can improve walking in individuals with mobility impairments. We evaluated accelerometers, force sensitive resistors, segment angles, and segment angular velocities to identify which sensor best determines the activation and deactivation times of the main muscles used during walking. This sensor(s) can be used in the future in conjunction with FES systems to improve walking. Able-bodied subjects walked at various speeds. Threshold levels were set for each sensor that minimized the difference between the times of activating and deactivating the electromyogram (EMG) of six muscles and the times of sensor threshold crossings as a percent of the step cycle. Mobility-impaired subjects walked at their preferred speed with and without FES to correct foot drop. Thresholds were set for these subjects so that sensor signals would cross at times that matched those of able-bodied subjects. Segment angles were generally the most effective sensor signals. Using segment angles of the thigh, shank, and foot, activation and deactivation times of the six muscles could be determined to within 6% of the step cycle. The shank segment angle produced the lowest overall error and was among the top three sensors for 10 of the 12 events (activation and deactivation of six muscle groups). A segment angle sensor was implemented using a complementary filter (accelerometer/gyroscope combination). Using this sensor improved rule-based timing of FES in subjects with foot drop as compared to accelerometers alone.

Three-dimensional kinematic analysis of the golf swing using instantaneous screw axis theory, part 1: methodology and verification

A number of recent studies have measured the extent and timing of segment rotation during the golf swing. A promising technique, instantaneous screw axis (ISA) theory, could provide a better expression of segment rotation. In Part 1 of this two-part study, the objectives are to identify the ISA of the pelvis, shoulders and left arm during the downswing, compute segment angular velocity relative to that segment’s ISA and verify that ISA theory is a valid tool to analyse segment rotation during the golf swing. Results indicate that for all subjects, at least 71% of marker velocity is a result of rotation about their respective ISA, when averaging results over the duration of the downswing, confirming that motion is primarily rotational. Furthermore, ISA position and orientation of each segment approaches, on average, the expected gross axis of rotation, confirming that motion about the ISA is representative of joint motion.

Three-dimensional kinematic analysis of the golf swing using instantaneous screw axis theory, Part 2: golf swing kinematic sequence

Recent studies have measured body segment rotation to study the kinematic sequence of the downswing. However, this sequence has yet to be determined relative to an instantaneous screw axis (ISA), free to change position and orientation during motion to reflect shifts in a segment’s dominant axis of rotation. In Part 2 of this two-part study, the objectives were to compute the amplitude of segment angular velocity relative to the corresponding ISA of that segment and verify if the magnitude of segment angular velocity followed the proximal to distal sequence of the summation of speeds principle. Results indicate that the kinematic sequence of 2 of the 5 subjects analyzed supports the summation of speeds principle, where the sequence in which the maximum angular velocity about the pelvis, shoulders and left arm occurred, for one subject, at 68.2 ± 3.2, 72.8 ± 1.7 and 100 ± 0.0% of the downswing.

A Review of New Analytic Techniques for Quantifying Symmetry in Locomotion

We present a review of novel techniques developed by our research group to improve quantitative assessment of human movement, especially assessments related to symmetric and asymmetric gait patterns. These new methods use motion capture data of the lower limb joints (e.g., joint and body segment angular position and/or velocity, or joint center locations) and include: (1) Regions of Deviation (ROD) analysis, (2) complexity and variability of phase portraits, and (3) multivariate shape-alignment and decomposition. We provide example demonstrations of these techniques using data from infants, typical and atypically developing children, simulated injuries of a knee or ankle, and wheelchair propulsion.