Differences In Joint Angles Research Articles

Activity distribution among the hamstring muscles during high-speed running: A descriptive multichannel surface EMG study.

This study assessed activity distribution among the hamstring muscles during high-speed running. The objective was to compare within and between muscle activity, relative contribution and hip and knee joint angles at peak muscle activity during high-speed running. Through multichannel electromyography, we measured muscle activity in male basketball players during high-speed running on a treadmill at 15 locations: five for biceps femoris long head, four for semitendinosus, and six for semimembranosus. Muscle activity was calculated for each location within each hamstring muscle individually for each percent of a stride cycle. Twenty-nine non-injured basketball players were included (mean age: 17 ± 1 years; mass, 85 ± 9kg; height, 193 ± 9cm). Heterogeneous activity was found for all individual hamstring muscles across multiple events of the stride cycle. In the late-swing phase, muscle activity and relative contribution of the semimembranosus was significantly higher than of the semitendinosus. There was no significant difference in hip and knee joint angles at instant of peak muscle activity, assessed locally within individual hamstring muscles, as well as in general over the whole hamstring muscle. Hamstring muscles were most active in the late-swing phase during high-speed running. In this phase, the semimembranosus was most active and the semitendinosus was least active. Within the biceps femoris long head, the most proximal region was significantly more active in the late-swing phase, compared to other muscle regions. For each muscle and location, peak muscle activity occurred at similar hip and knee joint angles.

Differences in joint angles during pole vaulting between male pole vaulters with and without chronic low back pain

Abstract Study aim: To determine the difference in joint angles of the shoulder, hip, and trunk (angle of the upper torso and lower torso) during vaulting between male pole vaulters with and without chronic low back pain (LBP) and to examine the relationship between the range of motion (ROM) and maximum angle of the same joint during vaulting in all participants. Material and methods: This cross-sectional study included 17 male vaulters. The participants were divided into two groups (chronic LBP and control) based on their questionnaire results. Four high-speed cameras were used to record at 240 Hz from the touchdown of the last step on the run-up to the pole straight phase. The vaulter cleared the bungee bars that were set at 90% of their personal best record. The ROM of hip flexion and extension, shoulder flexion, and straight leg raise were measured. Results: There was no difference in the joint angles between the chronic LBP group and control group. In contrast, there was a significantly positive correlation between ROM and the maximum joint angle during hip extension (p = 0.01, r = 0.58). Conclusions: Insufficient hip ROM may result in compensatory motion in lumbar extension during pole vaulting.

The effect of joint angle differences on blade velocity in elite and novice saber fencers: A kinematic study

After many years of training, elite saber fencers exhibit extremely rapid blade velocity. However, no prior kinematic research has explained how fencers achieve this. In this work, we measure the influence of arm kinematics on blade velocity in both elite and novice saber fencers. We hypothesized that elite fencers would exhibit smaller elbow joint angle and wrist angle changes, both indicative of blade thrust optimization. Furthermore, we predicted that these kinematic variables would correlate positively with peak blade tip velocity. Three novice and three elite saber fencers of two and six years of experience, respectively, performed a standard vertical saber cut, which we captured on high frame rate video. We discovered a significant difference between the novice and elite elbow joint angle at initiation, the angle at termination, and the angle change. The elbow joint angle change exhibited a strong negative correlation with the peak blade tip velocity (r = -0.83). We determined that angular differences in the wrist were non-significant. Our results suggest that coaches should place greater importance on optimizing elbow joint angles earlier in training. Based on the elite fencer performance, our evidence suggests that the optimal elbow joint angle at initiation for saber fencers may be 110°.

An Improved Kinect Recognition Method for Identifying Unsafe Behaviors of Metro Passengers.

In order to solve the problem of the low action recognition accuracy of passengers’ unsafe behaviors caused by redundant joints, this study proposes an efficient recognition method based on a Kinect sensor. The method uses the pelvis as the starting point of the vector and high-frequency bone joints as the end point to construct the recognition feature vector. The joint angle difference between actions is obtained by using the cosine law, and the initial test result is converted into action similarity combined with the DTW similarity algorithm. Considering the combination of 3 angle features and 4 joint feature selection methods, 12 combined recognition models are formed. A comparative experiment was carried out to identify five types of unsafe behaviors of metro passengers—punch, one-armed call for help, arms for help, trip forward and trip backwards. The results show that the overall selection of joints has a poor similarity effect and cannot achieve the purpose of recognition. The overall recognition model effect of the local “pelvis divergence method” is higher than that of the local “adjacent joint method”, and the local “pelvis divergence method” has the highest recognition result of the maximum angle difference model, and the recognition results of the five unsafe behaviors are 86.9%, 89.2%, 85.5%, 86.7%, and 88.3%, respectively, and the recognition accuracy of this method is 95.7%, indicating the feasibility of the model. The recognition results are more concentrated and more stable, which significantly improves the recognition rate of metro passengers’ unsafe behavior.

Short term outcomes and complications of distal ulnar ostectomy in 23 juvenile dogs with carpal valgus secondary to discordant radial-ulnar physeal growth.

ObjectiveThe goal of this study was to report short term clinical and radiographic outcomes after distal ulnar ostectomy in dogs with carpal valgus due to discordant radial-ulnar growth.Study designRetrospective case study.Sample groupClient owned dogs under 1 year of age with carpal valgus and open distal radial physes pre-operatively.MethodsMedical records from four veterinary referral centers were searched from January 1, 2015 to January 1, 2022 for juvenile dogs that had been treated with distal ulnar ostectomy for carpal valgus due to premature closure of the distal ulnar physis. Patients were excluded if they were skeletally mature at the time of ostectomy; medical records were incomplete; radial physis was closed at surgery; or definitive corrective osteotomy was performed. Radiographs were evaluated pre-operatively and for short term follow up at ~8 weeks. Complications and short term clinical outcomes were evaluated also.Results31 limbs from 23 dogs were evaluated. Patients ranged from 4 to 10.8 months of age. All dogs presented for visible carpal valgus and varying degrees of thoracic limb lameness. Sixty-four percent of patients showed resolution of lameness while an additional 13% showed an improvement in clinical lameness without complete resolution. Complications were seen in 32% of patients with 70% percent of those being minor, bandage related complications. Radiographically, 38% of limbs showed bridging callus formation of the ostectomy at an average of 7.5 weeks post operatively and 75% percent of patients with elbow incongruity improved radiographically. There was no significant difference in radial joint angles pre-operatively and at the time of follow up.ConclusionDistal ulnar ostectomy ameliorates lameness in juvenile dogs with premature distal ulnar physeal closure and shows lack of progression of distal carpal valgus deformity, but does not improve joint angulation.Clinical significanceDistal ulnar ostectomy is associated with mild bandage-related complications and halting of progressive limb deformity within the time frame evaluated, and should therefore be considered a treatment for premature closure of the distal ulnar physis. It does not lead to deformity correction at 8 weeks following surgery but is associated with improved elbow congruity.

이압요법이 슬관절염 노인 근로자의 슬관절 통증, 관절각 및 수면에 미치는 효과: 유사실험연구

Purpose: The purpose of this study was to examine the effects of auricular acupressure on the knee pain, joint angle and sleep among elderly workers with knee osteoarthritis. Methods: This study conducted with a randomized, single-blind, and quasi-experimental design. Participants were 41 elderly workers with knee osteoarthritis and they were allocated to the experimental group (n=21) and sham control group (n=20). The intervention lasted six weeks. In order to examine intervention effects of auricular acupressure, Visual Analogue Scale (VAS), and extension, flexion, Pittsburg Sleep Quality Index (PSQI), Fitbit tracker were measured in order to examine the effects of auricular acupressure. Results: Auricular acupressure was effective for knee pain relief after 6 weeks (F=2.83, p=.024). There was no difference in joint angle. Sleep quality was significantly affected by sleep duration (t=3.02, p=.004), habitual sleep efficiency (t=2.36, p=.029), and daytime dysfunction (t=2.16, p=.038), and the sleep stage was effective on slight sleep (t=2.19, p=.034). Conclusion: The findings of this study suggest that auricular acupressure can be a complementary nursing intervention for the elderly workers with knee osteoarthritis to decrease knee pain and to improve sleeping disorder, and has advantages such as reduction of medical expenses, convenience, and high safety.

Analysis of Healthcare Push and Pull Task via JACK: Predicted Joint Accuracy during Full-Body Simulation

The posture accuracy of full-body dynamic simulation has been successfully evaluated in JACK Siemens software via analyzing two common push and pull tasks. The difference in joint angles between the actual and predicted human movement directly results in the strength of force exposed on the lumbar spine. In this study, the individual factors, such as body height, body weight, trunk and hip flexion, shoulder movement, and muscle strength between genders, have shown a strong association with the adopted postures and exposed spinal forces during task performance. To provide robust ergonomics analysis, these individual variables should be adequately considered in software design for the long-term goal of injury prevention in diverse occupational workplaces.

Analysis and Comparison of Motion Biomechanics Characteristics of Squat Jump and Half-Squat Jump

In order to study the biomechanical characteristics of squat jump and half-squat jump, analysis and comparison were made. This paper tests and analyzes the kinematics and dynamics of 63 young men’s squat jump, and synchronously collects the kinematics and dynamics data of subjects in the process of weight-bearing squat, in-situ free jump, and high platform landing. The experimental results showed that there was significant difference in knee joint angle at the time of toe off ( P < 0.05), and there was significant difference in ankle joint angle at the time of toe off ( P < 0.05). The time law of squat jump and semi squat jump in vertical jump was the same. In vertical jump, the reaction time law of squat jump and semi squat jump is the same, and the recovery standing time is the longest, followed by the take-off time and reaction time. The two vertical jump methods have no effect on the height, time, and speed of exercise take-off.

Conclusion or Illusion: Quantifying Uncertainty in Inverse Analyses From Marker-Based Motion Capture due to Errors in Marker Registration and Model Scaling.

Estimating kinematics from optical motion capture with skin-mounted markers, referred to as an inverse kinematic (IK) calculation, is the most common experimental technique in human motion analysis. Kinematics are often used to diagnose movement disorders and plan treatment strategies. In many such applications, small differences in joint angles can be clinically significant. Kinematics are also used to estimate joint powers, muscle forces, and other quantities of interest that cannot typically be measured directly. Thus, the accuracy and reproducibility of IK calculations are critical. In this work, we isolate and quantify the uncertainty in joint angles, moments, and powers due to two sources of error during IK analyses: errors in the placement of markers on the model (marker registration) and errors in the dimensions of the model’s body segments (model scaling). We demonstrate that IK solutions are best presented as a distribution of equally probable trajectories when these sources of modeling uncertainty are considered. Notably, a substantial amount of uncertainty exists in the computed kinematics and kinetics even if low marker tracking errors are achieved. For example, considering only 2 cm of marker registration uncertainty, peak ankle plantarflexion angle varied by 15.9°, peak ankle plantarflexion moment varied by 26.6 N⋅m, and peak ankle power at push off varied by 75.9 W during healthy gait. This uncertainty can directly impact the classification of patient movements and the evaluation of training or device effectiveness, such as calculations of push-off power. We provide scripts in OpenSim so that others can reproduce our results and quantify the effect of modeling uncertainty in their own studies.

Effects of a Medial Unloader Brace on Gait Mechanics in Patients with Osteochondritis Dissecans

Background:Non-operative treatment for osteochondritis dissecans (OCD) of the knee traditionally includes casting, bracing, and activity restrictions. An unloader brace is an option that may result in improved compliance due to the ability of the patient to continue daily activities while maintaining brace wear, and it may have biomechanical advantages for lesion healing. However, the biomechanical efficacy of a medial unloader brace has not been confirmed in a pediatric population.Hypothesis/Purpose:To determine whether the use of a medial unloader brace alters gait mechanics in patients with medial femoral condyle OCD. We hypothesized that while knee alignment in the coronal plane will remain unaltered, the valgus moment will decrease due to the applied tension of the adjusted unloader brace.Methods:Fifteen medial femoral condylar OCD patients (14 male, 12.7±2.6 years, 156.9±14.8 cm, and 52.0±16.2 kg) were tested utilizing a medial Ossur Unloader One knee brace. All patients performed over-ground walking at a self-selected speed under three brace conditions: no brace (NB), unadjusted (U), and adjusted (A; prescribed tension applied). Pelvis and lower extremity kinematic and kinetic data were computed in the sagittal, coronal, and transverse planes during single-limb stance phase (SLS). Wilcoxon signed-rank tests were performed to identify statistical differences between brace conditions (α=0.05), and clinical significance was only determined when statistically significant joint angle and moment differences were greater than 3° and 0.1Nm/kg, respectively.Results:Between braced conditions, mean knee valgus was not statistically significant, however, peak internal knee valgus moment consistently decreased with each brace condition (NB-A: 0.06 Nm/kg, p=0.017). Similarly, hip abduction moment at the second peak of SLS decreased while wearing the brace (NB-U: p=0.061, NB-A: 0.07 Nm/kg, p=0.009).Conclusion:Peak knee valgus moment was decreased during walking with an adjusted medial unloader brace. These results highlight potential biomechanical advantages of a medial unloader brace for medial femoral condylar OCD. Future work will measure compliance of brace wear and compare additional brace designs.Table 1.Coronal plane hip and knee kinematics and kinetics (Mean ± SD) for each brace condition.Figure 1.Average coronal knee angle and moment throughout gait cycle

Shape-model scaled gait models can neglect segment markers without consequential change to inverse kinematics results

Inverse Kinematics (IK) is an optimisation to estimate joint angles from motion capture data, where marker trajectories and weighting strategies determine the outcome. Skin-mounted markers are subject to Soft Tissue Artefact (STA), particularly thigh markers. Our first aim was to test the effect of neglecting thigh markers on IK results across different markersets. Our second aim was to investigate inter-markerset differences using varying weighting strategies. Twenty participants participated in a treadmill walking motion capture session. Inverse kinematic analysis was performed using three markersets, termed Contemporary (segment clusters), NoThigh (Contemporary without thigh markers), and Traditional (modified Helen Hayes). Seven weighting schemes were used with varying magnitudes with each markerset. Joint angles (comprising tri-planar hip angles, and sagittal knee and ankle angles) were compared across all three conditions. NoThigh and Traditional generated joint angle results that differed from the Contemporary markerset by a median of 1.2° and 1.5°, respectively. Non-sagittal hip angles differed the most. Most average joint angle differences were smaller than previously-estimated STA error. NoThigh generated less difference from Contemporary than Traditional for the hip and knee joints. Intuitively, weighting strategies that heavily favour shared markers resulted in IK results with closer inter-markerset agreement. Thigh markers can be neglected without introducing more error than STA, and different markersets (with validation) can be compared against each other when using strategic weighting. This creates new research pathways for collaboration and data re-use, as well as freeing researchers (and participants) of their attachment to thigh markers.

Variations of lower-limb joint kinematics associated with the use of different ankle joint models

Skeletal computational models relying on global optimisation are widely used alongside gait analysis for the estimate of joint kinematics, but the degrees of freedom (DOFs) and axes definitions to model the ankle complex are still debated. The aim of this paper is to establish whether ankle modelling choices would also critically affect the estimate of the other joints' kinematics. Gait and MRI data from fifteen juvenile participants were used to implement three ankle joint models (M1, one-DOF sagittal motion; M2, two-DOFs sagittal and frontal motions; M3, three-DOFs) as part of a full lower-limb skeletal model. Differences in lower-limb joint and foot progression angles calculated using global optimisation were evaluated both at individual and group level. Furthermore, the influence of these differences on the correlations between joints and on the calculations of the root mean square deviation (RMSD) were investigated. Inter-model variations at individual level reached up to 4.2°, 9.1°, and 15.0° for hip flexion, adduction, and rotation, respectively, and up to 6.5° for knee flexion. Despite the tibiotalar axis being the same for all models, up to 19.3° (9.1° on average) larger dorsiflexion was found at push-off with M2. A stronger correlation between foot progression and ankle and knee sagittal movements was found for M1. Finally, RMSD led to inconsistent ranking of the participants when using different models. In conclusion, the choice of the ankle joint model affects the estimates of proximal lower-limb joint kinematics, which should discourage comparisons across datasets built with different models.

The validation of a low-cost inertial measurement unit system to quantify simple and complex upper-limb joint angles

The purpose of this research was to validate the use of a low-cost IMU system to measure upper-limb joint angles by comparing it to passive optical motion capture measures. Fifteen participants (five females; 25.9 ± 4.7 years) completed one trial of four simple range of motion (ROM) movements (elbow flexion/extension, shoulder abduction/adduction, shoulder flexion/extension, and shoulder internal/external rotation), and three complex functional daily tasks [hand to: back pocket (HBP), contralateral shoulder (HCS), head (HTH)]. Movements were measured, simultaneously, using fourteen OptiTrack cameras and five Notch® IMUs. The mean joint angle difference between devices ranged from 0.10° ± 3.11° for the HBP shoulder internal/external movement to 44.95° ± 3.50° for the simple ROM shoulder internal/external rotation movement. Nine of sixteen movement and plane comparisons showed significant differences between the device–specific movement cycle waveforms. Eleven of the comparisons showed either fixed and/or proportional biases (fixed only: 9; proportional only: 1; both fixed and proportional: 1). Due to multiple movements having large amplitude errors, low waveform similarities, and/or statistically significant mean differences between the Notch® IMUs and the gold-standard motion capture devices, we cannot recommend that Notch® IMUs are valid devices for measuring upper-limb joint angles during simple ROM and complex functional daily tasks.

The effects of stature, age, gender, and posture preferences on preferred joint angles after real driving

Few studies have investigated preferred driving posture involving real-world driving. For this purpose, seven preferred joint angles of 127 participants were recorded three times from sagittal plane photographs after a short, standardized drive on public roads. Participants' individual driving posture preferences were determined using a word-based questionnaire. The inter- and intraindividual joint angle differences were calculated and some significant effects of stature, age, and gender on these joint angle differences were found. Additionally, significant correlations were found between posture preferences and joint angles, except for the lower extremities. The results show that the factors stature, age, gender, and posture preferences have influence on the preferred joint angles. However, other human-, vehicle-, and context-related factors also seem relevant and should be considered in future studies.The results provide important field-based knowledge for an application-oriented understanding of driving posture and for the human-centered design process of future vehicle interior research and development.

Novice Female Exercisers Exhibited Different Biomechanical Loading Profiles during Full-Squat and Half-Squat Practice.

Simple SummaryThis study adapted a customized OpenSim model aiming to analyze the loadings difference between full-squat and half-squat in novice females. The joint moment and joint angle of the hip, knee, and ankle increase significantly in the full-squat, which might increase the risks of potential injury. In the case of training, the cohort of young females could perform half-squat practice when muscle strength is insufficient. This study may present implications for the design of novice strength training programs and the formulation of rehabilitation plans.Background: Females with different practice experience may show different body postures and movement patterns while squatting in different depths, which may lead to changes of biomechanical loadings and increase the risks of injuries. Methods: Sixteen novice female participants without squat training experience participated in this study. A 3D motion capture system was used to collect the marker trajectory and ground reaction force data during bodyweight squatting in different depths. The participants’ kinematic data and joint moment were calculated using OpenSim’s inverse kinematics and inverse dynamics algorithm. In this study, authors adapted a model especially developed for squatting and customized the knee joint with extra Degree-of-Freedom (DoF) in the coronal and horizontal plane with adduction/abduction and internal/external rotation. A paired-sample t-test was used to analyze the difference of joint range of motions (ROM) and peak moments between full-squat (F-SQ) and half-squat (H-SQ). One-Dimensional Statistical Parametric Mapping (SPM1D) is used to analyze the difference of joint angle and moment between the process of squatting F-SQ and H-SQ. Results: (1) Compared with H-SQ, F-SQ showed larger ROM in sagittal, coronal, and transverse planes (p < 0.05). (2) SPM1D found that the difference in joint angles and joint moments between F-SQ and H-SQ was mainly concentrated in the mid-stance during squatting, which suggested the difference is greatly pronounced during deeper squat. (3) Peak hip extension moment, knee extension moment, hip adduction moment, and plantar flexion moment of F-SQ were significantly higher than H-SQ (p < 0.05). (4) Difference of hip and knee extension moments and rotation moments between the F-SQ and H-SQ were exhibited during descending and ascending. Conclusions: The study found that novice women had larger range of joint motion during the F-SQ than H-SQ group, and knee valgus was observed during squatting to the deepest point. Greater joint moment was found during F-SQ and reached a peak during ascending after squatting to the deepest point. Novice women may have better movement control during H-SQ. The findings may provide implications for the selection of lower limb strength training programs, assist the scientific development of training movements, and provide reference for squat movement correction, thus reducing the risk of injury for novice women in squatting practice.

Development of Immersive VR Device for Gait Training Rehabilitation with Biofeedback System-Preliminary Study

Gait-training rehabilitation machines (MGTR) are contraptions used for the motor rehabilitation of patients with movement disorders resulting from stroke and Parkinson’s disease. This study was aimed at implementing a walking pattern similar to the normal gait. Background: Immersion and motivation are important factors in repetitive rehabilitation exercises. This was addressed by synchronizing walking speed and virtual reality (VR) visons to provide a sense of immersion in a convergence environment of MGTR and VR. Methods: The difference in joint angle and gait event was confirmed when the step length was adjusted in this system to control the joint movement. Results: It was confirmed that the joint range of motion also increased significantly as the step length increased. Conclusions: The possibility of developing a more immersive MGTR system that feedback the actual gait state in the VR system was confirmed by applying that the joint movement varies according to the step length. It will be possible to provide an immersive feeling more similar to the actual walking by modifying the gait trajectory of the MGTR.

Running biomechanics in football players with and without hip and groin pain. A cross-sectional analysis of 116 sub-elite players

ObjectiveExamine whether football players with hip and/or groin (hip/groin) pain have impaired running biomechanics when compared to pain-free players, analysing men and women independently. DesignCross-sectional. SettingBiomechanics laboratory. ParticipantsSeventy-eight (62 men, 16 women) football players with >6months of hip/groin pain and a positive flexion-adduction-internal rotation test and 38 (25 men, 13 women) asymptomatic players. Main outcome measuresPelvis angles and hip, knee, and ankle joint angles and moments were analysed during the stance phase of overground running at 3–3.5 m⋅s−1. Continuous joint angle and moment data were compared between symptomatic and asymptomatic football players of the same sex using statistical parametric mapping. Joint moment impulses (area under the curve) were compared between groups using linear regression models. ResultsSymptomatic football players did not display significant differences in pelvis angles or lower-limb joint angles, moments, or moment impulses during the stance phase of running, when compared to asymptomatic players of the same sex. ConclusionOur large sample of football players with hip/groin pain who were still participating in competitive sport displayed similar running biomechanics to asymptomatic players. Impaired running biomechanics might exist in people with worse hip/groin pain, warranting future investigation.

Gait on slopes: Differences in temporo-spatial, kinematic and kinetic gait parameters between walking on a ramp and on a treadmill

BackgroundInclined treadmills or static ramp constructions can be used to investigate downhill gait in a standardised laboratory condition. There is a lack of information how the gait patterns are affected when walking on a ramp or an inclined treadmill during uphill and downhill walking. Research questionIs there a difference in temporo-spatial parameters, sagittal ankle, knee and hip joint angle as well as ground reaction force when walking uphill and downhill on a ramp and a treadmill. MethodsUphill and downhill gait of 15 healthy participants was assessed during walking on a treadmill and on a ramp with slope gradients of 12 °, 6 ° and 0 °. Participants were instructed to walk with the same speed on each slope-system. Kinematic and temporo-spatial paramters were collected using a 3D motion capture system (Qualisys, Gothenburgh, Sweden), kinetic data were collected using pressure insoles (loadsol®, Novel, Germany). Temporo-spatial parameters were analysed using a Friedman ANOVA, time series of kinematic and kinetic data were compared using statistical parametric mapping with a sigificance level of 5%. ResultsOn the treadmill participants walked with significantly shorter steps and shorter contact times, while they significantly increased step frequency compared to walking on a ramp, regardless of slope gradient. In uphill conditions, treadmill gait increased hip and knee flexion angles during the stance phase and increased the forward tilt of the thorax during the entire gait cycle. During downhill walking a significant decrease in dorsiflexion during initial contact, midstance and the second half of the swing phase was observed. Peak resultant forces remained similar compared to walking on the ramp. These alterations might be due to mechanical and psychological effects. SignificanceKnowledge about these differences is important in future study design and data interpretation from existing literature.

Joint Angle, Range of Motion, Force, and Moment Assessment: Responses of the Lower Limb to Ankle Plantarflexion and Dorsiflexion.

There is limited research on the biomechanical assessment of the lower limb joints in relation to dynamic movements that occur at the hip, knee, and ankle joints when performing dorsiflexion (DF) and plantarflexion (PF) among males and females. This study investigated the differences in joint angles (including range of motion (ROM)) and forces (including moments) between the left and right limbs at the ankle, knee, and hip joints during dynamic DF and PF movements in both males and females. Using a general linear model employing multivariate analysis in relation to the joint angle, ROM, force, and moment datasets, the results revealed significant main effects for gender, sidedness, phases, and foot position with respect to joint angles. Weak correlations were observed between measured biomechanical variables. These results provide insightful information for clinicians and biomechanists that relate to lower limb exercise interventions and modelling efficacy standpoints.

Scapulothoracic and Glenohumeral Contributions to Humerothoracic Kinematics in Single Versus Double Tendon Transfers in Patients With Brachial Plexus Birth Injury

Evidence suggests that patients with brachial plexus birth injury are more likely to retain midline function following a teres major tendon transfer without a concomitant latissimus dorsi transfer. Both procedures increase shoulder external rotation and abduction, but whether increased loss of midline frequency following double transfer is due to glenohumeral (GH) joint motion or scapulothoracic (ST) compensation is unknown. We hypothesized that double tendon transfers would exhibit greater GH external rotation than single tendon transfers, thus requiring greater ST rotation to internally rotate the shoulder, while GH and ST contributions to elevation remained equivalent between both groups. Twenty-six postsurgical children with C5/C6 brachial plexus birth injuries participated in this study. Thirteen patients with single tendon transfers were matched with 13 with double tendon transfer. Coordinate systems of the thorax, scapula, and humerus were measured utilizing motion capture in 6 arm positions. Joint angles were calculated by the helical (ST) and modified globe method (GH and humerothoracic [HT]). Differences between groups were compared with repeated measures of multivariate analyses of variance for each position. Pending significant multivariate analyses of variance, univariate analyses of variance determined joint differences between transfer groups. Joint rotations from neutral were similar between groups in 5 of 6 tested positions, with double tendon transfers consistently demonstrating 15°-20˚ more internal rotation at the GH and HT joints. Still, only the internal rotation position showed statistically significant differences in GH and HT joint angles. The ST joint angles were similar in this position (45.2˚ and 48.5˚). The arc of motion for patients with double tendon transfer was more internally rotated than in patients with single tendon transfer at the GH and HT joints for all positions. However, both groups demonstrated little active rotation from neutral. Based on this data, teres major-only tendon transfers may not reduce the risk of loss of midline function. Therapeutic III.