Wheelchair rugby players maintain sprint performance but alter propulsion biomechanics after simulated match play.

The study aimed to explore the influence of a sports-specific intermittent sprint protocol (ISP) on wheelchair sprint performance and the kinetics and kinematics of sprinting in elite wheelchair rugby (WR) players with and without spinal cord injury (SCI). Fifteen international WR players (age 30.3 ± 5.5 years) performed two 10-s sprints on a dual roller wheelchair ergometer before and immediately after an ISP consisting of four 16-min quarters. Physiological measurements (heart rate, blood lactate concentration, and rating of perceived exertion) were collected. Three-dimensional thorax and bilateral glenohumeral kinematics were quantified. Following the ISP, all physiological parameters significantly increased (p ≤ 0.027), but neither sprinting peak velocity nor distance traveled changed. Players propelled with significantly reduced thorax flexion and peak glenohumeral abduction during both the acceleration (both -5°) and maximal velocity phases (-6° and 8°, respectively) of sprinting post-ISP. Moreover, players exhibited significantly larger mean contact angles (+24°), contact angle asymmetries (+4%), and glenohumeral flexion asymmetries (+10%) during the acceleration phase of sprinting post-ISP. Players displayed greater glenohumeral abduction range of motion (+17°) and asymmetries (+20%) during the maximal velocity phase of sprinting post-ISP. Players with SCI (SCI, n = 7) significantly increased asymmetries in peak power (+6%) and glenohumeral abduction (+15%) during the acceleration phase post-ISP. Our data indicates that despite inducing physiological fatigue resulting from WR match play, players can maintain sprint performance by modifying how they propel their wheelchair. Increased asymmetry post-ISP was notable, which may be specific to impairment type and warrants further investigation.

Alterations in shoulder kinematics are associated with shoulder pain during wheelchair propulsion sprints.

The study purpose was to examine the biomechanical characteristics of sports wheelchair propulsion and determine biomechanical associations with shoulder pain in wheelchair athletes. Twenty wheelchair court-sport athletes (age: 32 ± 11 years old) performed one submaximal propulsion trial in their sports-specific wheelchair at 1.67 m/s for 3 min and two 10 s sprints on a dual-roller ergometer. The Performance Corrected Wheelchair User's Shoulder Pain Index (PC-WUSPI) assessed shoulder pain. During the acceleration phase of wheelchair sprinting, participants propelled with significantly longer push times, larger forces, and thorax flexion range of motion (ROM) than both the maximal velocity phase of sprinting and submaximal propulsion. Participants displayed significantly greater peak glenohumeral abduction and scapular internal rotation during the acceleration phase (20 ± 9° and 45 ± 7°) and maximal velocity phase (14 ± 4° and 44 ± 7°) of sprinting, compared to submaximal propulsion (12 ± 6° and 39 ± 8°). Greater shoulder pain severity was associated with larger glenohumeral abduction ROM (r = 0.59, p = 0.007) and scapular internal rotation ROM (r = 0.53, p = 0.017) during the acceleration phase of wheelchair sprinting, but with lower peak glenohumeral flexion (r = -0.49, p = 0.030), peak abduction (r = -0.48, p = 0.034), and abduction ROM (r = -0.44, p = 0.049) during the maximal velocity phase. Biomechanical characteristics of wheelchair sprinting suggest this activity imposes greater mechanical stress than submaximal propulsion. Kinematic associations with shoulder pain during acceleration are in shoulder orientations linked to a reduced subacromial space, potentially increasing tissue stress.

Adjustments in Shoulder and Back Kinematics during Repetitive Palletizing Tasks.

Repetitive task performance is a leading cause of musculoskeletal injuries among order-picking workers in warehouses. The repetition of lifting tasks increases the risk of back and shoulder injuries among these workers. While lifting in this industry is composed of loaded and unloaded picking and placing, the existing literature does not address the separate analysis of the biomechanics of the back and shoulder for these events. To that end, we investigated the kinematics of the back and shoulder movements of nine healthy male participants who performed three sessions of a simulated de/palletization task. Their back and shoulder kinematics were sensed using an optical motion capture system to determine the back inclination and shoulder flexion. Comparison of the kinematics between the first and last sessions indicated statistically significant changes in the timings, angles, coordination between the back and shoulder, and moments around the shoulder (p<0.05). The majority of the significant changes were observed during the loaded events, which confirms the importance of the separation of these events for biomechanical analysis. This finding suggests that focusing worker evaluation on the loaded periods can provide important information to detect kinematic changes that may affect musculoskeletal injury risk.

A Comprehensive Analysis of the Validity and Reliability of the Perception Neuron Studio for Upper-Body Motion Capture.

The Perception Neuron Studio (PNS) is a cost-effective and widely used inertial motion capture system. However, a comprehensive analysis of its upper-body motion capture accuracy is still lacking, before it is being applied to biomechanical research. Therefore, this study first evaluated the validity and reliability of this system in upper-body capturing and then quantified the system's accuracy for different task complexities and movement speeds. Seven participants performed simple (eight single-DOF upper-body movements) and complex tasks (lifting a 2.5 kg box over the shoulder) at fast and slow speeds with the PNS and OptiTrack (gold-standard optical system) collecting kinematics data simultaneously. Statistical metrics such as CMC, RMSE, Pearson's r, R2, and Bland-Altman analysis were utilized to assess the similarity between the two systems. Test-retest reliability included intra- and intersession relations, which were assessed by the intraclass correlation coefficient (ICC) as well as CMC. All upper-body kinematics were highly consistent between the two systems, with CMC values 0.73-0.99, RMSE 1.9-12.5°, Pearson's r 0.84-0.99, R2 0.75-0.99, and Bland-Altman analysis demonstrating a bias of 0.2-27.8° as well as all the points within 95% limits of agreement (LOA). The relative reliability of intra- and intersessions was good to excellent (i.e., ICC and CMC were 0.77-0.99 and 0.75-0.98, respectively). The paired t-test revealed that faster speeds resulted in greater bias, while more complex tasks led to lower consistencies. Our results showed that the PNS could provide accurate enough upper-body kinematics for further biomechanical performance analysis.

Myoelectric prosthesis users and non-disabled individuals wearing a simulated prosthesis exhibit similar compensatory movement strategies.

BACKGROUND: Research studies on upper limb prosthesis function often rely on the use of simulated myoelectric prostheses (attached to and operated by individuals with intact limbs), primarily to increase participant sample size. However, it is not known if these devices elicit the same movement strategies as myoelectric prostheses (operated by individuals with amputation). The objective of this study was to address the question of whether non-disabled individuals using simulated prostheses employ the same compensatory movements (measured by hand and upper body kinematics) as individuals who use actual myoelectric prostheses. METHODS: The upper limb movements of two participant groups were investigated: (1) twelve non-disabled individuals wearing a simulated prosthesis, and (2) three individuals with transradial amputation using their custom-fitted myoelectric devices. Motion capture was used for data collection while participants performed a standardized functional task. Performance metrics, hand movements, and upper body angular kinematics were calculated. For each participant group, these measures were compared to those from a normative baseline dataset. Each deviation from normative movement behaviour, by either participant group, indicated that compensatory movements were used during task performance. RESULTS: Results show that participants using either a simulated or actual myoelectric prosthesis exhibited similar deviations from normative behaviour in phase durations, hand velocities, hand trajectories, number of movement units, grip aperture plateaus, and trunk and shoulder ranges of motion. CONCLUSIONS: This study suggests that the use of a simulated prosthetic device in upper limb research offers a reasonable approximation of compensatory movements employed by a low- to moderately-skilled transradial myoelectric prosthesis user.

Asymmetrical trunk movement during walking improved to normal range at 3 months after corrective posterior spinal fusion in adolescent idiopathic scoliosis.

PURPOSE: To investigate the effects of posterior spinal fusion (PSF) and curve type on upper body movements in Adolescent Idiopathic Scoliosis (AIS) patients during gait. METHODS: Twenty-four girls (12-18 years) with AIS underwent PSF. 3D-Gait-analyses were performed preoperatively, at 3 months and 1 year postoperatively. Mean position (0° represents symmetry) and range of motion (ROM) of the trunk (thorax-relative-to-pelvis) in all planes were assessed. Lower body kinematics and spatiotemporal parameters were also evaluated. RESULTS: Mean trunk position improved from 7.0° to 2.9° in transversal plane and from 5.0° to - 0.8° in frontal plane at 3 months postoperative (p < 0.001), and was maintained at 1 year. Trunk ROM in transverse plane decreased from 9.6° to 7.5° (p < 0.001) after surgery. No effects of PSF were observed on the lower body kinematics during the gait cycle. Patients with a double curve had a more axial rotated trunk before and after surgery (p = 0.013). CONCLUSION: In AIS patients, during gait an evident asymmetrical position of the trunk improved to an almost symmetric situation already 3 months after PSF and was maintained at 1 year. Despite a reduction of trunk ROM, patients were able to maintain the same walking pattern in the lower extremities after surgery. This improvement of symmetry and maintenance of normal gait can explain the rapid recovery and well functioning in daily life of AIS patients, despite undergoing a fusion of large parts of their spine.

The longitudinal relationship between shoulder pain and altered wheelchair propulsion biomechanics of manual wheelchair users.

The purpose of this study was to investigate the longitudinal association between within-subject changes in shoulder pain and alterations in wheelchair propulsion biomechanics in manual wheelchair users. Eighteen (age 33 ± 11 years) manual wheelchair users propelled their own daily living wheelchair at 1.11 m.s-1 for three minutes on a dual-roller ergometer during two laboratory visits (T1 and T2) between 4 and 6 months apart. Shoulder pain was assessed using the Performance Corrected Wheelchair User's Shoulder Pain Index (PC-WUSPI). Between visits mean PC-WUSPI scores increased by 5.4 points and varied from - 13.5 to + 20.9 points. Of the eighteen participants, nine (50%) experienced increased shoulder pain, seven (39%) no change in pain, and two (11%) decreased pain. Increasing shoulder pain severity correlated with increased contact angle (r = 0.59, P = 0.010), thorax range of motion (r = 0.60, P = 0.009) and kinetic and kinematic variability. Additionally, increasing shoulder pain was associated with reductions in peak torque (r = -0.56, P = 0.016), peak glenohumeral abduction (r = -0.69, P = 0.002), peak scapular downward rotation (r = -0.68, P = 0.002), and range of motion in glenohumeral flexion/extension and scapular angles. Group comparisons revealed that these biomechanical alterations were exhibited by individuals who experienced increased shoulder pain, whereas, propulsion biomechanics of those with no change/decreased pain remained unaltered. These findings indicate that wheelchair users exhibit a protective short-term wheelchair propulsion biomechanical response to increases in shoulder pain which may temporarily help maintain functional independence.

Non-specific chronic low back pain elicits kinematic and neuromuscular changes in walking and gait termination.

BACKGROUND: Chronic low back pain (CLBP) is associated with an increased trunk stiffness and muscle coactivation during walking. However, it is still unclear whether CLBP individuals are unable to control neuromechanically their upper body motion during a sudden termination of gait (GT), which involves a challenging balance transition from walking to standing. RESEARCH QUESTION: Does CLBP elicit neuromuscular and kinematic changes which are specific to walking and GT?. METHODS: Eleven individuals with non-specific CLBP and 11 healthy controls performed walking and sudden GT in response to an external visual cue. 3D kinematic characteristics of thorax, lumbar and pelvis were obtained, with measures of range of motion (ROM) and intra-subject variability of segmental movement being calculated. Electromyographic activity of lumbar and abdominal muscles was recorded to calculate bilateral as well as dorsoventral muscle coactivation. RESULTS: CLBP group reported greater transverse ROM of the lumbar segment during walking and GT compared to healthy controls. Thorax sagittal ROM was higher in CLBP than healthy participants during GT. Greater overall movement variability in the transverse plane was observed in the CLBP group while walking, whereas GT produced greater variability of lumbar frontal motion. CLBP participants showed higher bilateral lumbar coactivation compared to healthy participants after the stopping stimulus delivery during GT. SIGNIFICANCE: These results suggest that CLBP can elicit a wider and more variable movement of the upper body during walking and GT, especially in the transverse plane and at lumbar level. Alterations in upper body motor control appeared to depend on task, plane of motion and segmental level. Therefore, these findings should be considered by practitioners when screening before planning specific training interventions for recovery of motor control patterns in CLBP population.

Propulsion biomechanics do not differ between athletic and nonathletic manual wheelchair users in their daily wheelchairs.

The purpose of this study was to investigate whether athletic and nonathletic manual wheelchair users (MWU) display differences in kinetic and kinematic variables during daily wheelchair propulsion. Thirty-nine manual wheelchair users (athletic n = 25; nonathletic n = 14) propelled their own daily living wheelchair on a roller ergometer at two submaximal speeds for three minutes (1.11 m s-1 and 1.67 m s-1). A 10 camera Vicon motion capture system (Vicon, Motion Systems Ltd. Oxford, United Kingdom) collected three-dimensional kinematics of the upper limbs and thorax at 200 Hz during the final minute of each propulsion trial. Kinetics, kinematics and kinematic variability were compared between athletic and nonathletic groups. Kinematic differences were investigated using statistical parametric mapping. Athletic MWU performed significantly greater physical activity per week compared to nonathletic MWU (920 ± 601 mins vs 380 ± 147 mins, respectively). However, no significant biomechanical differences between athletic and nonathletic MWU were observed during either propulsion speed. During the 1.11 m s-1 trial wheelchair users displayed a stroke frequency of 53 ± 12 pushes/min and a contact angle of 92.5 ± 16.2°. During the 1.67 m s-1 trial the mean stroke frequency was 64 ± 22 pushes/min and contact angle was 85.4 ± 13.6°. Despite the hand being unconstrained during the recovery phase the magnitude of joint kinematic variability was similar across both glenohumeral and scapulothoracic joints during recovery and push phases. To conclude, although athletic MWU participate in more physical activity per week they adopt similar strategies to propel their daily living wheelchair. Investigations of shoulder pain and dailywheelchair propulsion do not need to distinguish between athletic and nonathletic MWU.

Scapular kinematic variability during wheelchair propulsion is associated with shoulder pain in wheelchair users.

The purpose of this study was to investigate whether wheelchair propulsion biomechanics differ between individuals with different magnitudes of shoulder pain. Forty (age 36 ± 11 years) manual wheelchair users propelled their own daily living wheelchair at 1.11 m·s-1 for three minutes on a dual-roller ergometer. Shoulder pain was evaluated using the Performance Corrected Wheelchair User's Shoulder Pain Index (PC-WUSPI). Correlation analyses between spatio-temporal, kinetic and upper limb kinematic variables during wheelchair propulsion and PC-WUSPI scores were assessed. Furthermore, kinematic differences between wheelchair users with no or mild shoulder pain (n = 33) and moderate pain (n = 7) were investigated using statistical parametric mapping. Participant mean PC-WUSPI scores were 20.3 ± 26.3 points and varied from zero up to 104 points. No significant correlations were observed between kinetic or spatio-temporal parameters of wheelchair propulsion and shoulder pain. However, lower inter-cycle variability of scapular internal/external rotation was associated with greater levels of shoulder pain (r = 0.35, P = 0.03). Wheelchair users with moderate pain displayed significantly lower scapular kinematic variability compared to those with mild or no pain between 17 and 51% of the push phase for internal rotation, between 31-42% and 77-100% of the push phase for downward rotation and between 28-36% and 53-65% of the push phase for posterior tilt. Lower scapular variability displayed by wheelchair users with moderate shoulder pain may reflect a more uniform distribution of repeated subacromial tissue stress imposed by propulsion. This suggests that lower scapular kinematic variability during propulsion may contribute towards the development of chronic shoulder pain.

Characterization of normative angular joint kinematics during two functional upper limb tasks.

BACKGROUND: Optical motion capture is a powerful tool for assessing upper body kinematics, including compensatory movements, in different populations. However, the lack of a standardized protocol with clear functional relevance hinders its clinical acceptance. RESEARCH QUESTION: The objective of this study was to use motion capture to: (1) characterize angular joint kinematics in a normative population performing two complex, yet standardized upper limb tasks with clear functional relevance; and (2) assess the protocol's intra-rater reliability. METHODS: Twenty non-disabled adults performed the previously developed Pasta Box Task and Cup Transfer Task. The kinematics of the upper body were captured using an optoelectronic motion capture system and rigid plates with reflective markers. Angular joint trajectories, peak angle, range of motion (RoM), and peak angular velocity were extracted for the trunk, shoulder, elbow, forearm, and wrist. Intra-class correlation was used to assess the intra-rater reliability of the kinematic measures. RESULTS: Both tasks required minimal trunk motion. Cross-body movements required greater RoM at the trunk, shoulder, and elbow joints compared to movements in front of the body. Reaches to objects further away from the body required greater trunk and elbow joint RoM compared to reaches to objects closer to the body. Transporting the box of pasta required the wrist to maintain an extended position. The two different grasp patterns in the Cup Transfer Task forced the wrist into a flexed and ulnar-deviated position for the near cup, and an extended and radial-deviated position for the far cup. For both tasks, the majority of measures displayed intra-class correlation values above 0.75, indicating good reliability. SIGNIFICANCE: Our protocol and functional tasks elicit a degree of movement sensitivity that is not available in current clinical assessments. Our study also provides a comprehensive dataset that can serve as a normative benchmark for quantifying movement compensations following impairment.

The effects of walking speed on upper body kinematics during gait in healthy subjects.

Patients undergoing a clinical gait analysis often walk slower than healthy people. However, data on how speed affects upper body movements, especially of the arms and shoulders, are scarce. Therefore, in this descriptive study, we examined how changes in walking speed affect upper-body kinematics and aspects of intersegmental coordination between upper and lower body during overground walking in a group of healthy adult subjects. Three-dimensional gait data were collected on 20 healthy subjects (aged between 22 and 31 years) walking at six speeds ranging from extremely slow to very fast. Our results showed significant speed-related changes of upper body kinematic movement curves in three aspects, namely in amplitude (curves for shoulder flexion and abduction, elbow flexion, pelvic obliquity and rotation), timing (curves for shoulder extension and abduction, elbow extension, pelvic rotation) and curve pattern (curves for shoulder and elbow flexion, shoulder rotation, pelvic tilt). The intersegmental coordination between the thorax and pelvis and arm and leg was also affected by a change of walking speed. Our data supplement the already available data in the literature examining the effects of walking speed on lower extremity motion. Furthermore, the data can be used as a reference for both basic biomechanical and clinical gait studies. The results will help in clinical practice to differentiate between effects caused by walking speed and underlying pathology.

Upper body movements in children with hemiplegic cerebral palsy walking with and without an ankle-foot orthosis.

BACKGROUND: It has previously been discussed that treatment of the hemiplegic arm in patients with cerebral palsy can improve gait parameters in the lower body. Our question was whether improving the ankle rocker with an orthosis has an effect on the upper body during walking. The main aim was to investigate, which trunk and arm kinematics of toe walking children with hemiplegic cerebral palsy are changed by wearing a hinged ankle-foot orthosis, restoring an initial heel contact. METHODS: Specific parameters of the pelvis, thorax, and arm kinematics were investigated. Differences in the hemiplegic side between the barefoot and the orthotic condition were calculated by Students t-tests. Additionally, the 95% confidence intervals were used to explore clinically relevant differences between the controls and the patients and asymmetries within the patients' affected and unaffected sides. FINDINGS: Pelvic tilt range of motion (barefoot: 7.5° (6.1-9.0°), orthosis: 6.6° (5.1-8.1) P=0.040) and mean shoulder abduction (barefoot: 14.3° (10.2-18.4°), orthosis: 12.1° (8.4-15.8) P=0.027) were the only two parameters with statistically significant differences, although not clinically relevant, between the barefoot and orthotic conditions. Abnormalities in all three planes were explored between the patients and controls. The entire trunk was more externally rotated, the pelvis stood lower, and the elbow was more flexed on the hemiplegic side compared to the unaffected side. INTERPRETATION: A hinged ankle-foot orthosis, restoring the first ankle rocker, had no clinically relevant effects on trunk kinematics. None of the observed upper body gait deviations seemed to be secondary to or caused by toe walking.