Differential relationships between physical activity and pain phenotypes in individuals with spinal cord injury.

BACKGROUND: Chronic pain affects 70% of individuals with spinal cord injury (SCI) and leads to declines in health and quality of life. Neuropathic and nociceptive pain are phenotypes derived from different mechanisms that contribute to pain perception. The objective of this research was to investigate differential pain responses to moderate-to-vigorous physical activity (MVPA) in two chronic pain phenotypes: neuropathic and nociceptive pain. METHODS: Community-based physical activity levels were collected for one week in 17 individuals with SCI using a wrist-worn accelerometer, and daily pain ratings were assessed and categorized by phenotype. Physical activity levels were summarized to calculate minutes of MVPA. Correlational analyses were conducted to compare relationships between pain intensity and MVPA across individual participants and between pain phenotype groups. RESULTS: The neuropathic pain group revealed significant negative correlation between MVPA and pain intensity. In the nociceptive pain group, there was no significant correlation between MVPA and pain intensity. Further analysis revealed two subgroups of positive (N = 4) and negative (N = 3) correlations between MVPA and pain intensity. Pain location differed between the subgroups of nociceptive pain. Individuals with negative correlation experienced neck and upper back pain, whereas individuals with positive correlation experienced unilateral upper extremity pain. CONCLUSION: Differential relationships exist between pain phenotypes and MVPA in individuals with SCI. Pain location differed between the subgroups of nociceptive pain, which we presume may indicate the presence of nociplastic pain in some individuals. These results may contribute to the advancement of personalized pain management by targeting non-pharmacological interventions for specific pain phenotypes.Trial registration: ClinicalTrials.gov identifier: NCT05236933..

Relationship between pain, fatigue, and physical activity levels during a technology-based physical activity intervention.

Objective: The majority of individuals with spinal cord injury (SCI) experience chronic pain. Chronic pain can be difficult to manage because of variability in the underlying pain mechanisms. More insight regarding the relationship between pain and physical activity (PA) is necessary to understand pain responses during PA. The objective of this study is to explore possible relationships between PA levels and secondary conditions including pain and fatigue.Design: Prospective cohort analysis of a pilot study.Setting: Community.Participants: Twenty individuals with SCI took part in the study, and sixteen completed the study.Interventions: Mobile-health (mHealth) based PA intervention for two-months during the three-month study.Outcome measures: Chronic Pain Grade Scale (CPGS) questionnaire, The Wheelchair User's Shoulder Pain Index (WUSPI), Fatigue Severity Scale (FSS), and PA levels measured by the mHealth system.Results: A positive linear relationship was found between light-intensity PA and task-specific pain. However, the relationship between moderate-intensity PA and pain interference was best represented by a curvilinear relationship (polynomial regression of second order). Light-intensity PA showed positive, linear correlation with fatigue at baseline. Moderate-intensity PA was not associated with fatigue during any phase of the study.Conclusion: Our results indicated that PA was associated with chronic pain, and the relationship differed based on intensity and amount of PA performed. Further research is necessary to refine PA recommendations for individuals with SCI who experience chronic pain.Trial registration: ClinicalTrials.gov identifier: NCT03773692.

Movement Coordination During Humeral Elevation in Individuals With Newly Acquired Spinal Cord Injury.

Humeral elevation is a critical motion for individuals who use a manual wheelchair given that, in a typical day, wheelchair users reach overhead 5 times more often than able-bodied controls. Kinematic analyses in individuals with chronic spinal cord injury (SCI) have focused on weight-bearing tasks rather than overhead reaching. This technical report presents shoulder movement coordination during overhead reaching in individuals with newly acquired SCI. Eight volunteers with acute SCI and 8 matched, uninjured controls participated. Three-dimensional kinematics were collected during seated, humeral elevation. Scapular and thoracic rotations during humeral elevation were averaged across repetitions. The linear relationship of scapular upward rotation to humeral elevation provided movement coordination analysis. Maximal elevation was reduced in SCI with increased thoracic kyphosis. Medium to large effect sizes were found at each elevation angle, with reduced scapular external rotation, posterior tilt, and increased thoracic kyphosis for those with SCI. The linear relationship occurred later and within a significantly (P = .02) smaller range of humeral elevation in SCI. Altered movement coordination, including a diminished linear association of scapular upward rotation and humeral elevation (scapulohumeral rhythm), is found with reduced maximal elevation and increased thoracic kyphosis during overhead reaching tasks in those with acute SCI.

Relationships of hip abductor strength, neuromuscular control, and hip width to femoral length ratio with peak hip adduction angle in healthy female runners.

A large peak hip adduction angle during running is a risk factor for several overuse injuries in women. The purpose of this study was to determine if female runners with a large peak hip adduction angle have differences in eccentric hip abductor muscle strength, hip neuromuscular control, and/or hip width to femoral length ratio (HW:FL) compared to those with a small angle. Hip adduction during running, hip strength, hip control, and HW:FL were measured in sixty healthy female runners (1.66 ± 0.06 m; 63.2 ± 8.3 kg; 27 ± 6 years). Data from twenty runners with the largest and twenty with the smallest peak hip adduction angles were analysed. Between-group differences in hip strength, control, and HW:FL were determined using independent t-tests (p < 0.05). Variables that were significantly different between groups were entered into a regression model. Runners in both groups had similar hip strength (p = 0.90) and control (p = 0.65). HW:FL was greater in the large peak angle group (p = 0.04), but only explained a small amount of peak hip adduction angle variance for all sixty runners (R2 = 0.05). Alarge peak hip adduction angle in some healthy female runners may simply be instinctive as there were no deficiencies in the strength or neuromuscular control constructs assessed.

Association of musculoskeletal pain, fear-avoidance factors, and quality of life in active manual wheelchair users with SCI: A pilot study.

Objective: Limited evidence examines the association of psychological factors, such as fear of movement and pain catastrophizing, with musculoskeletal pain patterns in active manual wheelchair users with spinal cord injury (SCI). This study investigated the relationship among musculoskeletal pain, fear avoidance factors, quality of life (QoL), activity and duration of injury in individuals with SCI. Design: Cross-sectional correlational. Setting: Community setting. Participants: Twenty-six individuals with SCI (age = 42 ± 14 years, duration manual wheelchair use = 17 ± 13 years, work/school/volunteer hours/week = 31 ± 14; recreation/sports hours/week 10 ± 12). Outcome Measures: Demographics and self-report measures including the Musculoskeletal Pain Survey (MPS), Wheelchair Users Shoulder Pain Index (WUSPI), Tampa Scale of Kinesiophobia (TSK-11), Pain Catastrophizing Scale (PCS), Fear of Pain (FPQ), Subjective Quality of Life Questionnaire (SQoL), and the Social Interaction Inventory (SII). Spearman's rho (ρ) assessed correlation among measures. Results: Strong association existed between age and duration of injury (ρ = 0.66, P < 0.001). SQoL offered a strong, direct correlation with age (ρ = 0.63, P = 0.01), duration of injury (ρ = 0.70, P = 0.001), and strong, inverse relationship with MPStotal (ρ = -0.66, P = 0.003) and MPS shoulder subscore (ρ = -0.64, P = 0.004). WUSPI demonstrated strong, inverse association with self-reported work hours (ρ = -0.52, P = 0.02) and a strong, direct relationship to PCS (ρ = 0.79, P = <0001). PCS demonstrated a strong, inverse relationship to work/school/volunteer hours (ρ = 0.71, P < 0.001) and strong association to TSK-11_total (ρ = 0.61, P = 0.001). A moderate, inverse relationship was identified for recreational/sports hours and FPQ (ρ = 0.48, P = 0.03). Conclusion: This cyclical relationship of musculoskeletal pain, reduced activity, and maladaptive psychological factors allude to interdependence of factors, supporting the multidisciplinary approach to care.

Instrument-Assisted Soft-Tissue Mobilization for the Management of Chronic Plantar Heel Pain: A Pilot Study.

BACKGROUND: The purpose of this study was to determine feasibility of further investigation of treatment with instrument-assisted soft-tissue mobilization (IASTM), using the Graston technique, compared with conservative care for treatment of chronic plantar heel pain (CPHP). METHODS: Eleven participants with plantar heel pain lasting 6 weeks to 1 year were randomly assigned to one of two groups, with each group receiving up to eight physical therapy visits. Both groups received the same stretching, exercise, and home program, but the experimental group also received IASTM using the Graston technique. Outcome measures of pain and function were recorded at baseline, after final treatment, and 90 days later. Feasibility of a larger study was determined considering recruitment and retention rates, compliance, successful application of the protocol and estimates of the treatment effect. RESULTS: Both groups demonstrated improvements in current pain (pain at time of survey), pain with the first step in the morning, and function after final treatment and at 90-day follow up. Medium-to-large effect sizes between groups were noted, and sample size estimates demonstrated a need for at least 42 participants to realize a group difference. A larger-scale study was determined to be feasible with modifications including a larger sample size and higher recruitment rate. CONCLUSIONS: This pilot study demonstrates that inclusion of IASTM using the Graston technique for CPHP lasting longer than 6 weeks is a feasible intervention warranting further study. Clinically important changes in the IASTM group and moderate-to-large between-group effect sizes suggest that further research is warranted to determine whether these trends are meaningful.

Relationship of the Patient-Specific Functional Scale to commonly used clinical measures in hand osteoarthritis.

STUDY DESIGN: Prospective cohort correlation study. INTRODUCTION: There is no known published research on correlations between the Patient-Specific Functional Scale (PSFS), hand grip strength, and the Disability of the Arm, Shoulder and Hand (DASH) in a population with hand osteoarthritis (OA). PURPOSE: The purpose of this study is to establish reliability of the PSFS and to evaluate the relationship between the PSFS, hand grip strength, and the DASH for a population with hand OA. METHODS: Thirty-five participants in 4 hand clinics completed the PSFS, hand grip strength testing, and the DASH at the onset of therapy and at discharge. Eighteen participants enrolled at the primary investigator's site completed a baseline PSFS one week before the pretreatment collection with data used to establish relative and absolute reliability. Data were analyzed separately at pretreatment and posttreatment with Spearman's rho correlation (P < .05). Intraclass correlation (2, 1), standard error of the measurement, and minimum detectable change (MDC90 and MDC95) were calculated from the repeated baseline and pretreatment PSFS. RESULTS: Intraclass correlation for PSFS was (r = 0.80) with the standard error of the measurement = 0.56, MDC90 = 1.30, and MDC95 = 1.56. Small correlation between the PSFS and DASH scores was found pretreatment (ρ = -0.10) and change scores (ρ = 0.13). CONCLUSION: Excellent reliability with small measurement error has established clinical utility of the PSFS for the population with hand OA. These outcome measures were shown to measure different constructs and therefore should not be used interchangeably. LEVEL OF EVIDENCE: 3.

Association of Pectoralis Minor Muscle Extensibility, Shoulder Mobility, and Duration of Manual Wheelchair Use.

OBJECTIVE: To assess the relation of pectoralis minor muscle (PMm) length and extensibility to shoulder pain, shoulder girdle motion, and duration of manual wheelchair (MWC) use, and to compare differences in muscle length, muscle extensibility, peak humeral elevation, and pain among groups based on duration of wheelchair use. DESIGN: Cross-sectional cohort study. SETTING: Laboratory setting. PARTICIPANTS: Individuals with spinal cord injury (SCI) who used an MWC for daily community and home mobility (N=22; 18 men; mean age, 41.7y; duration wheelchair use, 14.6y). Participants were stratified into groups based on duration of wheelchair use: <5 years (n=6), 5 to 15 years (n=8), and >15 years (n=8). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Clinical measures of PMm length and extensibility, shoulder girdle motion, and shoulder pain (Wheelchair User's Shoulder Pain Index). RESULTS: Significant high correlations were found among duration of wheelchair use, passive PMm length, passive PMm extensibility, and peak humerothoracic elevation. Moderate correlation of peak humerothoracic elevation to pain was found. Individuals with >15 years wheelchair use had reduced PMm extensibility and reduced peak humerothoracic elevation than those with <5 years duration of use. CONCLUSIONS: To our knowledge, this is the first investigation to identify the association of reduced PMm extensibility with reduced shoulder girdle mobility, pain, and duration of wheelchair use in individuals with SCI.

Effects of a repetitive gaming intervention on upper extremity impairments and function in persons with chronic stroke: a preliminary study.

PURPOSE: The purpose of this study was to examine the feasibility and effects of an upper extremity gaming system on impairments, activity and participation restrictions in persons with chronic stroke. METHOD: Nine participants with chronic (5.4 SD 3 years after stroke) upper extremity impairment due to stroke completed 18 sessions over 6 weeks with the Hand Dance Pro™ gaming system that included trunk restraint. Measures collected at pretest and posttest included three-dimensional motion analysis of paretic upper extremity reaching, Wolf Motor Function Test (WMFT) and Stroke Impact Scale (SIS). Data were analyzed across time, with effect sizes (Cohen's d), and by categorizing participants with Fugl-Meyer Upper Extremity Motor Assessment scores (mild >50/66, moderate 26-50/66 and severe <26/66). RESULTS: Statistically, significant improvements and medium-to-large effect sizes from pretest to posttest were found with ipsilateral reaching kinematic outcomes of movement duration, mean velocity and elbow excursion (p < 0.05). Participants with mild impairment demonstrated the greatest change in elbow excursion. No significant differences and small effect sizes were found for the WMFT and SIS. CONCLUSION: The gaming intervention with high repetitions of reaching to targets and trunk restraint was feasible and led to improvements in upper extremity movement kinematics in this group of participants with chronic stroke.

Three-dimensional shoulder complex kinematics in individuals with upper extremity impairment from chronic stroke.

PURPOSE: To evaluate shoulder complex kinematics in persons with chronic upper extremity (UE) impairments due to stroke and determine if kinematics predicts motor function based on the Fugl-Meyer Motor Assessment (FMA). METHODS: Sixteen stroke survivors with chronic UE impairments (age range = 46-80 years, male = 8, female = 8, mean (SD) 66 (40) months post-stroke) performed the UE portion of the FMA with the shoulder/elbow subscale (FM_se) documented. Three-dimensional kinematics of the shoulder complex was collected with the Motion Monitor™ (Innsport, Chicago, IL, USA). Participants performed three repetitions of arm elevation in the frontal, sagittal and self-selected planes. The third repetition was analyzed. Scapular and humeral kinematics were calculated in the self-selected plane. Scapulohumeral rhythm was analyzed at peak elevation. Backward stepwise regression analysis predicted kinematic contributions to the FM_se. RESULTS: Mean (SD) FM_se score was 25.3 1(10.9). Peak humeral elevation ranged from 45.6° to 129.2° (median 106.7°). Scapulohumeral rhythm was 4.1:1 when humeral elevation ranged from 45° to 50°, 1.5:1 from 80° to 95° and 2.1:1 from 105° to 130°. Humeral elevation, scapular upward rotation and scapular internal rotation predicted 65.4% of FM_se score variability. CONCLUSIONS: Persons with chronic UE impairments from stroke demonstrated reduced peak elevation and altered scapulohumeral rhythm. Three predictors of the FM_se were humeral elevation, scapular upward rotation and scapular internal rotation.

Effect of gravity on robot-assisted motor training after chronic stroke: a randomized trial.

OBJECTIVES: To determine the efficacy of 2 distinct 6-week robot-assisted reaching programs compared with an intensive conventional arm exercise program (ICAE) for chronic, stroke-related upper-extremity (UE) impairment. To examine whether the addition of robot-assisted training out of the horizontal plane leads to improved outcomes. DESIGN: Randomized controlled trial, single-blinded, with 12-week follow-up. SETTING: Research setting in a large medical center. PARTICIPANTS: Adults (N=62) with chronic, stroke-related arm weakness stratified by impairment severity using baseline UE motor assessments. INTERVENTIONS: Sixty minutes, 3 times a week for 6 weeks of robot-assisted planar reaching (gravity compensated), combined planar with vertical robot-assisted reaching, or intensive conventional arm exercise program. MAIN OUTCOME MEASURE: UE Fugl-Meyer Assessment (FMA) mean change from baseline to final training. RESULTS: All groups showed modest gains in the FMA from baseline to final with no significant between group differences. Most change occurred in the planar robot group (mean change ± SD, 2.94 ± 0.77; 95% confidence interval [CI], 1.40-4.47). Participants with greater motor impairment (n=41) demonstrated a larger difference in response (mean change ± SD, 2.29 ± 0.72; 95% CI, 0.85-3.72) for planar robot-assisted exercise compared with the intensive conventional arm exercise program (mean change ± SD, 0.43 ± 0.72; 95% CI, -1.00 to 1.86). CONCLUSIONS: Chronic UE deficits because of stroke are responsive to intensive motor task training. However, training outside the horizontal plane in a gravity present environment using a combination of vertical with planar robots was not superior to training with the planar robot alone.

The effect of repeated measurements using an upper extremity robot on healthy adults.

We are expanding the use of the MIT-MANUS robotics to persons with impairments due exclusively to orthopedic disorders, with no neurological deficits. To understand the reliability of repeated measurements of the robotic tasks and the potential for registering changes due to learning is critical. Purposes of this study were to assess the learning effect of repeated exposure to robotic evaluations and to demonstrate the ability to detect a change in protocol in outcome measurements. Ten healthy, unimpaired subjects (mean age = 54.1 +/- 6.4 years) performed six repeated evaluations consisting of unconstrained reaching movements to targets and circle drawing (with and without a visual template) on the MITMANUS. Reaching outcomes were aiming error, mean and peak speed, movement smoothness and duration. Outcomes for circle drawing were axis ratio metric and shoulder- elbow joint angles correlation metric (was based on a two-link model of the human arm and calculated hand path during the motions). Repeated-measures ANOVA (p < or = .05) determined if difference existed between the sessions. Intraclass correlations (R) were calculated. All variables were reliable, without learning across testing sessions. Intraclass correlation values were good to high (reaching, R > or =.80; circle drawing, R > or =.90). Robotic measurement ability to differentiate between similar but distinct tasks was demonstrated as measured by axis ratio metric (p < .001) and joint correlation metric (p = .001). Outcome measures of the MIT-MANUS proved to be reliable yet sensitive to change in healthy adults without motor learning over the course of repeated measurements.

Effect of 2-speed geared manual wheelchair propulsion on shoulder pain and function.

OBJECTIVE: To investigate the impact of a manual 2-gear drive wheelchair wheel (MAGICWheels) on shoulder pain and function in manual wheelchair users. DESIGN: A single-group, repeated-measures pre- and postdesign with baseline and retention. SETTING: General community. PARTICIPANTS: Full-time manual wheelchair users (N=17) currently experiencing shoulder pain (mean age, 46+/-14 y; wheelchair use, 15+/-10 y). INTERVENTION: Five-month trial using a 2-gear wheelchair wheel. MAIN OUTCOMES MEASURES: The Wheelchair Users Shoulder Pain Index (WUSPI), Wheelchair Users Functional Assessment (WUFA), and timed hill climb test with rating of perceived exertion (RPE). RESULTS: There was significant reduction in shoulder pain after the intervention at week 2 (P=.004) through week 16 (P=.015). The difference was not found at week 20; however, 1 participant reported an increase in pain from unrelated factors during week 20. Change from baseline was calculated without this subject's data; there was a significant reduction in shoulder pain (P=.003). There was no difference in WUFA after using the 2-gear wheel (P=.06). Hill climb time was longer when using the 2-gear wheel (P=.01), but no difference in the RPE (P=.13) resulted. Shoulder pain during the 4-week retention phase showed a trend toward increasing, as indicated by increased WUSPI scores. There was not a significant percentage increase, however, in comparison with the final week of using the MAGICWheels (P<.05). CONCLUSIONS: There were pain reductions 2 weeks after using the MAGICWheels, indicating a rapid response to the intervention. These findings indicate the potential for shoulder pain reduction with the use of a manual drive wheel during mobility, even in highly functional manual wheelchair users.

Short-duration robotic therapy in stroke patients with severe upper-limb motor impairment.

Chronic motor deficits in the upper limb (UL) are a major contributor to disability following stroke. This study investigated the effect of short-duration robot-assisted therapy on motor impairment, as measured by clinical scales and robot-derived performance measures in patients with chronic, severe UL impairments after stroke. As part of a larger study, 15 individuals with chronic, severe UL paresis (Fugl-Meyer < 15) after stroke (minimum 6 mo postonset) performed 18 sessions of robot-assisted UL rehabilitation that consisted of goal-directed planar reaching tasks over a period of 3 weeks. Outcome measures included the Fugl-Meyer Assessment, the Motor Power Assessment, the Wolf Motor Function Test, the Stroke Impact Scale, and five robot-derived measures that reflect motor control (aiming error, mean speed, peak speed, mean:peak speed ratio, and movement duration). Robot-assisted training produced statistically significant improvements from baseline to posttreatment in the Fugl-Meyer and Motor Power Assessment scores and the quality of motion (quantified by a reduction in aiming error and movement duration with an increase in mean speed and mean:peak speed ratio). Our findings indicate that robot-assisted UL rehabilitation can reduce UL impairment and improve motor control in patients with severe UL paresis from chronic stroke.

Scapular kinematics during transfers in manual wheelchair users with and without shoulder impingement.

BACKGROUND: Scapular function during humeral elevation has been reported in groups with and without shoulder impingement pathology. To date, no one has assessed scapular kinematics during upper extremity loaded tasks that manual wheelchair users must perform on a daily basis. Therefore, the objective of this study was to compare scapular kinematics and muscle activation patterns during two different wheelchair transfers in groups of manual wheelchair users with and without shoulder impingement. METHODS: A case controlled study of manual wheelchair users, with and without shoulder impingement was performed. Twenty-three male manual wheelchair users (13 without shoulder impingement, 10 with shoulder impingement) performed transfers toward the involved or dominant limb (lead limb transfer) and away from the instrumented limb (trail limb transfer). Position and orientation measures of the thorax, scapula and humerus were obtained using an electromagnetic tracking system. Muscle activity data were collected using telemetered electromyography. Each subject performed three trials of wheelchair transfers to each side. FINDINGS: Manual wheelchair users with impingement performed transfers with reduced thoracic flexion, increased scapular internal rotation, and increased humeral internal rotation as compared to those without impingement. Differences were found between the tasks in the scapular motions and EMG amplitude. Trail limb transfer presented with reduced scapular upward rotation and posterior tip as compared to the lead limb transfer task. Increased muscle activity for the lower trapezius and serratus anterior muscles was demonstrated in the trail limb transfer. INTERPRETATION: This study provides the first kinematic description of scapular kinematics during transfer tasks. Shoulder impingement and direction of transfer does affect transfer task performance in manual wheelchair users. Scapular kinematics and muscle patterns during transfers may predispose manual wheelchair users to the development of shoulder pathology.

The biomechanics of wheelchair propulsion in individuals with and without upper-limb impairment.

We used an instrumented wheelchair ergometer and 3D motion analysis system to collect joint kinematic and temporal data, as well as hand rim and joint kinetics, in 47 manual wheelchair users (MWCUs) (15 with upper-limb impairment and 32 without upper-limb impairment). The group with upper-limb impairment propelled with a higher stroke frequency and reduced hand-rim contact time, and smaller peak joint angles and joint excursion of the wrist, elbow, and shoulder during the contact phase. They also propelled with a reduced power output and reduced hand-rim propulsive and resultant forces, moments, and joint compressive forces. We concluded that these kinematic and kinetic strategies might be a mechanism for allowing MWCUs with upper-limb impairment to remain independent. Additionally, the reduced joint excursion and reduced magnitude of forces may protect them from the development of secondary upper-limb pathologies.

Prevalence and identification of shoulder pathology in athletic and nonathletic wheelchair users with shoulder pain: A pilot study.

Although many wheelchair users report shoulder pain, the prevalence of specific pathologies remains controversial. Rotator cuff impingement, glenohumeral instability, and biceps tendonitis have been stated as the most commonly found pathology. This study investigated the prevalence and identity of shoulder pathology in athletic and nonathletic manual wheelchair users (MWCUs). Fifty-two MWCUs (26 athletes, 26 nonathletes) completed a survey regarding the nature of their injury, sports involvement, history, and presence of current and/or past shoulder pathology. Subjects currently experiencing shoulder pain underwent a clinical examination of both shoulders. Analysis of variance (p

Effect of sitting posture on 3-dimensional scapular kinematics measured by skin-mounted electromagnetic tracking sensors.

OBJECTIVE: To determine the effect of trunk sitting posture on scapular kinematics during humeral elevation by using skin-mounted electromagnetic tracking sensors. DESIGN: Repeated-measures design contrasting scapular kinematics in 2 different sitting postures. SETTING: A biomechanics laboratory in Hong Kong with a real-time, 3-dimensional electromagnetic tracking device for measuring movements of the scapula. PARTICIPANTS: A sample of 16 healthy adults (12 women, 4 men; age, 21.6+/-3.92y) with full, pain-free shoulder range of motion and no history of shoulder pathology. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Movements of the scapula were measured while each subject performed humeral elevation in an upright seated position and a slouched seated position. RESULTS: In both postures, posterior tip, lateral and upward rotation of the scapula, and lateral rotation of the humerus were observed during humeral elevation. When the slouched posture was adopted, there were significant decreases in the posterior tip and lateral rotation of the scapula, but there was no significant change in the magnitude of the upward rotation of the scapula. CONCLUSION: Increased thoracic kyphosis significantly alters the kinematics of the scapula during humeral elevation.

Upper-limb fatigue-related joint power shifts in experienced wheelchair users and nonwheelchair users.

This paper evaluates power transfer or shifting across upper-limb segments, resulting from fatigue-inducing wheelchair propulsion. Nineteen manual wheelchair users (WCUs) and ten nonwheelchair users (NUs) participated in this study. Subjects propelled an instrumented wheelchair ergometer at a workload corresponding to 75% of the peak oxygen uptake attained during a maximal-graded exercise tolerance test. Subjects were required to propel the wheelchair for as long as they could at a constant velocity of 3 km/h (32 rpm). The test was terminated when subjects could no longer maintain the target velocity. Peak Performance video-capture system was used to determine upper-limb kinematics. Handrim forces and joint kinematics were used to calculate joint moments and power with the use of an inverse dynamics approach. Results showed that with fatigue, joint power shifts from the shoulder joint to the elbow and wrist joints. Implications for joint injury and propulsion efficiency are discussed.

Reliability of biomechanical variables during wheelchair ergometry testing.

Wheelchair ergometer testing is used to characterize wheelchair propulsion mechanics. The reliability of kinematic and kinetic measures has not been investigated for wheelchair ergometer testing. In this study, test-retest reliability of biomechanical measurements on a wheelchair ergometer was determined during a submaximal endurance test. Ten nondisabled subjects (seven male, three female), inexperienced in wheelchair propulsion, completed three separate submaximal fatigue tests. An instrumented wheelchair ergometer was used to measure handrim kinetics while three-dimensional kinematic data were collected. Analysis of variance was used to determine if measurement differences existed across the tests. Intraclass correlation coefficients (ICC) were calculated to determine the reliability of the measurements. The majority of handrim and temporal variables were found to be reliable. Joint kinematic variables were less reliable, especially those involving wrist movements in the fatigued state. It was concluded that most biomechanical variables obtained during wheelchair ergometry were reliable.