Sara J. Mulroy

Effects of Task-Specific Locomotor and Strength Training in Adults Who Were Ambulatory After Stroke: Results of the STEPS Randomized Clinical Trial

Background and Purpose: A phase II, single-blinded, randomized clinical trial was conducted to determine the effects of combined task-specific and lower-extremity (LE) strength training to improve walking ability after stroke. Subjects: The participants were 80 adults who were ambulatory 4 months to 5 years after a unilateral stroke. Method: The exercise interventions consisted of body-weight–supported treadmill training (BWSTT), limb-loaded resistive leg cycling (CYCLE), LE muscle-specific progressive-resistive exercise (LE-EX), and upper-extremity ergometry (UE-EX). After baseline assessments, participants were randomly assigned to a combined exercise program that included an exercise pair. The exercise pairs were: BWSTT/UE-EX, CYCLE/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX. Exercise sessions were 4 times per week for 6 weeks (total of 24 sessions), with exercise type completed on alternate days. Outcomes were self-selected walking speed, fast walking speed, and 6-minute walk distance measured before and after intervention and at a 6-month follow-up. Results: The BWSTT/UE-EX group had significantly greater walking speed increases compared with the CYCLE/UE-EX group; both groups improved in distance walked. All BWSTT groups increased walking speed and distance whether BWSTT was combined with LE strength training or not. Discussion and Conclusion: After chronic stroke, task-specific training during treadmill walking with body-weight support is more effective in improving walking speed and maintaining these gains at 6 months than resisted leg cycling alone. Consistent with the overtraining literature, LE strength training alternated daily with BWSTT walking did not provide an added benefit to walking outcomes.

Use of cluster analysis for gait pattern classification of patients in the early and late recovery phases following stroke.

The mixture of gait deviations seen in patients following a stroke is remarkably variable. An objective system for classification of gait patterns for this population could be used to guide treatment planning. Quantitated gait analysis was conducted for 47 individuals at admission to in-patient rehabilitation and again at 6 months post-stroke for 42 subjects. Non-hierarchical cluster analysis was used to classify the gait patterns of patients based on the temporal-spatial and kinematic parameters of walking. Four clusters of patients were identified at both assessment intervals. At the admission test walking velocity, peak knee extension in mid stance and peak dorsiflexion in swing were the three factors that best characterized the groups. At 6 months the explanatory variables were velocity, knee extension in terminal stance, and knee flexion in pre swing. Differences in muscle strength and muscle activation patterns during walking were identified between groups.

Electromyographic activity of shoulder muscles during wheelchair propulsion by paraplegic persons

OBJECTIVE Phasing and intensity of shoulder muscle activity during wheelchair propulsion were documented to identify muscles at risk for fatigue and overuse. DESIGN AND PARTICIPANTS Electromyographic (EMG) activity of 12 muscles was recorded with wire electrodes in 17 paraplegic men during propulsion on a stationary ergometer. MAIN OUTCOME MEASURES Push and recovery phases of the propulsion cycle were determined with an instrumented pushrim. Onset and cessation of EMG were compared between muscles with a repeated measures ANOVA. Average and peak EMG intensity also were identified. RESULTS All muscles functioned either in push or recovery phases, except supraspinatus, which displayed both patterns, and latissimus dorsi, which was inconsistent. The 6 push phase muscles--anterior deltoid, sternal pectoralis major, supraspinatus, infraspinatus, serratus anterior, and long head of biceps brachii--had onsets in late recovery (78% to 93% cycle) with peak EMG in the first 10% of the cycle. Pectoralis major and supraspinatus had the highest peak (58% and 67%MAX) and average (35% and 27%MAX) EMG intensities in this group. Cessation occurred in late push (17% to 23% cycle) except in biceps brachii (8% cycle) (p < .01). The 5 recovery muscles--middle and posterior deltoid, subscapularis, supraspinatus, and middle trapezius--had EMG onsets in late push (17% to 26% cycle) with moderate average intensities (21% to 32%MAX). These muscles had two EMG peaks (end of push and mid-recovery). Cessation was in late recovery (82% to 91% cycle). CONCLUSIONS Muscles most vulnerable for fatigue were pectoralis major, supraspinatus, and recovery muscles. Endurance training was recommended.

Shoulder joint kinetics during the push phase of wheelchair propulsion.

The purpose of this investigation was to quantify the forces and moments at the shoulder joint during free, level wheelchair propulsion and to document changes imposed by increased speed, inclined terrain, and 15 minutes of continuous propulsion. Data were collected using a six-camera VICON motion analysis system, a strain gauge instrumented wheel, and a wheelchair ergometer. Seventeen men with low level paraplegia participated in this study. Shoulder joint forces and moments were calculated using a three-dimensional model applying the inverse dynamics approach. During free propulsion, peak shoulder joint forces were in the posterior (46 N) and superior directions (14 N), producing a peak resultant force of 51 N at an angle of 185° (180° = posterior). Peak shoulder joint moments were greatest in extension (14 Newton-meters [Nm]), followed by abduction (10 Nm), and internal rotation (6 Nm). With fast and inclined propulsion, peak vertical force increased by greater than 360%, and the increase in posterior force and shoulder moments ranged from 107% to 167%. At the end of 15 minutes of continuous free propulsion, there were no significant changes compared with short duration free propulsion. The increased joint loads documented during fast and inclined propulsion could lead to compression of subacromial structures against the overlying acromion.

Gains in Upper Extremity Function After Stroke via Recovery or Compensation: Potential Differential Effects on Amount of Real-World Limb Use

Abstract In terms of integration of the paretic upper extremity in activities of daily living (ADLs), outcome is poor after stroke. Furthermore, amount of real-world arm use appears only weakly correlated with laboratory motor function scales. Therefore, amount of arm use may depend critically on the location, extent, and type of functional gains, which can be quantified with comprehensive kinematic and EMG analysis of ADL performance. Gains in upper extremity function can occur via compensation or recovery of premorbid movement and EMG patterns, and traditional treatment approaches encourage adoption of compensatory strategies early in the postacute period that can inhibit potential recovery. A new treatment approach called Accelerated Skill Acquisition Program (ASAP) focuses on impairment reduction coupled with repetitive, task-specific training of the paretic arm during ADLs. We present pilot data that show recovery in subjects who received the ASAP, while a usual care control subject showed increased use of compensation over the same period. Finally, we discuss the advantages of data reduction methods such as principal components analysis, confirmatory factor analysis, and structural equation modeling, which can potentially distill large kinematic and EMG data sets into the key latent variables that predict amount of real-world use.

Gait parameters associated with responsiveness to treadmill training with body-weight support after stroke: an exploratory study.

Background Task-specific training programs after stroke improve walking function, but it is not clear which biomechanical parameters of gait are most associated with improved walking speed. Objective The purpose of this study was to identify gait parameters associated with improved walking speed after a locomotor training program that included body-weight–supported treadmill training (BWSTT). Design A prospective, between-subjects design was used. Methods Fifteen people, ranging from approximately 9 months to 5 years after stroke, completed 1 of 3 different 6-week training regimens. These regimens consisted of 12 sessions of BWSTT alternated with 12 sessions of: lower-extremity resistive cycling; lower-extremity progressive, resistive strengthening; or a sham condition of arm ergometry. Gait analysis was conducted before and after the 6-week intervention program. Kinematics, kinetics, and electromyographic (EMG) activity were recorded from the hemiparetic lower extremity while participants walked at a self-selected pace. Changes in gait parameters were compared in participants who showed an increase in self-selected walking speed of greater than 0.08 m/s (high-response group) and in those with less improvement (low-response group). Results Compared with participants in the low-response group, those in the high-response group displayed greater increases in terminal stance hip extension angle and hip flexion power (product of net joint moment and angular velocity) after the intervention. The intensity of soleus muscle EMG activity during walking also was significantly higher in participants in the high-response group after the intervention. Limitations Only sagittal-plane parameters were assessed, and the sample size was small. Conclusions Task-specific locomotor training alternated with strength training resulted in kinematic, kinetic, and muscle activation adaptations that were strongly associated with improved walking speed. Changes in both hip and ankle biomechanics during late stance were associated with greater increases in gait speed.

The effect of level of spinal cord injury on shoulder joint kinetics during manual wheelchair propulsion

OBJECTIVE The effects of spinal cord injury level on shoulder kinetics during manual wheelchair propulsion were studied. DESIGN Single session data collection in a laboratory environment. METHODS Male subjects were divided into four groups: low level paraplegia (n=17), high level paraplegia (n=19), C7 tetraplegia (C7, n=16) and C6 tetraplegia (C6, n=17). Measurements were recorded using a six-camera VICON motion analysis system, a strain gauge instrumented wheel, and wheelchair ergometer. Shoulder joint forces and moments were calculated using the inverse dynamics approach. RESULTS Mean self-selected propulsion velocity was higher in the paraplegic (low paraplegia=90.7 m/min; high paraplegia=83.4 m/min) than tetraplegic (C7=66.5 m/min; C6=47.0 m/min) groups. After covarying for velocity, no significant differences in shoulder joint moments were identified. However, superior push force in subjects with tetraplegia (C7=21.4 N; C6=9.3 N) was significantly higher than in those with high paraplegia (7.3 N), after covarying velocity. CONCLUSIONS The superior push force in the tetraplegic groups coupled with weakness of thoraco-humeral depressors increases susceptibility of the subacromial structures to compression. RELEVANCE Increased vertical force at the shoulder joint, coupled with reduced shoulder depressor strength, may contribute to shoulder problems in subjects with tetraplegia. Wheelchair design modifications, combined with strength and endurance retention, should be considered to prevent shoulder pain development.

The relationship of shoulder pain intensity to quality of life, physical activity, and community participation in persons with paraplegia.

Abstract Background/Objective: For persons with spinal cord injury (SCI), severe bodily pain is related to a lower quality of life. However, the effect of pain from a specific body region on quality of life has yet to be determined. The shoulder joint is a common site of pain among persons with SCI. Therefore, our purpose was to identify the relationship of self-reported shoulder pain with quality of life, physical activity, and community activities in persons with paraplegia resulting from SCI. Methods: Eighty participants with shoulder pain who propel a manual wheelchair (mean age: 44.7 years; mean duration of injury: 20 years; injury level T1-L2) completed the following questionnaires: Wheelchair Users Shoulder Pain Index, Subjective Quality of Life Scale, Physical Activity Scale for Individuals with Physical Disabilities, and Community Activities Checklist. Correlations between shoulder pain scores and quality of life, physical activity, and community activities were determined using Spearmans rho test. Results: Shoulder pain intensity was inversely related to subjective quality of life (rs=-0.35; P=0.002) and physical activity (rs =-0.42; P < 0.001). Shoulder pain intensity was not related to involvement in community activities (rs = -0.07; P= 0.526). Conclusions: Persons with SCI who reported lower subjective quality of life and physical activity scores experienced significantly higher levels of shoulder pain. However, shoulder pain intensity did not relate to involvement in general community activities. Attention to and interventions for shoulder pain in persons with SCI may improve their overall quality of life and physical activity.

Electromyographic analysis of the shoulder muscles during depression transfers in subjects with low-level paraplegia

OBJECTIVE To document and compare the intensity of selected shoulder muscle activity during depression transfers. DESIGN Intramuscular electrodes were used to record the activity of 12 shoulder muscles while transferring to and from a wheelchair. PARTICIPANTS Twelve adult men with spinal cord injuries resulting in low paraplegia. OUTCOME MEASURES Three phases of the transfer were analyzed: preparation, lift, and descent. Median intensities were compared between muscles, transfer phase, and direction of transfer using Freidmans test. RESULTS Trunk elevation was accomplished mainly by sternal pectoralis major and latissimus dorsi activity. Lateral body displacement required other muscles to control the elevated body. Rotator cuff muscles contributed to shift mechanics and, together with anterior deltoid, provided anterior glenohumeral wall protection. Lower serratus anterior stabilized the scapulothoracic articulation and contributed to the lateral movement. CONCLUSIONS Assessment of depression transfer skill should not be based on the ability to lift body weight. Movement of the trunk required vigorous activity of key shoulder musculature. Differences in leading and trailing arm EMG intensities will assist in modifying transfer style in individuals with weakness, strength imbalances, and shoulder pathologies.

Strengthening and Optimal Movements for Painful Shoulders (STOMPS) in Chronic Spinal Cord Injury: A Randomized Controlled Trial

Background Shoulder pain is a common problem after spinal cord injury (SCI), with negative effects on daily activities and quality of life (QOL). Objective The purpose of this study was to determine the effect of an exercise program and instruction to optimize performance of upper-extremity tasks on shoulder pain in people with paraplegia from SCI. Methods/Design Eighty individuals with paraplegia from SCI and shoulder pain were randomly assigned to receive either an exercise/movement optimization intervention or an attention control intervention. The exercise/movement optimization intervention consisted of a 12-week home-based program of shoulder strengthening and stretching exercises, along with recommendations on how to optimize the movement technique of transfers, raises, and wheelchair propulsion. The attention control group viewed a 1-hour educational video. Outcome measures of shoulder pain, muscle strength (force-generating capacity), activity, and QOL were assessed at baseline, immediately after intervention, and 4 weeks later. Results Shoulder pain, as measured with the Wheelchair Users Shoulder Pain Index, decreased to one third of baseline levels after the intervention in the exercise/movement optimization group, but remained unchanged in the attention control group. Shoulder torques, most 36-Item Short-Form Health Survey questionnaire (SF-36) subscale scores, and QOL scores also were improved in the exercise/movement optimization group, but not in the attention control group. Improvements were maintained at the 4-week follow-up assessment. Limitations Many of the outcome measures were self-reported, and the participant dropout rate was high in both groups. Additional studies are needed to determine whether the results of this study can be generalized to individuals with tetraplegia. Conclusions This home-based intervention was effective in reducing long-standing shoulder pain in people with SCI. The reduction in pain was associated with improvements in muscle strength and health-related and overall QOL.