A Clinical Practice Guideline for the Use of Ankle-Foot Orthoses and Functional Electrical Stimulation Post-Stroke.

BACKGROUND: Level of ambulation following stroke is a long-term predictor of participation and disability. Decreased lower extremity motor control can impact ambulation and overall mobility. The purpose of this clinical practice guideline (CPG) is to provide evidence to guide clinical decision-making for the use of either ankle-foot orthosis (AFO) or functional electrical stimulation (FES) as an intervention to improve body function and structure, activity, and participation as defined by the International Classification of Functioning, Disability and Health (ICF) for individuals with poststroke hemiplegia with decreased lower extremity motor control. METHODS: A review of literature published through November 2019 was performed across 7 databases for all studies involving stroke and AFO or FES. Data extracted included time post-stroke, participant characteristics, device types, outcomes assessed, and intervention parameters. Outcomes were examined upon initial application and after training. Recommendations were determined on the basis of the strength of the evidence and the potential benefits, harm, risks, or costs of providing AFO or FES. RESULTS/DISCUSSION: One-hundred twenty-two meta-analyses, systematic reviews, randomized controlled trials, and cohort studies were included. Strong evidence exists that AFO and FES can each increase gait speed, mobility, and dynamic balance. Moderate evidence exists that AFO and FES increase quality of life, walking endurance, and muscle activation, and weak evidence exists for improving gait kinematics. AFO or FES should not be used to decrease plantarflexor spasticity. Studies that directly compare AFO and FES do not indicate overall superiority of one over the other. But evidence suggests that AFO may lead to more compensatory effects while FES may lead to more therapeutic effects. Due to the potential for gains at any phase post-stroke, the most appropriate device for an individual may change, and reassessments should be completed to ensure the device is meeting the individual's needs. LIMITATIONS: This CPG cannot address the effects of one type of AFO over another for the majority of outcomes, as studies used a variety of AFO types and rarely differentiated effects. The recommendations also do not address the severity of hemiparesis, and most studies included participants with varied baseline ambulation ability. SUMMARY: This CPG suggests that AFO and FES both lead to improvements post-stroke. Future studies should examine timing of provision, device types, intervention duration and delivery, longer term follow-up, responders versus nonresponders, and individuals with greater impairments. DISCLAIMER: These recommendations are intended as a guide for clinicians to optimize rehabilitation outcomes for people with poststroke hemiplegia who have decreased lower extremity motor control that impacts ambulation and overall mobility.A Video Abstract is available as supplemental digital content from the authors (available at: http://links.lww.com/JNPT/A335).

Bone Mineral Density Testing in Spinal Cord Injury: 2019 ISCD Official Position.

Spinal cord injury (SCI) causes rapid osteoporosis that is most severe below the level of injury. More than half of those with motor complete SCI will experience an osteoporotic fracture at some point following their injury, with most fractures occurring at the distal femur and proximal tibia. These fractures have devastating consequences, including delayed union or nonunion, cellulitis, skin breakdown, lower extremity amputation, and premature death. Maintaining skeletal integrity and preventing fractures is imperative following SCI to fully benefit from future advances in paralysis cure research and robotic-exoskeletons, brain computer interfaces and other evolving technologies. Clinical care has been previously limited by the lack of consensus derived guidelines or standards regarding dual-energy X-ray absorptiometry-based diagnosis of osteoporosis, fracture risk prediction, or monitoring response to therapies. The International Society of Clinical Densitometry convened a task force to establish Official Positions for bone density assessment by dual-energy X-ray absorptiometry in individuals with SCI of traumatic or nontraumatic etiology. This task force conducted a series of systematic reviews to guide the development of evidence-based position statements that were reviewed by an expert panel at the 2019 Position Development Conference in Kuala Lumpur, Malaysia. The resulting the International Society of Clinical Densitometry Official Positions are intended to inform clinical care and guide the diagnosis of osteoporosis as well as fracture risk management of osteoporosis following SCI.

Musculoskeletal Effects of 2 Functional Electrical Stimulation Cycling Paradigms Conducted at Different Cadences for People With Spinal Cord Injury: A Pilot Study.

OBJECTIVE: To compare the musculoskeletal effects of low cadence cycling with functional electrical stimulation (FES) with high cadence FES cycling for people with spinal cord injury (SCI). DESIGN: Randomized pre-post design. SETTING: Outpatient rehabilitation clinic. PARTICIPANTS: Participants (N=17; 14 men, 3 women; age range, 22-67y) with C4-T6 motor complete chronic SCI were randomized to low cadence cycling (n=9) or high cadence cycling (n=8). INTERVENTIONS: Low cadence cycling at 20 revolutions per minute (RPM) and high cadence cycling at 50 RPM 3 times per week for 6 months. Cycling torque (resistance per pedal rotation) increased if targeted cycling cadence was maintained. MAIN OUTCOME MEASURES: Dual-energy x-ray absorptiometry was used to assess distal femur areal bone mineral density, magnetic resonance imaging was used to assess to assess trabecular bone microarchitecture and cortical bone macroarchitecture and thigh muscle volume, and biochemical markers were used to assess bone turnover. It was hypothesized that subjects using low cadence cycling would cycle with greater torque and therefore show greater musculoskeletal improvements than subjects using high cadence cycling. RESULTS: A total of 15 participants completed the study. Low cadence cycling obtained a maximal average torque of 2.9±2.8Nm, and high cadence cycling obtained a maximal average torque of 0.8±0.2Nm. Low cadence cycling showed greater decreases in bone-specific alkaline phosphatase, indicating less bone formation (15.5% decrease for low cadence cycling, 10.7% increase for high cadence cycling). N-telopeptide decreased 34% following low cadence cycling, indicating decreased resorption. Both groups increased muscle volume (low cadence cycling by 19%, high cadence cycling by 10%). Low cadence cycling resulted in a nonsignificant 7% increase in apparent trabecular number (P=.08) and 6% decrease in apparent trabecular separation (P=.08) in the distal femur, whereas high cadence cycling resulted in a nonsignificant (P>.3) 2% decrease and 3% increase, respectively. CONCLUSIONS: This study suggests that the greater torque achieved with low cadence cycling may result in improved bone health because of decreased bone turnover and improved trabecular bone microarchitecture. Longer-term outcome studies are warranted to identify the effect on fracture risk.

Electrical Stimulation Exercise for People with Spinal Cord Injury: A Healthcare Provider Perspective.

Electrical stimulation exercise has become an important modality to help improve the mobility and health of individuals with spinal cord injury (SCI). Electrical stimulation is used to stimulate peripheral nerves in the extremities to assist with muscle strengthening or functional activities such as cycling, rowing, and walking. Electrical stimulation of the peripheral nerves in the upper extremities has become a valuable tool for predicting the risk of hand deformities and rehabilitating functional grasping activities. The purpose of this paper is to provide healthcare providers perspective regarding the many rehabilitation uses of electrical stimulation in diagnosing and treating individuals with SCI. Electrical stimulation has been shown to improve functional mobility and overall health, decrease spasticity, decrease the risk of cardiometabolic conditions associated with inactivity, and assist in the diagnosis/prognosis of hand deformities in those with tetraplegia. Studies involving non-invasive stimulation of the spinal nerves via external electrodes aligned with the spinal cord and more invasive stimulation of electrodes implanted in the epidural lining of the spinal cord have demonstrated improvements in the ability to stand and enhanced the stepping pattern during ambulation. Evidence is also available to educate healthcare professionals in using functional electrical stimulation to reduce muscle spasticity and to recognize limitations and barriers to exercise compliance in those with SCI. Further investigation is required to optimize the dose-response relationship between electrical stimulation activities and the mobility and healthcare goals of those with SCI and their healthcare providers.

Implementing functional electrical stimulation clinical practice guidelines to support mobility: A stakeholder consultation.

Functional Electrical Stimulation (FES) has been used to support mobility for people with upper motor neuron conditions such as stroke and multiple sclerosis for over 25 years. Recent development and publication of clinical practice guidelines (CPGs) provide evidence to guide clinical decision making for application of FES to improve mobility. Understanding key barriers to the implementation of these CPGs is a critical initial step necessary to create tailored knowledge translation strategies. A public involvement and engagement consultation was conducted with international stakeholders including researchers, clinicians and engineers working with FES to inform implementation strategies for CPG use internationally. Reflexive thematic analysis of the consultation transcripts revealed themes including inconsistent use of CPGs, barriers to implementation such as limited access to FES and low clinician confidence, and the need for a tiered education approach with ongoing support. Insights derived from this consultation will inform the development of knowledge translation strategies to support the next steps to implementing FES use for mobility.

Effects of a supported speed treadmill training exercise program on impairment and function for children with cerebral palsy.

AIM: To compare the effects of a supported speed treadmill training exercise program (SSTTEP) with exercise on spasticity, strength, motor control, gait spatiotemporal parameters, gross motor skills, and physical function. METHOD: Twenty-six children (14 males, 12 females; mean age 9y 6mo, SD 2y 2mo) with spastic cerebral palsy (CP; diplegia, n=12; triplegia, n=2; quadriplegia n=12; Gross Motor Function Classification System levels II-IV) were randomly assigned to the SSTTEP or exercise (strengthening) group. After a twice daily, 2-week induction, children continued the intervention at home 5 days a week for 10 weeks. Data collected at baseline, after 12-weeks' intervention, and 4 weeks after the intervention stopped included spasticity, motor control, and strength; gait spatiotemporal parameters; Gross Motor Function Measure (GMFM); and Pediatric Outcomes Data Collection Instrument (PODCI). RESULTS: Gait speed, cadence, and PODCI global scores improved, with no difference between groups. No significant changes were seen in spasticity, strength, motor control, GMFM scores, or PODCI transfers and mobility. Post-hoc testing showed that gains in gait speed and PODCI global scores were maintained in the SSTTEP group after withdrawal of the intervention. INTERPRETATION: Although our hypothesis that the SSTTEP group would have better outcomes was not supported, results are encouraging as children in both groups showed changes in function and gait. Only the SSTTEP group maintained gains after withdrawal of intervention.

Muscle changes following cycling and/or electrical stimulation in pediatric spinal cord injury.

OBJECTIVE: To determine the effect of cycling, electrical stimulation, or both, on thigh muscle volume and stimulated muscle strength in children with spinal cord injury (SCI). DESIGN: Randomized controlled trial. SETTING: Children's hospital specializing in pediatric SCI. PARTICIPANTS: Children (N=30; ages, 5-13y) with chronic SCI. INTERVENTIONS: Children were randomly assigned to 1 of 3 interventions: functional electrical stimulation cycling (FESC), passive cycling (PC), and noncycling, electrically stimulated exercise (ES). Each group exercised for 1 hour, 3 times per week for 6 months at home. MAIN OUTCOME MEASURES: Preintervention and postintervention, children underwent magnetic resonance imaging to assess muscle volume, and electrically stimulated isometric muscle strength testing with the use of a computerized dynamometer. Data were analyzed via analyses of covariance (ANCOVA) with baseline measures as covariates. Within-group changes were assessed via paired t tests. RESULTS: All 30 children completed the training. Muscle volume data were complete for 24 children (8 FESC, 8 PC, 8 ES) and stimulated strength data for 27 children (9 per group). Per ANCOVA, there were differences between groups (P<.05) for quadriceps muscle volume and stimulated strength, with the ES group having greater changes in volume and the FESC group having greater changes in strength. Within-group analyses showed increased quadriceps volume and strength for the FESC group and increased quadriceps volume for the ES group. CONCLUSIONS: Children receiving either electrically stimulated exercise experienced changes in muscle size, stimulated strength, or both. These changes may decrease their risk of cardiovascular disease, insulin resistance, glucose intolerance, and type 2 diabetes. CLINICAL TRIALS REGISTRATION NUMBER: NCT00245726.

Characterizing Cycling Smoothness and Rhythm in Children With and Without Cerebral Palsy.

Stationary cycling is a practical exercise modality in children with cerebral palsy (CP) that lack the strength for upright exercises. However, there is a lack of robust, sensitive metrics that can quantitatively assess the motor control during cycling. The purpose of this brief report was to characterize the differences in motor control of cycling in children with CP and with typical development by developing novel metrics to quantify cycling smoothness and rhythm. Thirty one children with spastic diplegic CP and 10 children with typical development cycled on a stationary cycle. Cycling smoothness was measured by cross-correlating the crank angle with an ideal cycling pattern generated from participant-specific cadence and cycling duration. Cycling rhythmicity was assessed by evaluating the revolution-to-revolution variability in the time required to complete a revolution. Statistically significant differences (p < 0.001) using the Wilcoxon Rank Sum test were found between the two groups for both the metrics. Additionally, decision tree analysis revealed thresholds of smoothness <0.01 and rhythm <0.089-0.115 s for discriminating a less smooth, irregular cycling pattern characteristic of CP from typical cycling. In summary, the objective measures developed in this study indicate significantly less smoothness and rhythm of cycling in children with CP compared to children with typical development, suggestive of altered coordination and poor motor control. Such quantitative assessments of cycling motion in children with CP provide insights into neuromotor deficits that prevent them from cycling at intensities required for aerobic benefits and for participating in cycling related physical activities with their peers.

Risk Factors for Stress Fractures in Female Runners: Results of a Survey.

BACKGROUND: Few studies compare women with and without stress fractures and most focus on younger, elite runners. HYPOTHESIS/PURPOSE: Compare risk factors between female runners with and without a stress fracture history. STUDY DESIGN: Case control. METHODS: An online survey targeting women age ≥18 years was distributed primarily via social media. Questions included demographics, running details, cross training, nutrition, injury history, medical/menstrual history, and medications. Women with stress fracture histories answered questions about location, number, and changes made. Data were compared between groups using t-tests, chi-square tests, or Fisher's exact tests. Multivariable logistic regression models simultaneously investigated associations of multiple factors using backward variable selection. RESULTS: Data from 1648 respondents were analyzed. Mean age was 40 years, and 25.4% reported stress fractures. Significant differences were found between groups for days/week running, mileage/week, running pace, years running, having a coach, cycling or swimming, calorie consumption for activity, other running injuries, medical history, medication/supplement intake, age at menarche, and going ≥6 months without a menstrual period. Odds of having a stress fracture were increased with osteopenia (OR 4.14), shin splints (OR 3.24), tendon injuries (OR 1.49), running >20 miles/week (OR 1.74-1.77) compared to 11-20 miles/week, having a coach (OR 1.86), and cycling (OR 1.15). Women running 11:00-11:59 minutes/mile or slower were less likely to have a stress fracture compared to those running 9:00-9:59 minutes/mile (OR 0.43-0.54). The odds of having a stress fracture were 1.43 times higher for going ≥ 6 months without a menstrual period. Use of calcium, probiotics, and vitamin D increased odds. Post fracture, common changes made were with cross training (49%), mileage (49%), and strength training (35%). CONCLUSIONS: Multiple intrinsic and extrinsic factors were identified for female runners who sustained one or more stress fracture during running. Prospective studies are warranted to infer a cause and effect relationship amongst these variables and stress fracture risk. LEVEL OF EVIDENCE: Level IV.

Perceptions of risk for stress fractures: A qualitative study of female runners with and without stress fracture histories.

OBJECTIVES: To gain insight into perceived factors related to bone health and stress fracture (SF) prevention for female runners and to understand their experiences within the medical community. DESIGN: Cohort qualitative study. SETTING: University health system. PARTICIPANTS: Forty female runners, 20 who had SF histories and 20 age-and-running-distance matched women without SF. MAIN OUTCOME MEASURES: Women participated in audiotaped qualitative semi-structured interviews. For women with a SF history, questions sought their perspectives on factors that they felt contributed to SF, experiences with the medical community, and changes made post SF. For women without a SF history, questions sought perspectives on factors felt important to perceived running-related bone health. RESULTS: Six themes emerged; 1) Previous/Recurrent Musculoskeletal Injuries, 2) Activity Patterns and Training Regimens, 3) Nutrition, 4) Prevention and Intervention, 5) Pain, and 6) Mindset. Within these themes, between group differences are characterized by differences in knowledge and/or application of knowledge for health and wellness. Compared to women without SF, women with SF histories increased training load more quickly, had poorer nutrition, performed less cross-training, and kept running despite pain. CONCLUSIONS: More education is needed for female runners to decrease risks for SF.

Physiological Factors of Female Runners With and Without Stress Fracture Histories: A Pilot Study.

BACKGROUND: Female runners are at increased risk of stress fractures (SFs) compared with men. Literature is lacking with regard to best practice for preventing and treating SFs in women. The purpose of the study was to compare physiological measures and running-related factors between women of various ages and running abilities with and without a history of running-related SFs. HYPOTHESIS: Women with and without SF histories will differ with regard to medical and menstrual history, bone health, body composition, nutrition, and running history. STUDY DESIGN: Prospective cohort study. LEVEL OF EVIDENCE: Level 2. METHODS: A total of 20 female runners with SF histories were matched based on age and running distance with 20 women without SF histories. Data included medical, menstrual, running, injury, and nutritional histories; blood histology related to nutritional, hormonal, and bone-related risk factors; and bone density, fat, and lean tissue using dual energy x-ray absorptiometry. Paired t tests were used to examine differences between women with and without SF histories, and Spearmen correlations were conducted to examine relationships between physiological factors. RESULTS: Women with SF histories had lower hip bone mineral density compared with women without SF histories (P < 0.05). SF history was moderately correlated with menstrual changes during increased training times (r = 0.580; P < 0.0001) but was not correlated with any other physiological factor. There was a moderate correlation within the SF group (r = 0.65; P = 0.004) for bone markers for resorption and formation both increasing, indicating increased bone turnover. CONCLUSION: Female runners with low hip bone mineral density, menstrual changes during peak training, and elevated bone turnover markers may be at increased risk of SF. CLINICAL RELEVANCE: Female runners need routine screening for risks associated with SF occurrence. As bone mineral density and bone turnover markers are not routinely assessed in this population, important risk factors may be missed.

A randomized controlled trial on the effects of cycling with and without electrical stimulation on cardiorespiratory and vascular health in children with spinal cord injury.

OBJECTIVE: To examine the cardiorespiratory/vascular effects of cycling with and without functional electrical stimulation (FES) in children with spinal cord injury (SCI). DESIGN: Randomized controlled trial. SETTING: Pediatric referral hospital. PARTICIPANTS: Children with SCI (N=30), ages 5 to 13 years, with injury levels from C4 to T11, and American Spinal Injury Association grades A, B, or C. INTERVENTIONS: Children were randomly assigned to 1 of 3 groups: FES leg cycling exercise, passive leg cycling, or noncycling control group receiving electrical stimulation therapy. After receiving instruction on the use of the equipment, children exercised for 1 hour 3 times per week for 6 months at home with parental supervision. MAIN OUTCOME MEASURES: Oxygen uptake (Vo(2)) during an incremental arm ergometry test, resting heart rate, forced vital capacity, and a fasting lipid profile. RESULTS: There were no differences (P>.05) between groups after 6 months of exercise when comparing pre- and postvalues. However, there were differences between groups for some variables when examining percent change. The FES cycling group showed an improvement (P=.035) in Vo(2) (16.2%+/-25.0%) as compared with the passive cycling group (-28.7%+/-29.1%). For lipid levels, the electrical stimulation-only group showed declines (P=.032) in cholesterol levels (-17.1%+/-8.5%) as compared with the FES cycling group (4.4%+/-20.4%). CONCLUSIONS: Cycling with FES led to gains in Vo(2), whereas electrical stimulation alone led to improvements in cholesterol.

Impact of cycling on hip subluxation in children with spinal cord injury.

BACKGROUND: Hip subluxation is common in children with spinal cord injury, especially in those younger than 10 years. The effects of standing with functional electrical stimulation (FES) on hip subluxation have been studied in these children. However, FES cycling is now available to children with spinal cord injury, but the effect of this intervention on hip subluxation has not been studied. METHODS: Hip migration indices were measured before and after a 6-month program of FES cycling, passive cycling, or electrical stimulation exercise without cycling performed 3 times per week. During cycling, children were positioned to avoid hip adduction and internal rotation to decrease potential stress on the hip. RESULTS: There were no changes in the hip migration indices for children in any group after participating in the study. CONCLUSIONS: These findings suggest that the 3 interventions used in this study may be safe for the hip, provided that the hips are positioned to avoid adduction and internal rotation while cycling. LEVEL OF EVIDENCE: Randomized controlled trial, level 2.

The effects of a shank guide on cycling biomechanics of an adolescent with cerebral palsy: a single-case study.

OBJECTIVE: To examine 3-dimensional lower-extremity joint kinematics and muscle activity during cycling with and without a shank guide for a single subject with spastic diplegic cerebral palsy (CP). DESIGN: Single case. SETTING: Pediatric referral hospital. PARTICIPANT: A 13-year-old adolescent with spastic diplegic CP and limited ambulation abilities. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Kinematic data were collected for 6 joint motions and electromyographic data for 7 muscles during 10- to 15-second trials. Average variability in the kinematic curves was calculated, and kinematic and electromyographic data were analyzed descriptively. RESULTS: With the guide, the subject cycled at 40.1+/-2.0 rpm compared with 13.7+/-4.0 rpm without it. In addition, there was less variability in the kinematic curves (P=.03) and muscles tended to turn on sooner and off later. These results indicate that this subject could cycle faster with the guide, which is desirable for cardiovascular health, and that there was a possible increase in motor control due to reduced needs to control excessive joint motions. CONCLUSIONS: Based on these findings, a shank guide may allow some people with CP to cycle faster and provide improved joint kinematics.

The effectiveness of progressively increasing stimulation frequency and intensity to maintain paralyzed muscle force during repetitive activation in persons with spinal cord injury.

OBJECTIVE: To compare the effectiveness of progressively increasing stimulation intensity, progressively increasing frequency, or progressively increasing both frequency and intensity on paralyzed quadriceps femoris muscle force maintenance during repetitive activation. DESIGN: Factorial design with different stimulation protocols as independent variables. SETTING: A muscle performance laboratory. PARTICIPANTS: People (N=8) with spinal cord injury (SCI) (age, 14.63+/-1.77y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Number of contractions when the peak force was 90% or more of a subject's maximal twitch force. RESULTS: The protocol involving progressively increasing stimulation intensity and then frequency generated more successful contractions (189.88+/-53.33) than progressively increasing the frequency followed by intensity (122.75+/-26.56 contractions). Regardless of the order, progressively increasing both intensity and frequency generated more successful contractions than progressively increasing intensity (97 contractions) or frequency (62 contractions) alone. CONCLUSIONS: Our findings suggest that during repetitive electric activation, progressively increasing both stimulation frequency and intensity can produce more successful contractions than progressively increasing only frequency or intensity. These findings can help researchers and clinicians design more effective stimulation protocols for persons with SCI during functional electric stimulation applications.

Biomechanics of recumbent cycling in adolescents with cerebral palsy with and without the use of a fixed shank guide.

New stationary cycles can decrease motion in the frontal and transverse planes with a shank guide. However, there are no studies comparing cycling with and without this guide. The purpose of this study was to compare cycling with and without a shank guide for adolescents with cerebral palsy (CP). Three males and seven females (15.6+/-1.8 years) with CP, classified as levels III and IV with the Gross Motor Functional Classification System, underwent biomechanical analysis of stationary recumbent cycling with and without a shank guide at 30 and 60 rpm if able. Data collected included three-dimensional lower extremity joint kinematics using motion analysis, surface electromyography of eight lower extremity muscles, cocontraction of six agonist/antagonist pairings, efficiency (power output divided by oxygen consumption), and perceived exertion (OMNI Scale of Perceived Exertion). Non-circular data were analyzed via ANOVAs, and circular data were analyzed using circular t-tests. The shank guide altered joint kinematics in all three planes (p<0.008), had a minor impact on muscle activity (p<0.006), and had no impact on cocontraction (p>0.008), efficiency (p=0.920), or perceived exertion (p=0.318). The results suggest that a shank guide during cycling may be beneficial for individuals with CP to decrease the amount of hip and knee frontal and transverse plane motion. Knee movement in these planes has been associated with pain in healthy adults; therefore the guide may help to prevent long-term complications from cycling for adolescents with CP.

Lower extremity muscle activity during cycling in adolescents with and without cerebral palsy.

BACKGROUND: In individuals with cerebral palsy, adaptation and plasticity in the neuromuscular system can lead to detrimental changes affecting gait. Cycling may be an effective method to improve mobility. The biomechanics of cycling in adolescents with cerebral palsy have been studied, but further analysis of the frequency and amplitude characteristics of the electromyographic signals can assist with interpretation of the cycling kinematics. METHODS: Data were analyzed from 10 adolescents with typical development (mean=14.9, SD=1.4 years) and 10 adolescents with cerebral palsy (mean=15.6, SD=1.8 years) as they cycled at two different cadences. Analyses of the lower extremity electromyographic signals involved frequency and amplitude analysis across the cycling revolution. FINDINGS: Examination of cycling cadence revealed that adolescents with cerebral palsy had altered electromyographic characteristics in comparison to adolescents with typical development across the entire crank revolution for all muscles. Analyses of individual muscles indicated both inappropriate muscle activation and weakness. INTERPRETATION: A more comprehensive analysis of electromyographic activity has the potential to provide insight into how a task is accomplished. In this study, the control of the several muscles, especially the rectus femoris, was significantly different in adolescents with cerebral palsy. This, combined with muscle weakness, may have contributed to the observed deviations in joint kinematics. Interventions that increase muscle strength with feedback to the nervous system about appropriate activation timing may be beneficial to allow individuals with cerebral palsy to cycle more efficiently.

Differences in pedal forces during recumbent cycling in adolescents with and without cerebral palsy.

BACKGROUND: We showed that subjects with cerebral palsy had greater transverse and frontal plane hip and knee motion, increased duration of muscle activity, increased cocontraction, and decreased efficiency during recumbent cycling than subjects with typical development. However, it is also important to understand the forces exerted on the pedals. The purpose of this report was to compare pedal forces during cycling between adolescents with and without cerebral palsy. METHODS: Ten subjects (3 male, 7 female) with spastic diplegic or quadriplegic cerebral palsy (15.6 years, SD 1.8) and 10 subjects (3 male, 7 female) with typical development (14.9 years, SD 1.4) cycled on a stationary recumbent cycle at 30 and 60 revolutions per minute if able. Three-dimensional piezoelectric force transducers measured pedal forces. Data were analyzed using two-way ANOVAs. FINDINGS: Subjects with cerebral palsy spent a smaller percentage (P<.001, r2=.09, power=1.0) of the revolution applying positive force (pushing into the pedal during the extension phase) and a greater percentage (P<.001, r2=.09, power=1.0) of the revolution applying negative force (pulling away from the pedal during the flexion phase). There was no effect of cadence and no interaction effect. INTERPRETATION: These findings compliment our earlier findings of altered joint kinematics and muscle activity indicating that subjects with cerebral palsy and typical development have different cycling strategies. Methods to increase the duration of the positive force may allow subjects with CP to cycle more successfully and cycle vigorously enough to reach a heart rate necessary for improving fitness.

Examination of spasticity of the knee flexors and knee extensors using isokinetic dynamometry with electromyography and clinical scales in children with spinal cord injury.

BACKGROUND/OBJECTIVE: To examine the role of reflex activity in spasticity and the relationship between peak passive torque, Ashworth Scale (AS), and Spasm Frequency Scale (SFS) of the knee flexors and extensors during the measurement of spasticity using an isokinetic dynamometer in children with spinal cord injury (SCI). METHODS: Eighteen children with chronic SCI and 10 children of typical development (TD) participated. One set of 10 passive movements was completed using an isokinetic dynamometer at 15, 90, and 180 degrees per second (deg/s) while surface electromyographic data were collected from the vastus lateralis (VL) and medial hamstrings (MH). Spasticity was clinically assessed using the AS and SFS. RESULTS: There were no significant differences in peak passive torque of the knee flexors and extensors at any velocity for children with SCI compared to children with TD. Children with TD demonstrated significantly more reflex activity of the MH during the assessment of knee flexor spasticity at all movement velocities than did children with SCI. Children with TD demonstrated significantly more reflex activity of the VL during the assessment of knee-extensor spasticity with movements at 180 deg/s. The relationship between peak passive torque, AS, and SFS was significant during movements at a velocity of 90 deg/s only. CONCLUSIONS: The role of increased reflexes in spasticity needs further examination. Isokinetic dynamometry may be measuring a different aspect of spasticity than the AS and SFS do in children with SCI.