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Background. Functional outcomes with early rehabilitation in the acute care setting have improved; however, an improved understanding of muscle fatigue using surface electromyography (sEMG) is warranted to better guide patient-centered exercise prescription. Objectives. The objectives of this study were to assess the safety and feasibility of collecting sEMG at the acute care bedside and to determine differences in muscle fatigue during isometric and dynamic submaximal contractions among patients in the hospital, healthy younger participants, and healthy older participants. Design. The study used an observational cohort design. Methods. There were 37 participants. Median frequency ([F.sub.med]) of the myoelectric signal of the quadriceps femoris muscles and time to task failure (TTTF) were measured using sEMG during an isometric and dynamic fatiguing contraction. Primary analysis compared TTTF between groups for both types of contractions. Secondary analysis compared [F.sub.med] at initiation and termination of fatiguing contraction. Results. High-quality sEMG measures were safe and feasible to collect at the acute care bedside with no adverse events. There was a statistically significant difference in TTTF between groups after isometric and dynamic contractions; hospitalized patients fatigued faster than healthy younger and healthy older participants after both contractions. With the exception of the vastus lateralis during a dynamic contraction in healthy younger and hospitalized patients, there was a statistically significant difference between [F.sub.med] at initiation and termination of contraction, indicating that subjects' muscles did truly fatigue. Limitations. A limitation of the study was the small sample size of patients who were hospitalized without matched controls. Conclusions. sEMG is a lab quantitative technique that was found to be safe and feasible to assess muscle fatigue in the acute care environment. The protocol yielded similar results to previously published literature for healthy younger and healthy older people. Further research is needed to better understand how to integrate sEMG findings into patient-centered exercise prescriptions., During an acute care hospitalization, older adults spend 83% of their time in bed. (1) Immobility, in combination with other factors, (2) contributes to hospital-associated deconditioning (HAD), a condition described [...]

Background. Poor control of postural muscles is a primary impairment in people with cerebral palsy (CP). Objective. The purpose of this study was to investigate differences in the timing characteristics of trunk and hip muscle activity during walking in young children with CP compared with children with typical development (TD). Methods. Thirty-one children (16 with TD, 15 with CP) with an average of 28.5 months of walking experience participated in this observational study. Electromyographic data were collected from 16 trunk and hip muscles as participants walked at a self-selected pace. A custom-written computer program determined onset and offset of activity. Activation and coactivation data were analyzed for group differences. Results. The children with CP had greater total activation and coactivation for all muscles except the external oblique muscle and differences in the timing of activation for all muscles compared with the TD group. The implications of the observed muscle activation patterns are discussed in reference to existing postural control literature. Limitations. The potential influence of recording activity from adjacent deep trunk muscles is discussed, as well as the influence of the use of an assistive device by some children with CP. Conclusions. Young children with CP demonstrate excessive, nonreciprocal trunk and hip muscle activation during walking compared with children with TD. Future studies should investigate the efficacy of treatments to reduce excessive muscle activity and improve coordination of postural muscles in CP., Poor control of trunk postural muscles is a primary impairment in people with cerebral palsy (CP). (l-3) To date, the majority of work investigating postural control in CP has done [...]

Background and Purpose. Spasticity is a common impairment in children with cerebral palsy (CP). The purpose of this study was to examine differences in passive resistive torque, reflex activity, coactivation, and reciprocal facilitation during assessments of the spasticity of knee flexor and knee extensor muscles in children with CP and different levels of functional ability. Subjects. Study participants were 20 children with CP and 10 children with typical development (TD). The 20 children with CP were equally divided into 2 groups: 10 children classified in Gross Motor Function Classification Scale (GMFCS) level I and 10 children classified in GMFCS level III. Methods. One set of 10 passive movements between 25 and 90 degrees of knee flexion and one set of 10 passive movements between 90 and 25 degrees of knee flexion were completed with an isokinetic dynamometer at 15°/s, 90°/s, and 180°/s and concurrent surface electromyography of the vastus lateralis and medial hamstring muscles. Results. Children in the GMFCS level III group demonstrated significantly more peak knee flexor torque with passive movements at 180°/s than children with TD. Children in the GMFCS level I and level III groups demonstrated significantly more repetitions with medial hamstring muscle activity, vastus lateralis muscle activity, and co-contraction than children with TD during the assessment of knee flexor spasticity at a velocity of 180°/s. Discussion and Conclusion. Children with CP and more impaired functional mobility may demonstrate more knee flexor spasticity and reflex activity, as measured by isokinetic dynamometry, than children with TD. However, the finding of increased reflex activity with no increase in torque in the GMFCS I group in a comparison with the TD group suggests that reflex activity may play a less prominent role in spasticity., Cerebral palsy (CP) is a heterogeneous collection of nonprogressive motor disorders of the developing brain that may occur antenatally or postnatally up to the age of 2 years. (1) The [...]