title: Force assessment of the stimulated arm flexors: quantification of contractile properties.
abstract: The primary objective was to develop equipment and evaluate protocols for non-invasive assessment of contractile properties of human arm flexors. The research design consisted of a non-randomized control trial, with repeated measures. Data from six males and two females were gathered in a clinical research laboratory. The elbow flexor torque following motor point or direct nerve stimulation was measured in response to single pulses or short trains of electrical pulses. Length--tension relationships were determined; comparative data were obtained at the identified optimal muscle lengths. Twitch waveforms and peak torques following either type of stimulation were reproducible (within 10%). Peak torques following a 4-pulse small interpulse interval stimulation were nearly identical for motor-point activation and direct nerve stimulation (15.2+/- 6.6Nm for motor point stimulation; 14.5 +/- 6.6Nm for nerve stimulation). Average perceived pain indexes associated with 4-pulse stimuli were slightly higher following nerve stimulation (782 for nerve versus 6.23 for motor-point, n=8). A reliable methodology (motor-point stimulation) has been identified to perform stimulated force assessment of human arm flexors.
authors.affiliation: Center for Muscle and Muscle Disorders, Department of Anesthesiology, University of Minnesota, Minneapolis 55455, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Hong
authors.forename: P A
authors.initials: PA
authors.lastname: Iaizzo
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004550:Elbow / Q000294:innervation / Q000502:physiology*; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods*; D004594:Electrophysiology / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D009138:Musculocutaneous Nerve / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods; D011187:Posture; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019415:Torque