title: Comparing passive angle-torque curves recorded simultaneously with a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments.
abstract: The purpose of the present study was to compare the passive angle-torque curves and the passive stiffness (PS, N m °(-)(1)) values recorded simultaneously from a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments in vivo. Nine healthy men (mean ± SD age = 21.4 ± 1.6 years) completed stretch tolerance assessments on a custom-built apparatus where passive torque was measured simultaneously from an isokinetic dynamometer and a load cell. Passive torque values that corresponded with the last 10° of dorsiflexion, verified by surface electromyographic amplitude, were analyzed for each device (θ1, θ2, θ3, …, θ10). Passive torque values measured with the load cell were greater (p ≤ 0.05) than the dynamometer torque values for θ4 through θ10. There were more statistical differentiations among joint angles for passive torque measured by the load cell, and the load cell measured a greater (p ≤ 0.01) increase in passive torque and PS than the isokinetic dynamometer. These findings suggested that when examining the angle-torque curves from passive dorsiflexion stretch tolerance tests, a load cell placed under the distal end of the foot may be more sensitive than the torque recorded from an isokinetic dynamometer.
authors.affiliation: University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Buckner
authors.affiliation: University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
authors.forename: Nathaniel D M
authors.initials: ND
authors.lastname: Jenkins
authors.affiliation: California State University-San Bernardino, San Bernardino, CA 92407, United States.
authors.forename: Pablo B
authors.initials: PB
authors.lastname: Costa
authors.affiliation: University of North Carolina-Chapel Hill, Chapel Hill, NC 27514, United States.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Ryan
authors.affiliation: University of Kansas, Lawrence, KS 66045, United States.
authors.forename: Trent J
authors.initials: TJ
authors.lastname: Herda
authors.affiliation: University of Nebraska-Lincoln, Lincoln, NE 68583, United States. Electronic address: jcramer@unl.edu.
authors.forename: Joel T
authors.initials: JT
authors.lastname: Cramer
mesh_terms: D001696:Biomechanical Phenomena; D004548:Elasticity; D055615:Electrical Equipment and Supplies; D004576:Electromyography; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D019415:Torque; D055815:Young Adult
keywords: Muscle–tendon unit; Passive stiffness; Stretching; Viscoelastic