title: Adaptive response of human tendon to paralysis.
abstract: To gain insight into the adaptive response of human tendon to paralysis, we compared the mechanical properties of the in vivo patellar tendon in six men who were spinal cord-injured (SCI) and eight age-matched, able-bodied men. Measurements were taken by combining dynamometry, electrical stimulation, and ultrasonography. Tendon stiffness and Young's modulus, calculated from force-elongation and stress-strain curves, respectively, were lower by 77% (P < 0.01) and 59% (P < 0.05) in the SCI than able-bodied subjects. The cross-sectional area (CSA) of the tendon was 17% smaller (P < 0.05) in the SCI subjects, but there was no difference in tendon length between the two groups. Our results indicate that paralysis causes substantial deterioration of the structural and material properties of tendon. This needs to be taken into consideration in the design of electrical stimulation protocols for rehabilitation and experimental purposes, and when interpreting changes in the contractile speed of paralyzed muscle.
authors.affiliation: Institute for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, Alsager ST7 2HL, United Kingdom. c.n.maganaris@mmu.ac.uk
authors.forename: Constantinos N
authors.initials: CN
authors.lastname: Maganaris
authors.forename: Neil D
authors.initials: ND
authors.lastname: Reeves
authors.forename: Joern
authors.initials: J
authors.lastname: Rittweger
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Sargeant
authors.forename: David A
authors.initials: DA
authors.lastname: Jones
authors.forename: Karin
authors.initials: K
authors.lastname: Gerrits
authors.forename: Arnold
authors.initials: A
authors.lastname: De Haan
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D004558:Electric Stimulation; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D010243:Paralysis / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000150:complications; D013710:Tendons / Q000503:physiopathology* / Q000648:ultrastructure; D014463:Ultrasonography