title: Passive ankle stiffness in subjects with diabetes and peripheral neuropathy versus an age-matched comparison group.
abstract: OBJECTIVE
  Patients with diabetes mellitus and peripheral neuropathy (DM and PN) often complain of joint stiffness. Although stiffness may contribute to some of the impairments and functional limitations found in these patients, it has not been quantified in this population. The purpose of this study was to quantify and compare passive ankle stiffness and dorsiflexion (DF) range of motion in subjects with DM and PN versus an age-matched comparison group.
  
  
  METHODS
  Thirty-four subjects were tested (17 subjects with DM and PN and 17 subjects in an age-matched comparison group). There were 10 male subjects and 7 female subjects in each group.
  
  
  METHODS
  A Kin-Com dynamometer was used to measure passive plantar flexor torque as each subject's ankle was moved from plantar flexion into dorsiflexion at 60(/s. The following variables were compared using a Student t test: initial angle (angle of onset of plantar flexor torque), maximal dorsiflexion angle, plantar flexor muscle excursion (difference between initial angle and maximal dorsiflexion angle), slope of the first half of the plantar flexor torque curve (stiffness 1 measurement), and slope of the second half of the plantar flexor torque curve (stiffness 2 measurement).
  
  
  RESULTS
  The subjects with DM and PN had smaller maximal dorsiflexion angles and less plantar flexor muscle excursion than the comparison group. There was no difference in initial angle, stiffness 1 measurement, or stiffness 2 measurement.
  
  
  CONCLUSIONS
  Although the subjects with DM and PN had less dorsiflexion range of motion than did the comparison group, there was no difference in stiffness between the groups. This finding suggests that people with DM and PN have "short" versus "stiff" plantar flexor muscles.
authors.affiliation: Department of Biokinesiology and Physical Therapy, University of Southern California, 1540 E Alcazar St, CHP-155, Los Angeles, CA 90089, USA. salsich@hsc.usc.edu
authors.forename: G B
authors.initials: GB
authors.lastname: Salsich
authors.forename: M J
authors.initials: MJ
authors.lastname: Mueller
authors.forename: S A
authors.initials: SA
authors.lastname: Sahrmann
mesh_terms: D000328:Adult; D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D004548:Elasticity; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D015588:Observer Variation; D016059:Range of Motion, Articular / Q000502:physiology*; D013314:Stress, Mechanical; D019415:Torque