title: Effects of Lumbosacral Manipulation on Isokinetic Strength of the Knee Extensors and Flexors in Healthy Subjects: A Randomized, Controlled, Single-Blind Crossover Trial.
abstract: OBJECTIVE
  The purpose of this study was to investigate the effect of manual manipulations targeting the lumbar spine and/or sacroiliac joint on concentric knee extension and flexion forces. Torque production was measured during isometric and isokinetic contractions.
  
  
  METHODS
  This was a randomized, controlled, single-blind crossover design with 21 asymptomatic, college-aged subjects who had never received spinal manipulation. During 2 separate sessions, subjects' peak torques were recorded while performing maximal voluntary contractions on an isokinetic dynamometer. Isometric knee extension and flexion were recorded at 60° of knee flexion, in addition to isokinetic measurements obtained at 60°/s and 180°/s. Baseline measurements were acquired before either treatment form of lumbosacral manipulation or sham manipulation, followed by identical peak torque measurements within 5 and 20 minutes posttreatment. Data were analyzed with a repeated measures analysis of variance.
  
  
  RESULTS
  A statistically significant difference did not occur between the effects of lumbosacral manipulation or the sham manipulation in the percentage changes of knee extension and flexion peak torques at 5 and 20 minutes posttreatment. Similar, nonsignificant results were observed in the overall percentage changes of isometric contractions (spinal manipulation 4.0 ± 9.5 vs sham 1.2 ± 6.3, P = .067), isokinetic contractions at 60°/s (spinal manipulation - 4.0 ± 14.2 vs sham - 0.3 ± 8.2, P = .34), and isokinetic contractions at 180°/s (spinal manipulation - 1.4 ± 13.9 vs sham - 5.5 ± 20.0, P = .18).
  
  
  CONCLUSIONS
  The results of the current study suggest that spinal manipulation does not yield an immediate strength-enhancing effect about the knee in healthy, college-aged subjects when measured with isokinetic dynamometry.
authors.affiliation: Exercise Science Doctoral Candidate, College of Education, Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY.
authors.forename: Grant D
authors.initials: GD
authors.lastname: Sanders
authors.affiliation: Professor, College of Health Sciences, Division of Physical Therapy, University of Kentucky, Lexington, KY.
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Nitz
authors.affiliation: Associate Professor, College of Education, Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY.
authors.forename: Mark G
authors.initials: MG
authors.lastname: Abel
authors.affiliation: Assistant Professor, College of Education and Human Development, Department of Health and Sport Sciences, University of Louisville, Louisville, KY.
authors.forename: T Brock
authors.initials: TB
authors.lastname: Symons
authors.affiliation: Professor and Associate Dean for Research and Innovation, College of Education, Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY.
authors.forename: Robert
authors.initials: R
authors.lastname: Shapiro
authors.affiliation: Physician, University Health Service, UK Healthcare, Lexington, KY.
authors.forename: W Scott
authors.initials: WS
authors.lastname: Black
authors.affiliation: Emeritus Faculty, College of Education, Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY.
authors.forename: James W
authors.initials: JW
authors.lastname: Yates
keywords: Knee; Muscle strength; Spinal manipulation