title: Isokinetic muscle strength of the trunk and bilateral knees in young subjects with lumbar disc herniation.
abstract: METHODS
  Cross-sectional study comparing normal subjects and patients with lumbar disc herniation.
  
  
  OBJECTIVE
  To evaluate trunk and knee muscle strength in patients with L4-L5 and/or L5-S1 disc herniation.
  
  
  BACKGROUND
  Numerous studies have shown that patients with low back pain have weaker trunk muscles. The strength of trunk and knee muscles has not been investigated simultaneously in patients with lumbar disc herniation.
  
  
  METHODS
  Forty-one controls and 2 patients were included. Isokinetic strength of the trunk and bilateral knees was tested on a calibrated isokinetic testing machine (Biodex System 3 Pro) regardless of the laterality of the radiculopathy. The testing was carrying out at two different velocities: 60 degrees and 120 degrees per second.
  
  
  RESULTS
  Total trunk strength and knee strength were significantly lower in these patients (4.34 +/- 1.06 and 4.06 +/- 1.16 vs. 6.21 +/- 1.05 and 5.83 +/- 1.09 Nm/kg at 60 degrees and 120 degrees per second, respectively, P < 0.001). In patients with unilateral sciatica, there was no significant difference (P > 0.05) in unilateral knee strength between sciatica-involved and -uninvolved limbs (1.89 +/- 0.5, 1.08 +/- 0.45, 1.48 +/- 0.58, 0.93 +/- 0.41 vs. 1.68 +/- 0.45, 0.91 +/- 0.38, 1.41 +/- 0.48, 0.79 +/- 0.39 Nm/kg in sciatica-uninvolved vs. sciatica-involved limbs during extension and flexion at 60 degrees and 120 degrees per second, respectively). Total trunk strength was significantly correlated with total knee strength in both groups.
  
  
  CONCLUSIONS
  In the patients with lumbar disc herniation, muscle strength of the trunk and knees was decreased to a similar extent. Weaker knee strength was found on either side of the lower extremity in the patients with unilateral sciatica, regardless of its location.
authors.affiliation: Institute of Aerospace Medicine, Taiwan, Republic of China. cwhodr@yahoo.com.tw
authors.forename: Cheng-Wen
authors.initials: CW
authors.lastname: Ho
authors.forename: Liang-Cheng
authors.initials: LC
authors.lastname: Chen
authors.forename: Hsian-He
authors.initials: HH
authors.lastname: Hsu
authors.forename: Shang-Lin
authors.initials: SL
authors.lastname: Chiang
authors.forename: Min-Hui
authors.initials: MH
authors.lastname: Li
authors.forename: Shuu-Hai
authors.initials: SH
authors.lastname: Jiang
authors.forename: Kao-Chung
authors.initials: KC
authors.lastname: Tsai
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000503:physiopathology*; D007717:Knee; D008159:Lumbar Vertebrae; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology*; D012585:Sciatica / Q000503:physiopathology; D013909:Thorax