Isokinetic muscle strength of the trunk and bilateral knees in young subjects with lumbar disc herniation.
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.
Ho
Cheng-Wen
CW
Institute of Aerospace Medicine, Taiwan, Republic of China. cwhodr@yahoo.com.tw
Chen
Liang-Cheng
LC
Hsu
Hsian-He
HH
Chiang
Shang-Lin
SL
Li
Min-Hui
MH
Jiang
Shuu-Hai
SH
Tsai
Kao-Chung
KC
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