[Isokinetic trunk strength testing in chronic low back pain. The role of habituation and training to improve measures].
Isokinetic dynamometers put subjects in very different conditions from natural movement. Familiarization with the isokinetic device may therefore explain better performance without showing any improvement in strength.


OBJECTIVE
To determine the part of habituation and training in improved trunk isokinetic performance on isometric assessment after a back rehabilitation program for chronic low back pain.


METHODS
A total of 26 patients with chronic low back pain consecutively admitted to the same rehabilitation department for a 4-week rehabilitation program underwent isometric assessment of the trunk flexors and extensors on the day of admission and 2 days and 21 days after admission. The maximal torque and total work were registered at 30 degrees , 90 degrees and 120 degrees/s.


RESULTS
Values for all parameters, except flexor values at 30 degrees/s, were significantly improved between day 0 and day 2 after admission. Between day 2 and day 21 after admission, values for all parameters were improved significantly. Except for flexor values at 30 degrees/s, the parameter values at day 2 showed improvement ranging from 33% to 58% of the improvement seen at day 21.


CONCLUSIONS
The improvement in parameter values found on isokinetic assessment two days after a one-day rehabilitation program for low back pain is probably explained by a habituation effect. We can expect that increase in the maximal torque and total work after 3 weeks of rehabilitation is, at least in part, the consequence of the strengthening program.


CONCLUSIONS
We should interpret with caution the results of studies involving an isokinetic dynamometer to measure the strength of trunk muscles without a learning training.
Urzica
I
I
Service de médecine physique et de réadaptation, centre hospitalier régional universitaire de Lille, rue du Professeur-A.-Verhaeghe, 59037 Lille cedex, France.
Tiffreau
V
V
Popielarz
S
S
Duquesnoy
B
B
Thevenon
A
A
D000009:Abdominal Muscles / Q000502:physiology*; D000328:Adult; D002908:Chronic Disease; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology / Q000534:rehabilitation*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer