Assessing hip abduction and adduction strength: can greater segmental fixation enhance the reproducibility?
OBJECTIVE
To improve the reproducibility of testing hip abduction and adduction using an isokinetic dynamometer by a novel testing protocol.


METHODS
Test-retest design.


METHODS
Biodynamics laboratory.


METHODS
Fifteen healthy subjects (9 men, 6 women; age, 22.4+/-0.5 y) were recruited.


METHODS
Two setups were compared: the first according to manufacturer's guidelines (setup A) and the second a novel setup incorporating pelvic fixation (setup B). Setups A and B were performed in a random order. Both setups included the same battery of isokinetic (30 degrees/s, 60 degrees/s) and isometric tests, and were repeated 1 week later.


METHODS
The peak torque for each abduction and adduction exercise was noted and pelvic motion during testing was recorded.


RESULTS
Setup B significantly (P<.05) reduced transverse pelvic rotation by between 7.5 degrees and 8.0 degrees dependent on test speed. Mean differences for reproducibility of peak torque, ranged from 0.8 to 11.7 Nm. The coefficients of repeatability of both setups were similar, ranging from 21.4 to 56.3 Nm across isokinetic exercises. A similar observation was noted for isometric exercises, with the differences between the coefficients of repeatability ranging from 18.6 to 40.0 Nm.


CONCLUSIONS
Reducing pelvic rotation does not enhance reproducibility of the system and is not related to torque production. Further research is required to determine the optimal test setup.
Laheru
Dhruvkumar
D
Biosurgery and Surgical Technology, Division of Surgery, Oncology and Reproductive Medicine, Faculty of Medicine, Charing Cross Hospital, Imperial College London, UK.
Kerr
Jack C
JC
McGregor
Alison H
AH
D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000295:instrumentation; D005260:Female; D006615:Hip / Q000502:physiology*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results