Introduction: Quantification of muscle strength is an essential component of assessment
and treatment in rehabilitation. Considering the measurement of the muscle strength,
mostly two methods are used. They are qualitative and quantitative measures. Maximum
voluntary isometric contraction (MVIC), measured using dynamometer and manual muscle
testing (MMT) are the most common measurement techniques used in the clinical and
research setting. Objectives: This study's aim was to observe, if greater activity
is produced using mechanical instruments for torque measurements (since the resistance
is adjusted to subject's maximum capacity) or if tests, position of MMT, and resistance
offered by trained physiotherapist are effective. We compared the IEMG (Integrated
electromyography) output between manual and mechanical testing during maximal voluntary
isometric contraction. Subjects and Methods: Forty normal healthy subjects including
20 males and 20 females were selected for the study. The measuring system comprises
an EMG (Noraxon USA, INC, Scottsdale, Arizona) and ®HUR 5340 (Kokkola, Finland) leg
extension/curl computer controlled machine for isometric evaluating peak torque. MVIC
of the Vastus medialis oblique (VMO), Vastus lateralis (VL), Rectus femoris (RF),
Semitendinosis (ST) and Biceps Femoris (BF) were measured from dominant leg using
SEMG and then subjects were seated on HUR with hip flexed and chest, pelvis, thigh
stabilized. The axis of rotation of HUR aligned with the joint axis and moment arm
is fixed for every subject. Each subject performed maximal contraction of 10sec at
60°of test angle to get the peak torque and myoelectrical activity are also recorded
while performing the same. Result: Paired t-test analysis were used to see the difference
between MMT and HUR IEMG amplitude and the results show significance difference(p<
.05) for each muscle when comparing between the EMG amplitude between MMT and HUR.
Conclusion: HUR system has very good reliability in measuring muscle strength of the
knee extensors and flexors as compared to the MMT, suggesting that it will be useful
in clinical applications, especially for professional athletes or physically powerful
populations.
Key-words:
Muscle strength - IEMG - Isometric contraction
