Effects of Different Test Positions on Quantitative Muscle Strength of Wrist and Finger Flexor Muscle Groups and Its Standardization.

Objectives: To explore the effects of different test positions on quantitative muscle strength of wrist and finger flexor muscle groups and to establish a standardized muscle strength test protocol for each muscle group.
Methods: Forty healthy subjects (12 males and 28 females) were recruited. A portable digital quantitative muscle strength tester, Micro FET2 ^TM , was used to measure the flexor muscle strength of each finger and the wrist joint at the 30° extension, 0° neutral, and 30° flexion, respectively. Palmar abduction strength of the thumb was measured at 30° and 60°, respectively. Ten subjects were randomly selected from the 40 subjects, and the quantitative muscle strength of each muscle group was tested again by the same operator after an interval of 10 to 15 days.
Results: Except for the fact that in males, there was no significant difference in flexor muscle strength of thumb and wrist joint between 30° of wrist extension and neutral 0° position, the muscle strength of the other fingers flexion and wrist palmar flexor showed the following characteristics：30° of wrist extension > neutral 0° position > 30° of flexion, and the PAST was 30°>60°; The flexor muscle strength of all the subjects was thumb > index finger > middle finger > ring finger > little finger; All muscle strength values of male were greater than those of female, and the difference was statistically significant ( P <0.05); There was no significant difference between the left and right side muscle strength values of all subjects ( P >0.05). The reliability of muscle strength values measured at different times in 10 subjects was good.
Conclusions: The quantitative muscle strength of each muscle group of the hand and wrist is affected by the test position, and a standardized and uniformed test position should be adopted in the actual identification. Micro FET2 ^TM has good reliability for hand and wrist quantitative muscle strength testing. The 30° extension of the wrist can be used as the best standardized test position for the flexion muscle strength of each finger and wrist joint. The 30° position can be used as the best standardized test position for PAST.