ACTIVITY OF THE EXTRINSIC FINGER FLEXORS DURING MOBILIZATION IN THE KLEINERT SPLINT

This study investigated the activity of the extrinsic finger flexor mu scles during active extension in the Kleinert splint. Electromyographi c data on the activity of the profundus and superficialis flexor muscl es in 10 healthy subjects were recorded with use of fine needle electr odes. The subjects exercised in the original Kleinert splint as well a s in several modifications of the splint, which varied with respect to (1) wrist position, (2) position in which extension of the metacarpop halangeal joint was blocked, (3) number of fingers dynamically splinte d, (4) nature of the spring mechanism, (5) amount of resistance, and ( 6) use of a palmar pulley. Persistent flexor muscle activity during ac tive extension was observed in the majority of subjects. This coactivi ty was more often observed for the superficialis muscle than for the p rofundus muscle. The least amount of coactivity was found when extensi on was least resisted. This study does not support the concept that th e flexor muscles relax during resisted extension in the Kleinert splin t.