myochronoscope

my·o·chron·o·scope

(mī'ō-kron'ō-skōp),
An instrument for timing a muscular impulse, that is, the interval between the application of the stimulus and the muscular movement in response.
[myo- + G. chronos, time, + skopeō, to examine]

myochronoscope

(mī″ō-krō′nō-skōp) [″ + chronos, time, + skopein, to examine]
Device used for timing a muscular contraction.