Table 1.

Initial, post-tetanic, and postfatigue EMG and contractile properties

Parameter	Initial	Post-tetanic	Post-fatigue
EMG latency (ms)	10.3	10.8	10.7*
	8.6–15.3	8.6–15.3	8.9–15.3
EMG duration (ms)	10.9	12.1	12.6*
	5.0–17.0	5.0–17.7	5.9–16.7
EMG amplitude (μV)	48.2	58.6	67.4*
	8.1–327.0	8.5–362.0	11.0–351.5
EMG area (μV s)	0.10	0.11	0.18*
	0.01–1.10	0.02–1.23	0.02–1.32
Twitch force (mN)	13.5	14.4	6.4*†
	4.5–69.7	7.5–86.6	1.0–36.2
Twitch contraction time (ms)	58.3	61.8	71.5*
	46.7–102.0	49.6–101.8	33.1–120.7
Twitch half-relaxation time (ms)	56.2	78.9*	104.9*
	41.0–150.0	44.7–275.0	25.5–211.7
Maximum tetanic force (mN)	45.2	—	30.4*
	18.2–269.9		14.3–254.3
Twitch/max tetanic force ratio	0.30	0.41*	0.21*†
	0.11–0.58	0.17–0.59	0.02–0.37
F50 (Hz)	11.3	—	12.3*
	1.0–18.3		8.0–20.4

Values are medians and ranges for 16 units, except for twitch half-relaxation time (n = 13), maximum tetanic force (n = 10) and F₅₀ (n = 10). EMG properties correspond to unit twitch responses. Initial twitch EMG and contractile properties were recorded prior to delivery of any stimuli at tetanic frequencies. Post-tetanic twitch data were recorded after a series of pulse trains at frequencies of 5–100 Hz. Post-fatigue data were recorded after the 2 min fatigue test.

^*P < 0.05 compared to initial value

^†P < 0.05 compared to post-tetanic value.