. 2019 Aug 21;7:181. doi: 10.3389/fbioe.2019.00181

Table 1.

Neuromuscular function of the wrist flexors depending on the wrist joint angle.

	Wrist joint angle			P-values
	Extension (– 30°)	Neutral (0°)	Flexion (30°)	−30° vs. 0°	−30° vs. 30°	30° vs. 0°
Maximal voluntary torque (N·m)	16.08 ± 2.78	19.17 ± 3.12	18.46 ± 2.46	<0.001^**	0.001^**	0.552
Voluntary activation (%)	98.11 ± 2.65	97.40 ± 3.52	96.06 ± 4.05	0.742	0.005^**	0.055
Central activation ratio (%)	99.21 ± 1.05	99.20 ± 1.01	98.89 ± 1.06	n.a.	n.a.	n.a.
Interpolated twitch torque (N·m)	0.118 ± 0.154	0.149 ± 0.186	0.200 ± 0.191	1	0.039^*	0.186
Control twitch torque (N·m)	6.02 ± 0.93	5.68 ± 0.85	5.17 ± 0.87	0.192	0.002^**	0.017^*
RMS·M⁻¹
Flexor carpi radialis (FCR)	0.088 ± 0.023	0.087 ± 0.030	0.084 ± 0.030	n.a.	n.a.	n.a.
Extensor carpi radialis brevis (ECRB)	0.042 ± 0.018	0.041 ± 0.016	0.046 ± 0.015	n.a.	n.a.	n.a.
ECRB·FCR⁻¹ ratio	0.50 ± 0.24	0.52 ± 0.23	0.62 ± 0.30	1	0.021^*	0.174
M_max (mV)
FCR	9.00 ± 3.03	9.29 ± 2.95	10.63 ± 3.77	1	0.009^**	0.033^*
ECRB	6.98 ± 2.53	6.90 ± 2.05	6.47 ± 2.03	n.a.	n.a.	n.a.
Peak twitch torque (N·m)
SS	1.58 ± 0.34	1.25 ± 0.28	0.98 ± 0.24	<0.001^**	<0.001^**	<0.001^**
PS100	4.01 ± 0.65	3.44 ± 0.66	2.90 ± 0.51	<0.001^**	<0.001^**	<0.001^**
SS_POT	2.99 ± 0.38	2.69 ± 0.44	2.29 ± 0.36	0.006^**	<0.001^**	<0.001^**
PS100_POT	6.29 ± 0.99	5.93 ± 0.92	5.40 ± 0.95	0.31	<0.001^**	0.06
Rate of twitch torque development (N·m·s^–1)
SS	23.16 ± 4.27	18.55 ± 3.46	15.63 ± 4.00	<0.001^**	<0.001^**	0.032^*
PS100	52.32 ± 9.22	47.10 ± 8.76	40.40 ± 7.12	0.009^**	<0.001^**	0.001^**
SS_POT	53.42 ± 8.91	50.30 ± 7.84	45.01 ± 7.11	0.46	0.001^**	0.067
PS100_POT	86.32 ± 14.74	85.98 ± 12.68	83.27 ± 15.70	n.a.	n.a.	n.a.
Rate of twitch torque relaxation (N·m·s^–1)
SS	12.77 ± 3.05	11.09 ± 2.94	9.65 ± 2.87	0.009^**	0.001^**	0.016^*
PS100	31.60 ± 5.44	30.68 ± 5.35	29.30 ± 5.93	n.a.	n.a.	n.a.
SS_POT	30.01 ± 4.15	30.37 ± 4.05	27.91 ± 4.64	n.a.	n.a.	n.a.
PS100_POT	52.15 ± 9.71	56.36 ± 6.86	57.76 ± 7.94	0.114	0.038^*	1
Electromechanical delay (ms)
SS	9.04 ± 0.82	9.80 ± 1.03	11.61 ± 2.65	0.009^**	0.004^**	0.017^*
PS100	9.11 ± 0.78	9.87 ± 1.07	11.70 ± 2.55	0.004^**	0.002^**	0.008^**
SS_POT	8.56 ± 0.96	8.94 ± 0.85	10.72 ± 1.63	0.556	<0.001^**	<0.001^**
PS100_POT	8.22 ± 1.18	9.22 ± 1.03	10.67 ± 1.70	0.073	<0.001^**	0.001^**
Twitch contraction time (ms)
SS	68.24 ± 5.27	67.31 ± 5.29	63.41 ± 8.49	1	0.029^*	0.211
PS100	77.09 ± 5.85	73.02 ± 3.98	71.94 ± 5.61	<0.001^**	0.002^**	0.757
SS_POT	56.56 ± 6.18	53.61 ± 4.98	51.78 ± 8.97	0.173	0.074	0.701
PS100_POT	73.06 ± 4.01	69.06 ± 5.15	65.44 ± 6.52	0.003^**	<0.001^**	0.036^*
Twitch half-relaxation time (ms)
SS	63.17 ± 9.92	57.63 ± 7.67	51.97 ± 6.94	0.019^*	0.002^**	0.010^**
PS100	63.96 ± 7.64	56.09 ± 5.52	50.09 ± 7.08	0.001^**	<0.001^**	0.001^**
SS_POT	50.33 ± 7.10	44.78 ± 8.50	41.67 ± 6.19	<0.001^**	<0.001^**	0.406
PS100_POT	61.00 ± 7.13	52.72 ± 6.23	46.72 ± 5.01	<0.001^**	<0.001^**	<0.001^**
Percentage changes peak twitch torque
SS vs. SS_POT	92.84 ± 27.71	119.59 ± 34.52	142.88 ± 49.17	<0.001^**	<0.001^**	0.111
PS100 vs. PS100_POT	57.82 ± 15.44	75.75 ± 26.12	88.74 ± 28.77	0.010^**	0.002^**	0.189
SS vs. PS100	158.89 ± 47.04	180.52 ± 54.37	205.49 ± 60.15	0.013^*	<0.001^**	0.002^**
SS_POT vs. PS100_POT	111.23 ± 26.52	122.66 ± 28.02	136.56 ± 31.61	0.074	<0.001^**	0.063

Please note that post-hoc comparisons are only available if the ANOVA with repeated measures indicated a statically significant difference (P-values in bold are significant,

P ≤ 0.050,

^**

P ≤ 0.010). n. a., not applicable because the ANOVA did not indicate a main effect of angle; RMS·M⁻¹, root mean square of the EMG signal normalized to the maximal M-wave (M_max); SS, unpotentiated peak twitch torque evoked by a single stimulus; PS100, unpotentiated peak twitch torque evoked by paired stimuli at 100 Hz [inter-stimulus interval (ISI) 10 ms]; SS_POT, potentiated peak twitch torque evoked by a single stimulus; PS100_POT, potentiated peak twitch torque evoked by paired stimuli at 100 Hz (ISI 10 ms). Values are expressed as means ± standard deviations.