Menstrual Cycle Associated Alteration of Vastus Lateralis Motor Unit Function

Sports Medicine - Open

Table 1 Multilevel model analysis summary for motor unit parameters across three points of the menstrual cycle, at 10% and 25% MVC

	10% MVC			25% MVC
	Beta	95 CI	p value	Beta	95 CI	p value
Firing rate (Hz)
EF v Ov	− 0.804	− 1.206 to − 0.402	< 0.001	0.005	− 0.341 to 0.352	0.976
EF v ML	− 0.855	− 1.255 to − 0.456	< 0.001	− 0.110	− 0.464 to 0.245	0.546
Ov v ML	− 0.051	− 0.432 to 0.330	0.792	− 0.114	− 0.474 to 0.244	0.532
Firing rate variability
EF v Ov	0.005	− 0.002 to 0.010	0.146	− 0.001	− 0.008 to 0.005	0.692
EF v ML	− 0.003	− 0.009 to 0.004	0.376	0.002	− 0.005 to 0.009	0.540
Ov v ML	− 0.007	− 0.013 to − 0.001	0.078	0.003	− 0.003 to 0.010	0.323
MUP area (µV ms)
EF v Ov	− 70.79	− 142 to 0.53	0.059	− 27.64	− 100.8 to 45.6	0.460
EF v ML	32.19	− 39.62 to 104.1	0.381	70.44	− 3.05 to 143.9	0.061
Ov v ML	102.9	35.19 to 170.78	0.003	98.09	23.1 to 173.1	0.031
MUP turns
EF v Ov	0.095	− 0.243 to 0.433	0.582	− 0.031	− 0.255 to 0.193	0.788
EF v ML	0.604	0.264 to 0.944	0.001	0.385	0.159 to 0.610	0.001
Ov v ML	0.509	0.188 to 0.830	0.003	0.415	0.186 to 0.645	0.001
NMJ transmission instability (%)
EF v Ov	0.283	− 1.94 to 2.51	0.804	0.221	− 2.01 to 2.46	0.846
EF v ML	− 1.029	− 3.15 to 1.09	0.345	− 0.475	− 2.85 to 1.35	0.490
Ov v ML	− 1.311	− 3.45 to 0.83	0.688	− 0.966	− 3.15 to 1.22	0.999

Model outputs show unstandardised beta, 95% confidence interval and associated p values
MVC Maximum voluntary contraction, EF Early follicular, Ov Ovulation, ML Mid luteal, MUP Motor unit potential, NMJ Neuromuscular junction
Bold indicates significantly different