Table 1.

Anthropometrics and neuromuscular function of the knee extensor muscles

			Young		Old		P value
Variable		Units	Men (6)	Women (7)	Men (6)	Women (6)	Age	Sex	Age × Sex
	Age	years	25.4 ± 4.2	23.5 ± 3.3	76.1 ± 7.4	72.6 ± 5.9	<0.001	0.709	0.204
	Height	cm	178.3 ± 10.2	168.6 ± 3.2	174.5 ± 6.9	163.5 ± 4.4	0.107	<0.001	0.817
	Weight	kg	81.4 ± 18.3	63.1 ± 7.6	77.5 ± 8.2	69.1 ± 10.3	0.831	0.010	0.305
	BMI	kg m−2	25.3 ± 3.0	22.2 ± 2.4	25.5 ± 3.3	25.9 ± 4.0	0.150	0.304	0.187
	Body fat	%	17.2 ± 3.5 (5)	26.0 ± 6.2 (6)	26.7 ± 7.3	38.7 ± 8.3	<0.001	0.001	0.576
	Thigh lean mass	kg	7.8 ± 2.1 (5)	5.7 ± 0.6 (6)	6.2 ± 0.8	4.6 ± 0.5	0.008	0.001	0.524
Knee extensor function
	MVC torque – Absolute	Nm	296.6 ± 62.0 (5)	164.3 ± 30.3 (6)	191.4 ± 44.6	100.8 ± 16.6	<0.001	<0.001	0.234
	MVC torque – Mass specific	Nm kg−1	38.4 ± 5.9 (5)	28.8 ± 3.6 (6)	31.0 ± 5.7	21.9 ± 2.4	0.001	<0.001	0.895
	Power – Absolute	W	342.2 ± 149.0 (5)	211.1 ± 58.0 (6)	139.6 ± 30.2	79.3 ± 14.2	<0.001	0.007	0.283
	Power – Mass specific	W kg−1	42.3 ± 7.3 (5)	36.9 ± 7.3 (6)	22.5 ± 3.0	17.3 ± 2.9	<0.001	0.032	0.968
	Fatigability – Power	% ∆	−26 ± 14 (5)	−17 ± 16 (6)	−36 ± 22 (5)	−38 ± 15	0.045	0.615	0.486

Body fat percentage and lean mass were measured via dual X‐ray absorptiometry. MVC torque was the highest torque output recorded from the MVC attempts in the whole‐muscle function testing session. Mechanical power was the highest average obtained from five sequential contractions of the first 10 contractions performed during the dynamic fatiguing exercise. Mass‐specific torque and power were calculated with the thigh lean mass. The sample size (n) for each cohort is reported in parentheses. A significant age or sex difference is indicated in bold when P < 0.05. Values are the mean ± SD.