Table 1. Muscle activity of the quadriceps femoris (mean value of rectus femoris, vastus lateralis, and medialis) and hamstrings (mean value of biceps femoris and semitendinosus) with vibration peak amplitude of 1.3 mm, 2.6 mm and 3.9 mm at different knee angles (30°, 45° and 60°) according to different frequency groups. Values are presented as a percentage of muscle activity during an isolated MVC (100%). Values are mean (± SE.

			30°	1.3 mm 45°	60°	30°	2.6 mm 45°	60°	30°	3.9 mm 45°	60°
6 Hz	n = 10	Quadriceps	18.2 (2.1)	33.0 (4.7)	44.4 (6.5)	19.9 (3.3)	32.9 (5.2)	42.9 (6.7)	24.8 (4.3)	34.5 (4.5)	45.5 (6.5)
	(4 ♂, 6 ♀)	Hamstring	7.9 (2.3)	5.2 (.7)	6.8 (1.0)	10.3 (2.3)	7.4 (1.3)	7.2 (1.1)	11.3 (2.1)	9.4 (1.8)	8.4 (1.6)
12 Hz	n = 10	Quadriceps	19.2 (2.7)	33.1 (4.0)	44.0 (4.5)	22.4 (2.7)	35.2 (4.4)	44.3 (4.0)	29.5 (4.0)	40.2 (5.6)	45.2 (4.0)
	(3 ♂, 7 ♀)	Hamstring	5.9 (1.2)	6.3 (1.3)	8.6 (1.6)	9.0 (1.5)	8.0 (1.5)	15.9 (6.5)	15.6 (2.3)	13.2 (2.6)	11.4 (1.9)
18 Hz	n = 10	Quadriceps	19.0 (2.8)	32.2 (4.2)	42.2 (5.3)	24.3 (3.8)	38.0 (5.5)	46.5 (5.7)	36.5 (6.0)	43.7 (5.3)	51.6 (6.2)
	(3 ♂, 7 ♀)	Hamstring	5.8 (.9)	6.9 (1.3)	8.9 (1.3)	8.5 (2.1)	8.3 (1.5)	9.9 (1.6)	18.9 (5.1)	10.5 (1.6)	12.4 (2.1)
24 Hz	n = 10	Quadriceps	20.4 (2.1)	37.1 (3.3)	50.4 (4.6)	25.0 (3.7)	42.0 (4.5)	57.1 (6.2)	36.6 (5.5)	51.1 (6.7)	62.6 (6.9)
	(3 ♂, 7 ♀)	Hamstring	7.9 (1.7)	8.8 (1.4)	11.2 (2.0)	13.1 (2.1)	11.0 (1.4)	13.1 (1.7)	18.2 (3.0)	17.2 (2.2)	18.3 (3.1)
30 Hz	n = 11	Quadriceps	28.2 (1.9)	46.7 (3.4)	60.2 (6.5)	37.9 (4.1)	55.0 (4.8)	68.5 (7.1)	50.3 (6.7)	61.6 (7.5)	74.1 (8.0)
	(4 ♂, 7 ♀)	Hamstring	12.1 (2.3)	11.8 (3.1)	12.8 (3.3)	20.6 (3.3)	17.2 (4.0)	17.3 (5.2)	27.3 (5.1)	19.3 (5.0)	19.0 (6.1)