Table 2 Mean muscle activity (± standard deviation) for each muscle during the four extension exercises (%MVC)

Dyn trunk

27.38 ± 6.94

79.03 ± 31.51

64.12 ± 20.72

89.07 ± 19.49

91.47 ± 25.60

78.69 ± 23.88

44.87 ± 30.03

Concentric phase

Dyn-stat trunk

19.43 ± 2.73

69.64 ± 14.57

77.87 ± 23.19

86.90 ± 29.9

75.04 ± 28.92

82.00 ± 30.57

38.18 ± 23.18

Dyn leg

9.72 ± 3.44

67.84 ± 20.68

62.95 ± 10.26

75.24 ± 20.82

88.25 ± 21.64

55.39 ± 8.57

30.33 ± 16.18

Dyn-stat leg

22.64 ± 11.01

81.93 ± 26.91

63.16 ± 31.14

81.36 ± 17.54

79.60 ± 22.21

65.10 ± 36.65

43.25 ± 19.38

Dyn trunk

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

Isometric phase

Dyn-stat trunk

19.30 ± 2.10

69.92 ± 26.48

74.05 ± 21.64

81.54 ± 25.49

70.12 ± 27.10

70.23 ± 29.52

35.49 ± 12.99

Dyn leg

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

N.A.

Dyn-stat leg

20.56 ± 11.63

66.23 ± 31.16

61.15 ± 27.07

77.00 ± 19.56

72.73 ± 21.67

65.77 ± 30.66

35.27 ± 30.29

Dyn trunk

26.57 ± 7.09

52.67 ± 22.15

50.19 ± 15.19

59.45 ± 17.29

57.94 ± 15.53

62.35 ± 24.44

33.09 ± 15.25

Eccentric phase

Dyn-stat trunk

19.06 ± 3.97

60.17 ± 27.79

44.02 ± 15.61

57.56 ± 23.71

66.57 ± 23.00

56.15 ± 30.65

29.38 ± 19.62

Dyn leg

9.84 ± 3.51

46.84 ± 14.60

44.22 ± 10.42

49.81 ± 19.81

53.20 ± 17.70

53.21 ± 34.36

20.33 ± 9.56

Dyn-stat leg

20.85 ± 7.51

54.76 ± 10.05

51.16 ± 26.47

48.03 ± 11.03

47.71 ± 15.60

58.59 ± 30.25

14.94 ± 9.59