Medial and lateral hamstrings and quadriceps co-activation affects knee joint kinematics and ACL elongation: a pilot study

Table 1 Maximum absolute muscle activation (RMS EMG), and co-activation index for both step-up conditions (mean ± SD)

	Vastus medialis RMS EMG (mV)	Vastus lateralis RMS EMG (mV)	Semimembranosus RMS EMG (mV)	Biceps femoris RMS EMG (mV)	Co-activation index
	Vastus medialis RMS EMG (mV)	Vastus lateralis RMS EMG (mV)	Semimembranosus RMS EMG (mV)	Biceps femoris RMS EMG (mV)	Semimembranosus: Vastus Medialis activation index (mV)	Biceps Femoris: Vastus Lateralis Co-activation index (mV)	Semimembranosus: Biceps Femoris Co-activation index (mV)
Low level co-activation step-up	280.67 ± 111.10	438.00 ± 347.63	248.84 ± 84.14	159.07 ± 82.14	0.94 ± 0.33	0.59 ± 0.47	2.28 ± 1.84
95 % confident interval
Upper limit	378.05	742.71	322.60	231.07	1.23	1.00	3.89
Lower limit	183.29	133.29	175.09	87.07	0.65	0.17	0.67
Step-up with deliberate co-activation	302.08 ± 137.74	430.48 ± 279.11	346.04 ± 143.47	311.70 ± 190.18	1.16 ± 0.14	0.88 ± 0.78	1.50 ± 1.02
95 % confidence interval
Upper limit	422.82	675.13	471.79	478.40	1.29	1.56	2.40
Lower limit	181.35	185.84	220.28	145.01	1.04	0.20	0.60

NB: RMS = Root Mean Square. Co-activation index values are hamstrings divided by quadriceps or medial hamstrings divided by lateral hamstrings

ISSN: 1471-2474