Table 2.

Equations used to calculate co-activation co-efficient

Net knee moment = moment (agonist) - moment (antagonist)     (Eq. 1)

Extension knee moment = Quadriceps moment - Hamstrings moment     (Eq. 2)

Flexion knee moment = Hamstrings moment - Quadriceps moment     (Eq. 3)

Quadriceps muscle moment = constant (a) × Quadriceps EMG     (Eq. 4)

Hamstrings muscle moment = constant (b) × Hamstring EMG     (Eq. 5)

$Co-activation=\frac{\text{b}\times \text{HMSEMG}}{\text{a}\times \text{QCSEMG}}\times 100\%\left(\text{Eq}.6\right)$