In the video, at a time of 0.00 and 0.15 Uke attacks with an overhead strike with a knife. Tori steps towards Uke and appears to block Uke's arm. Tori induces Uke to apply Aiki by pressing down on Uke's attacking arm whilst pushing it sideways with his other arm. Pressing down on Uke's attacking arm induces him to momentarily relax his upper body whilst extending his front leg in preparation to push upwards.  Consequently, the muscle torque about the foot joint of Uke's front leg, due to him pushing upwards, is then in the opposite direction to that required to balance the contact reaction force, due to Tori pushing Uke's arm to the side. Uke is then unbalanced to the side. Aiki-Lead

The application of Aiki in the Aikijujutsu techniques video by Bernie Lau is analysed below.

In the video, at a time of 14.17, Uke holds Tori's wrists from the rear. Tori moves his left hand towards his right and grasps Uke's right wrist. This action locks Uke's left wrist joint at the base of the thumb. Tori induces Uke to apply Aiki by turning his body towards the left which increases the pressure on Uke's locked wrist joint and causes him to bring his body forward, to reduce the pressure, by relaxing his upper body and reversing the muscle torque about his front foot ankle joint.  Consequently, Uke is unbalanced as the muscle torque about the ankle joint of Uke's front foot is now in the opposite direction to that required to resist Tori moving forwards.  Uke releases Tori's right wrist to prevent being thrown forwards. Aiki-Lead

In the video, at a time of 14.44, Uke holds Tori's upper arms from the rear. Tori induces Uke to apply Aiki by lowering his weight onto his left foot and rotates his body to the left about his left foot. As Tori lowers his weight, Uke relaxes his upper body and extends his leg(s) upwards in preparation to resist Tori's downward movement. Consequently, Uke is unbalanced as the muscle torque about Uke's foot joints are now in the opposite direction to that required to resist Tori moving forwards and to the left.  With Uke being unbalanced he is unable to resist Tori extracting his right arm from the hold as he moves forward. Aiki-Lead

The application of Aiki in the Aikijujutsu techniques video by Bernie Lau is analysed below.

In the video, at a time of 05.20 Uke attacks with a knife thrust. Tori side steps Uke's thrust and lightly makes contact with Uke's wrist so as not to stop its forward movement. As the knife comes to a stop, Tori induces Uke to apply Aiki by restraining Uke's wrist as he applies an atemi to Uke's face.  The atemi induces Uke to straighten his body as he pulls against the restraint.  Consequently, the muscle torque about the foot joint of Uke's front leg, due to him straightening his body, is then in the opposite direction to that required to balance the contact reaction force, due to Uke pulling against the restraint. Uke is then unbalanced to the front. Aiki-Lead

In the video, at a time of 06.17 Uke attacks with a knife thrust. As Uke steps forward Tori induces Uke to apply Aiki by pressing down on Uke's arm whilst pushing him to his front side. Pushing down induces Uke to momentarily relax his upper body whilst he prepares his lower body to resist the downward movement by extending his legs. Consequently, the muscle torque about the foot joint of Uke's front leg, due to him extending his legs, is then in the opposite direction to prevent Tori pushing him to the front. Uke is then unbalanced to the front. Aiki-Lead