Real-World Explanation of What Can Be Done to Modify the Application Time Concept to Create the Desired Outcome
When landing after a vertical jump, four (4) real-world actions must be performed in order to increase the application time of the external forces slowing the body down.
First, initial contact must be on the forefoot (i.e., the heels should not be in contact with the ground).
Second, the ankle joints should be maximally plantar flexed prior to contact with the ground and then upon contact with the ground, the ankle plantar flexor muscles should be contracted to create eccentric ankle dorsiflexion torques. These torques will slowly lower the heels towards the ground.
Third, the knee joints should be slightly flexed prior to contact with the ground. If these joints are fully extended when contact is made with the ground, large external forces will be created to slow the body down because the application time of these external forces will be very small. Upon contact with the ground, the knee extensor muscles should be contracted to create eccentric knee flexion torqes. These torques will slowly lower the knees towards the ground.
Fourth, the hip joints should be slightly flexed prior to contact with the ground. If these joints are fully extended when contact is made with the ground, large external forces will be created to slow the body down because the application time of these external forces will be very small. Upon contact with the ground, the hip extensor muscles should be contracted to create eccentric hip flexion torques. These torques will slowly lower the hips towards the ground.
When landing after a horizontal jump, initial contact is made with the heels. The length of the time of application of the external forces is thus dependent on the surface that you land on and the time of application of the eccentric knee and hip flexion torques. Three (3) real-world actions must be performed in order to increase the application time of the external forces slowing the body down.
First, the ground that you land on should be soft. This will allow the heels to continue to move while you perform real-world actions 2 and 3. If the heels stop moving, the application time of the torques to slow the body down will stop.
Second, the knee joints should be slightly flexed prior to contact with the ground. If these joints are fully extended when contact is made with the ground, large external forces will created to slow the body down because the application time of these external forces will be very small. Upon contact with the ground, the knee extensor muscles should be contracted to create eccentric knee flexion torques. These torques will slowly lower the knees towards the ground as well as slow the forward motion of the knees, hips and torso.
Third, the hip joints should be slightly flexed prior to contact with the ground. If these joints are fully extended when contact is made with the ground, large external forces will be created to slow the body down because the application time of these external forces will be very small. Upon contact with the ground, the hip extensor muscles should be contracted to create eccentric hip flexion torques. These torques will slowly lower the hips towards the ground as well as slow the forward motion of the hips and torso.