Am I correct that they propose to bend your leg (while it's in the air after a ground contact) with an additional force, which is used to conserve energy in an

Am I correct that they propose to bend your leg (while it's in the air after a ground contact) with an additional force, which is used to conserve energy in an attached spring. Upon a next contact with ground this energy will be released, which gives a better boost than ordinary jumping stilts, since they are loaded only at the moment of contact?