No it's all done with compression. On the Tank it is a resiviour(SP) filled with fluid and a paddle set at the "rest" position E.G. sitting still. As you hit obsicals the paddle compresses the fluid and bingo "shock absortion" a torsion bar acts as the rebound. In bikes I can see the system but the problem is the "paddle" It would have to be a plunger with a bleed or pressure release hole in it to allow the fluid to pass to afford the dampining. I am guessing they will have to have the same setup as rear shocks, a nitrogen piggy back to force the fluid back into the lower portions of the schock for the next whoop or jump.