Moreover, the “second leg” corresponds to {HEAD ~ the standing leg} in {TAIL ~ the next single leg grounded period} 
in
Moreover , the “ second leg ” corresponds to { HEAD ~ the standing leg } in { TAIL ~ the next single leg grounded period }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL