a pair of arm assemblies 54 and 55 and a pair of leg assemblies 56 and 57 all of which are configured to undergo oscillating or reciprocating movement about a pivot axis 32 the arm assemblies 54 and 55 include lower levers 60 and 61 which extend forward and upward from the pivot axis 32 to elbows 74 and 75 thereafter the arm assemblies 54 and 55 extend rearward and upward toward the seat 28 along upper extensions 64 and 65 handles 66 and 67 are slidably received in the upper extension 64 and 65 and are provided with keyway slots 53 so as to prevent their rotation relative to the upper extensions 64 and 65 the handles 66 and 67 can be adjusted in length and for this reason locking levers 68 and 69 are provided on the upper extensions 64 and 65 to secure them at the desired length the ends of the handles 66 and 67 are generally bent upward and inward relative to the remainder of the handles 66 and 67 and are provided with padded grips as seen in fig1 the leg assemblies 56 and 57 similarly extend upward from the pivot axis 32 along levers 72 and 73 the pedals 76 and 77 are preferably secured to the levers 72 and 73 and linkages 80 and 81 in a pivotable manner but could alternatively be rigidly secured thereto the levers 72 and 73 and linkages 80 and 81 create a four bar linkage which keeps the angle of the pedals 76 and 77 with reference to the user in a biomechanically correct position throughout the length of stroke the linkages 80 and.