This study compared lower limb dynamic joint loading after hamstring (HS) and patellar tendon (PT) anterior cruciate ligament (ACL) reconstruction. A three-dimensional motion analysis and force plate system were used to determine sagittal plane kinematics and kinetics in 20 subjects who had undergone ACL reconstruction (10 HS, 10 PT) whilst they performed both horizontal and vertical hopping tasks. Results for both activities showed significantly smaller knee flexion angles and external flexion moments in the operated than the non-operated limbs in PT subjects but no difference between limbs in HS subjects. There was no difference in the summated moment (hip plus knee plus ankle) between limbs for either graft type. The peak vertical ground reaction force was greater in the operated than the non-operated limb in PT subjects during the horizontal hop. These data show functional knee kinematic and kinetic differences between the two graft types that point to an earlier or better functional recovery in patients undergoing ACL reconstruction with HS graft than PT graft.