Is leaping a missing piece of the rehabilitation puzzle? A biomechanical comparison

Rehabilitation programmes must be progressive and prepare the musculoskeletal system for daily activity demands, sport performance, and reducing the risk of further injuries. Practitioners and coaches should understand optimal progression pathways, and exercise biomechanical demands. Jumping and hopping are commonly prescribed rehabilitation exercises to develop physical attributes such as strength, power, and balance. Leaping visually looks similar to jumping and hopping, but it is often neglected in rehabilitation. Unlike jumping and hopping, a leap takes off on one foot and lands on the other (Jaffri et al,2017,Int J Sports Phys Ther,12(4),512-519), making it a very functional exercise closely mimicking walking and running. The biomechanics of leaping have not been studied. The aim of the study was to compare lower limb kinematics and vertical forces for jumping, hopping, and leaping with the purpose to inform rehabilitation protocols and progressions. With institutional ethics approval, eight healthy participants (4 females, 4 males, 21±0.4 years old) attended a single laboratory session. Each performed 3 maximum effort jumps, hops, and leaps, of which the trial resulting in highest vertical height of pre-determined pelvic marker was analysed for each task. Vicon Plug-in-Gait determined lower limb kinematics and vertical ground reaction forces (vGRF). vGRF data was captured for single limbs for leaping and hopping, and both limbs for jumping. Mean filtered (Woltering) right and left kinematic and vGRF data were combined and analysed in MATLAB. The movements were split up into two phases: propulsion and landing. Peak hip and knee flexion, hip abduction, and vGRF were significantly greater in jumping compared to hopping and leaping during the propulsion phase (P<0.05). During landing, jumping peak hip abduction was greater than leaping (P<0.05), and jumping vGRF was greater compared to both hopping and leaping (P<0.05). No significant differences were found for peak joint angles or vGRF between leaping and hopping during propulsion or landing (P>0.05). The results convey that leaping and hopping produce equivalent kinematics and vGRF. This suggests leaping to have similar biomechanical advantages to that of hopping, thus there is scope for leaping to be implemented into progressive rehabilitation protocols. Leaping may be utilized for patients who struggle to balance when hopping, as moving from one foot to the other is already a natural daily movement. Future research should explore stability and specific joint contributions of the 3 movements on a larger sample to further distinguish and define the role each dynamic movement plays in successful rehabilitation.