LAUSR

BACKGROUND Bounce rope-skip holds immense scope as an aerobic exercise in space and time constrained urban setting with additional constraints placed by pandemic situations such as Covid 19, wherein adherence to commonly performed weight-bearing, aerobic activities like walking and running is a challenge. Limited knowledge informing biomechanical demands and misconceptions about knee joint loading, confines safe application of bounce rope-skip in health promotion. Thus, present study aimed to explore kinematics and lower-extremity joint loading during rope-skipping compared to walking and running. METHODS Following ethical approval, 3D motion analysis of bounce rope-skip, walk and run was captured from 22 healthy female participants aged 18-25yr using 12-camera Vicon system and 2AMTI force plates. Three trials for bounce rope-skip were recorded with five skip-jumps on force-plates at a cadence of 105 skips/min. Mid-skip, mid-gait and mid-run data were averaged to compute kinetic and kinematic variables for hip, knee and ankle during loading/initial contact, take-off/push-off and flight/mid-swing phases of rope-skip, walk and run. RESULT Average time of one rope-skip cycle was 1.2sec; mean foot contact time was 0.55sec and flight time was 0.65sec. In one bounce rope-skip cycle, hip motion ranged between 13.4o-35.3oflexion; knee between 13.6 o-67.9° flexion and ankle between 34.5odorsiflexion to-13.40plantarflexion. Vertical ground reaction force (vGRF) during rope-skip (landing-phase) was lower compared to run; however, it was higher than walk (p < 0.001). In coronal plane, peak hip and knee adductor moment during rope-skip were lower compared to run and higher than walk (p < 0.001). CONCLUSION Bounce rope-skip generated low lower extremity joint loading compared to run; supporting its prescription as a hip and knee joint-protective aerobic weight-bearing exercise for health promotion in young adults.