The characteristics of takeoff movement and joint kinetics during the rebound-type jump using single-leg takeoff: comparison with the rebound-type jump using double-leg takeoff

Abstract

AbstractThe present study was conducted to clarify points for attention, and to determine an eŠective method for the single-leg rebound-type jump (SRJ) and double-leg rebound-type jump (DRJ) in plyometrics, by investigating the joint kinematics and kinetics of the takeoŠ leg in the sagittal plane. Twelve male track andˆeld athletes (sprinters and jumpers) performed the SRJ and DRJ with maximal eŠort. Jumping motions in the sagittal plane were videotaped with a high-speed video camera (300 Hz), and ground reaction force was recorded with a force platform (1000 Hz). Kinematics and kinetics were calculated. To evaluate the force output characteristics for a single leg in the DRJ, the ground reaction force was divided into half, and the data were used to calculate the other kinetic parameters. The overall results of these analyses were as follows: 1. In the SRJ, the jump height for a single leg and the landing height for a single leg were higher than in the DRJ because of the higher mechanical power used during the eccentric and concentric phases.

Relationships between lower-limb joint kinetic parameters of sprint running and rebound jump during the support phases

“…The RJ index for rebound jump, which indicates mechanical power per kg of body mass during take-off 19) , was calculated as follows 7,11,19,23) :…”

“…The support phase (from the point of touchdown to toeoff) was divided into two parts 11,13) : the eccentric phase (from the point of touchdown to the lowest point of the body's center of gravity) and the concentric phase (from the lowest point of the body's center of gravity to toeoff). Moreover, mean ankle-, knee-, and hip-joint torque (eccentric and concentric phases) and mean ankle-, knee-, and hip-joint power (negative and positive values) were calculated using plantar flexion and/or extension joint torque only.…”

“…For the rebound jump, participants wore their own training shoes (without spikes), which they usually wore during plyometric training. The rebound jump consisted of five repeated rebound-type jumps in the vertical direction with a double-leg takeoff from a standing position 7,11,14,19) . Participants were orally instructed to jump as high as possible and to minimize ground contact time.…”

“…Therefore, in order to develop a suitable plyometric training plan, it is important to understand the relationship between the joint kinetic parameters in sprinting and jumping exercises. The characteristic joint kinetic parameters of rebound jump including the countermovement jump vs. counter-movement-type drop jump vs. rebound-type drop jump using a double-leg jump in the vertical direction 10) , double-leg vs. single-leg jump in the vertical direction 11,12) , and vertical vs. horizontal direction 12,13) have been investigated. Such studies have shown that the rebound jump has the highest ankle-joint kinetic parameters (joint torque, joint power, and joint work) of these jumps.…”

“…Such studies have shown that the rebound jump has the highest ankle-joint kinetic parameters (joint torque, joint power, and joint work) of these jumps. Moreover, rebound jump performance is known to be primarily affected by the ankle joint 11,14) . During sprinting, the ankle joint plays an important role in achieving high sprinting performance by producing a large vertical force 15,16) , reducing ground contact time 17,18) , and enhancing mechanical efficiency 18) .…”