Muscle power patterns in the mid-acceleration phase of sprinting

Abstract

To assess the role of the lower limb joints in generating velocity in the mid-acceleration phase of sprinting, muscle power patterns of the hip, knee and ankle were determined. Six male sprinters with a mean 100 m time of 10.75 s performed repeated maximal sprints along a 35 m indoor track. A complete stride across a force platform, positioned at approximately 14 m into the sprint, was video-recorded for analysis. Smoothed coordinate data were obtained from manual digitization of (50 Hz) video images and were then interpolated to match the sampling rate of the recorded ground reaction force (1000 Hz). The moment at each joint was then calculated using inverse dynamics and multiplied by the angular velocity to determine the muscle power. The results showed a proximal-to-distal timing in the generation of peak extensor power during stance at the hip, the knee and then the ankle, with the plantar flexors producing the greatest peak power. Apart from a moderate power generation peak towards toe-off, knee power was negligible despite a large extensor moment throughout stance. The role of the knee thus appears to be one of maintaining the centre of mass height and enabling the power generated at the hip to be transferred to the ankle.

Excessive fluctuations in knee joint moments during early stance in sprinting are caused by digital filtering procedures

“…Such IDA approaches have been widely used in an attempt to understand the lower limb RJMs during discrete stance phases in the fastest form of gait, sprinting [1][2][3][4][5][6][7] .…”

The acute effects of heavy sled towing on subsequent sprint acceleration performance

“…2,3 As such, literature reports propulsive forces within acceleration to be 46% greater than those observed within maximal velocity running. [4][5][6] Fundamentally therefore, a large training consideration should be noted for training modalities which provide overload to the propulsive nature of GRF application within the acceleration phase of sprint running.…”

The Effect of Shoe Weight on Sprint Performance: A Biomechanical Perspective

“…For the purpose of this study, biomechanical differences between the light and heavy shoe were only considered relevant if they relate to the performance outcome. Previous research and sprinting coaches have mainly suggested the following variables to promote sprint start performance: High vertical and propulsive GRFs [18,19] and high angular velocities of the lower-extremity joints in the sagittal plane [20][21][22], leading to a high concentric joint power (joint moment x joint angular velocity) [5]. Therefore, the input for the SVM was a data matrix containing data rows, of individual trials and data columns of time-normalized waveforms of 11 biomechanical variables: Vertical and anterior-posterior GRFs, and sagittal angular velocities, moments and power of the ankle, knee, and hip joint.…”

“…In order to achieve high propulsive forces, athletes have to generate maximum joint power at the hip, knee and ankle joint in a proximal to distal order [5,6,22]. Since the ankle transfers the power generated by the leg to the ground before push-off, it plays an important role for high horizontal sprinting velocities [5]. Therefore, the increase in plantarflexion velocity and corresponding ankle power in the light shoe compared to the heavy shoe during the second 50% of the stance phase might explain the increased sprint start performance in the light shoe.…”

“…High performance in a sprint start results from maximal power generation at the lower extremity joints [5,6], determined by joint kinematics and ground reaction forces (GRFs). Optimizing these biomechanical variables may be achieved by providing appropriate sports equipment.…”