RESUMO
This study sought to (a) characterize the kinematics aspects of a popular strongman-type event, the heavy sprint-style sled pull, and (b) gain some insight into the kinematic factors that could distinguish the within- and between-subjects' fastest and slowest trials. Six resistance-trained subjects with experience in the heavy sled pull gave informed consent to participate in this study. Subjects performed three 25-m sets of sled pulls with a load of 171.2 kg with 3 minutes of rest between sets. Kinematic variables were obtained from 2 video cameras positioned perpendicularly 11 m from the intended direction of the sled pull. Camera 1 recorded the first 5 m (acceleration phase) and Camera 2 recorded the last 5 m (maximum velocity phase). Effect sizes and paired and independent t-tests were used to determine the within- and between-subject effects, respectively, with significance set at p < 0.01. Heavy sled pulls shared many kinematic similarities to acceleration phase sprinting, although the sled pull had somewhat smaller step lengths and step rates, longer ground contact times, and a more horizontal trunk. Within- and between-subject analyses of the fastest and slowest trials typically revealed more significant differences in the maximum velocity than the acceleration phase. Although the fastest trials were often characterized by significantly greater step lengths, step rates, and shorter ground contact times, differences in the segment/joint angles were less consistent. Based on the impulse-momentum relationship, our results imply that greater anteroposterior forces/impulses were produced in the fastest sled pulls. Accordingly, the heavy sled pull may improve acceleration sprinting performance in many athlete types and the ability to break and make tackles in contact sports such as American football and the rugby codes.
