Kinematic Alterations Due to Different Loading Schemes in Early Acceleration Sprint Performance From Starting Blocks

Abstract

The purpose of this study was to examine the changes to block start and early acceleration sprint kinematics with resisted sled towing. Ten male sprinters performed 12 sprints (four each of unresisted and approximately 10 and 20% body mass [BM]) for 10 m from a block start. Two-dimensional high-speed video footage (250 Hz) of the starting action and the first three steps of each sprint were recorded to enable the sagittal sprinting kinematic parameters to be obtained using APAS motion analysis software. The overall results of this study indicated that early acceleration sprint performance from starting blocks decreases with increasing load during resisted sled towing. A load of approximately 10% BM had no "negative" effect on sprint start technique or step kinematic variables measured in this study (with the exception of one variable) and was also within the "no greater than 10% decrease in speed" limits suggested by Jakalski. Towing a load of approximately 20% BM increased the time spent in the starting blocks and induced a more horizontal position during the push-off (drive) phase. The approximately 20% BM load also caused the sprinters to shorten their initial strides (length), which may have resulted from the decreased flight distances. Such results suggest that the kinematic changes produced by the 10% BM load may be more beneficial than those of the 20% BM load. Future training studies will, however, need to investigate how these acute changes in sprinting technique impact on long-term adaptations in sprinting performance from resisted sprinting.

Biomechanical Comparison Between Sprint Start, Sled Pulling, and Selected Squat-Type Exercises

“…Because of this more pronounced horizontal force production, also the angle of force production (angle of FP) was smaller (more horizontal) during the 6 th step and also during the 2 nd step in Sled20. The results of the present study (longer performance time, FPT, and smaller step frequency and angle of FP) support the findings of the earlier studies (Maulder et al 2008 andLockie et al 2003). It can be suggested that sled-pulling is a good exercise (especially during later steps of 10 m start), if the aim is to develop horizontal force production and that heavier sled-pulling (Sled20 in the present study) might be more efficient in this aspect.…”

“…There has been only a few studies comparing biomechanics of sprinting and strength exercises: sprint start vs. sled-pulling (Maulder et al 2008 andLockie et al 2003) and maximum speed sprinting vs. forward bounding exercises (Mero & Komi 1994). …”

“…Maulder et al (2008) compared the kinematics of sprint start and sled-pulling. As subjects they had 10 male sprinters (100 m: 10.87 s).…”

“…) Despite the common use of speed-strength / strength exercises in training of sprinters, there is a lack of knowledge of biomechanical characteristics of these exercises (e.g. force production, angular velocities, EMG activity) as compared to sprinting (Lockie et al 2003, Maulder et al 2008and Mero & Komi 1994. The purpose of the present study was to compare kinetics, kinematics and muscle activity between the sprint start, sled pulling and selected squat type exercises and thus to acquire more information about the relations between these exercises.…”

The Reliability of the Prowler in High School Male Football Players

“…The incorporation of sled training as part of strength and power training regimes is now common practice with various sports integrating its use for improvements in speed which is well documented in the literature [1,2]. Although initial research has focused upon the benefits of sled training on improving speed [1], subsequent studies have investigated the optimal load [3][4][5], biomechanical analyses of sprinting kinematics (technique, stride length, contact time) [6,7] and establishing coefficients of friction to determine the amount of work performed during the activity [8]. These studies have primarily focused upon sled pulling, whereas investigations into sled pushing are quite limited and have focused upon either bob-skeleton athletes [9], strongman athletes [10] or EMG muscle activation [11].…”