The effects of raising relative centre of mass height on maximal sprint performance.
Jacobs, Michael Benjamin
Sprinting is the maximal velocity of bipedal locomotion via the horizontal displacement of a sprinter’s centre of mass (CoM). Few studies have investigated morphological properties in maximal velocity sprinting. While morphological properties are known to affect sprint mechanics, the influence of relative CoM height is presently unclear. The aim of this study was to identify how modifications to the location of CoM affected kinematic parameters during maximal velocity sprinting. Ten high performance athletes (age = 22.2 ± 3.13yr, weight = 89.5 ± 7.52kg, height = 183.3 ± 4.55cm, 35m sprint = 4.8 ± 0.19s, and leg length = 90.25 ± 4.18cm), from two sporting codes involving sprinting completed a series of maximal 35m sprints manipulated across three loading conditions: 1. Unloaded; 2. Weighted vest, raising relative CoM location by 3% of total body height; and 3. Weighted belt, using an identical load as condition 2 without change to CoM location. Free loaded squat jump was monitored as a covariate to negate for the effects of individualistic strength. Our results indicate that in comparison to unloaded conditions, increasing the CoM by 3% of total body height significantly (p<0.0003) decreased maximal velocity (7.45 ± 0.28m.s-1 and 7.21 ± 0.28m.s-1 respectively). Similarly, maximal velocity was significantly impaired (p<0.001) when additional mass was added around the CoM compared to the unloaded condition (7.24 ± 0.25m.s-1 and 7.45 ± 0.28m.s-1 respectively). Indirectly leg length was found to positively (p<0.024) correlate with maximal velocity by 0.01m.s-1 per 1cm increase in leg length. To date, no known empirical literature exists examining the manipulation of CoM within sprinters. Therefore it is not possible to draw comparisons with other research. However we can assume that additional mass, external or internal, decreases maximal velocity when located on or around the shoulders and waist. Our results suggest the location of CoM makes no practical difference that can be discerned in 35m sprint performance, which in effect is contradictory to the theoretical model constructed by Bejan and associates (2010) whereby raising CoM by 3% total body height improves maximal velocity.
Advisor: Button, Chris; Ross, Angus; Gibbons, Megan
Degree Name: Master of Physical Education
Degree Discipline: Division of Sciences
Publisher: University of Otago
Keywords: Sprinting; Centre of Mass; Sprint Kinematics; Maximal Velocity; Morphology
Research Type: Thesis