P3-67  Wednesday, Jan. 6 15:30  Push it, Push it Real Good: The Energetic Cost of Stroller Running ALCANTARA, R.S*; WALL-SCHEFFLER, C.M; Seattle Pacific University; Seattle Pacific University alcantarar@spu.edu

Humans living in societies with stroller use often engage in stroller running following the transition to parenthood. The addition of a stroller into the running experience has the potential to be disruptive of gait and put a premium on stamina. This study investigates some of changes of embarking on stroller running, including potential changes in metabolic cost, speed and stride length. While stroller running is a uniquely human endeavor, doing something with upper extremities whilst locomoting, is something in which other bipeds could potentially engage. Additionally, people have potential options in how they push a stroller, and we investigated each of our variables at different stroller pushing styles. People with limited stroller experience prior to our study (N=16, 10 men and 6 women) pushed a stroller loaded with 16kg while running around a track for 800m at each of four conditions, performed in a randomized order. Each runner was instructed to “maintain a consistent pace” within and across their conditions. The conditions consisted of three stroller-pushing conditions, in addition to the non-stroller control: (1) Pushing with both hands, (2) Pushing with one hand, (3) Pushing and Chasing. There were not significant differences in speed, stride length, or cost between the three stroller conditions and speed, though pushing with one hand did show a different slope in a model predicting cost from mass and speed. There was a significant decrease in stride length (p<0.001) and in speed (p<0.01) between non-stroller running and all three stroller conditions. There was not however a significant change in metabolic cost, suggesting that for a given speed, the metabolic cost of running with a stroller is higher than without, and that humans adapt to stroller running by slowing their pace in proportion to the additional effort. Additionally, men and women showed slightly different patterns of cost and speed changes, potentially due to the fact that in this sample, men ran significantly faster than women (p<0.05).