Evaluating the Physical Activity Impacts of Riding Electric Kick Scooters
Background
As a representative of micro-mobility, electric kick scooters (e-scooters) have flooded cities around the world recently. In 2018 alone, about 38.5 million e-scooters trips have been reported in the United States. Some posit that e-scooters are an active transportation mode. Yet, the physical activity of riding an e-scooter relative to other competing modes has not been measured. More importantly, without a concrete understanding of these health impacts, it becomes a growing challenge for planners to deliver public health benefits through transportation planning and policies.

Purpose
Primarily, this study attempts to answer the question if riding an e-scooter can provide physical activity health benefits to riders. In San Francisco, about 40% of scooter trips replace car trips, and 30% replace walking trips. This study also compares the physical activity level of e-scooter riding to driving and walking. In addition, it discusses the implications for policy-making and transportation planning.

Methods
The study relies on a field experiment with 20 subjects and includes two parts: measuring metabolic physical activity level and muscle activity of e-scooter riding. For the first part, we applied a similar approach as in our previous e-bike physical activity study with necessary modifications (Langford et al 2017). The recruited participants are asked to walk, drive, and ride an e-scooter on a 4.4 km fixed course that encompasses a level, an uphill and a downhill segment. We used the Cosmed Fitmate Pro to measure their oxygen consumption rate (VO2) and energy expenditure. For the second part, we used 16-channel wireless electromyography (EMG) to monitor muscle activities of 16 trunk, upper, and lower limb muscles during walking, driving and e-scooter riding for a series of typical maneuvers.

Results
The data collection process study is currently in progress with full result (N=20) expected in August 2019. Our preliminary trials (n=3) suggests that riding an e-scooter only provides light physical activity level (MET=1.78), similar to driving (MET=1.48); energy expenditure and oxygen consumption rate are 20% higher than driving. In addition, both energy expenditure and oxygen consumption rate of riding an e-scooter are lower than walking (MET=4.17), which offers moderate physical activity (MET>3). Our EMG trials to date (n=5) have not been evaluated yet.

Conclusion
Understanding physical activity of e-scooter riders is crucial as e-scooter riders may substitute other modes such as walking, biking and driving. Our study measures the metabolic and isometric physical activity levels of riding an e-scooter and compares it to walking and driving. Our preliminary metabolic data shows that riding an e-scooter may only provide limited metabolic benefits compared to driving. Therefore, if e-scooters are growingly replacing active transportation modes such as walking and biking but not driving, e-scooter riders, planners and policy-makers should be alert to the ultimate health impacts. This study only explores the act of riding an e-scooter and does not consider the entire tour, in which most riders access an e-scooter by walking. Still, this important finding reveals important results about scooter use.

Presenter: Yi Wen
Agency Affiliation: University of Tennessee, Knoxville

Presenter Biographical Statement: [biography]