The emergence and characteristics of the Australian Mamil.

BACKGROUND: The Mamil (middle-aged man in Lycra) appears to be an emergent cycling-focused species.

OBJECTIVES: To explore the nature and distribution of the Mamilian species; to determine whether rates of cycling by middle-aged men in Australia have changed since the pre-Mamilian era.

SETTING: Secondary analysis of representative population-based datasets. National sport participation data from the Exercise, Recreation and Sport (2002-2004, 2008-2010) and Ausplay surveys (2016) were analysed to assess trends in recreational and exercise-related cycling, including by middle-aged men (45-64 years of age). Data from New South Wales Population Health Surveys (2006, 2010, 2014) and Australian censuses (2006, 2011, 2014) were analysed to assess trends in cycling to work.

MAIN OUTCOME MEASURES: Cycling participation rates (at least once or at least once a week in the past 12 months); rates of cycling to work.

RESULTS: The proportion of middle-aged men who cycled for exercise or recreational purposes at least once a week during the previous year increased from 6.2% (95% CI, 5.5-7.0%) during 2002-2004 to 13.2% (95% CI, 11.9-14.6%) in 2016. The prevalence of Mamils in the most affluent residential areas has more than doubled since 2002-2004, and is twice as high as in the least advantaged locations. Media reports of "Mamils" corroborate these temporal trends.

DISCUSSION: Mamils in Australia are socially graded, and also grade themselves according to bicycle-related expenditure and hill gradients overcome. They often form cohesive and supportive groups, but may not reflect a population-wide social movement to increase physical activity among adult Australians.