Almost half the population of Australia is insufficiently active to achieve recommended levels of physical activity [1]. Strategies that encourage sustained increases of physical activity at the population level are needed, and this applies to most western countries. Increasing population levels of cycling, either for recreation or transport, has considerable potential to increase physical activity. In Australia, cycling is the fourth most popular physical activity after walking, aerobics and swimming [2], with annual participation in cycling growing by 15.3% from 2001 to 2004. Almost half of Australian households have access to a bicycle, with bicycle ownership varying from 39% in Sydney to 65% in Canberra [3].

Strategies that encourage cycling range from individual or group education skills programs, mass media education programs, infrastructure programs that separate people riding bicycles from motorists, and traffic calming approaches which seek to slow the speed of motor traffic [4]. Community events, such as organized mass bicycle rides, are another approach that combines a large group participation program with mass media, as well as temporary infrastructure modifications and traffic calming through police support.

There is substantial interest in the potential for elite sporting events with mass exposure, such as the Olympic Games, to positively influence community interest in physical activity [5]. However, there is very little evidence that elite sporting events contribute to general population participation in physical activity [5], and the 2000 Sydney Olympics showed no effect on physical activity prevalence [6]. In fact, just watching elite sport may be hazardous to health [7].

Less is known about the role of participation in mass community events that are sub-elite. Large-scale fun runs, marathons, walking and cycling events are carried out in many cities, often with sponsorship and fundraising objectives. The distances are accessible, and these events are promoted to all segments of the general community [8]. The unanswered research question is whether these events have public health potential for influencing some sedentary individuals to trial physical activity, or whether they mostly attract those who are already regular runners and cyclists. Further, does participation in such community events lead to engagement with the activity, and short term maintenance of the specific physical activity behaviour post event? The purpose of this study was to examine the attributes of the participants and the effect of participation in a mass community cycling event on cycling behaviour.

The results indicate that participants who were novice riders or were first time participants in this particular cycling event significantly increased their number of bicycle rides in the month after the event. Half of the participants who rated their level of cycling ability low at baseline then rated themselves as high a month after the mass cycling event.

The participants in a Sydney mass cycling event were more likely to be male, middle aged, cycling-experienced, and most were considered sufficiently physically active for a health benefit by population health standards. Approximately 85% of respondents to the follow-up questionnaire reported engaging in 150 minutes of physical activity over five or more sessions, compared to the 2005 state estimate of 52% of all New South Wales residents aged 16 years and older (57% of males, 47% of females) [10]. However, the finding that the prevalence of sufficient physical activity was much higher among respondents with low pre-event/high post-event cycling ability than among respondents with low pre-event/low post-event cycling ability warrants future investigation. The event targeted cycling activity, but may have contributed to the difference in lifestyle physical activity observed between these groups.

A small proportion of event participants rated their level of cycling ability as high at baseline, but subsequently rated themselves as low a month after the event. This could reflect injury or acute illness rather than true behavioural relapse. Studies of endurance runners have found an increased risk of illness during periods of heavy training and in the weeks following participation in a mass event [11, 12]. Information about the epidemiology of injury and illness among participants in mass bicycling events is scant and comes from studies of events with distances longer than the Sydney mass cycling event. Serious injuries associated with participation in a 42-mile (67.59 kilometer) mass cycling event were uncommon, with only 5 injuries per 1,000 bicyclists, 95% of which were bruises and abrasions [13]. Data from long, multi-day bicycling tours indicate most injuries associated with participation are overuse injuries [14, 15]. The repetitive mechanics of bicycling make cyclists susceptible to lower extremity injuries, the most common types being injuries to the knee, usually attributable to riding with excessive force [16]. To lower the risk of illness or overuse injury, a heavy training load can be accomplished with fewer negative health outcomes if training programs are designed to minimize strain and monotony [17]. Training materials were provided to participants in the Sydney mass cycling event through the event website.

There are limitations to the application of these results, including the small number of low active participants, which prevented a comprehensive analysis to examine change in self-rated physical activity in the low active subsample. Reliance on self-reported physical activity data is another limitation. However, the self-rated physical activity question used in this study has been validated previously [18], and we compared self-rated physical activity level with total minutes of physical activity assessed by the Active Australia questions, and found significant differences (p < .05) in mean number of weekly minutes of physical activity across the self-rated categories. The lower response rate (55%) of the follow-up internet survey raises the possibility that the respondents were the most positive ride participants, and participants who did not enjoy their ride experience or may have decreased their cycling frequency chose not to respond to the follow-up survey. Lack of power may have contributed to the inability to detect confounders in the regression models. Despite these limitations, this study is one of the first to examine the public health potential of a mass cycling event to promote adoption and maintenance of physical activity in a community.

Few mass participation events, related to bicycling, running or any other sport, have ever been evaluated to determine the effects upon population levels of physical activity. [8]. Prior mass event research has focused on process evaluation indicators, such as participant numbers or finishing times. Community level events, such as the mass cycling event examined by this study, could be used as part of integrated physical activity promotions if they attract less active and novice individuals to participate. Most participants in the Sydney cycling event were competent or regular cyclists, suggesting an event organizational orientation towards elite or competitive participation over the public health potential for increasing community participation. However, mass events have the potential to encourage participants to trial new behaviours in a non-competitive, controlled, and enjoyable environment, as well as have a broader agenda setting role across the community.

Other kinds of mass participation events have demonstrated the potential to attract inactive adults or adults with little cycling experience, such as single-day health promotion events to encourage physically active commuting instead of vehicle use for transportation. For example, participation in the Victoria Ride to Work Day has more than doubled since 2002, and attracted over 5,000 participants in 2005, approximately a fifth of whom were first time riders [19]. Other structured health promotion events also seem to have the potential to increase walking for transportation [20].

Further knowledge about the public health applicability of mass events is needed, and methods for attracting less active and novice individuals to participate remain to be developed. Partnerships between public health agencies and event organizers could result in promotional activities to encourage less active community members to trial new physical activity behaviours. This would require shared planning and marketing, and clear targeting of the less regularly active. Shorter event options, post-event reinforcement (including post-event promotions and additional events) may also be required in order to maintain motivation for these new event participants. If these partnerships were explored they could provide a novel approach to reaching inactive adults at the population level, and encourage many of them to contemplate trialing an active behaviour.