Mountain biking has developed to a popular sporting activity since its beginning in the early 1970s (Chow and Kronisch, 2002; Gaulrapp et al., 2001; Kim et al., 2006). Recreational and competitive athletes likewise follow this sport, promoting the onset of racing events for all kinds of riding levels and mountain biking styles (Jeys et al., 2001; Lareau and McGinnis, 2011). Consequently, mountain bike related injuries increased, affecting simultaneously the health-care and socio-economic costs (Cumps et al., 2008; Ozturk and Kilic, 2013). Following the literature, overuse syndromes occur more frequently than acute injuries, but the latter force athletes to stop riding more often (Campbell and Lebec, 2015; Oehlert et al., 2004). Contradictory statements for the prevalence of acute injuries in recreational bikers are mentioned in the literature (Kim et al., 2006; Nelson and McKenzie, 2011). Following Nelson and McKenzie (2011) acute mountain bike related injuries requesting treatment in an emergency department significantly dropped by 56% between 1994 and 2007, whereas Kim et al. (2006) reported a threefold increase over a 10-year period of 1992-2002. The present study aimed to assess the prevalence of all acute mountain bike injuries a rider has received during his to-date mountain biking career. To the authors' knowledge, there is a lack of data on acute injuries in elites. Therefore, in the present study, elite and amateur riders were analyzed separately. The authors hypothesized that elite riders train more, wear more protective gear items, get injured less frequently and less severely compared to amateur riders. Additionally, this study aimed to reveal predictive factors, which determine events of severe injuries for elite and amateur riders separately.
Design and participants
In this cross-sectional observational study, male elite and amateur mountain bikers, attending the Swiss Epic Mountain Bike Event held in Valais in 2017, were asked to fill out a retrospective survey on mountain bike related injuries. The Swiss Epic Mountain Bike Event 2017 comprised four racing formats; 1) Swiss Epic = five stages over five consecutive days with in total 342 km riding distance and 11'800 m uphill altitude difference, 2) Swiss Epic flow = five stages over five consecutive days with 285 km riding distance, 6'350 m uphill and 13'400 m downhill altitude difference, 3) Swiss Epic two days = 130 km and 4'700 m uphill altitude difference, and 4) Swiss Epic two days flow = 88 km, 1'950 m uphill and 3'800 m downhill altitude difference. All four race formats can be contested as team or one-man race, which makes the event attractive for amateur and elite mountain bike riders. No ethical approval was required for this observational study as no personal data was collected.
Inclusion and exclusion criteria were set a priori. In a first step, incomplete data sets in terms of gender, age, riding level and injury reporting were excluded. In a next step, due to the low number of female respondents, female participants were excluded to ensure comparability and homogeneity of the data. The remaining data sets were used to assess the prevalence of injuries. In a last step, to document injury related outcomes and predictive factors for severe injuries of elite and amateur riders, participants never been injured were excluded from the final analysis.
A face-validated questionnaire was designed in accordance with existing literature (Gaulrapp et al., 2001; Lareau and McGinnis, 2011). To access a maximum range of participants, the questionnaire was translated into English, German, Spanish, French and Italian by bilingual persons familiar with mountain biking. The participants were asked to tick the most appropriate answer. The questionnaire aimed to assess the athletes' 1) basic demographics, riding level and years of experience, 2) number of races per year and mean hours of training per week, 3) number and kind of suffered injuries related to mountain biking and medical treatment requirement, 4) and amount and kind of protective gear items.
Self-reported riding levels were classified into recreational, amateur, semi-professional, and professional mountain biker. For this study, the authors grouped recreational and amateur as amateur, semi-professional and professional as elite mountain bikers. Injury was defined as stated in Chow et al. (1993), namely, 'the presence of pain, discomfort, or disability'. An injury was categorized as severe, when a concussion and/ or bone fracture and/ or joint injury was reported. Skin and soft tissue injuries were classified as mild injuries as defined in previous studies (Gaulrapp et al., 2001; Kim et al., 2006). The number of races per year and the mean hours of training per week were used to estimate the total exposure time per year, meaning the total time at risk to suffer a mountain biking related injury. For that purpose, considering that a cross-country race lasts 1 to 4 hours (Lareau and McGinnis, 2011), the number of races per year was multiplied by factor 4 to transform 'racing hours' into 'training hours'. The injury rate per 1000 hours exposure time was calculated. First, the hours of exposure time per year were multiplied by the number of years practicing mountain biking to get the total hours at risk. Then, the total amount of injuries ever was divided by...