The first aim of the present study was to analyze participation trends of East African runners in Swiss half-marathons and marathons held between 2000 and 2010. The second aim was to compare performance and age of African runners and Non-African runners. The main findings were (i) a stable annual number of Kenyan and Ethiopian finishers in both half- and full-marathons while the number of Non-African finishers increased for both men and women, (ii) a higher number of male African finishers compared to female African finishers, (iii) faster race times for African athletes in half-marathons for both men and women, (iv) similar race times for Africans and Non-Africans for both sexes for marathons, and (v) no difference in the age of peak performance for top African and top Non-African runners for both sexes in half-marathons and marathons.
Participations of East African runners remained stable in the last decade
In contrast to our hypothesis, the number of Kenyan and Ethiopian finishers remained stable for both men and women in both half-marathons and marathons. The increase of African men in half-marathon and marathon was due to other African countries, which were not analysed in details. In contrast, the numbers of male and female finishers in Non-Africans increased in both marathons and half-marathons. This finding correlates with results presented by Jokl et al.  reporting an increased participation in general over the last 30 years in a large city marathon such as the ‘New York City Marathon’.
Regarding the studied running events, African mainly competed at larger marathon and half-marathon events (e.g. Greifenseelauf, Lausanne Marathon, Hallwilerseelauf, Genève Marathon for UNICEF and Zürich Marathon). In all other races, there were five or fewer Africans competing during this period. We assume for smaller events lower budgets and these events were less prestigious. Interestingly, the ‘Lucerne Marathon’, the ‘Maratona Ticino’ and the ‘Winterthur Marathon’ were all among the seven largest running events for half-marathons and marathons. However, fewer than four Africans were participating annually per race between 2000 and 2010. In personal conversation with the race directors from the ‘Lucerne Marathon’ and the ‘Winterthur Marathon’ we learned that prize money was less than 200 Swiss francs (i.e. about 220 US dollars) and no promotional fees were offered either for African or for Non-African athletes. They further reported a decline of the prize money over years leading to less attraction for elite African athletes. Therefore, they races become more attractive for regional marathoners and half-marathoners. So in common beliefs the opportunity to win the race increased in absence of the elite East African athletes. Other personal communications with the race directors of the ‘Greifenseelauf’, the ‘Hallwilerseelauf’, the ‘Zurich Marathon’ and the ‘Lausanne Marathon’ (i.e. races with a high number of African participants) revealed that special prize money and promotional fee (especially for board and lodge) for elite African athletes were offered. They specially invited elite athletes in general to make their competition more interesting. Perhaps from the ‘Maratona Ticino’ and the other races no data for prize money were available and beside the ‘Winterthur Marathon’ only from the ‘Lausanne Marathon’ an amount of the prize money was given .
According to poverty and unemployment in East African countries, Onywera  and Onywera et al. reported that the motivation to become a competitive athlete was mainly based on economic reasons for Kenyan elite athletes especially for 39% of all national athletes and 33% for international athletes. The international success of the East African running pioneers such as Mike Boit, Kipchoge Keino and others implicated a ‘westernation’ of the culture, especially in Kenya . Therefore, running became more professional and more popular in Kenya. Affected by the great international success of the East African running pioneers, young athletes know about the possibility of becoming a successful international athlete. Motivation of competitive running therefore increased and young East-African athletes became support by managers of Western countries. So the East African athletes came closer to the Western civilisation and according to this theory of closeness the chance to make money with competitive running increased. Based on this sociocultural background and according to our different findings in participation of East African athletes in Swiss long-distance running events and personal conversation with the race directors the question about a correlation between prize money and participation went up. In addition, the respondent race directors from running events with a large number of Africans reported a stable budget for invited elite athletes. Therefore, the possibility to make money with competitive running in Switzerland is limited and the annual number of Kenyan and Ethiopian participants remains stable. For further studies it would be interesting to analyse potential correlations between prize money and participation of African elite athletes in larger countries (e.g. USA).
Kenyan and Ethiopian participation
During the studied period there were more African men than African women competing. The same can be reported for Non-African athletes. Participation differences between men and women are common findings in sports events. In 1988 at the Olympic Games in Seoul (KOR) only 26.1% of all participants were women . Compared to the XXIX Olympic Games in Beijing (CHN) in 2008 women increased their percentage of participants up to 42.4% . So, especially in earlier years there were restrictions on female athletes. In Kenya, women were banned from international competitions until the 1970s . Regarding the percentage of female participants at the Olympic Games in Seoul, 5.5% of the Kenyan team were women. They increased their participation also up to 39.1% in the Olympic Games in Beijing (2008) . Therefore, the female running culture has not such a long time history as that of men. The Kenyan men were well established in long-distance running since years. But today, a female running culture is growing in Kenya and it is also a great honour for female athletes to represent their country in international competitions . Participation of Kenyan woman increased with a delay of several years compared to Kenyan men. Also in Ethiopia, there was a similar development. Comparing Olympic Games in 1980 (Ethiopia took not part in the Olympic Games in 1988 and 1984) and 2008, Ethiopian women increased their participation from 4.9% to 48.1% . These reports may explain the difference between female and male participation trends of Kenyan athletes in marathons and Ethiopian athletes in half-marathons.
More interesting seems the fact of the difference in participation in male Ethiopian and Kenyan athletes in both half-marathons and marathons. Compared to their Ethiopian counterparts, more Kenyan men were participating in marathons and fewer in half-marathons. A possible explanation for this might be differences in anthropometry between Kenyan and Ethiopian runners. Ethiopians are more mesomorphic in somatotype, which includes more muscle mass especially expressed in a high thigh circumference . Kenyans in contrast are more ectomorphic with slender legs . Zillmann et al. showed differences in anthropometric characteristics between recreational marathoners and recreational half-marathoners competing in Switzerland. They reported for half-marathoners a thicker thigh circumference compared to marathoners . To the best of our knowledge anthropometric characteristics of Ethiopian runners have not been analysed yet. Based on reported differences in anthropometry between Ethiopians and Kenyans  we can only speculate that Ethiopian runners were more predestined for running half-marathons than marathons. Therefore, we had a higher number of Ethiopian participants in half-marathons than in marathons. Also in the IAAF top list from 2011 in marathons and half-marathons there was a significant difference between the number of Ethiopian and Kenyan runners for the top 20 race times . In the top 20 marathoners there were 20 Kenyans . In half-marathons there were 13 Kenyans and 9 Ethiopians ranked . Future studies need to analyse anthropometric differences between Ethiopian and Kenyan long-distance runners.
In the two largest marathons held in Switzerland, the ‘Zurich Marathon’ and the ‘Lausanne Marathon’, a reverse trend was found regarding the participation of male East African marathoners. While the participation decreased in the ‘Lausanne Marathon’, it increased in the ‘Zurich Marathon’. Most probably the prize money was higher in ‘Zurich Marathon’ compared to ‘Lausanne Marathon’ during this period.
Elite African marathoners were not faster than elite Non-African marathoners
There was no difference in race times between elite African finishers and elite Non-African finishers in marathons. This finding does not support the hypothesis of a better running performance of elite African runners compared to Non-African runners and was not in line with the anecdotal well-known African dominance in the literature regarding long-distance running [8, 9, 20–23]. Comparing maximum oxygen uptake (VO2max) between elite Kenyan and elite Non-African runners, disparate findings were reported [8, 21–23]. Therefore, VO2max as an important predictor variable of performance was critically discussed and in general there is no difference between Kenyan and Non-African runners . Also, no differences were found in proportion of muscle fibers and muscle oxidative enzymes [8, 21]. Running economy, defined as the steady-state of submaximal oxygen uptake at a given running velocity, was further critically discussed as an important factor of performance . Saltin et al. reported a better running economy for Kenyans while Bosch et al. reported no difference in the oxygen uptake at given performance levels. In summary, no significant physiological differences between elite African runners and elite Non-African runners could have been found yet and this goes in line with our unique results in marathons.
Nevertheless, regarding the IAAF top list of marathons and half-marathons and corresponding to common beliefs, East African runners had better running performances than Non-African runners . Why do marathon events in Switzerland differ to marathons held in other countries? A plausible explanation might be the thesis that not the top of the top East African athletes were competing in Swiss long-distance running events because they were less prestigious and there was less prize money to win. For example in the Lausanne marathon there were about 2,150 U.S. Dollar (i.e. 2,000 Swiss francs) for winning the marathon . Comparing to the ‘New York City Marathon’ as the most prestigious marathon event worldwide the winner got about 100’000 U.S. Dollars . To confirm this thesis about ‘second class’ elite East African runners in Swiss marathons further studies should analyze East African performance trends in larger countries. Especially performance findings of East African athletes from the World Marathon Majors (i.e. a collective of the worlds’ largest marathon events) should be compared to our data of smaller country with smaller races.
Top African runners were faster than top Non-African runners in half-marathons
Interestingly, elite African athletes were faster than elite Non-African athletes in half-marathons. This finding reflects the general opinion, anecdotal findings and international top lists of the IAAF  and goes not in line with our results found for marathons. Based on scientific literature we cannot explain this fact with physiological differences between Africans and Non-Africans. An explanation might be different sociocultural backgrounds and differences in running experience. A recent study compared a variety of predictor variables for performance between half-marathons and marathons . The authors reported that marathoners had a larger number of completed long-distance competitions in their running history than half-marathoners. So in Switzerland, marathoners start their running career with half-marathons to gain experience . Relatively to the world records 2011 in half-marathons and marathons  Non-African half-marathoners differ to Non-African marathoners in race times. The top Non-African race time in men’s half-marathons was 7.3% away of the world record. In marathons, however, there was only a gap of 3.4%. In Swiss long-distance events Non-African marathoners were better than half-marathoners in the worldwide ranking. More newcomers and recreational runners were competing in Swiss half-marathons might be a possible explanation for this. Non-African recreational runners were motivated for running by health benefits [2, 4]. It is possible to run a favorable performance beside a workaday life because not as many training kilometers and training units are needed for half-marathons compared to marathons  which is essential in Switzerland. Therefore, with a lot of newcomers in Non-Africans the possible top race time have not been reached yet. In contrary, top African runners were professional runners with a large running history since childhood and they were also driven by economical reasons to compete in Swiss half-marathons [25–27]. So, they run better performances compared to Non-African athletes in half-marathons.
Elite African runners were not younger than elite Non-African runners
In contrast to our second hypothesis, elite African finishers were not younger than elite Non-African finishers neither in half-marathons nor in marathons. First, the majority of African runners in Switzerland between 2000 and 2010 were elite East African runners (76.7%) from Ethiopia (39.5%) and Kenya (37.21%). Performance is limited by age-related physiological changes. The maximal oxygen uptake (VO2max), as one of the most important factors, declines with age [3, 10, 14, 16, 18]. In addition to VO2max, the maximum heart rate (HRmax), the lactate threshold and the running economy change with age. HRmax significantly decreases with age [10, 15, 16], the lactate threshold, as the exercise intensity (%VO2max), increases significantly with age [10, 17, 19]. Top performances in long-distance running events will be achieved at younger ages (<40 years) [1, 3, 6] for both Africans and Non-Africans. Therefore, we can explain the same age of top performances comparing African and Non-African athletes in marathons and half-marathons. Especially in half-marathons, there was no age difference but a significant difference in performance between Africans and Non-Africans. This could be explained by an age-dependent loss in performance as well. The correlation between age and performance is relatively and not absolutely. So, within each group peak performance will be achieved at the same age regardless of a difference in performance between these two groups. The difference in performance would be explained by the fact that Non-African athletes have not reached their possible peak performance yet and not by age-differences.
Strength, weakness, limitations and implications for future research
A strength of the present study is the high number of runners analyzed in marathons and half-marathons from one country for an entire decade. To date, a demographical analysis about participation in marathons and half-marathons in such a way is unique. However, this study is limited in that determining factors for performance such as training, anthropometry, physiology, nutrition and motivation were not included. A limitation is also that data about prize money only was given in personal conversations with the race directors. Future studies should investigate participation, age and performance trends in marathoners and half-marathoners in larger countries such as the United States of America in order to strengthen demographic research. In addition, psychological and sociocultural backgrounds of the motivation of East African runners in relation to participation trends in half marathons and marathons should be analyzed in-depth.