 The long distance track events gained popularity in the 1920s by the achievements of the " Flying Finns " , such as multiple Olympic champion Paavo Nurmi . The successes of Emil Zátopek in the 1950s promoted intense interval training methods , but Ron Clarke 's world record @-@ breaking feats established the importance of natural training and even @-@ paced running . The 1990s saw the rise of North and East African runners in long distance events . Kenyan and Ethiopian athletes , in particular , have since remained dominant in these events . 
 The long distance track events gained popularity in the 1920s by the achievements of the " Flying Finns " , such as multiple Olympic champion Paavo Nurmi . The successes of Emil Zátopek in the 1950s promoted intense interval training methods , but Ron Clarke <a href='null_genetive' title='1'><mark>'s</mark></a>world record @-@ breaking feats established the importance of natural training and even @-@ paced running . The 1990s saw the rise of North and East African runners in long distance events . Kenyan and Ethiopian athletes , in particular , <a href='been_done' title='2'><mark>have</mark></a> since remained dominant in these events . 
The long distance track events gained popularity in da 1920s by the achievements of the " flyin Finns " , such as multiple Olympic champion Paavo Nurmi . Tdasuccesses of Emil Zátopek in the 1950s promoted intense interval training methods , but Ron Clarke  world record @-@ breaking feats established the importance of natural training and even @-@ paced runnin . The 1990s saw thdaise of North and East African runners in long distance events . Kenyan and Ethiopian athletes , in particular , done since remained dominant in these events .