Method for Long runs in trails containing up-hills and down-hills

Suggested by coach Mr. Chen (wes):

在起伏多變的山路，則有變通辦法：上坡跑馬拉松強度（不是配速），極緩下坡跑馬拉松配速（不是強度），陡下坡慢跑（龜速），一般下坡和平地（如果有的話）則輕鬆跑（80~90% MP）。

Translation:

Run up-hills with marathon-intensity (instead of the pace), run very gentle down-hills with marathon pace (instead of the intensity), run very steep down-hills with very slow pace (like turtles), run general down-hills and flat surface with easy-run pace (80-90% marathon pace).