You have upvote from me.
Because iam also learn something from it. Usually we want to do some havy works but we did not know that its have practice. As you say if 300 miles running target. Its not possbl in 1st time when we practice in regularrly.
for exmpl
1st day 100 miles and next day 200 miles and your stamina will be good . then one day you complte your target 3oo miles will complte.