10k run, on your own and report time back to me.
4 x 100′ sprint, all times must be equal to or less than the previous
2 x 200m sprint, all times must be equal to or less than the previous
Working on shorter distances will help you with longer distances. This has been proven time and again. What is important is to work your way up to these longer distances so you can truly train your endurance and stamina. Sometimes we avoid these longer distances becuase they seem too hard, too long, too boring, whatever the reason. By doing this we are essentially cutting out 2 of the 10 elements of optimal physical fitness. So start where you can; one mile, two miles, walk half and jog the rest until you can get the distance. If you aren’t able to run for injury or medical reasons, do the bike or rower. Ask what a comparable distance would be.