The below chart may help...
https://www.google.com/url?sa=t&sou...FjAAegQIAhAB&usg=AOvVaw2tWV2vIzW36huztOfpzaDx
This gives you a whole table of times for various race and rep distances... A good idea to start with would be to look at your 5km time. Then pick a 400mtr time which corresponds to about 30-45secs faster than your 5km time. Run the reps close to that speed. See how you get on and adjust from there....
https://www.google.com/url?sa=t&sou...FjAAegQIAhAB&usg=AOvVaw2tWV2vIzW36huztOfpzaDx
This gives you a whole table of times for various race and rep distances... A good idea to start with would be to look at your 5km time. Then pick a 400mtr time which corresponds to about 30-45secs faster than your 5km time. Run the reps close to that speed. See how you get on and adjust from there....