ive been jogging for a short while now and i have built up some endurence. but i wanna incorporate sprints into my runs. but i dont understand the whole concept. how fast should i be jogging before i sprint and how fast should i sprint. ive read you should jog for say 30 secs then sprint for 30 secs. but i jog pretty fast so how much faster do i need to go? also though ive never done this it sounds intense, so how long should a session last. i normaly jog for about 30 mins. also i run 4 times a week is that to much. i dont wanna waste to much muscle. so far no strength losses.
ps........i know these subjects have been gone over and over again. and i will probley get alot of "use the
search button" reply's but i coudnt find the specific answers. sorry about the long post. any answers appreciated
