Last time I weigh 153lbs and I ran a 8km in 29:40 and now I weigh 157 and ran a 18:40 5km I'm disappointed
Last time I weigh 153lbs and I ran a 8km in 29:40 and now I weigh 157 and ran a 18:40 5km I'm disappointed
3 pounds isn't going to make/break your PR.
Age?
Current training schedule?
How much pace work did you do prior to the PR attempt?
Did you plan the PR to a specific window of time?
Diet?
Sleep schedule?
99% confident - yes losing weight will help you run faster.
Are you 4'10" tall? If so, then 4 lbs could be a big deal. Secondly, if you are comparing two race results then that isn't very representative. Run more races to get an idea of what you are really capable of.