@RoddersJ good luck! My best 5ks are around the same as yours and have had a long-standing vague goal of sub 20. Fartlek is fun (keeps the run interesting - aim for a lamppost or something) and conditions you to intensity.
As I was brain-farting above, don't neglect a warm up. If you're running at moderate pace now you might be warming up as part of the run to some extent. 4/km is going to hurt without some jogging first.
@RoddersJ good luck! My best 5ks are around the same as yours and have had a long-standing vague goal of sub 20. Fartlek is fun (keeps the run interesting - aim for a lamppost or something) and conditions you to intensity.
As I was brain-farting above, don't neglect a warm up. If you're running at moderate pace now you might be warming up as part of the run to some extent. 4/km is going to hurt without some jogging first.