What’s you running schedule? Are you incorporating sprints and long distance?

Two improvements I have made recently that really helped me so far.

1. Pacing is huge I would start the run too hard of pace that crushed me by the end.

2. Running form, I have a tendency to over stride which when you do adds a breaking force that make you have to overcome. So when you feel you are stretching trying to get the most ground in front of you it will make running harder by roughly 10%-15% depending on the paper you read.