To get yourself more acclimate to a higher rate for the 5K distance try shorter more focused pieces to get in touch with the higher rate rhythm while keeping strong on power.

Try:
warm up 5 minutes – 20, 22, 24, 26, 28 (85%)

Then:
1. 24 (5K pace), 26 (5k-2), 24
2. 26 (5K-2), 28, 24
3. 26, 30, 26
4. 24, 26, 30
5. 10 strokes ON, 10 strokes OFF FULL POWER for 3 minutes.