2500m x 4 (rest 3m) R24/26/24/28 R24 at 2km plus 12. Increase 2-3s/500m for the R26 and a further 2-3s for the R28. 2K plus 12 means that the pace for 500m shown on the monitor is 12 seconds slower than their average pace for their fastest 2000m effort (so for a 8:00 2K – the average would be 2:00 – therefore 2km plus 12 would be 2:12/500m)