2500m x 4 (rest 90s) R20 Stick tight to 2km plus 18 2K plus 18 means that the pace for 500m shown on the monitor is 18 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 18 would be 2:18500m)