Constant 18 s/m
/2100 8:57.6 .5 .5 .5 (19.5)
2:08.0 7.9 7.9 7.9 (3.4 for 79m)
Was trying to do 1st half marathon ever in 1:30 but ran out of steam - found staying at 18 constantly very difficult - Maybe alternate and make it easier by doing 18 @ 2:10 & 20 @ 2:06 (as opposed to normal 2:08/2:04 respectively)