"Intervals of this nature train the anaerobic lactic acid system, while also providing aerobic benefits." Use the following running program to get fighting fit.

WEEK 1
3km time trial (max effort)

WEEK 2
4 x 600m run (85%)
90 seconds' rest between,then 3 minutes' rest, then
5 x 60m sprint (95%+) walk back recovery

WEEK 3
4 x 600m run (85%)
90 seconds' rest between,then 3 minutes' rest, then
6 x 60m sprint (95%+) walk back recovery

WEEK 4
5 x 600m run (85%)
90 seconds' rest between,then 3 minutes' rest, then
6 x 60m sprint (95%+) walk back recovery

WEEK 5
3km time trial (max effort), then 3 minutes' rest, then
20-minute easy-pace run

WEEK 6
8 x 400m run (85%)
90 seconds' rest between,
3 x 150m sprint (95%+)
jog back (90 sec max)

WEEK 7
10 x 400m run (85%)
90 seconds' rest between,
3 x 150m sprint (95%+)
jog back (90 sec max), then
3 minutes' rest, then
3 x 150m sprint (95%+)
jog back (90 sec max)

WEEK 8
10 x 400m sprint (85%)
90 seconds' rest between,
3 x 150m sprint (95%+)
jog back (90 sec max), then
3 minutes' rest, then
3 x 150m sprint (95%+)
jog back (90 sec max), then
3 minutes' rest, then
3 x 150m sprint (95%+)
jog back (90 sec max)

WEEK 9
10 x 400m sprint (100%)
90 seconds' rest between,
3 x 150m sprint (100%)
jog back (90 sec max), then
3 minutes' rest, then
3 x 150m sprint (100%)
jog back (90 sec max), then
3 minutes' rest, then
3 x 150m sprint (100%)
jog back (90 sec max)

WEEK 10
3km time trial (max effort), then 3 minutes' rest, then
20-minute easy-pace run