(Sorry, in spite of numerous attempts, I cannot post to the original
thread.)
I was very impressed with it's effects on me. I used to use it twice a
week for just two weeks in the periodised buildup that Lydiard
specified in his book. My version: 15--30 mins warmup; 400m. up hill
with exaggerated knee-lift (about 90 secs.), about 30 secs. jog, back
down the hill quite fast with 200m. fast stride. Each lap = 3 mins.
Four to eight repeats. But even four was very beneficial -- and in
just 12 mins. meaning that you could do a useful session in 15 + 12 +
15 = 42 minutes; and only 50 mins for six repeats.
Looking back through the diary, it seems I rarely did eight; six
often.
And after those two weeks onto light fartlek; and then after that,
some track.
One theory I heard about the springing action -- that the large
muscles above the knee (name?) are the largest in the body; and hence
the greatest consumers of oxygen; hence significant training of the
cardiovascular system. Plus flexibility training.
From my point of view, the downhill strides/sprints were important.
Many runners are scared to let themselves go on a downhill. I was able
to easily make 20 m. per 100m. on a downhill section on runners of
similar ability; and all for very little effort.
Best regards,