Have you read any of the stuff written by the East Germans or former Soviets on aerobic conditioning and special strength training? I haven't read much of their actual work, but I have read some of the stuff of people who apply their work. At least with Verkhoshansky, he doesn't recommend traditional strength training. With long distance runners who do not have any strength training background, he does recommend traditional strength training as a primer for his special strength training recommendations. He primarily utilizes light jumping squats for strength training. He also utilizes cable hip flexor exercises, which I don't know if are useful. In addition, he utilizes slight incline hill runs and skipping-type running with little to no bending of the knees.
I don't know if many elite endurance athletes follow the Block Training Model, but in the block training model for endurance athletes, the various components are developed in this manner:
Block 1 cardiac output and peripheral circulation, oxidative capacity of slow twitch fibers, contractile capacity of slow twitch and fast twitch fibers (LSD, bouncy running, aerobic fartleks, uphill running, etc.)
Block 2 myocardial (contractile) power, contractile capacity of slow twitch and fast twitch fibers, oxidative capacity of fast twitch fibers (repeated and interval running),
Block 3 power output of specific work (interval running and competition running)
Basically, Block 1 is low intensity work on both the running and strength training side. These have the longest residual training effects and interfere with each other the least. Block 2 is higher intensity work. Block 3 brings everything together with specific competition work.
Also, Lyle has an article series going on right now on endurance training that is probably worth reading.
Also, note this from Chapter 9 in "Strength and Power in Sport," which is edited by Paavo Komi. Chapter 9 is written by Walter Herzog and Rachid Ait-Haddou from the University of Calgary:
Research that Dr. Herzog has performed indicates that the force-length
relationship of a muscle will adapt to the particular activity the
individual performs. In runners, the in-vivo force-length relationship
of the Rectus Femoris muscle is exactly opposite that of a cyclist. In
runners, in-vivo measurements of the force-length relationship of the
Rectus Femoris muscle revealed a positive slope while for cyclists the
force-length relationship had a negative slope. This occurs because in
running the rf. muscle undergoes a SSC and larger force is required at
longer muscle lengths whereas for cyclists, the rf. muscle only
shortens and force is produced at shorter muscle lengths.
It was concluded that the specific mechanical muscle adaptations that
occur in response to chronic running versus chronic cycling would
prevent a champion in cycling from becoming a champion in running and