This is a pretty convincing 40 week study - using 20 competitive distance runners - demonstrating the beneficial effect of strength training on performance indicators in distance runners, those being running economy (RE) and vVo2max (velocity at VO2max), due to the increase in maximal, explosive, and reactive strength.
There was an initial phase, building maximal strength, then a secondary phase adding plyometrics etc. to increase reactive strength/explosive strength while also maintaining maximal strength gains.
I've always been a believer in using plyometrics as an adjunct to both my and my athletes' strength training programs and have seen the results. The evidence is both empirically and objectively convincing. Serious caveat: Build a strong foundation so your tendons and joints can withstand the force of landings. Strength first, then power.
The intervention group showed significant improvements in maximal and reactive strength qualities, RE, and VV̇o2max, at weeks 20 (p ≤ 0.05) and 40 (p ≤ 0.05).
This study demonstrates that 40 weeks of strength training can significantly improve maximal and reactive strength qualities, RE, and VV̇o2max, without concomitant hypertrophy, in competitive distance runners.