No surprises.

Three groups of runners were equalized as Novices (layoff from any training for an equal amount of time) and then conducted the same running program. The training difference was the three groups used a 5x5 program ("heavy strength training"), 3x5 lifting with plyo ("complex training") and high repetition ("endurance strength training").

The two group training with sets of five had similar good benefits to their running results while the high rep group had the worst results despite being novice trainees in an endurance sport.

Concurrent complex and endurance training for recreational marathon runners: Effects on neuromuscular and running performance - PubMed

Why Heavy Strength Training is Most Effective for Runners - Jason Koop

"HST (heavy strength training) and CPX (complex training, mix of strength training with plyo) produced similar improvements in maximum strength, power (as ascertained through the squat jump and countermovement jump) running economy and vV02max. Additionally, HST and CPX resulted in greater eccentric strength and running economy improvements than the low weight, high repetition EST (endurance strength training), which showed some marginal and not significant improvement. This adds to the body of literature that overall favors heavy and/or plyometric strength training being superior to low weight, high repetition strength training specifically for running (and in many cases other types of endurance) performance.

"In addition to this, one of the interesting ways the research team standardized the groups was that all of them abstained from strength training for the prior 6 months before the intervention. Normally when this is the case, any intervention results in a meaningful positive adaptation simply because the training stimulus is novel as well as an overall increase in training load (you are adding strength training on top of your normal run training). So, when you look at the fact that the EST (low weight, high rep) produced basically no response despite the intervention being additive to the underlying run training load and despite it being novel, you could easily say that it was a waste of the athlete’s time.

"The literature is starting to demonstrate more and more, you are better off taking that time you are spending doing a billion bodyweight step-ups and redirecting it into a handful of heavy squats"