What a ridiculous study.     Of course all the participants in the study responded to changes in cadence and stride length by expending more energy.  It is hard to change! 

From personal experience, I had been jogging regularly (2x per week) for 1 year.  I was frequently dealing with pain from running.  In January this year I purchased a Garmin watch.   It highlighted that my cadence was very low (around 150) relative to strong endurance runners (around 180).  As a result I consciously paid attention to my cadence.   It took some weeks to change.   I've noticed a significant difference.  I'm able to run faster and longer and the injuries have stopped. 

Tweaking my stride was incredibly helpful.