Run Faster With Long Legs?

As I tire in races my stride becomes longer. Psychologically, I think I am going further faster. Where is that finish line?
But studies show that athletes (I'm just a runner) shorten their stride as they speed up. They increase their cadence (foot step per minute.) They become a more efficient running machine.
In races, as diversion, I check out runners' strides; some step very high, others kick out behind. Some appear to have way more energy than me. I feel like a sloth... but often I beat them to the finish line.

"One of the most common mistakes novice runners make is over-striding, which is landing the foot fall too far in front of their center of gravity, actually reducing momentum and increasing chance of injury." - RGR

GALLOWAY confirms over striding can set yourself up for injury.
Knee pain -> stride to long?
Sore hamstrings -> stride to long?
Shin pain -> stride too long?

So my goal is to evaluate and then increase my cadence.
{I still need a new watch - any recommendations?}