It's been three days and I am on track with my streak: 10 miles on Saturday, 2.75 miles on Sunday, and soccer on Monday. And so far I'm feeling great!
"But Liz, does soccer count as running?"
"Well, you run when you play soccer, right?"
"So yeah! Soccer counts as running!"
Okay, but what exactly is running?
Running is defined as a gait in which all feet are in the air during a gait cycle. For humans, this is essentially a bounding or leaping effort: you push off one foot to leap into the air, both feet suspended above the ground, and then follow through on the movement via landing and then propelling forward to initiate the next leap.
Jogging and running are distinguished only by speed, unlike other pedestrian animals like dogs or horses who have distinct gaits for trots and gallops. Beyond these definitions you could spend hours poring over biomechanics books and slow motion videos to analyze gaits of runners. (I might have spent the last 30 minutes geeking out over available resources on the Internet looking for fresh tidbits, but I'll spare you the research paper).
I distinctly remember when I was a kid trying out for the first time for the local Classic soccer team. I initially struggled on the sprints. The assistant coach who was watching the sprints and recording times was marking me down very average in the list on his clipboard. My dad, who was a track and field runner in high school, noticed and yelled to me from the bleachers "Run on your toes!" On my next sprint I was faster, and over the years I became one of the faster players on the team. A significant source of the improvement came from working on my gait and foot strikes. There are essentially three types of foot strikers: heel strikers, midfoot strikers, and forefoot strikers.
Heel striking is exactly how it sounds: when your foot first makes contact with the ground it's via the heel. The majority of runners are heel-strikers, and there are several elite athletes who are heel strikers (though it's worth noting the majority of elite athletes are midfoot or forefoot strikers). While there's nothing out there supporting this, I suspect heel striking is a major reason you see running shoes with significant drop - that is, the thickness of the heel sole is greater than the thickness of the forefoot sole, so you'll see a "drop" in height towards the front of the shoe. The idea would be to provide greater cushioning in the area of most impact.
Midfoot striking is where you first make contact with the ground around the middle of your foot. You're not heel striking and you're not landing on your toes, but you're usually making contact somewhere around the middle of the foot.
Forefoot striking involves making contact with the ground on your toes or the ball of your foot. Some people who run forefoot strike may not even have their heel ever touch the ground. They look like they are just bounding along on their toes, keeping all their weight and power at the front of the foot. Most sprinters run with a forefoot strike.
So what's the correct foot strike?
Ha! Hahahahaha oh I am so not going to answer this question. 1) I'm not an expert in running mechanics, 2) I'm not a running coach, 3) Everyone is different and so the "correct" foot strike can vary widely, 4) There's a fun debate going on over the merits of different foot strikes, the forces on the leg and how the impact is absorbed, and so much more. Basically, there are a lot of conflicting opinions.
But I will tell you that I'm most definitely a forefoot striker. ;)
So what else do I need to know?
Of course there's so much more to the what of running besides just leaps and foot strikes: cadence, arm swings, torso posture, etc. etc. etc. But in my (non-medical-please-consult-a-doctor-before-you-ever-listen-to-me) opinion, the most important thing to know about what is running is what is running for you. Know how you run - what feels efficient and pain-free to you - and pay attention to how that changes, whether you experiment with improving your gait or if you just notice how your gait changes when you get tired through the progression of a run. For as many people there are in the world, there is an equal number of ways of running, and that's okay, as long as you're running happy and injury-free.