Both when I run “regularly” and when I run “in place“ I try to spend as much time on the balls of my feet.
It allows me to control the impact like a spring.
Running heel first, which feels more natural when running distance, leaves my knees hurting.
Running on the balls of your feet can tire your calves out quickly if you’re new to it, and can leave you too sore for the next day, so start slow.
Do 10m for a week or two until you feel your recovery has caught up, then 15m then 20m then 30m.
If I want to up the amount of energy I am expelling I will bring my knees up higher for as many strides as I can.
You will want to force yourself to keep a good running form when stationary because you can easily “fake it” and fall back on bad form of “kicking out” or “wobbling” which can impact your joints negatively.
Keep your feet pointing forward, raise your knees, and swing your arms just like you would when running distance.
Do it in a way that feels comfortable to you rather than in a way that feels weird and performative.
All in all the important thing is to get your heart rate up, and sweating is usually a sign that you’re getting some good cardio done.
The biggest thing for me was I wanted to get it done in 30m, but when running distance it took me 15m to prep myself for the run (get water and music ready, find my clothes and shoes, get dressed, ..). But with running in place my run is literally 30m of my time, every time.
Which made the most important part: just keeping a regular routine where you move your body; so much easier.