Running barefoot or forefoot takes time:

After running a little faster with more focus on forefoot landing, we noticed our knees got a little sore. This might be more due to where my foot lands.
So today hit the treadmill in my vibrams. Hitting the foot with my big toe and one next to it first. How one's foot and foot muscles work harder this way. Maybe we just have to get used to this.

So for those with runner's knee or just trying to transition to forefoot running, it takes time and a gradual build up.

There's also the glute, hamstrings and hip exercises along with balance and running drills. So far haven't found the magic 3 exercises to strengthen your core for running. It's more like the dozen.

My list of core exercises for running include:
Crunches
Wall sits
Glute bridges
Walking sideways with stretchy
Single leg squats on step
Quick straight legged jumps on forefoot (good for warmups)
Plank
Side plank
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