I find the best way to off-road prepare for the rigors of barefoot outdoor running includes a few bracing-balance combo drills. Try these as recommended & notice the on-road positive shift immediately:
1. 1-legged bent forward row – 60 secs/leg with hand weights (amt. determined by level of muscular endurance). Must brace whole core prior to action & centre weight over big toe of support foot
2. 1-legged squat with hand weights held tight vs. chest. Knee MUST align over 2nd toe during each squat. Hips must stay square. Whole core must be braced throughout. 60 secs./leg
3. 1-legged clean & overhead press. Hand weights that you can handle for 60 secs./leg. Must brace whole core throughout. Must pull weights from knee level to shoulders then press
4. 1-legged external rotation to overhead lateral raise with hand weights. Must centre over big toe with hips square & core braced. Arms rotate away from body with palms forward & then rotate overhead with palms forward. Must get arms overhead
Do this circuit 3 times every other day. You will notice significant improvement in your ability to hold the squat/scoot style of safe, efficient & powerful mid-foot running.