RE: Running

To improve running, I'd focus on the legs (obviously) and core.

For legs,

1. Calf strength is very important and the primary force propelling you forward when running. Calf raises are the go-to exercise. You can do them simply on the floor or from the edge of an elevated platform (like stairs) for added range of motion. Hold weight for increased difficulty. Note: I would not recommend holding weights while doing calf raises off the edge of something.




2. Tip toe exercises are another good way to focus on the calves. Tip toe/Sneaky lunges are great. You stand on your toes and deep lunge forward (back leg straight, front leg's knee over the ankle, & try to step forward as far as you can). Hold the tip toe lunge for a few seconds. Then bring your back leg forward back to starting position and repeat. Find yourself a fairly large area to do this. I workout in a large room and lunge from once side to the other. Ideally, you could do this on your walking path. Just set a distance for yourself. Doing the lunges while remaining on your toes the entire time may be hard at first, depending on your balance and leg strength, but gets easier with practise as most things tend to do. Another good one is Gap Jump or Monster Truck Tires. Just pretend there's large tires on the ground and you're jumping from and landing on your toes from the center of each imaginary tire.
   




3. Squats are good. Aside from the normal ones, there's Goblet Squats where you hold a weight in your hand while squatting. Deep/Floor Touch Squats (no vid?!) where the feet are pointed slightly outward and you squat down as low as you can and/or touch the floor with hands then squat back up. Two one-legged squat variations with [Super] Skater Squats and Dead lift Squat. Oh and then there's the Wall Squat. If you're feeling froggy, there's One Leg Wall Squat.
   




4. Lunges can be done with body weight or added weights. Besides tip toe, there's three way lunges.

Core, I would suggest Wide leg Situps (you can cross legs indian style to make harder) & Pulse Ups (don't rock the legs back and forth as much as the guy in the vid does, should mostly be an up&down movement).

I recommend watching these videos and grabbing various exercises from it. Ab Ripper X Part 1 and Part 2. Legs and Back. Plyometrics (sorry, this is the best vid I could find of it).

I'll post about P90X sometime this weekend.