First, here's an excellent NY Times video link demonstrating several good knee strengthening exercises.
Secondly, Brent Vaughn, sub 13:20 5,000m runner and former University of Colorado star, discusses the role of General Strength (GS) in his training. While he discusses this topic I've included an "uncut" example of pedestal routine (aka plank routine).
Brent Vaughn on General Strength from CoachJayJohnson on Vimeo.
Swiss Ball Exercises for Runners:
Swissball Exercises for Runners from CoachJayJohnson on Vimeo.
Five general strength routines (excerpted from link). These exercises are best done after training. But if you can't do them then, find another time during the day to set aside a few minutes for this routine. Your running body will thank you for the small investment in time. Demonstrating the exercises is Sara Vaughn, who owns PRs of 2:03 for 800m and 4:11 for 1500m.
Without further ado, here is the first video, which outlines the first phase of pedestal poses and the Myrtl routine.
Running Times: Part 1 from CoachJayJohnson on Vimeo.
The second video features a leg circuit as well as a more challenging pedestal routine than the first video.
Running Times: Part 2 from CoachJayJohnson on Vimeo.
The third video adds leg lifts to the pedestal routine and introduces the "Cannonball cooldown" routine. (Jazz fans will be happy to hear it's named for Cannonball Adderly.)
Running Times: Part 3 from CoachJayJohnson on Vimeo.
The fourth video introduces the "Grant Green" routine (more fun for jazz fans!), which adds few new exercises but is more than challenging thanks to its duration.
Running Times: Part 4 from CoachJayJohnson on Vimeo.
The fifth video showcases Leg Circuit #2, which we guarantee to cause a few wobbles the first few times.
Running Times: Part 5 from CoachJayJohnson on Vimeo.
Finally, here's a video link to usage of the Medicine Ball for Runners, which might be of interest: