I am training to compete in the New York Senior Games and at the Masters Levels in the US Track and Field events.  I have very active  for the last 15 years and recently joined a small racewalking group near Albany, NY.   My goal is to compete next  year when I hit 55, but I want to shed about 15lbs, work on my racewalking form, and enter at least six or seven events  5K in 2009.  Eventually I would like to compete in the 10K.

I am currently walking, rollerblading or biking at least 5 days a week.  My walking program consists of some speed training of 1-2 minutes with 30 to 60 second recovery time for 3 miles,   5K time trial,   and 4 to 5 mile walks. 

What else could I add to my routine to increase my strength or stamina of my racewalking ?

Any suggestions to improve my efforts would be appreciated.