Stiff Knees

I'm rather new to running.  I started about two months ago and average about 10 miles a week.  I'm wondering about the stiffness in my knees.  Not pain, just tightness.  Soon I plan to bump my running up to 5 days a week and want to make sure I don't injure myself in the process.  Research needed.

Currently my running plan (provided through the Memphis Run Walk Training Program) is as follows:

Workout Plan

 

Weeks 1&2 at 17:00-18:35 minute/mile pace.

 Week 1: Run 1 min, walk 2 min for a total of 20 min.Week 2: Run 2 min, walk 3 min for a total of 25 min.

Weeks 3&4 at 16:30-18:05 minute/mile pace

 Week 3: Run 2 min, walk 3 min for a total of 30 min.Week 4: Run 3 min, walk 3 minute for a total of 30 min.

Weeks 5&6 at 16:00-17:35 minute/mile pace

 Week 5: Run 3 min, walk 2 min for a total of 35 minWeek 6: Run 3 min, walk 1 min for a total of 40 min

Week 7, 8 & 9 at 15:00-16:35 minute/mile pace

 Week 7: Run 4 min, walk 2 min for a total of 40 minWeek 8: Run 4 min, walk 1 min for a total of 45 min LABOR DAY WEEK

Week 9: Run 4 min, walk 1 min for a total of 50 min

 

Week 10:  Taper and Saturday is RACE DAY!!