This week was a good example of a four-day workout week.
Monday - 2.5-mile Run; 1 Core Strength Training Circuit
Tuesday - 2.5-mile Run, 1 Mile on the StairMaster
Wednesday - Day Off
Thursday - Day Off
Friday - Weight Training
Saturday - Day Off
Sunday - 4-mile Run
Dead Lifts w/ a Row (I use a 35 or 40 lbs. bar)
Forward Lunge with Press(using a lat pull down machine or something similar, ensuring that it's set at shoulder height)
50 Jumping Jacks Holding a Balance Bar at Chest Level (15 lbs.)
I can't stress how much I believe in interval and core strength training when you're race training. Check out Hal Higdon's website. His training programs always incorporate interval and core training, which will prevent injury and increase your endurance as you log miles. The best part is that you can find ways to incorporate these in your schedule if you can't get to a gym.