A new challenge (looking for feedback!)

TRAINING REPORT:

Not much of a training report today.  It was Wednesday, and therefore I did Kettlebells. I put in a moderate effort, going more for sustained cardio and higher reps on one weight down from what I'd use if I was going to shoot for lower reps and working to fatigue.  My inner hammies and glutes were still recovering from my previous workouts and throwing around the heavier kettlebell is known to target those areas.  

Thinking ahead to the 5 mile tempo run Thursday, I elected to not beat the crap out of myself.  I had hoped to do some more work on getups with the 24kg weight, but after doing a set of pushups to failure in the middle of class, my shoulders were having enough trouble with the 16 and I didn't feel like getting concussed as a 24kg kettlebell bounced off my skull.  Maybe next week.

2011-MAR-16 Diet Log

I found that I mis-tracked a few items earlier in the week, so for a few days my Bonus 500 was more of a Bonus 400

MUSINGS:

Tonight, on somewhat of a whim, I obliterated one of my 2011 fitness goals - the 4-minute plank.  It was one I knew was going to be a soft-ball as a goal for the year and I planned to reset the goal once it was accomplished.  A friend of mine from college has recently been stalking me on Facebook and has been getting himself back into shape and is also training for a marathon.  I had mentioned that I had this goal and was (at the time) hanging around the 3 minute mark.

He was new to the concept of the plank (image above) and, after trying one and "shaking like a leaf" (I think that was the quote), he, too, set his sights on the 4 minute mark.  This week, the little bastard got there.  I hadn't tried one for duration in at least a month, so I gave it a go to see where I was.  What I didn't count on was the display on my Droid going to sleep within the first minute, so I didn't have much of a reference point for most of the duration.  After what felt like an eternity holding the plank, I was able to wake up the phone without breaking form.  The display read 4:33.  Holy crap!  At 5 minutes, I dropped my knees and killed the timer.

So now I'm trying to figure out how to raise the bar.  5 minutes was tough, but there was more in the tank tonight.  I don't know where to go from here.  Plank with weight on my back?  Plank with feet elevated?  Plank with alternating leg raises (lack of coordination may defeat that idea; I also think that shifting position takes something away from the challenge)?  One idea I had was to, in the same workout session, run a mile in the same time I would hold a plank for.  So, if I could get to run a 6-minute mile, I would have to do a 6 minute plank.  If I can hold a plank for 6:30, I have to run a mile in 6:30.  If I go that route, I'm trying to think of a good 3rd exercise to throw in for equal duration.  Any ideas??