This exercise will strengthen your lower abdominals.  It's sometimes easy to forget how important the abdominals are to runners.  We just don't use our legs and arms when we run.  We also rely heavily on our abs.  Without them, we wouldn't be able to lift our knees high off the ground. 

Also known as "bird dogs," this is a great overall core exercise.  It not only strengthens

the abs and back, but also involves the glutes and improves balance and stability.

When you do any exercise routine, it can be tempting to start compensating with your

back.  Avoid this at all costs!  Try to remember the muscles that you are targeting in

each exercise and AVOID relying on your back when it is not supposed to be used. 

No matter how careful you are, your back will probably feel some tightness from the

running and the whole body routine.  Stretch it out as you are nearing the end of the

exercises. 

Runners need loose calves!  A tight calf will cause the hamstring to tigheten...and a

tight hamstring will cause glutes and hip rotators to overextend and tighten....That's why

stretching the whole chain of muscles is so important.