My wife and I just went out to walk our dogs (boxers, see attached). We walked about 1 1/2 miles at a pretty good pace. After 1/2 mile or so, my shins started hurting, almost like shin splints. My question is, are they shin splints? I just started back exercising and have ridden my road bike the last two days, 10 miles the 1st day, 13 1/2 miles yesterday. Do you think this is probably related to the biking or is it from the walking?