My husband John, my sister-in-law Tracy, and I ran the Philadelphia Marathon yesterday, along with 7,465 other marathon finishers. The Philly was Tracy’s first marathon ever. For John and I, this was the first race we’ve ever done with more than 1,000 entrants. Including the half marathon and the 8k, there were about 15,000 runners in yesterday’s events. The last race I ran had about 600 runners. The collective energy of that many runners along with the thousands of spectators was invigorating, contributing mightily to a successful race day for all three of us. Philadelphia is a special place for …