Frank Ruona, the flinty 71-year-old at the hub of “26.2 to Life,” is not prone to effusiveness. When addressing members of the 1000 Mile Club, Mr. Ruona keeps his remarks to the point: “Less than 1 percent of the population have finished a marathon. So, if you can go out and finish a 26.2-mile marathon you’re … doing pretty good.” Body language tells all, as Mr. Ruona’s hand gestures and general demeanor intimate the strenuousness, if not the impossibility, of the endeavor at hand.