Running Formula reader wrote:
Question dude3 wrote:You also may just be too old or may not train for shorter races--or be too heavy. Most competitive runners are about 135-145 pounds at 5'10." Add or subtract about 5 pounds for each inch above or below that height.
A heavy person usually has less problem with shorter distances. If OP has run multiple marathons and half marathons, weight is probably not a major issue.
My suspicion is that OP is a relatively old runner who doesn't do much of speed work.
He could still be fat. Marathon Manics has a bunch of overweight, though not obese members that complete a lot of marathons with little training. These guys run 15 miles a week and then run/walk two marathons a weekend. Craziness.\
But your suposition is more likely.