As the London Marathon approaches along with the Beijing Olympic Marathon, training seems to be going quite well for the young American.
However, based on most research, and I am sure Renato Canova would agree, that perhaps it is a mistake that Hall has increased the pace of his long tempo runs. The key to marathon training lies in extension, not speed.
For example, if prior to NYC-Olympic Trials, Hall ran a 10M tempo at 4:55 pace at altitude, a progressive improvement upon that fitness and workout would not be 10M at 4:50 pace, but perhaps 12-14M at 4:55 pace. Extension is the key, not running faster, a common mistake among the American training system.
Just some thoughts, but I am looking forward to Hall attempting to break the field at 35km.