Anyone is fairly range-limited when it comes to mpw, so what is the consensus here? Would running at or near-peak mileage + adding some doubles on the Arc Trainer help? Hurt because of recovery time? Hurt because the "distribution" of muscles used isn't exactly that of running? The lack of impact means that certain muscles are by definition underused, but perhaps is ideal in the case of someone (for example) suffering from posterior tibial tendonitis, or a stress reaction, I don’t know. I'm mostly asking about regular joes in their 30-40-50s, not college athletes. I am of the belief that we must constantly build a runner's body to continue running...even if/when hurt (if can still run).