It's well known that tapering back from intense training before a major competition can improve muscle strength and overall performance. This relates mainly to a particular muscle fiber, the Type IIa muscle fiber. This is the fiber that gives our muscles short bursts of power for activities like sprinting and lifting. This fiber gets larger and has more power and spring when it has been given a break after a long, intense period of exercise. Significantly, it becomes smaller and less effective after months of heavy and intense training. Your coach is on the right track by having you taper your training before going to the championships.