The athlete should be capable of normal running before starting this exercise. (sportsinjuryclinic.net)
It sounds like your control system is working for pump / cold start assist, but not providing fuel at all for normal run operation. (mechanics.stackexchange.com)
The team tested two different «assistance profiles,» or patterns of wire - pulling: one based on human biology that applied force starting at the point of maximum hip extension observed in normal running, and one based on a simulation of exoskeleton - assisted running from a group at Stanford University that applied force slightly later in the running stride and suggested that the optimal point to provide assistive force might not be the same as the biological norm. (sciencedaily.com)