I suspect those are Phil Wood style axles with a dropout adapter sleeve covering an oversized steel axle. The oversize axle is substantially more resistent to bending. Bent alxles are more a case of the wheels taking heavy impacts (i.e. rail lines, potholes, etc.) than rider power. At 170 lbs you're not light and this will be a factor in the impacts, unless you're off the saddle and try to unweight the wheels and/or absorb the impact with the knees and elbows.

Matrix was Trek's house brand of components.