Yes they did. Coan and Karwoski used a linear periodization program (and Westside hasn’t touched their strength levels) that began with loads less than 80% for several weeks. Hatfield and most European lifters, past and present, used a preparatory or hypertrophy phase with lighter weights.
10-15% is a HUGE difference than “relying on” +90% weights. Of course maximal weights must be used to peak for competition. However I personal make much better strength gains with 75-85% weights and testing a 5RM instead of 1RM. Since sprinting involves an endurance component, training exclusively for a 1RM doesn’t make sense.