Please gimme some ideas on how to strengthen them.
Do you do dead lifts? Any type or variation of any of the Olympic lifts (i.e., cleans, snatches, and pulls)? Check out issues #7 and #14, Charles gives some workouts for the traps. In # 39, Ian King has a workout. Also, type “traps” into the search box and click on the first “Question of Strength” that comes up, I couldn’t find the issue number for it, but it’s another Poliquin routine. Also, follow Ian’s advice for bringing up a lagging body part, work it first in the week, first in the workout.
Do deadlifts, barbell shrugs, dumbell shrugs, power cleans, power snatches…not all at the same time…but alternate between those exercises.
Traps respond very well to german volume training. I would use either 10 x 10, 1 minute rest using dumbbells (20 rep max weight) OR do Clean Deadlifts (first portion of a power clean, do not go beyond bending the arms) 10 x 6 using barbell with 10 Rep max.