For lat activation without biceps involvement try stiff (straight) arm pushdowns using a cable machine.

For trap activation, mostly Trapezius III and IV (the "lower" traps) try lying face down on an incline bench and performing dumbbell or barbell raises with the arms straight. Lift the weights until your arms as completely in line with your upper body (arms will be straight over your head). You can also perform this on the Smith machine, using the arms as "hooks", keeping the completely straight and lifting the shoulders.

Craig

Author of Bodybuilding: From Heavy Duty to SuperSlow

For lat activation without biceps involvement try stiff (straight) arm pushdowns using a cable machine.

For trap activation, mostly Trapezius III and IV (the "lower" traps) try lying face down on an incline bench and performing dumbbell or barbell raises with the arms straight. Lift the weights until your arms as completely in line with your upper body (arms will be straight over your head). You can also perform this on the Smith machine, using the arms as "hooks", keeping the completely straight and lifting the shoulders.