If you truly want to attack the three-headed muscle at the back of the arm, you need to use heavy artillery. The triceps contain a high percentage of type II muscle fibers (67.4%), and all three heads of the triceps are activated only when the resistance is high. After an adequate strength base is acquired, individuals who strive for symmetrical triceps should refrain from using light weights for high reps – many females fall into this trap.

The rectus abdominus is another muscle that’s often trained inappropriately. It too contains a higher percentage (greater than 50%) of type II fibers and should thus be trained accordingly. Doing an excessive amount of lower intensity reps for the “six-pack” muscle is not effective.

Bottom Line: If you’re tired of your arms flapping around in the wind, stop doing triceps kickbacks with pink dumbbells and start doing multiple sets of close-grip bench presses and parallel-bar dips. Use a decent weight, do them on a frequent basis, and you’ll shrink-wrap those arms in no time!