In weight training, and usually in regard to powerlifting, the term "ancillary" refers to muscles that offer support and aid other muscle groups. The ancillary muscles are those that help the main muscles in the three lifts -- squats, bench presses and deadlifts. The main muscles working in these moves are the quads and hamstrings when squatting, the chest in bench pressing and the hamstrings and lower-back in the deadlift. All ancillary work should target the other muscles that help out with the lifts.
Supporting the Squat
Your quads may bear the brunt of the load when squatting, but your hamstrings, glutes and core are also of massive importance. Three moves should make up the bulk of your squat ancillary work, according to strength coach Chad Wesley Smith, holder of a 905-pound raw squat. The first of these is the speed squat, performed with the same form as normal squats but using only around 60 to 75 percent of your usual squatting weight and focusing on moving as quickly and explosively as possible. Next up are dead squats, performed with every rep starting from a dead-stop on safety pins in a power rack. Third, Smith recommends squats performed with a safety bar -- a specialist bar that has handles protruding from the front and forces you to keep a more upright torso than regular squats.
Building the Bench Press
Your chest is involved heavily in bench press, so chest moves such as dumbbell presses and incline bench presses can make up some of your ancillary training, but you also need to work your shoulders, triceps and upper back. Elite powerlifter and trainer Eric Lilliebridge recommends triceps extensions, close-grip bench presses and partial bench presses for your triceps along with lateral raises for your shoulders. Powerlifting coach and trainer Andy Bolton suggests targeting your upper back with pullups or pulldowns, dumbbell rows, machine rows and shrugs.
Dominating the Deadlift
Aside from your glutes and lower back, the ancillary muscles in the deadlift are your glutes, core and middle and upper back. If you're weak off the floor when deadlifting, include deficit deadlifts standing on a small box, good mornings and box jumps, coach Jordan Syatt of Syatt Fitness advises. If you tend to struggle near the lockout portion of the deadlift, however, you need hip thrusts, elevated deadlifts or rack pulls and extra glute and hamstring work, he notes.
While working your ancillary muscles is important, don't lose sight of the fact that to get a bigger squat, bench press and deadlift, you need to squat, bench press and deadlift. That means performing all three regularly and aiming to consistently add more weight or more reps while maintaining good technique. Start each workout with one of the main lifts for three to six sets of three to eight lifts, then pick two to three appropriate ancillary exercises for three or four sets of six to 12 reps each.