Whether you’re working with die weight of a physical object (be it a barbell or a soup can), against the tension of stretchable exercise bands, or against the pull of gravity on your own body (leg lifts and curlups), the proper resistance-training program takes into account your fitness requirements, including: strength, flexibility, and stamina, in a way that does not overemphasize any one muscle group.

One day’s workout might focus on legs, buttocks, and midsection; another might center on back, shoulders, arms, and chest.

Major Muscle Groups

Gluteals – This group of muscles (often referred to as ‘glutes’) includes the gluteus maximus, which is the big muscle covering your butt. Common exercises are the squat and the leg press machine. The glutes also come into play during lunges, tall box step ups, and plyometric jumps.

Quadriceps – This group of muscles makes up the front of the thigh. Exercises include squats, lunges, leg extension machine, and leg press machine.

Hamstrings – These muscles make up the back of the thigh. Exercises include squats, lunges, leg press machine, and leg curl machine

Hip abductors and adductors – These are the muscles of the inner and outer thigh. The abductors are on the outside and move the leg away from the body. The adductors are on the inside and pull the leg across the centerline of the body. These muscles can be worked with a variety of side-lying leg lifts, standing cable pulls, and multi-hip machines.

Calf – The calf muscles are on the back or the lower leg. They include the gastrocnemius and the soleus. The gastrocnemius is what gives the calf its strong rounded shape. The soleus is a flat muscle running under the gastrocnemius. Standing calf raises give the gastrocnemius a good workout, while seated or bent knee calf raises place special emphasis on the soleus. These small muscles can handle a relatively large amount of weight.

Low back – The erector spinae muscles extend the back and aid in good posture. Exercises include the back extension machine and prone back extension exercises. These muscles also come into play during the squat and dead lift.

Abdominals – These muscles include the rectus abdominus, a large flat muscle running the length of the abdomen, and the external obliques, which run down the sides and front of the abdomen. Exercises such as standard crunches and curls target the rectus abdominus. Reverse curls and crunches (where the hips are lifted instead of the head and shoulders) target the lower portion of this muscle. Crunches involving a rotation or twist work the external obliques.

Pectoralis major – Large fan shaped muscle that covers the front of the upper chest. Exercises include push-ups, pull-ups, regular and incline bench press, and the pec deck machine.

Rhomboids – Muscles in the middle of the upper back between the shoulder blades. They’re worked during chin-ups, dumbbell bent rows, and other moves that bring the shoulder blades together.

Trapezius – Upper portion of the back, sometimes referred to as ‘traps.’ The upper trapezius is the muscle running from the back of the neck to the shoulder. Exercises include upright rows, and shoulder shrugs with resistance.

Latisimus dorsi – Large muscles of the mid-back. When properly trained they give the back a nice V shape, making the waist appear smaller. Exercises include pull-ups, chin-ups, one arm bent rows, dips on parallel bars, and the lat pull-down machine.
Deltoids – The cap of the shoulder. This muscle has three parts, anterior deltoid (the front), medial deltoid (the middle), and posterior deltoid (the rear). Different movements target the different heads. The anterior deltoid is worked with push-ups, bench press, and front dumbbell raises. Standing lateral (side) dumbbell raises target the medial deltoid. Rear dumbbell raises (done while seated and bent at the waist, or lying face down on a flat bench) target the posterior deltoid.

Biceps – The front of the upper arm. The best moves are biceps curls. They can be done with a barbell, dumbbells, or a machine. Other pulling movements like chin-ups and upright rows also involve the biceps.

Triceps – The back of the upper arm. Exercises include pushing movements like push-ups, dips, triceps extensions, triceps kick-backs, and overhead (French) presses. The triceps also come into play during the bench press and military press. 

As for exercises, there are dozens. Abdominal curl-ups or workouts on a back-extension machine strengthen abdominal and back muscles, improv¬ing strength and posture. Floor or machine crunches can work the stomach muscles; wrist curls strengthen the forearms; heel raises tone the calves. There are push-ups, pull-ups, and sit-ups, lunges and dips. And these are a limited sampling, to be sure.

Which exercises are the "right" ones? ‘The best exercises are the ones you’re going to do! Remember, there are lots of good ways to get strong— push-ups, sit-ups, ab and lower-back exercises—that don’t require any weights."

Check with a certified fitness professional to learn which exercises are appropriate, and the safe and effective technique involved. Otherwise you can hurt yourself. Seated leg extensions can dam¬age the cartilage on the underside of the kneecap, for instance. Although squats can strengthen the thighs, they can also injure your back.

How you do the exercise is key. "Subdeties of ex¬ercise performance are the thing," says Charles Sta-ley. "It can’t be stressed enough how nuance of performance can take you from an exercise doing nothing to that same exercise doing everything."