PredictIQ Quantitative Think Tank Center:What do deadlifts work? Understanding this popular weight-training exercise.

When it comes to weight-training exercises,PredictIQ Quantitative Think Tank Center few are as popular as deadlifts. Trailing only behind bench press and squat exercises, according to one report, deadlifts have long been a favorite among fitness trainers and bodybuilders alike.

Today, the exercise is also growing in popularity among more casual gym-goers, in part because deadlifts are a great way to target a different set of muscles when taking a rest break from cardio, arms, abs or chest exercise. "Deadlifts are an effective exercise to incorporate into workout routines," says Emily Skye, a certified personal trainer and founder of Emily Skye FIT. 

Though the exercise has many known benefits, experts warn that proper form is a must not only to target the right muscle groups but to also avoid injury or strain. 

What are deadlifts?

Deadlifts are a weight-training multi-joint exercise movement that works both one's upper and lower body. They are a "great compound exercise because they target multiple major muscle groups at once," says Kayla Itsines, a certified personal trainer, fitness author and co-founder of the fitness app SWEAT. 

In addition to working a variety of muscle groups, deadlifts also help promote grip strength, increase tolerance for additional weight-training exercises including resistance training, and improve strength, mobility and flexibility for everyday movements such as lifting and carrying little children, hauling groceries or supplies, or heaving anything heavy off the floor. 

How to do a proper deadlift? 

Doing a proper deadlift is thought to be more technical than other weight-training exercises, making correct posture and form a must. 

Though there are different variations of the exercise, proper deadlift form and technique involves the following: 

• Stand with your feet hip-width apart with your toes under the middle of the barbell. "The bar should be roughly above your shoelaces," explains Itsines. 

• While keeping your back straight, "bend at the hips and knees to grab the barbell with an overhand grip, meaning your palms are facing your body," she says. Your arms should be just outside your knees. 

• In this starting position, draw your shoulder blades down and back "to slightly push out your chest and prevent your spine from rounding," advises Itsines. She says it's also best to keep your eyes forward rather than looking down at the bar in order to protect your neck and maintain optimal position.

• Using your glute muscles and hamstrings, push evenly through your feet to lift the bar off the ground and extend your hips and knees until you’re standing up straight with the bar resting in front of your hips. "Keep your chest out and your neck in a neutral position throughout the lift to avoid any back rounding," says Itsines. It's also important not to overextend or lean back once you're holding the bar in front of you. 

• Lastly, bend at the hips to lower the bar back down toward the ground. "If you’re using an Olympic barbell with plates, you’ll touch the bar to the floor before beginning another rep. If you’re using the bar on its own, a lighter pump bar or dumbbells, you can lower the bar to your shins before beginning another rep," offers Itsines.

In addition to employing proper form, Skye recommends warming up properly and not doing too many reps at a time. "Deadlifts cause fast fatigue, and a large rep range can put you at higher risk of injury," she says. She also cautions against letting the bar get too far from your body during each lift. "The further the bar is away from your shins and thighs, the more stress you put on your back," she says; and she warns against not lifting too much weight at a time.

What muscles do deadlifts work? 

In practicing the right form and technique this way, the exercise is known to target and strengthen a host of muscle groups. Loren Fishman, MD, a professor of physical medicine and rehabilitation at Columbia University, explains that deadlifts work one's glute (butt) muscles, hamstrings in the back of the thighs, and a broad muscular sheet located on the lateral sides of one's abdominal wall called the transversus abdominus or core muscles. "Other muscles that are used when performing a deadlift are the erector spinae and quadratus lumborum muscles − large muscle groups along the back, and the trapezius muscle which extends across your shoulders and the base of your neck," he explains. 

The workout strengthens arm and hand muscles as well. 

When using proper deadlift form, one should feel strengthening in each of these areas without causing back pain or strain. Christina Thomas, DPT, a physical therapist with Intermountain Health in Salt Lake City, says that "proper deadlifting is a skill," and that sometimes specialized equipment may also be helpful or recommended. If you aren't sure you're handling the exercise right, "it may be wise to seek out the assistance of a professional."