ELIZABETH PINYAN AND VERONIQUE HAUSCHILD
Directorate of Clinical Public Health and Epidemiology
U.S. Army Public Health Center
Aberdeen Proving Ground, Maryland
A primary goal of strength training is to develop stronger and better-functioning muscles and joints to more effectively and safely accomplish physical tasks. The deadlift and squat are common exercises performed to improve lower body strength.
Strength training exercises involve resistance in the form of the body itself, machines, resistance bands or free weights. To be effective, resistance should place enough stress on the muscles, tendons, ligaments and bones to challenge tissues to rebuild. Too much stress or improper form can damage tissues, resulting in injury.
Data indicate the injury risk is greatest for exercises involving heavy free weights. For example, heavier weights lifted during the deadlift and squat have been associated with injuries. Not only can these injuries be painful, they can result in costly treatments, extended physical restrictions or lost duty time, and possibly even chronic conditions.
Most injuries have been attributed to improper form and excessive weights (“overloading”). Working out too frequently or for too long can further increase your injury risk.
Personalizing your positioning, weight selection and workout frequency with a master fitness trainer or certified fitness instructor is recommended to prevent injuries while achieving performance goals. This article provides some general training principles and techniques that may help you reduce your chances of injury when training using the deadlift or squat.
The deadlift and squat
The deadlift and squat primarily engage the lower body muscles of the legs, hips and “glutes” (the group of muscles in the buttocks). Both exercises also require activation of muscles in the shoulders and upper back to hold the weight of the barbell, and muscles throughout the back, core and thighs to stabilize the body during the lifts.
“Including these multi-muscle exercises in your workout routine can help improve overall strength and fitness — as long as you gradually increase your weight and don’t try and lift too heavy before your body is used to the weight,” said Maj. Tim Benedict, a physical therapist at the APHC.
- The deadlift (Figure 1 below) is one of the six events required by the Army Combat Fitness Test (ACFT) as a way to measure lower body strength. For the ACFT, Soldiers must complete a three-repetition maximum deadlift using a hexagon (hex) bar instead of a straight bar. Hex bars, or “trap bars,” are designed to minimize your tendency to lean forward, which may occur with a straight barbell. Using the hex bar still engages lower body muscles, but reduces force on the back. Since the hex bar alone is 60 pounds, an additional 80 pounds is needed to meet the minimum ACFT deadlift standard (total 140 pounds). Heavier weights (totals of 180 or 200 pounds) are needed to meet ACFT standards for certain occupational specialties. The ACFT deadlift event maximum weight is 340 pounds (hex bar plus 280 pounds).
- While the squat (Figure 2 below) is not an ACFT event itself, Army doctrine describes several variations of this exercise to strengthen the back and leg muscles and improve performance on the deadlift event. Variations in form include stance (legs and feet being shoulder width versus the sumo stance with feet wide and turned out) and depth of lowering (thigh parallel to ground versus the lower deep squats). To reduce injury risk, Army doctrine advises you to work on proper positioning and technique prior to adding weight. For example, you can start with no weights and a light pole such as a plastic polyvinyl chlorine (PVC) pipe.
What injuries are caused by the deadlift and squat?
Most deadlift and squat injuries occur to the knee and lower back. Figure 3 below presents common injury types attributed to these two exercises.
The knee and back have been the most common locations of injuries seen among Army Soldiers. Running, ruck marching and sports like basketball are primary causes of these injuries. Exercises like the deadlift and squat may increase Soldiers’ resilience against some of these lower body injuries. The benefits of doing these lifts should be balanced with the potential for new injuries they could cause.
Soldiers usually instantly recognize an acute injury. For example, during the squat and deadlift, the knee joint may absorb too much pressure if knees are fully locked straight upon standing. The lower back is especially susceptible when the weights are too far in front of the body, resulting in excessive forward lean and rounding of the back. Overcorrecting can also lead to hyperextending (arching) the back, which can also hurt the mid to lower back.
Because acute injuries are felt immediately, they can be more directly linked to the exercise that caused them. Less obvious are overuse injuries that occur more gradually. Examples of overuse injuries associated with the deadlift and squat include tendonitis of the knee, low back pain and spinal stress fractures.
“Overuse injuries are three times more common among Soldiers than acute injuries,” said Dr. Bruce Jones, a medical doctor and retired U.S. Army colonel and physician epidemiologist at the APHC who has studied Army injuries for over 30 years. “These injuries occur when vigorous exercises, including heavy-weight exercises, continuously stress the legs, knees and lower back, not allowing the body time to recover between sessions.”
Repeated or untreated injuries can also lead to permanent damage, including chronic back pain and/or numbness (sciatica) in the lower back, hips or legs. Training smart means being aware of early signs of injury and not continuing painful exercises, as the condition may worsen.
How do I improve my lower body strength and avoid injury?
Army doctrine (Field Manual 7-22) provides basic tactics and techniques to safely perform the deadlift with a hex bar and many variations of the squat. While certified personal instruction should be your first step, here are some best practices for preventing injuries:
- Lower the weight, build strength and technique. Before going straight for the barbell, begin your deadlift or squat training using light weights to build muscle strength and technique. Squats can be beneficial even when performed just with body weight. Both the deadlift and squat can be performed with a light weight pole (such as PVC pipe or even a broom handle), an empty barbell (approximately 45 to 60 pounds) or dumbbells or kettlebells. Gradually add weight to your lifts and ensure you are maintaining good form.
- Choose the amount of weight and repetitions based on your goals. If your primary goal is to build muscle size and maximal strength, use higher weights but a lower number (six to eight) of repeated lifts or “reps.” If your goal is to increase lean muscle endurance and sustained strength, use less weight but more reps (12 to 15). In general, do two to three sets of your reps with short rest breaks. Rest breaks should be two to three minutes when using heavier weights, but only 30 seconds to one minute for higher-rep workouts with lower weights. With your planned reps and sets in mind, choose an amount of weight that will challenge you but not cause you to lose good form. When you can do entire sets without difficulty, increase the amount of weight by 10 percent.
- Train smart by maintaining good form and stopping when necessary. If you have difficulty completing your first set in good form, reduce the amount of weight. Signs of poor form include leaning forward, looking down or holding your breath. Be aware that muscle fatigue or complete muscle failure can increase injury risk. Avoid exercises that cause leg fatigue (including long road marches or distance runs) the day prior to and a couple days after squat and deadlift workouts. If you feel pain during or after a weight-training workout, give your muscles and joints a few days to heal. If pain persists, seek medical advice.
- Protect your lower back by stabilizing your core. A common problem that can increase your risk of low back injury is focusing too much on building strength in the glutes and leg muscles (e.g., quadriceps, hamstrings) while not focusing enough training on the core. The core includes many muscles that stabilize your spine (the abdominals in the front, obliques along your side, and erector spinae around your back). To reduce your risk of low back injury, include exercises to strengthen the core, such as the plank, in your training routine. During the deadlift and squat, ensure you activate your core muscles while moving in a slow, controlled manner.
- Be aware of the dangers of anabolic steroids and supplements. Don’t be tempted to use steroids to build muscle strength quickly. In addition to being illegal, overwhelming evidence shows steroids are associated with numerous health problems, including a higher injury risk. Certain supplements have also been linked to health concerns. For details see https://www.opss.org/opss-high-risk-supplement-list.
Authors’ note: This article reflects the views of APHC experts in consideration of American College of Sports Medicine (ASCM) positions. For additional information, email the APHC at usarmy.apg.medcom-phc.mbx.injuryprevention@mail.mil or see APHC factsheets at https://phc.amedd.army.mil/topics/discond/ptsaip/Pages/Army-Injury-Prevention-Factsheets-and-Training-Products.aspx.