Resistance exercise has remained a mainstay physical therapy treatment throughout most clinics in the United States. Specific to lower extremity recovery, two exercises have stood superior to others in their potential for improved strength while remaining functional and applicable to everyday activities: Dead lifts and squat. Both exercises boast compound movement and coordination of several muscle groups while remaining accessible and cost-free. But what, exactly, do these movements entail, which muscles do they target, and which patient populations would they most benefit?
Dead Lift:
Dead lifts, primarily Romanian dead lifts, serve as an excellent exercise to strengthen the hamstrings, the glutes, and the lumbar (low back) extensors. This motion begins in a standing position with feet shoulder-width apart, knees at a slight bend, and a straight back. The motion is performed by slowly bending at the hips with particular focus on a slow, controlled descent while keeping the knees only slightly flexed and pushing the buttocks backwards. The shoulders should fall forward as the hands reach towards the ground. When the hands reach mid-shin, the patient should begin extending their hips back to the standing position. Dead lifts can be performed with or without weight depending on the desired difficulty. This exercise relies on neuromuscular control as well as strength; Neuromuscular control of the hamstrings and glutes to moderate the rate of descent1 and strength to return the trunk to the starting position. It also relies on the lumbar muscles to stabilize the low back and prevent a slouched posture throughout the exercise.
Dead lifts will benefit individuals who have mild-moderate low back pain2, spondylolisthesis, or general hip pain. This exercise can also improve knee pain due to the attachment of the hamstrings below the knee joint. Glute med, max, and hamstring tendinitis or tendinopathy can also benefit from dead lifts as the exercise intensity is increased or decreased by a physical therapist dependent upon the muscle’s stage of healing.2
Squats:
Squats serve as a great exercise to strengthen the quadriceps, lumbar extensors, and glutes. This motion begins in a standing position with feet shoulder-width apart, knees extended and the back vertical to the ground. The motion is performed by slowly bending the knees, dropping the buttocks towards the ground while maintaining a straight back. When the femur (upper leg) is parallel to the ground, the patient should begin extending the knees, retuning to the starting, standing position. While there is debate about whether knees should go past toes or stay directly over them, we recognize potential benefit for either approach and advise that what is most important is the knees track in line with the feet and in a pain-free range. Like dead lifts, squatting also relies on neuromuscular control and strength; neuromuscular control of the quadriceps and glutes to control the rate of knee flexion and hip flexion eccentrically1 and strength of those same muscles to bring body back to a standing position. Squats also rely on lumbar muscles to stabilize the low back and prevent forward lean during the exercise that should interrupt balance.
Squats will benefit individuals who have mild low back pain, generalized hip pain, or who have had chronic knee pain3, knee replacement surgeries, ACL tears, or patellofemoral knee pain. Squatting can also benefit individuals who have a quadriceps tendinopathy, are generally deconditioned, or who have balance deficiencies.3
Summary
Despite significant overlap, squats and dead lifts are unique exercises with specific points of emphasis. They both utilize gluteal musculature to maintain proper hip positioning throughout exercise, they both utilize lumbar musculature to stabilize the low back throughout exercise, and they both can be used for similar patient populations. Dead lifts, however, put a specific emphasis on hamstring muscles4 while squatting puts a specific emphasis on the quadriceps muscles.5 Dead lifts are excellent to treat hip and low back pain, while squatting focuses more on treating knee pain. While there may be several similarities between dead lifts and squats, they remain distinct and separate interventions providing tools for the physical therapist to target specific muscles and movements.
References:
1) Lepley LK, Lepley AS, Onate JA, Grooms DR. Eccentric Exercise to Enhance Neuromuscular Control. Sports Health. 2017;9(4):333-340. doi:10.1177/1941738117710913
2) Fischer, S. C., Calley, D. Q., & Hollman, J. H. (2021). Effect of an Exercise Program That Includes Deadlifts on Low Back Pain, Journal of Sport Rehabilitation, 30(4), 672-675.
3) Willy RW, Hoglund LT, Barton CJ, et al. Patellofemoral Pain. J Orthop Sports Phys Ther. 2019;49(9):CPG1-CPG95. doi:10.2519/jospt.2019.0302
4) Martín-Fuentes I, Oliva-Lozano JM, Muyor JM. Electromyographic activity in deadlift exercise and its variants. A systematic review. PLoS One. 2020;15(2):e0229507. Published 2020 Feb 27. doi:10.1371/journal.pone.0229507
5) Slater LV, Hart JM. Muscle Activation Patterns During Different Squat Techniques. J Strength Cond Res. 2017;31(3):667-676. doi:10.1519/JSC.0000000000001323