The Single Leg Romanian Deadlift (SL RDL) is a unilateral hip hinge movement performed by balancing on one leg while lowering the torso and extending the free leg backward. This action forms a straight line from head to heel. The SL RDL is a powerful tool for addressing muscular imbalances between the left and right sides of the body. By demanding both strength and balance, it enhances functional strength and improves coordination across the entire lower body.
Primary Muscles Targeted
The SL RDL is specifically designed to isolate and strengthen the posterior chain of the standing leg. It is a premier movement for developing the muscles on the back side of the body. The gluteal muscles and the hamstrings are the primary movers responsible for executing the hip hinge and returning the body to an upright position.
The Gluteus Maximus, the largest muscle in this group, functions as the main hip extensor. It generates significant force to drive the upward phase of the movement. This powerful contraction at the top of the lift maximizes glute activation and contributes to overall lower body power.
The hamstring complex, which includes the Biceps Femoris, Semitendinosus, and Semimembranosus, is heavily involved in both controlling the descent and powering the ascent. As the torso lowers, the hamstrings lengthen under load, experiencing a deep stretch. This eccentric loading during the lowering phase is highly effective for strength and muscle growth.
Stabilizing Muscles Engaged
Beyond the primary movers, a wide array of muscles act as stabilizers to maintain balance and proper posture throughout the demanding unilateral movement. The core musculature, including the deep abdominals and obliques, must fire intensely to prevent the body from rotating or swaying. This continuous bracing action helps maintain a stable torso and enhances functional strength.
The Erector Spinae muscles work isometrically to keep the back flat and neutral. They prevent unwanted rounding or excessive arching of the spine. This static contraction develops endurance in the lower back, supporting the spine under load.
The Gluteus Medius and Gluteus Minimus work intensely on the standing leg to provide lateral hip stability. These smaller muscles prevent the hip from collapsing inward, helping to keep the pelvis level and square throughout the hinge. Additionally, the intrinsic muscles of the foot and the calf muscles (Soleus and Gastrocnemius) manage minute shifts in balance, stabilizing the ankle joint.
Key Elements of Proper Form
To maximize muscle engagement, proper form centers on mastering the hip hinge mechanism rather than simply bending over. The movement should initiate by pushing the hips directly backward, creating tension and stretch in the hamstrings of the standing leg. Maintaining a rigid, neutral back from the head to the hips requires keeping the core and spinal stabilizers engaged throughout the range of motion.
The non-weight-bearing leg should extend straight backward in line with the torso, acting as a counterbalance to the forward tilt. This creates a straight line resembling a “T” shape when viewed from the side. Utilizing a slow, controlled tempo on the descent (the eccentric phase) maximizes the time the primary muscles spend under tension, which is linked to strength gains and muscle development.