Technique, Variation, and Progression of the Rear-Foot-Elevated Split Squat

Abstract

THE REAR-FOOT-ELEVATED SPLIT SQUAT IS A MULTIJOINT EXERCISE USED TO TRAIN THE LOWER EXTREMITY MUSCULATURE IN ALL PLANES. THE BENEFITS INCLUDE PREVENTION OF LOWER EXTREMITY INJURY, IMPROVED GAIT AND SPORT PERFORMANCE, AND INCREASED MUSCLE SIZE AND STRENGTH. WITH AN ANTERIOR-POSTERIOR STANCE, THE EXERCISE IS PERFORMED PRIMARILY UNILATERALLY.

INTRODUCTION

The rear-foot-elevated split squat (RFESS) is similar to the single-leg squat, lunge, and split squat but also varies from each. Although all these exercises include flexion and extension predominantly in the sagittal plane, the narrow base common to these exercises introduces the demand for frontal plane control. The anterior-posterior stance also includes rotation in the hips that occurs in the transverse plane. Unique to the RFESS is significantly reducing the support of the load on the trail leg by placing the top of the foot on a raised supporting device. The lead leg has been shown to support approximately 85% of the load (⁶), which is greater than the split squat and lunge (75%) (⁴). Many modifications of the exercise can be performed to fit the beginner to advanced lifters. With added support from the trail leg, the exercise can be used as a progression before the single-leg squat when the exercise is performed with just the bodyweight or light dumbbells. This added support of the trail leg can also be used to increase the loads for lifters at various levels of experience.

Because of the level of instability present, the exercise can be used for joint stabilization; however, the RFESS can be included in the program design as a core exercise similar to the emphasis placed on other types of traditional, multijoint, lower-body exercises. Strength assessment can take place using 1 repetition maximum (1RM) loads as well as rep tests using various RM loads (⁵). For those without previous training using the RFESS but have resistance training experience, a practice session and pretest is suggested before a final assessment of strength to eliminate any possible learning effect. Heavy relative loads recommended to increase strength during training can also be used (⁵).

Although most ground reaction forces in sport are produced from a unilateral stance, the RFESS can be used for improvement in a wide variety of sports. Acceleration, deceleration, change of direction, sprinting at top speed, and jump performance all require stability of the lower extremity joints under loaded conditions to produce forces through the kinetic chain for efficient movement. The RFESS particularly trains the hip to support the upper body while also controlling the knee position in the unilateral stance.

MUSCLES INVOLVED

The hip (gluteus maximus and hamstrings) and knee extensors (quadriceps) are active in the sagittal plane (⁶). For frontal plane control and prevention of a lateral pelvic tilt, the hip abductors are required (gluteus medius, gluteus minimus, and tensor fascia latte) (⁶). Internal and external hip rotators maintain the degree of external rotation of the lead hip and internal rotation of the trail hip. The reduced base of support also activates the plantar flexors (gastrocnemius and soleus), inverters (anterior and posterior tibialis), and everters (peroneals). The active trunk musculature includes primarily the obliques and extensors (erector spinae and multifidus).

EXERCISE TECHNIQUE

• Place a mark on the floor to position the lead toe line.
• The distance from the lead foot toe line to the trail foot support is approximately the length of the iliac crest to the floor.
• Without added load, practice the RFESS to adjust the support box/bench distance that allows the lead knee to be positioned directly above the toe line. Tight hip flexors can create excessive forward lean of the torso to reach the pad with the trail leg, which may require reducing the distance of the support device.
• The trail leg support can range from approximately 6 inches to knee height.
• When using a free-weight bar and heavy relative loads for strength improvement, the exercise should be performed inside a squat rack with spotters positioned on both sides and 1 positioned behind the lifter. With dumbbells and lighter loads, spotters may not be necessary.
• After placing the bar on the shoulders or dumbbells in the hand, place the lead leg toe line on the mark then take a split squat stance with the trail leg just in front of the support device and the foot still on the floor. While shifting the weight toward the lead foot, place the top of the trail foot on the support pad.
• Positioning the trail ankle in slight to complete plantar flexion reduces instability of the exercise.
• Contact between the trail foot and support device should be on the metatarsals or the metatarsophalangeal joint.
• The stance width between the lead and trail foot should be approximately hip width.
• Maintain a near vertical torso in the starting position and throughout the movement. A forward lean (hip flexion), similar to the bilateral squat, is difficult to control with the split stance and rear foot elevated.
• Keep the weight of the lead foot distributed in the middle of the foot or near the heel.
• The bar should track in a vertical line during the descending and ascending phases. Instruct the lifter to sit straight down to improve bar path.
• The lead knee should track in line with the foot that is pointed forward.
• Bring the trail knee down until it touches a 1-2-inch foam pad placed on the floor.
• Complete the repetitions in the set before switching legs.

PROGRESSION AND VARIATIONS

• Bodyweight holding suspension bands (Figure 1).
• Smith machine—the stabilized load significantly reduces muscle activation in the frontal plane.
• Bodyweight—for untrained lifters, the weight of the body can provide an overload.
• Bodyweight split squat.
• Bodyweight with the trail leg supported with a suspension band (Figure 2). After placing the trail foot in the strap, you may need to hold onto the safety bars to position the lead leg on the mark.
• Dumbbells with a stable trail leg support—the dumbbells lower the center of mass which can improve the stability of the exercise. The lifter can set the dumbbells on a bench positioned on each side and elevated approximately knee height before performing the exercise. Once in position with the trail foot supported, the lifter can lift the dumbbells to begin.
• Unequal dumbbell—to increase the frontal plane overload on the lead leg, use a heavier dumbbell on the trail leg side. A dumbbell could be used on the trail leg side without one on the lead leg side to further increase the lateral pelvic tilt torque. With dumbbells of equal load held in each hand, the dumbbell on the lead leg side counterbalances a portion of the load creating the lateral pelvic tilt. For example, a 20-lb dumbbell held on the trail leg side creates more frontal plane torque toward that side than a 20-lb dumbbell held in each hand. This unilateral load creates more demand from the hip abductors and other musculature for frontal plane support (⁷). Variations of the load in each hand can be used to independently control the overload in the sagittal and frontal planes (Figure 3).
• Barbell on the shoulders—progression of loads can occur for strength training. Strength improvement has been found with progression up to 87% of 1RM loads performed for 6 repetitions during short-term training (⁵). The high center of mass increases the difficulty in maintaining the posture and in recovering from any angular motion of the torso due to the increase in torque (Figure 4); therefore, spotters are warranted.

Figure 1.: Bottom position using the suspension bands for improved balance and reduction of the load.

Figure 2.: Using the suspension band to support the trail leg reduces stability. Dumbbell load can be added. Using a bar on the shoulders is not recommended because of the reduced stability.

Figure 3.: Unequal dumbbell load increases the frontal plane load.

Figure 4.: Barbell on the shoulders can be an effective exercise to allow heavy loads to be added for maximum strength improvement.

COMMON ERRORS

• Lead knee not directly above the lead toe line (Figure 5). Although it is acceptable to have the knee slightly in front of the toe line, a knee position well behind the toe line with a vertical tibia places too much load on the trail leg.
• Excessive torso deviation from vertical (Figure 5). A forward leaning position is possible with bodyweight but is not recommended with the bar on the shoulders. Cue the lifter to stand tall with a vertical torso.
• Inaccurate trail foot support distance—before adding load, practice the technique to adjust the distance that allows a vertical torso and lead knee directly over the lead toe line.
• Trail foot support height. This can vary based on leg length and flexibility, but near knee height is recommended.
• Supporting the ankle/tibia of the trail leg on the support pad. Allows for more weight to be distributed to the trail leg. The lifter can shift more load to the trail leg resulting in the bar tracking posterior from vertical.
• Neutral or dorsiflexion in the trail ankle resulting in contacting the support device on the tip of the toes (Figure 5). A plantar-flexed position improves the stability of trail leg support.
• Excessive hip adduction/lateral pelvic tilt, which makes it difficult to control the resistance in the frontal plane (Figure 6).
• Increased knee valgus (Figure 6).
• Stance not hip width—a trail foot positioned directly in line with the front foot may be difficult to control the load in the frontal plane leading to increased lateral pelvic tilt.

Figure 5.: Errors include excessive anterior knee translation and trunk lean and toe contact in a neutral ankle position in the trail leg.

Figure 6.: Increased lateral pelvic trunk and knee valgus.

PRACTICAL APPLICATION

The RFESS has the potential to reduce the risk of hip and knee injuries. Frontal plane stabilization of the hip enhances muscular control of hip adduction in the stance leg (³). Repetitive excessive hip adduction/lateral pelvic tilt on the support leg during gait could lead to chronic soft tissue disorders of the hip and knee (²). Hip adduction can also lead to anterior cruciate ligament stress because of an increase in knee valgus (¹). This is a common occurrence during unilateral, weight-bearing activities, particularly in female athletes (⁸). Hip weakness in a unilateral stance can be assessed in clients with various levels of ability. For untrained and individuals with low levels of strength, the ability to maintain a level pelvis can be observed in a stationary unilateral stance (Trendelenburg's sign). To progress the assessment, a single-leg squat and jump landings can also be used to observe lateral pelvic tilting and the degree of knee valgus. Training with the RFESS can be used to provide improved trunk and lower-body joint stabilization mediated primarily by the hip musculature during unilateral based activities. Using the progression of the RFESS provided, the strength and conditioning specialist can assign an appropriate level of exercise that allows correct technique to be performed while monitoring the noted errors and providing corrective feedback.

Performance in a wide range of sports involving lower-body, weight-bearing skills occurs primarily under unilateral conditions. In addition to sprinting and change of direction, throwing, kicking, and striking patterns require the transfer of forces unilaterally that need to be simulated during training. With the majority of the resistance placed on the lead leg, the RFESS can be implemented in a resistance training program to increase strength of the lower body while achieving sport specificity. Although the exercise includes some degree of instability, loads recommended for improved muscle mass, strength, and power can be used to provide the necessary overload. To obtain maximum benefits, following proper technique and progression guidelines is essential during training with the RFESS.