Abstract
The J-motion squat—J refers to the trajectory of the hip during the squat—is a dynamic action combining the benefits of front and parallel squatting. The J-motion squat accentuates pelvic movement and enables the lifter to better utilize the hamstrings for further strength and power development. We describe the J-motion squat and provide a review of the practical benefits of teaching it as an ancillary lift within training programs for power athletes.
The J-Motion Squat: An Ancillary Lift for Enhancing Olympic-Style Lifts and Power Olympic-style lifts like the power clean and the snatch are essential lifts for training athletes in power sports. The lifts use numerous joints and large-mass muscle groups, and they require explosive pelvic tilting (Earle & Baechle, 2003). Anterior tilting of the pelvis acts to lengthen the hamstrings, potentially “pre-stretching” them and minimizing active insufficiency, which enables them to co-contract more optimally with the quadriceps (Pettitt & Bryson, 2002). Co-contraction increases leg extension power and is a mechanism to reduce noncontact knee ligament injuries during cutting and jumping maneuvers (Pettitt & Bryson, 2002). We describe the J-motion squat and provide a review of the practical benefits of teaching it as an ancillary lift within training programs for power athletes.
Squatting is a closed-kinetic-chain exercise, meaning the flexion–extension of the knee joint is accompanied by obligatory motion at the ankle, hip, or both (Potach & Borden, 2003). During parallel squatting, flexion–extension of the knee is accompanied by a large degree of flexion–extension of the hip, with minimal dorsiflexion–plantar flexion of the ankle. Conversely, during front squatting a greater amount of ankle dorsiflexion–plantar flexion occurs at the expense of hip extension–flexion (Earle & Baechle, 2003). Differences in the obligatory distal (ankle) and proximal (hip) joint motions influence the length-tension relations of two-joint muscles in the lower extremity, particularly the hamstrings (Umberger, 1998). The J-motion squat is a variation of the front squat, in which the body’s center of mass and the hips follow a J-shaped trajectory (Figure 1), generating optimum tension in the hamstrings.
Figure 1. Eccentric and concentric phases of the J-motion squat.
Technique and Kinematic Analysis
The J-motion squat is performed with the following steps:
- From a standing position, flex at the hips, keeping the shoulders directly over the toes (Figure 2a–b).
- Upon sensing a stretch of the hamstrings while in this pike position (Figure 2b), begin flexing the knees into a squatted position (Figure 2c–d).
- While descending into the squatted position (i.e., during the eccentric phase of the squat), shift the body weight forward over the balls of the feet, transitioning through the bottom of the J motion (Figure 2e–f).
- Reaching a front-squat position (knees slightly anterior to the toes, Figure 2g), begin the concentric phase by extending the knees and hips—squeezing with the hamstrings and gluteal muscles—and driving through the floor by rising off the heels and onto the balls of the feet (Figure 2g–h).
Figure 2. Strobe imaging of joint movements and tracing of hip trajectory during the J-motion squat.
Kinematic analysis of the J-motion squat illustrates its sequential nature. Peak extension velocity of the hip precedes peak extension of the knee, which in turn precedes peak extension (i.e., plantar flexion) of the ankle (Figure 3). Velocity of the hip decreases as velocity of the knee increases. These kinematic data suggest that the net change in hamstrings’ shortening velocity is near zero, thus enabling greater force production as defined by concentric force-velocity relationship (Umberger, 1998).
Figure 3. Angular velocity of the hip, knee, and ankle joints during the J-motion squat.
Sport Specific Training Objectives of the J-Motion Squat
The J-motion squat is useful for teaching athletes how to use the hamstrings during the first pull and scoop phases of explosive lifts (e.g., hang clean). Two common errors during these phases of the clean are (a) a failure to reach a position of stretch for the hamstrings preceding the first pull and (b) inadequate finishing of the scooping motion (that is, a lack of explosive posterior pelvic thrusting). Practicing the J-motion squat accentuates the two requirements.
In addition, the J-motion squat is useful for teaching athletes the kinesthetics of powerful hip extension. The concentric phase of the J-motion squat requires a coupling of ankle, knee, and hip actions commonly observed in running, in Nordic skiing, and for numerous pushing skills, like those required in American football’s blocking or as skills within wrestling or judo. For this reason, the J-motion front squat may be a useful ancillary lift for athletes in these sports.
Teaching the J-Motion Squat
To learn the J-motion squat, an athlete should begin by rocking the body weight backward and forward while squatting, ultimately rocking upward onto the balls of the feet; this should accustom the athlete to the rudimentary motion of the J-motion squat. Once an athlete is comfortable with this motion, the next step involves two phases. In the first phase, the athlete should transition from the standing position to the pike position, focusing on reaching a position of stretch through the hamstrings. Practice moving from the standing position to the pike position in slow motion, initially; this should speed the learning process. In forcing a stretch of the hamstrings as called for in this phase, a common mistake is poor flexion of the knees. Athletes should strive for good flexion, and they should also ensure that the shoulders are not too far forward of the balls of the feet (Figure 2d). The second phase comprises a forward weight transition with a rocking motion, followed by explosive hip extension. (An excellent example of this comes from Alpine skiers. They leave the starting gate by planting both poles into the ground and rocking the body weight first backward and then explosively forward.) The rudimentary movement of the second phase should first be mastered without the use of weight; then, add weight initially by holding a weight plate to the chest with one arm crossed in front of the other. When an athlete has become comfortable with the weight plate, practice can begin with lifting a barbell, which should be held in the exact same position as for front squatting.
A variety of resistance options and factors exist for prescription with the J-motion squat. Power athletes (e.g., sprinters, wrestlers) require heavier resistance options, fewer repetitions, and faster movement cadences when performing the J-motion squat. In contrast, endurance athletes (e.g., distance runners, Nordic skiers) would want to perform the J-motion squat with lower resistance options, greater numbers of repetitions, and slower movement cadences, in an effort to tax the endurance capacity of the extensor muscles.
Safety while performing the J-motion squat is enhanced when athletes are advised to avoid shifting body weight too far forward relative to the balls of the feet. When weight is too far forward, the knee can experience excessive strain and, potentially, injury. Additionally, athletes should be advised to avoid excessive lumbar extension; it is unnecessary and may lead to injury. Finally, the J-motion squat should be considered an ancillary lift: Training intensities exceeding 10–12 RM (repetition maximum)—for example, 3–5 RM—are better reserved for conventional power lifts and Olympic-style lifts.
Conclusion
The J-motion squat is useful for helping athletes develop the proper mechanics to produce powerful hip extension. An ancillary lift, the J-motion squat may help, for instance, in development of the hip extension power required for numerous conventional power and Olympic-style lifts. Moreover, the J-motion squat also may be useful for enhancing movements required in such athletic activities as jumping, running, and skiing.
References
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Pettitt, R. W., & Bryson, E. R. (2002). Training for women’s basketball: A biomechanical emphasis for preventing anterior cruciate ligament injury. Strength and Conditioning Journal, 24, 20–29.
Potach, D. H., & Borden, R. A. (2003). Rehabilitation and reconditioning. In T. R. Baechle & R. W. Earle (Eds.), Essentials of strength and conditioning (2nd ed., pp. 529–545). Champaign, IL: Human Kinetics.
Umberger, B. R. (1998). Mechanics of the vertical jump and two-joint muscles: Implications for training. Strength and Conditioning Journal, 19, 70–74.
