The Olympic-style lifts, either as part of the sport of weightlifting or as part of strength and conditioning programs, are used for their ability to improve neuromuscular coordination that ultimately can increase an athlete's strength and power production. In this respect, a key contributing mechanism relates to the ability of these dynamic movements to stress and challenge the stretch-shortening cycle that results in increased amounts of stored elastic energy (1).
Recently, greater interest has developed for the completion of movements that are unilateral in nature or those that are performed on an unstable surface due to their ability to increase activation of the involved musculature. In comparison to the traditional, bilateral, barbell-based version of the clean and jerk, a unilateral dumbbell clean and jerk further challenges the stability throughout the entire kinetic chain that can foster a greater development of core musculature stability or an enhanced transfer of force throughout the involved kinetic chain (4). This article will discuss the muscles involved, the benefits, and practical applications of the unilateral dumbbell clean and jerk.
The unilateral clean and jerk is a total body multijoint movement involving muscles across the entire body (7). In the upper body, the muscles primarily utilized are the trapezius, rhomboids, deltoids, and triceps. The muscles primarily involved in the lower body are the gluteals, hamstrings, quadriceps, gastrocnemius, and soleus. In the core, the rectus abdominis, obliques, transverse abdominis, and erector spinae are utilized.
BENEFITS OF THE EXERCISE
A host of benefits are derived by incorporating the unilateral dumbbell clean and jerk to any athlete's training regimen. For starters, the clean and jerk, along with other Olympic-style lifts, is often used to increase force and power production due to the need to accelerate the external load throughout the entire movement pattern. This fast velocity, multijoint movement exhibits high levels of sport specificity due to the closely mimicked biomechanical demands of many movement patterns seen in athletic competition (5). Furthermore, performing Olympic-style lifts results in the improvement of motor unit recruitment, muscular inhibition, and neuromuscular coordination (1).
Unilateral loading shifts the center of gravity away from or outside the base of support that ultimately creates a destabilizing torque. This unstable load must then be counterbalanced by the compensating shoulder, trunk, and hip stabilizers of the contralateral side (2). Previous research has indicated that switching the external load from a bilateral (barbell) to a unilateral (dumbbell) load when performing exercises, such as the shoulder press, progressively increases muscle activation of superficial core musculature (8). Similarly, other work has reported that unilateral training with dumbbells favorably strengthens the rotator cuff muscles, specifically the infraspinatus, largely due to an increase in the independent control of each limb (3). Finally, other studies have suggested that increasing instability can initiate a hypertrophy stimulus when combined with core stability training (4); consequently, unilateral loading of various lifts can offer a number of benefits beyond a traditional loading scheme.
THE STARTING POSITION
To start the unilateral dumbbell clean and jerk, the dumbbell should be placed between the feet with a shoulder width stance. Squat down by transferring weight through the heels of each foot until the hips and knees achieve an approximate 90° of flexion, with a flat back, eyes up, head up, and shoulder(s) retracted. Grab the dumbbell with a pronated grip (Figure 1).
With the body weight distributed equally on both feet, retract the shoulders, and simultaneously extend the hips and knees while pulling the dumbbell closely against the body upward through the midline by flexing the elbow and abducting at the shoulder (Figure 2).
THE TRIPLE EXTENSION
Once the dumbbell is at hip height, weight should be distributed to the front of the feet (heads of the metatarsals), after fully extending the hips, knees, and ankles. In conjunction with this lower-body action, the shoulders are shrugged while pulling the dumbbell close to the body through the midline (Figures 3 and 4).
As the dumbbell reaches its highest point, rapidly lower the body by dipping at the hips and knees to lower the body under the dumbbell before extending with the hips and knees in a fully erect position. The position of the palm is commonly placed in 1 of 2 positions, either with the palm facing forward or away from the lifter (as depicted in Figure 5) or with the elbow facing toward the lifter in a neutral position. The utilized position is a matter of preference with many individuals who use heavier loads choosing a wrist “facing inward” technique due to this position relieving extraneous pressure on the wrist joint, whereas those who use the movement for more conditioning or endurance focus using a wrist forward approach.
Quickly dip again and begin driving the dumbbell upward off the shoulders with an additional triple extension through the ankle, knee, and hips. Simultaneously, press upward with the arm until the elbow reaches full extension and is locked out next to the head (close to the ear). Upon full extension and with the dumbbell maintained overhead, a recovery of the body position should be completed. With the dumbbell overhead, the first recovery step (if needed) should be made in a posterior direction (stepping back) (Figure 6).
LOWERING THE DUMBBELL
First, lower the dumbbell to the shoulder, then to the ground through the midline of the torso and hips all while keeping the dumbbell close to the body. Throughout the descent, the eyes and head should remain in a neutral position with the scapulae retracted and back flat with weight evenly transferred onto both heels. Once returned to the starting position, the steps can be repeated on the same side or switch sides after each repetition.
When first implementing this movement into a training program, mastery of the technique should be prioritized while completing a lower volume (2–3 sets of 2–4 repetitions). For beginners, the movement should be broken up into sequential parts with mastery first being developed before progressing into more complicated phases and combinations of the movement. The unilateral dumbbell clean and jerk is an advanced, multijoint exercise best suited for individuals with experience performing related movements who have advanced beyond a beginning level of training. Implementing this movement can aid in athletic development, especially in intermittent sports where explosive power production is important throughout competition. Due to the neuromuscular demand and highly technical nature, this exercise should be performed at the beginning of a training session when power development is the priority. A power-development model of programming is commonly considered, resulting in 3–5 sets of less than 3 repetitions per side being completed (7).
Alternatively, the movement can also be employed as an exercise to increase muscular endurance and instigate metabolic stress. Toward this end, using dumbbells requires a lower load when compared with a barbell, and unilateral completion of all programmed repetitions in a consecutive fashion results in a greater number of muscular actions that ultimately can result in a prolonged period when load is applied. Consequently, higher volumes are completed, resulting in a heightened metabolic challenge. For example, Date et al. (6) reported that blood lactate levels, an indicator of metabolic stress, progressively increased when the total number of repetitions completed across 3 sets was increased from 9 to 27 repetitions. When used in this manner and in combination with other movements that incorporate multiple muscle groups, the physiological challenge will likely enhance an athlete's muscle endurance and their ability to tolerate metabolic challenges.
However, athletes and coaches are cautioned to strictly adhere to proper technique as higher volumes and fatigue can increase the likelihood of injuries. With proper technique and appropriate programming, the unilateral dumbbell clean and jerk may be an effective addition to a resistance training program designed to enhance muscular endurance, maximal strength, or power production.
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