Strength and conditioning coaches strive to facilitate movement change in athletes for both enhanced sports performance and injury prevention. With this in mind, Fave (14) suggested that to increase effectiveness in strength and conditioning, practitioners should become a “technician” in all aspects of coaching. Being technically aware and able to change movement is critical, as exercises performed incorrectly can result in unnecessary stress on the body potentially causing injury (1,15). In turn, injury limits quality training time. A common method used to change movement involves explicit instruction delivered by the coach (9,12,16,39). This approach, as reported by Rucci and Tomporowski (39), is where verbal instructions and feedback are given to athletes about the performance of a given skill. Usually, the template for instruction is drawn from the coaches' understanding of their own lifting technique. This method may be error prone, given that athletes are unlikely to share identical experiences or physical characteristics as the coach. Use of this approach is also grounded in the assumption that explicit instruction is optimally effective for changing movement behavior. Contemporary literature has challenged the role of explicit instruction as the best method for developing complex movements. Specifically, the explicit approach may be problematic when considering competitive performance demands (28). Negative effects linked to an explicit approach are reported to be decreased skill performance under pressure (26,30), greater skill deterioration under physiological stress (36), increased reliance on the coach (35,48), diminished skill retention (37), and poor decision-making (29). Thus, it seems useful to examine how skills can be acquired while attempting to avoid these problems.
A problem for contemporary strength and conditioning coaches is the poor connection between coaching and skill acquisition. Separating skill acquisition from physical training may be detrimental to athlete development, a view shared by Moir, who recently noted that skill acquisition is rarely mentioned in strength and conditioning textbooks. Here, we seek to reconnect strength and conditioning with skill acquisition. To begin with, a brief review of traditional coaching methods will be undertaken, contrasting the “coach-centered approach” with an “athlete-centered approach” (19). Then, an athlete-centered approach will be presented versus a constraints-led method because it is applied to the coaching of the power clean. This is offered as an example of how strength and conditioning practitioners may approach the coaching of movement using an alternative method that aligns with contemporary knowledge.
TRADITIONAL STRENGTH AND CONDITIONING COACHING METHODS
Within the field of strength and conditioning, a coach-centered approach is commonly presented (24); characteristically, power resides with the coach and training is more directive than collaborative (2). This is exemplified in a recent article (17), stating that removing the eccentric phase of a power clean allows for greater “control” of the athlete by the strength and conditioning coach. Elsewhere, Dorgo (9) found that the only methods used by National Collegiate Athletic Association Division I coaches when changing movement were feedback and instruction (9). The feedback provided was mostly verbal correction seeking to direct movement towards a perceived ideal technique. Similarly, Hang et al. (16) instructed 4 naive elite athletes to break the hang power clean into parts using a top-down linear method aimed at perfecting isolated elements of the movement (Figures 1 and 2 shrug, jump shrug (11)). Part practice of this kind is commonly prescribed throughout the strength and conditioning literature (10), despite a scarcity of theory for determining how skills should be broken down or evidence regarding the benefits to be gained from such an approach (13). Breaking skills into parts (decomposition) has been criticized in the sports coaching literature (34) because the approach may lead to the performance of abstract movements only partially relevant to the end skill. In this way, athletes no longer learn the movement per se, but a set of dissimilar skills. In many respects, this focuses on an athlete's ability to interpret and execute coach instructions rather than learn the skill. For discrete, coordinative skills, such as the power clean, research supports the whole practice methodology (13), which emphasizes the role of exploring the complete movement as one action. Top-down, coach-controlled approaches that decompose skills conflict with contemporary sports coaching literature because the coach makes all decisions, only allowing athletes to progress when deemed proficient. This coach-centered approach may be problematic because of the limited understanding created within an athlete, which in turn creates problems when the coach is not present (6,7).
The part practice model (in Figures 1 and 2 above) is referred to as a “top-down approach” in strength and conditioning. The skill sequence is started at the top, and then, the coach progresses athlete activities down toward the floor in a linear, stepwise manner. This approach does not fit with contemporary skill literature, specifically the ecological approach, because key information sources such as perception of weight and bar path are not explored as they would be when using a whole practice approach. A key tenet of the ecological (psychology) approach to skill acquisition is that practice includes important perceptual information that shapes skill. Emphasis is placed on how the environment around the athlete contributes to what they perceive and how they move (38). Internal and external environmental information sources such as visual perception of the horizon and proprioception from the floor are not the same for part practice as they would be in whole skill practice. Decomposed skills contain different perceptual information and are as such, different skills in comparison with whole practice. This supports the argument that decomposed movements become different skills (10,11). There is little evidence-based support from the coaching literature for the use of a “top-down” lifting approach.
The top-down approach is driven by the belief that the skill of the power clean should be taught in a serial fashion and athletes need to demonstrate the perfect or correct form before progressing (i.e., from the hang power clean to the power clean). The need to achieve perfect form drives explicit instruction. Underpinning the explicit instruction approach is the belief that elite athletes have very stable, unvariable skills, which when repeated, bring about success. This belief may be questioned (5) because experts often display more variability within their movement patterns than less skilled athletes (41,42). Variability is essential to adjust for differing environmental conditions, barbell loads, or fatigue states.
An important challenge to adopting contemporary coaching methods for strength and conditioning practitioners is the shift from coach-centered to athlete-centered practices (19). An athlete-centered approach views the athlete-coach relationship as a “we” style instead of “us” and “them” (19). Such an approach (19) has the ability to fundamentally change the decisions that coaches make when training athletes (19). Central to this is how athletes are seen (and treated) as a resource that coaches can draw on, making use of learner experiences, and their understanding of themselves to figure out what works. Respect for athlete knowledge establishes a relationship for the benefit of the athlete, where they can contribute actively to their development, as well as take greater ownership of performance (19). This approach views coaching as a complex, needs-driven, nonlinear process which fits poorly with the explicit, part-practice approach seen in strength and conditioning.
Contemporary approaches to coaching view learning as a nonlinear process which requires a matching nonlinear pedagogy (29). Some examples of nonlinearity in lifting include getting worse before you get better (exploring variability), stuck or flat phases (internal changes before improved performance), and slipping into bad habits (attractor decay). Consider an approach to coaching that addresses these challenges, a pedagogical approach that does not expect constant improvement and instant change in response to any instruction. Constraints-led pedagogy reflects a real-world process of developing technique through exploration, shifting emphasis away from telling athletes what a movement should look like, toward having them search for a solution while developing a “feel” for correct movement (6,32). Exploration creates the conditions for a more athlete-centered approach by allowing learners to come up with their own solutions to movement problems. Rather than mechanically following instruction (8), learners are allowed to focus on how a movement feels to them as well as how it looks to others (31). For this approach to be realized, coaches need to set out problems rather than present solutions (8). A constraints-led approach lets coaches set conditions for practice from which movement solutions emerge. This approach has the benefit of avoiding a “one size fits all approach” that comes with a perfect practice model. The coach remains essential to this process as a grasp of good technique is essential here; this is not unguided learning.
A constraints-led approach allows coaches to consider any of the 3 types of constraints in facilitating movement change (Figure 3). Organismic (athlete) constraints according to Davids (7) are characteristics specific to the individual such as height, weight, limb length, percentage of muscle mass, and flexibility. Some organismic constraints are more modifiable than others, for example, flexibility. If an athlete does not possess the prerequisite flexibility (e.g., wrist or shoulder), the ability to perform or explore a movement may be restricted until a suitable range of motion is acquired. Similarly, a coach can change individual organismic constraints by strengthening areas of weakness. When an athlete favors the use of their knees overloading the hip, for example, they can be directed to work on weaknesses in the lower back or hip musculature that limit technical proficiency.
Environmental constraints are physical in nature, examples being light, sound, gravity, weather, and ground surfaces. Other nonphysical environmental constraints are social, such as spectators or other performers. Task constraints are specific performance goals, rules, equipment, implements, and boundaries. This article gives examples of relevant task constraints for the power clean and hang power clean. The task constraints are linked to movement faults and will give coaches tools for shaping movements.
TEACHING THE POWER CLEAN
Athlete development from the perspective of a strength and conditioning coach is a broad undertaking demanding proficiency in a variety of exercise-related skills. One such skill is the power clean, commonly used to develop explosive power (44). The power clean requires a high level of intrapersonal coordination (40), with athletes often needing significant practice to achieve proficiency (47). Wary of the practice issue, experts have questioned the value of time invested in learning the skill when compared with other ways of improving performance (16); specifically that, if an athlete is slow to acquire an effective technique, they will have less time to maximize the stimulus needed for a training effect (47). With this in mind, more focus is needed on effective strategies for learning skills such as the power clean. Although the traditional instruction method is relatively effective, focus should be on whether it is the most efficient method for athletes who are not weightlifters. Athletes in the sport of weightlifting need to devote time to the specifics of technique where the goal is maximal lifting. Athletes elsewhere need to learn in less time while being able to transfer the skill of the power clean to other sporting environments. Presently, the longer, explicit instructional method is applied to the strength and conditioning of elite athletes in most sports. If transfer to sport performance is important, the instructional approach can be criticized (7,25). Verhoeff et al. (45) and Marriner et al. (27) have demonstrated the effectiveness of a constraints-led approach for the power clean in recreationally trained participants. Hence, a constraints-led approach can be viewed as a suitable tool for strength and conditioning coaches to use when coaching of weightlifting movements to athletes.
OPTIMAL CHARACTERISTICS OF THE POWER CLEAN PERFORMANCE
Weightlifting has been used as a power training tool in many strength and conditioning environments for decades. Weightlifting movements such as the power clean are considered to be beneficial to sports performance because they involve larger muscle groups of the lower body, triple extension of the hip, knee, and ankle, as well as fast movement velocities (16). More specifically, the power clean has frequently been used because it shares a close kinematic and kinetic relationship with skills such as jumping (3). The power clean skill is derived from sport weightlifting and involves moving a heavy barbell from the floor to the shoulders (3). The power clean is a good movement skill to use with a constraints-led approach because it requires whole-body, intrapersonal coordination to complete the movement.
To improve power clean performance, it is necessary to understand clearly what the critical performance features are and what individual differences may exist. A key performance capability in performing the power clean is producing a large amount of force rapidly (4,46,47). To help achieve this force output quickly and safely, the bar path direction needs to achieve certain positions in relation to the lifter during the movement (43).
POWER CLEAN KINEMATICS
The direction of the bar path during the power clean can be analyzed in 3 phases: the first pull (Figure 4A and 4B), second pull (Figure 4B–D), and catch phase (Figure 4D–F). Within these phases, there are also key positions identified by Stone et al. (44), which have been shown to relate to lifters being able to achieve better success in the movement.
It (Figure 4) is the lift off in this position the shoulders are over and in front of the bar (47). During this phase of the lift, the ideal bar path is toward the athlete in the horizontal plane. Stone et al. (42) identified significant factors that correlate to a higher load lifted during this phase. One of these factors is the torso angle remaining constant and controlled, as this is not the explosive phase of the lift.
The shoulders are still over and in front of the bar and knees have pulled back out of the way (Figure 4). The bar path is still tracking toward the athlete in the horizontal plane. The bar velocity should be controlled to this point (23).
It (Figure 4) corresponds with the double knee bend position or transition phase. The double knee bend is where the knees rebend driving forward under the bar. This double knee bend has been shown to be the most efficient technique (47). This technique allows the bar path to track toward the hip joint. Through this phase is the highest rate of force development and peak force expression, while the feet are still flat, and the torso is almost vertical. Kipp and Meinerz (20) highlighted the importance of this phase for successful 1-repetition power clean attempts, reporting that successful lifts were characterized by less peak forward barbell motion and more rearward force application during the second pull.
It (Figure 4) is the achievement of triple extension of the hip, knee, and ankle (18,44).
Positions E and F
These (Figure 4) are the catch phase; in this position, the bar path should be toward the athlete in the horizontal plane but no more than 20 cm behind the most forward position of the bar (39). Winchester et al. (47) identified differences between nonelite and elite lifters involving speed under the bar in this position, with shoulder flexibility a prerequisite. If the bar is not resting on the body, this significantly impacts the total weight athletes can lift (44).
The critical features above which correlate to best performance constitute a goal which can be facilitated by the coach using a constraints-led approach. Worth noting here is that the focus is on bar path as much as body position. Thus, task constraints should help guide athletes' actions while exploring movement to achieve the best bar path. As discussed elsewhere this is a “body adapts to skill approach” (38). The following task constraints are matched to these critical factors and designed to encourage better skill acquisition.
CONSTRAINT DEVELOPMENT PROCESS
Task constraints for first pull faults
The following constraints are given as examples of how to correct first pull faults (Figure 5).
CHALK ON THE BARBELL—REARWARD BAR PATH
Chalk is applied to the bar at hip width of the athlete (Figure 6). Chalk is placed on the bar so as to encourage the athlete to have more reward pull toward them on the first pull (45). Having chalk on the bar will help show the athlete where contact was (or was not) made on the thigh and allow exploration of different timings for the start of the second pull.
VARYING STARTING HEIGHTS—SLOWING DOWN THE FIRST PULL
The vertical distance between the lifter and the bar is decreased by having the lifter stand on a slightly raised (20–40 mm) surface (Figure 7). This allows the athlete to set their knees further over the bar, which in turn, changes the timing of the lift by making bar passage around the knees more difficult. The desired outcome is to slow movement down during the first pull and put focus on pulling the knees back while keeping the shoulders over the bar. Furthermore, the increased difficultly presented by the start height will help eliminate the frequency of the athlete attempting to yank the bar off the floor. Varying the starting heights (lower or higher) will change the length of the first pull, allowing the athlete to adjust the timing of their transition for (Figure 4C) each lift.
WEIGHTED VEST LOADED ON THE TORSO TO PULL FORWARD MORE IN SETUP
Mariner et al. (27) improved rearward barbell direction by making athletes wear a weighted vest of 12% body weight (Figure 8). The vest forces the athletes into a more forward position in the first pull, making them apply a reciprocal reward directional force. The resulting bar path travelled in a rearward direction.
TASK CONSTRAINTS FOR SECOND PULL FAULTS
The following constraints are given as examples of how to correct second pull faults (Figure 9).
DIFFERENT BARS WITH LIGHT AND HEAVY LOADS TO EMPHASIS HIP EXTENSION
Two bars are set up, one with a lower/lighter load than the other (Figure 10). With the heavier bar, the athlete performs clean high pull (power clean without the catch phase), and with the lighter bar, they perform a full power clean. This allows athletes to feel the heavier load pulling them forward out of position during the first pull then apply this feeling within the second bar power clean.
Increasing and varying the load on the bar will also stimulate different muscle groups, as a heavier bar will encourage more leg pushing/driving movement making it less likely that they will try and pull the bar mainly with their arms.
AGILITY POLES OR JERK BLOCKS TO AVOID EXCESSIVE HIPPING OR LOOPING DURING THE SECOND PULL.
Place jerk blocks or agility poles in front of the athlete, so that they restrict forward barbell passage (Figure 11). Athletes perform lifts close to an object in front, for example, wooden board/poles that could fall over when the participant moves the bar out in front of them (45). This is used to increase awareness of the bar path during the second pull phase. This allows the lifter to come up with their own movement solution to keep the bar tight to the body. For safety, where an unmovable object is the constraint, reduce the risk of injury by using a bar of lighter load.
BARRIER FOR FEET TO AVOID JUMPING FORWARD
A small block of wood/rubber/foam mat is placed in front of the participant (Figure 12). This barrier provides feedback to athletes if their feet touch the object, forcing them to explore a movement that avoids contact with the barrier, potentially encouraging a jump away from the barrier.
CLIFF CONSTRAINT TO AVOID JUMPING FORWARD
The athlete is positioned on the edge of an 8-cm “cliff” as shown in Figure 13. This constraint uses the intrinsic dynamics (perceived aversion) to cliffs found in studies of motor development (22). Athletes instinctively avoid and tend to jump away from the cliff while lifting, fixing a jump forward movement (45). This will promote optimal timing, and bar path as a common error is jumping forward due to the bar path tracking away from the body. A similar constraint is tape on the floor, where athletes are asked to stay behind the tape.
TASK CONSTRAINTS FOR CATCH FAULTS
The following constraints are given as examples of how to correct catch faults (Figure 14).
TWO BARS, SPINNING AND NOT SPINNING—USING A POORLY MAINTAINED OR QUALITY BAR AND A GOOD BAR
By using different types of barbells some with more or less ability to spin in the athlete's hand. Varying the barbell will draw the attention of athletes to elbow turnover speed during the catch and encouraging the feeling of a fastest catch.
BARBELL PLATE CLIPS TO MOVE FEET OR BARRIER TO STOP FEET SLIDING
To impede athletes attempting to lower the shoulders under the bar by jumping their feet side-to-side rather than lowering their hips, use a barrier, for example, plates as depicted in Figure 15. This will impede athletes who catch with their feet splayed apart (21). In addition, if the coach wishes the athlete to move their feet or drop under the bar, place objects that can easily be moved and ask the athlete to slide them out when they catch. When considering safety, ensure the object you have chosen is tall enough, so that if the athlete's feet leave the ground during the lift, they do not land on top of the object.
The field of skill acquisition draws on motor control, neuroscience, motor learning, and experimental psychology, presenting challenges to accepted practices. By contrast, the 2 major professional bodies for strength and conditioning, the American College of Sports Medicine (ACSM) and the National Strength and Conditioning Association (NSCA), provide limited guidelines with respect to coaching or skill acquisition. This highlights a lack of attention to skill development in strength and conditioning. It is suggested here that coaches who adopt practices based on recent work in skill and coaching will have greater impact on athletes. Through a close analysis of the power clean and skill acquisition, this article explores links between contemporary coaching theory and commonly used methods in strength and conditioning. There is significant benefit for coaches and athletes regarding performance outcomes if elements of coaching pedagogy are applied to the problem of movement change. Rather than using an explicit approach, it is argued that the adoption of a constraints-led approach, in particular, can result in greater performance improvements.
We acknowledge that a traditional approach has been and is effective for the teaching of many movements including the power clean. This article shows how a constraints-led approach and the use of task constraints specifically can be used to reshape movement behavior as exemplified through teaching the power clean. Adopting task constraints encourages athletes to explore varied movement solutions; unique to themselves in pursuit of good technique, this leaves athletes to do more learning on their own. Coaches and athletes familiar with a traditional approach will find this shift in method challenging, as providing feedback on every single attempt at a movement is common practice. Not giving feedback on every attempt trades improved short-term performance improvement for better long-term skill learning (6,7). A constraints-led approach is not based on instant, often verbal feedback, and thus give the appearance of limited focus on improvement, but the result leads to greater returns. Benefits include more successful lifts along with a skill that is robust under varying psychological and physical pressures. Given the potential benefits associated with using this approach, it seems important that strength and conditioning coaches adopt this approach as another tool to potentially better their practice.
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