Introduction
Over the years, the standing long-jump test has been adopted by a variety of sports and organizations, both professional and amateur, to evaluate and predict athletic success. Although physical training regimens have been researched and debated, what has not been considered is the influence of verbal instruction on standing long-jump performance. Although strength and conditioning professionals continually seek out new techniques and strategies to develop and test athletic performance, it is critical for coaches to identify the differential effects that various types of verbal instructions have on standing jump performance.
Through the use of verbal instructions, practitioners deliver critical information that, ideally, contributes to skill development through the creation of efficient movement patterns (23). One area of motor learning research that has received a considerable amount of investigation is the use of verbal instructions to induce an internal or external focus of attention (for a review, see [16,19]). An internal focus is characterized by focusing one's attention on their own body during the movement. This is in contrast to an external focus, which directs attention to features in the environment or movement effects (15). For example, when a coach is teaching an athlete jump mechanics, the coach may instruct the athlete to focus on achieving full limb extension during the jump (i.e., internal focus of attention) or instruct the athlete to focus on jumping to a specific spot in front of them (i.e., external focus of attention).
In a recent study by Porter et al. (11), it was reported that experienced track and field coaches provided instructions and feedback during practice and competition that caused their athletes to use an internal focus of attention. This is a noteworthy observation because many experiments have investigated instructional manipulations promoting an internal vs. external focus in a variety of sport settings; the findings are rather robust in that the directions that foster an external focus of attention elicit better performance than instructions that induce an internal focus of attention (15). Although this benefit in performance has been consistent in the literature, a vast majority of the research has used skills that require the manipulation of an object to achieve the action goal. For example, it has been demonstrated that instructing athletes to focus externally rather than internally improves soccer shooting accuracy ([18], experiment 2), volleyball serve placement ([18], experiment 1), basketball shooting accuracy (1), and golf shot accuracy (17,20). However, many strength and conditioning professionals teach skills that do not require object manipulation but require whole-body movements (e.g., sprinting, jumping, agility). Moreover, these types of skills are often used to evaluate athletic performance (2,4,12,13). Considering the continued growth of empirical evidence supporting the use of an external focus of attention, it is interesting to note that many popular testing manuals and textbooks do not address the use of this method to improve athletic performance (2,3,5,6,9,10). With these considerations in mind, understanding how to more effectively use verbal instruction to manipulate focus of attention should be of great concern for practitioners because it may have a direct effect on an athlete's motor performance.
There is some evidence that the performance of complex whole-body movements can be improved by using an external focus of attention. In a recent experiment by Wulf et al. (21), participants practiced a vertical jump using a Vertec™ instrument. Participants performed multiple vertical jumps following 3 different sets of instructions: Control, internal focus, and external focus. For the control condition, no attentional focus directions were given. For the internal condition, participants were instructed to reach the finger tips as high as possible during the jump, whereas the external instructions told participants to reach as high as possible while focusing on the rungs of the Vertec™. Results showed that participants jumped significantly higher when using an external attentional focus compared with the internal attentional focus and control conditions. This experiment provides initial evidence in support for verbal instructions that promote external attentional focus to enhance athletic performance for tasks requiring maximum effort and a whole-body movement. However, questions still remain about the generalizability of these findings because they relate to whole-body movements without object manipulation. One consideration that has not been established is whether or not the benefits of an external attentional focus are observed when the task requires a whole-body movement in the horizontal plane, as in the standing long jump. The standing long jump is commonly used by practitioners to measure and evaluate athletic performance (2,4,12,13). If a simple manipulation of verbal instructions can lead to enhanced jumping ability, then it is of great importance for practitioners to understand how to deliver instructions so they can enhance their athlete's performances, in addition to, providing accurate and reliable testing environments.
The benefits of an external focus have been observed in a variety of tasks requiring object manipulation (1,17,18,20). It seems plausible that focusing attention externally would also lead to enhanced standing long-jump performance when compared with instructions that focus attention internally. Thus, the purpose of this experiment was to examine this prediction. It was hypothesized that subjects who were instructed to focus externally (i.e., on the effects of their movements) would jump farther than subjects who were instructed to focus internally (i.e., on a specific body part).
Methods
Experimental Approach to the Problem
In the present study, a between-participant design was used to explore the performance benefits that may exist by using subtle differences in verbal instructions when directing a learner to perform a maximum effort whole-body movement. Practitioners commonly use performance outcome measures (7) to evaluate individuals; therefore, we decided to use jumping distance as the dependent measure in the current study. Untrained subjects (n = 120) were randomly assigned to 1 of 2 experimental conditions. After a 5-minute warm-up, all subjects completed a total of 5 standing long jumps following instructions that were designed to induce an internal or external focus of attention. The jumping distance of subjects in each condition was recorded and stored for later analysis. A statistical analysis was conducted between the jumping distances for the internal and external groups to examine significant differences in performance.
Subjects
Young adults (n = 120) were recruited from a general undergraduate student population. All participants signed an informed consent and completed a medical history questionnaire; both of these documents and all experimental methods were approved by the University's Institutional Review Board. After all paperwork was complete, participants were assigned to either the external attentional focus group (EXT) (n = 60) or the internal attentional focus group (INT) (n = 60). Both groups had equal numbers of men (n = 36) and women (n = 24). The average participant age was 21.72 ± 2.72 and 22.12 ± 4.05 years for the EXT and INT groups, respectively. The average participant height was 173.44 ± 13.82 and 173.99 ± 11.64 cm for the EXT and INT groups, respectively. The average participant weight was 77.89 ± 15.83 and 78.46 ± 13.59 kg for the EXT and INT groups, respectively. Upon recruitment for the study, participants were asked to wear athletic clothing and shoes to perform the long-jump experiment. Experimental subjects were considered moderately skilled jumpers, because this is a motor program that has existed in their repertoire of movements for most of their life. All subjects were screened to make sure they had not received formal jump training. If subjects had received formal jump training, they were excluded from the participation pool. The standing long jump was not considered a novel skill; however, the subjects used in the current study did not have specific training in the standing long jump.
Procedures
Before data collection, participants completed a 5-minute warm-up on a recumbent stationary exercise bike. At no time during the course of the study were subjects instructed or allowed to perform static stretching. The 5-minute warm-up was followed by a 2-minute seated rest. During this first rest period, each participant was read the following instructions: “Today you will be completing a total of five standing long jumps starting behind a designated starting line. Each jump will be followed by a seated 2-minute rest. Prior to each of the five trials I will read you an additional set of simple instructions.” Once the rest period expired, the participant was instructed to stand behind the starting line (but as close to it as possible) to prepare for the upcoming jump. Once the participant was behind the starting line and ready to jump, another set of instructions were read to him or her to prompt the proper attentional focus during the trial. Participants in the INT group received the instructions, “When you are attempting to jump as far as possible, I want you to focus your attention on extending your knees as rapidly as possible.” Participants in the EXT group received the instructions, “When you are attempting to jump as far as possible, I want you to focus your attention on jumping as far past the start line as possible.” Participants were read the appropriate set of instructions before each jump and then allowed to jump when ready. Jump distance was recorded into a computer immediately upon landing. A 2-minute seated rest followed each jump. All participants completed a total of 5 standing long jumps.
Apparatus and Task
Testing took place in a controlled research laboratory; thus, we were able to keep environmental conditions similar across subjects. A large black rubber composite floor mat 4.57 m in length and 0.61 m in width was used to assess the maximal distance jumped from a starting line clearly marked at one end of the mat (Figure 1). Measurement lines in 0.5-in. increments were printed and numbered on the rubber mat in bold white. These incremental lines continued out to 144 in. Data were originally collected in inches and later converted to centimeters for analysis. Measurements were taken immediately when the participant landed after each of the 5 jumps. Measurements were taken from the back of the heel that was nearest to the start line.
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Figure 1: Long-jump measurement mat. All subjects jumped from behind the same start line. Jumping distance was measured from the start line to the back of the heel closest to the start line. The subject pictured above is in the landing position.
Statistical Analyses
Data were analyzed using the Statistical Package for the Social Sciences (SPSS) version 16. The criterion for significance was set using an alpha level of p ≤ 0.05. An independent samples t-test was used to determine significance between the experimental conditions. The reliability of the dependent variable was determined by calculating intraclass correlation coefficient reliabilities (ICCRs). Cohen's effect size (ES) statistics (Cohen's d) were calculated to determine the magnitude of observed significant performance differences. Effect sizes were based on the criteria of d < 0.30, small; d = 0.31-0.70, moderate; and d > 0.71, large.
Results
An independent samples t-test revealed a significant difference (p = 0.003, ES = 0.12) in the distance jumped between the EXT (187.37 ± 42.66 cm) (SEM = 2.46) group and the INT group (177.33 ± 40.97 cm) (SEM = 2.37). The lower and upper limits of the 95% confidence interval of the difference were 3.32 and 16.74, respectively. The average jumping distance for each group is displayed in Figure 2. These results show that subjects in the EXT group jumped significantly farther than participants in the INT group. The ICCRs determined that the dependent variable was reliable for the EXT group (r = 0.99) and INT group (r = 0.97).
Figure 2: Mean jumping distances for the internal and external conditions.
Discussion
The purpose of the current experiment was to examine how instructional manipulations influenced the standing long jump. It was predicted that instructing participants to focus attention externally would lead to enhanced standing long-jump performance when compared with instructions that focus attention internally. The results of the experiment support this prediction. These findings add to a growing body of research showing the benefits of instructing performers to use an external attentional focus during skill execution (1,17,18,20). In addition, these findings are consistent with previous studies examining the benefits of an external attentional focus when performing a whole-body movement (21). This study makes a unique contribution to the field of strength and conditioning by demonstrating the influence that verbal instructions alone can have on standing long-jump performance. In addition, this study demonstrates the generalizability of using an external focus of attention to enhance the performance of skills that require a whole-body movement.
Wulf (15) proposes the constrained action hypothesis to explain why an external focus produces better performance. This hypothesis states that an internal focus increases conscious control in a movement and “constrains” or decreases automaticity in the motor control system thus decreasing performance outcomes. In contrast, an external focus facilitates unconscious control leading to greater automaticity and greater efficiency in a movement pattern. In accord with the constrained action hypothesis, findings from previous motor learning research provide empirical evidence and plausible explanations as to why adopting an external attentional focus enhanced standing broad jump performance. First, Wulf et al. (21) demonstrated that instructing participants to focus externally while performing a vertical jump led to greater force production. Although force was not measured in the current study, it seems reasonable that participants in the EXT group may have produced greater force compared with participants in the INT group, resulting in a significantly greater jumping distance. Second, it has also been demonstrated that focusing attention externally results in a more effective movement pattern by increasing the efficiency of muscle fiber recruitment (8,14,22). Through efficient muscle fiber recruitment, movement coordination is improved resulting in enhanced performance (8,14,21). Although outcome measures rather than performance production measures were used in the current study, the enhanced jumping distance for the EXT group was likely a result of greater force production or improved coordination pattern as a result of efficient muscle fiber recruitment. Future experimentation measuring force or movement coordination patterns is needed to validate this assumption. Regardless, the present results show that standing long-jump performance was increased when instructions induced an external rather than internal focus of attention.
It is common for coaches to use the standing long jump to develop and evaluate athletic performance (4,12,13). Therefore, it is important for coaches to use the most effective instructions to facilitate the best performances from their athletes. The present study demonstrates that minor manipulations in verbal instructions can result in significant changes in jumping ability. Future studies should continue to investigate the “mental” side of strength and conditioning. By using methods similar to the ones described above, it is important that future experiments address the potential performance differences that may exist when verbal instruction manipulations are provided for other tests of physical abilities such as sprinting, agility, and related power movements.
Practical Applications
The findings reported in this study suggest that strength and conditioning professionals must pay special attention when providing verbal instructions to athletes who are performing the standing broad jump. Coaches should design instructions that focus an athlete's attention externally rather than internally. Coaches can accomplish this goal by providing specific cues in their instructions that direct attention to key elements, targets, features in the environment, or a desired movement result. For example, a coach may instruct an athlete to focus on the trajectory of their jump, a specific landing location, or to focus on jumping to or past a designated target like a cone or strip of tape on the floor. Providing these types of verbal cues in their instructions will likely induce an external focus of attention. By inducing an external focus of attention in the athlete, the coach will likely enhance the athlete's physical abilities. In addition, the findings of this study provide converging evidence that coaches should avoid words in their instructions that reference specific body parts or body movements. For example, coaches should not tell athletes to think about their jumping technique, or to quickly contract their muscles during skill execution of a jump. Doing this may result in an internal focus of attention, likely depressing performance by reducing force output or the adoption of an inefficient movement pattern.
In addition to the training aspects of the standing long jump, this study also highlights the importance of verbal instructions in conducting the standing long jump for assessment purposes. In light of the results, coaches who administer the standing long jump as a test must ensure that test instructions are consistent and do not cause some athletes to focus internally, whereas others focus their attention externally. Inconsistency in providing verbal instructions may lead to various types of attentional focus which may provide unreliable performance measures.
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