Using Motor Imagery to Learn Tactical Movements in Basketball
Aymeric Guillot, Edyta Nadrowska and Christian Collet Université Claude Bernard Lyon I, France
While there is ample evidence that motor imagery (Ml) contributes to enhance motor performance, it is still unknown whether mental practice may help to improve game plans or strategies of play in open skills. The present study was thus devised to investigate the effect of Ml on the learning of basketball tactical strategies in 10 national female pickers. Three attack movements were objectively and subjectively evaluated during a pre-test. The first game strategy was physically and mentally practiced twice a week over a 6-week period The second was physically performed, while the third was not trained. The combination of MI and physical practice was found to significantly improve motor performance during the post-test. Scores awarded by the coach suggested that such a combination was the most efficient training condition, however, MI was not found to be significantly more efficient than physica¡ practice alone. Hence, the results support the assumption that MI may lead to improved motor performance in open skills when compared to the no-practice condition. However, additional research should be conducted to reach more conclusive results and MI should rather be considered an alternative technique to reduce physical training or prevent overtraining.
Address correspondence to: Aymeric Guillot, Centre de Recherche et d'Innovation sur le Sport, Université Claude Bernard Lyon I, 27-29 Boulevard du 11 Novembre 1918, 69622 Villeurbanne cedex, France. Phone: 33-4-72-43-16-25 Fax: 33-4-72-43-28-46, E-mail: aymCTÍ
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Motor imagery (MI) is a dynamic state during which an action is mentally simulated without any body movement. This technique is a multi-sensorial experience as images can include visual, auditory, tactile and kinesthetic components. Two of the principle imagery perspectives that athletes use, are internal and external visual imagery. These perspectives require the visualization of movement, using either a first- or a third-person perspective, whereas kinesthetic imagery requires to mentally perceiving muscle contractions and stretching, as well as joint amplitude. Although visual and kinesthetic imagery have been found to be significantly correlated (Callow & Hardy, 2004), specific characteristics of motor performance may be enhanced by various imagery modalities (White & Hardy, 1998). Experts have been differentiated from novices by their ability to use visual and kinesthetic imagery (BarT & Hall, 1992; Mahoney & Avener, 1977). Non-expert athletes have been found to have usually greater difficulty in feelingthe movement (Guillot & Coilet, 2005b; Guillot, Collet, & Dittmar, 2004), kinesthetic imagery being beneficial only with an adequate degree of expertise (Hardy & Callow, 1999). While there is ample evidence that MI contributes to enhance motor performance, self-confidence and motivation, it still remains unknown whether mental practice may help to improve game plans or strategies of play in open skills. According to the symbolic learning theory (Sackett, 1934), MI gives the opportunity to rehearse the sequence of movements as symbolic components of the task. Consequently, MI would facilitate the cognitive requirements of the skill, such as movement timing, sequencing and planning. However, when examining the functions of MI, it is important to match the imagery used with the intended outcome with the aim to improve the benefits of MI (Guillot & Collet, 2008; Martin, Moritz, & Hall, 1999). The analytic framework for imagery effects proposed by Paivio (1985) has suggested that MI may serve distinct functions (cognitive and motivational) operating on general and specific levels. The motivational components of this theory refer to the use of goal-oriented responses and the management of arousal level, while the cognitive components tap into skill improvement and refer to the imagery of game strategies. Furthermore, Hall, Mack, Paivio and Hausenblas ( 1998) have identified two components of the motivational general imagery (arousal and mastery). The majority of the studies that have investigated the effects of an imagery program in sport, focused on the cognitive specific function of imagery leading to the acquisition and performance of a specific motor skill. Hence, coaches often encourage their athletes to use MI, which is often a key component in the mental training programs developed and implemented by sport psychologists (Fenker & Lambiotte, 1987; Mclntyre & Moran, 1996; Munroe-Chandler, Hall, Fishbume, & Shannon, 2005). The combination of mental and physical practice is thought to be more efficient than physical practice alone when there is no decrease in total physical training (Driskell et al., 1994;
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Feltz & Landers, 1983; Guillot & Collet, 2008). Alongthis line, muscle strength has been found to increase after mental practice (Yue & Cole, 1992), as MI increases the cortical output signal, which brings muscles to a higher activation level resulting in an increase in strength. More generally, MI has been found to be more beneficial for closed than for open skills, i .e. when the execution ofthe skill takes place in a similar and monitored environment, without the influence of an opponent (Denis, 1985). However, several studies have reported some positive effects of mental training in open skills, such as in football (Fenker & Lambiotte, 1987), soccer (Blair, Hall, & Leyshon, 1993 ; Munroe-Chandler et al., 2005), canoe-slalom performance (Mclntyre & Moran, 1996), table tennis (Li-Wei, Qi-Wei, Orlick, & ZitzeIsberger, 1992;) and basketball free-throw performance, although the environment does not significantly change in the latter (Hall & Erf&neyer, 1983;Lemer,Ostrow,Yura,&Etzel, 1996;Onestak, 1997; Wrisberg& Anshel, 1989). In these studies, however, most ofthe mental practice designs used multiple interventions (e.g., relaxation, self-talk, video, in association with MI), so it appears to be difficult to determine the specific effect of MI. Furthermore, athletes have been systematically instructed to imagine a specific movement that did not directly depend on the opponent that was free of any spatial or temporal uncertainty, and where the environment remained stable. When considering an opponent's action, the effect of MI on performance enhancement has been found to be more selective. In a volleyball task (serve reception and pass to a motionless target player), Roure et al. ( 1998) observed that MI enhanced motor performance, but that the benefit of MI was not transferred, even in a closed motor sequence, in which the target player moved laterally before serve reception. To be efficient, spatial and temporal characteristics of MI should thus match those of physical execution (Guillot & Collet, 2005a; Holmes & Collins 2001). Even though some motor imagery experimental studies have been conducted in open skills, very few looked at the learning of tactical movements, in which the cognitive general ñinction of imagery is required (Paivio, 1985). The effect of MI on learning game strategies seems to be an area of research in sport that has received little attention and has shown inconsistent results. Therefore, it appears necessary that some experimental investigation be undertaken. Kendall, Hrycaiko, Martin and Kendall (1990) suggested that the combination of MI, relaxation and self-talk training was effective in enhancing the performance of a defensive basketball skill. However, Munroe-Chandler et al. (2005) reported that although a young elite female soccer team showed the potential to improve in the soccer strategies over the course of the season, no physical performance effects were found after the MI program. In basketball, the contribution of tactical knowledge has been highlighted in studies focusing on the information taught by expert basketball coaches in practice (Bloom, Cnimpton, & Anderson, 1999; Tharp & Gallimore, 1976). Players and coaches may use MI either as a mean to develop or
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create new strategies to get the best out of their teams, or to develop a variety of game plans to combat specific opponents before the competition (Martens, 2004; Morris, Spittle, & Watt, 2005). They may also use MI to rehearse strategies before a competition to become familiar with the role of their team-mates and see how to temporally and spatially position themselves among the others. Before undertaking mental training such as this, it is essential to model the motor skill, in order to identify with the main tactical schémas that are transferred from an earlier context to another (Guillot & Collet, 2003; McGany & Franks, 1994). In open skills, athletes usually assign the probability of occurrence of an event before initiating an action, in association with the most probable area of attack or type of movement adopted by the opponent. The final aim is to anticipate an opponent's action and to prepare them to respond faster. For instance, they try to impose their tactical superiority, using pre-determined offensive game strategies to force the opponent to defend and therefore to anticipate the subsequent actions more easily (Guillot & Collet, 2003). Considering its positive effects on performance enhancement and learning facilitation, MI may thus be combined with physical training to facilitate acquisition and execution of pre-determined offensive game schema. This study was therefore devised to evaluate the effect of cognitive general MI on acquisition and performance in an open-skilled configuration involving several movements of a basketball team. As soon as spatial, temporal and event-driven uncertainties were limited, MI was expected to facilitate the acquisition and to enhance perfonnance of a pre-determined offensive game sequence. The combination of mental and physical practice was expected to be more efficient than physical activity alone in improving performance, both objectively and subjectively. Method Participants Ten female basketball players, ranging in age from 17 to 30 (A/= 22.7), consented to participate in experimental procedures approved by the local Research Ethics Board. All were semi-professionals and were competing at "national level". Based on their self-report, they were free of any recent injuries that could affect performance. They played basketball for at least 10 years and trained 4 times a week. Instrumental design Before the imagery intervention was implemented, athletes individually completed the Movement Imagery Questionnaire (MIQ, Hall & Pongrac, 1983) in a quiet room. Tbe purpose
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of carrying out the MIQ, was to check that there was no difference in individual imagery abilities among the team, since one athlete may have trouble in forming the mental image of a movement, while another may generate a very accurate mental representation of the same action,. The MIQ is made up of 18 items known to evaluate individual differences in visual (9 items) and kinesthetic (9 items) movement imagery. Completing each item entails 4 steps. First, the starting position is described, and then a specific arm, leg or whole body movement is precisely described and the participant is required to perform it. Next, each individual is asked to resume the starting position and to imagine the movement, using visual or kinesthetic imagery altematively (no actual movement is made). Finally, a score is assigned using a 7-point scale based on the difficulty of mentally representing oneself each movement. Hall, Pongrac and Buckholz (1985) reported a test-retest coefficient of .83 for a 1-week interval, and intemal consistency coefficients of .87 and .91 for the visual and kinesthetic subscales respectively. A qualified national level basketball coach with several years of experience coaching girls' basketball teams evaluated the effectiveness of the execution strategies and the efficacy of each athlete within the game plans. Although he was made aware of a MI intervention being used in the study, he was requested to rate the effectiveness of the three set play strategies used by the players by allotting an individual score to each athlete's performance, using a 6point scale. Level 1 was considered the poorest performance, level 6 the best, 2, 3, 4 and 5 representing intermediate performance levels. Finally, in order to provide their self-estimation, players were requested to make individual rating assessments based on their own observation and the criteria provided by the coach, using the same 6-poim scale. This experimental design contains subsets with specific strengths and weaknesses. The best approach is to control as many confounding variables as possible in order to eliminate or reduce errors in the assumptions that they will be made. First, the present study did not include a control group, but the benefit of the experimental design is the inclusion of a pre-test to detemiine baseline scores. Second, the aim of the study was to examine the imagery use of athletes in an ecological valid way. Finally, this qualitative research design aimed to gather information on individual perfomiance rather than on group performance like in many sport psychology researches (Munroe-Chandler et al., 2005; Shambrook & Bull, 1996). Procedure In agreement with the requirements of the team coach, and taking into consideration the main objectives of the season, three attack movements were selected. All were performed with passive defenders. To evaluate the effect of mental training, the fu^t movement was perfomied both mentally and physically; the second was only performed physically, and the third was taken as a reference, i.e. no mental or physical practice was done. However, to avoid any effect
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of practice time, athletes spent equivalent stretching time instead of mental work. The procedure for having three different tactical strategies in three different conditions may help to determine whether MI will contribute to enhance motor performance with regards to physical practice alone or no practice at all. Such a distinction required selecting three game strategies, each of the same difficulty as evaluated by the basketball rater. Each motor sequence thus contained the same number of players, displacements and interchanges with similar movement durations. Week 1 - Pre-test session. First, the basketball rater allotted an individual score for each athlete's performance, using the 6-point scale. Similarly, athletes self-evaluated their initial performance for each tactical schema, using the same 6-point scale. Ten trials were performed diu-ing each condition. Actual and imagined durations were recorded (in seconds) to be compared, as the ability to preserve the temporal characteristics of the movement during MI is an important aspect when investigating MI quality (Guillot & Collet, 2005a). During MI, upon mental initiation of the first body movement and at the end of the sequence, each athlete pressed a button to start and stop the timer. Weeks 2 through 7 - Mental and physical training. The attack movements were performed by all players. Only strategies 1 and 2 were practised either mentally and/or physically, in a reversed order, between weeks 2 and 7, while schema 3 was considered the baseline condition. For the First movement ("Mental Practice - MP")> the tactical schema was mentally and physically performed 2 times a week (Figure 1). As athletes have usually been shown to have trouble in maintaining focused attention along successive MI trials (Guillot et al., 2004), only three series of three consecutive imagined trials were performed. Athletes were instructed to use either intemai or external visual imagery, which supposed self-visualization of all successive action stages using a fu-st- or a third-perspective respectively. Before the beginning of mental training, each player was required to indicate their preferential imagery perspective, and MI sessions were then conducted through an imagery script corresponding to either the intemai or extemal perspective. As athletes are usually known to switch MI perspectives (Nordin & Cumming, 2005), they were instructed not to use the chosen perspective for the whole experiment. Furthermore, as the compliance of the subjects with instructions could not be controlled accurately, the participants were regularly requested to describe the nature of the images they attempted to form during the MI session and to score their effort using a 6-point rating scale based on the difficulty of mentally representing oneself each movement ( 1 = difficult to imagine and 6= easy to imagine). The content of the scripts focused on visual representation of the game configuration but also included affective and physiological responses when players used the intemai visual imi^ery perspective. Players were told to close their
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eyes and to visualize their own movement as well as their partners. MI was performed during physical training sessions, as it has been found to be more efficient than when it is performed in a neutral environment (Callow, Roberts, & Fawkes, 2006; Guillot, Collet, & Dittmar, 2005; Holmes & Collins, 2001). Indeed, environmental parameters, close to those of actual performance, are thought to help athletes to represent the situation. Hence, in the present study, three series of three mental simulations lasting 10-12 minutes total, were performed during physical training sessions. Athletes performed a total of 108 MI trials (9 trials per session during 12 physical practice sessions) on this fyst schema (MP). Finally, the athletes were requested to perform MI during specific training sessions only, and were not allowed to use it outside of the experimental setting, (e.g. at home), whatever the tactical schema.
Figure 1. First tactical schema ("Mental Practice - MP"). Player A is at the top of the circle. Two interiors (B and C) are in the free-throw area. The last two players (D and E) are at left- and right-wing positions. Player A passes the ball to player E. Player C moves to the 3-point line and receives the ball on the right wing. Simultaneously, player A moves toward the target, using player E as a screen and player B moves to the ieft side of the racket. Player C then takes the place of player E, who returns to the free-throw line. Finally, player A passes the ball to player C for the shot.
For the second movement ("Physical Practice - PP"), the tactical schema was physically performed twice a week, but was not mentally practiced (Figure 2). The time spent training for this sequence was equivalent to the training done with the first movement, i.e. 12 physical practice sessions. To avoid the potential effect of practice time, athletes spent equivalent stretching time instead of mental work during 10-12 minutes periods per training session.
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Figure 2. Second tactical schema ("Physical Practice - PF'). Player A is behind the 3-point line with the ball (a few steps on the left). Two interiors (B and C) are at the bottom ofthe racket. The two last players (D and E) are at left- and right-wing positions. Player C moves to the 3point line to set a screen on player A, who makes a few steps to the r i ^ t . Player D moves to the right and receives the ball from player A, while player C moves up to player B. Player E then movesfromthe right- to the left-wing and receives the ball from player D, while player C returns to the free-throw line. Finally, player C moves straight to the target and receives the ball for the shot. For the third movement ("Control - CONP'), the tactical schema is illustrated by Figure 3. Individual performance was evaluated at the beginning and at the end ofthe training session, but athletes did not receive any mental or actual training for this scheme. It was thus considered the control condition. However, this tactical schema was not a totally novel movement as it had been performed and memorized during the previous season.
Figure 3. Third tactical schema ("Control - CONP'). Player A is behind the 3-point line with the ball. TVo interiors (B and C) are at the bottom ofthe racket. Player D is behind the 3-point line, a few steps to the left, and player E is on the free-throw line. Player E runs to the target, using player C as a screen, while player A dribbles with the ball on the right. Player C then returns to the free-throw line and player B moves from the left to a position on the right, at the bottom of the racket. Player A passes the ball to player C before using player E as a screen on the right wmg. Player C finally passes the ball to player B for the shot.
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Week 8 - Post-test session. Athletes took part to a post-test similar to the pre-test. During week 8, the basketball coach awarded an individual score for each player, as he had done during the first week. Players also self-evaluated their fmal performance for each tactical schema, using the same 6-point scale. Finally, data from both actual and imagined executions recorded during the pre-test (week I) were compared to those recorded during the post-test (week 8). Data analysis Taking the sample size into consideration, and because the distribution was not gaussian, result processing was based on non-parametric statistics only. Both objective and subjective measures were undertaken as dependent variables. Durations of actual and imagined movements, as well as rating assessments (indicating whether or not the MI was thought to woric in the particular strategy) were thus compared using the Friedman test. Two-by-two comparisons were then carried out using the Wilcoxon test for paired groups. The alpha level was set at 0.05. Results MIQ scores Mean MIQ scores (SD) were 18.8 (5.26) and 32.6 (2.17) in the visual and kinesthetic modalities respectively. Only one athlete obtained a score at least 1 SD below the mean, no one being 1 SD above the mean. Assessment of imagery use During the debriefmg following the MI sessions, players reported using the imagery outlined in the scripts. All used the internal visual imagery perspective without switching between the two MI perspectives. None reported changing the imagery script to suit individual needs, but rehearsed the motor sequence as they were requested to. Indeed, they were able to report each game plan, including an explicit knowledge of each key-component ofthe physical execution. Performance evaluation A significant difference was found between the pre- and post-test scores awarded by the coach for both "MP" and "PP"(Z=-2.65,/7
