From a coaching perspective, it is important that a practice session is organised in a way that will benefit learning and keep athletes motivated to attend practice. From a motor learning perspective, variable practice (practicing multiple skills in a practice session) provides for variety to keep athletes motivated, while the knowledge from the contextual interference (CI) effect phenomenon ensures that learning has taken place. This CI effect is created when motor skills are practiced following a random order whereby performance following practice is decreased but substantial learning has taken place. An opposite effect is derived from practicing skills in a repetitive or blocked order, whereby performance is enhanced following practice, but with little or no learning benefits.
The explanation for the CI effect has been largely postulated by Lee and Magill's (1985) action-plan reconstruction hypothesis and Shea and Zimny's (1983) elaboration hypothesis. Lee and Magill (1985) proposed that the degraded performance in random practice was due to a task being forgotten and learning was enhanced because a new and different preparation for action was reconstructed each time a task was executed. As for the elaboration hypothesis, the inter task processing in random practice allows the learner to compare and contrast his actions making them more distinct and meaningful to the learner. More recently, Lin et al. (2008) used transcranial magnetic stimulation (TMS) pulses to investigate whether the action-plan reconstruction hypothesis or the elaboration hypothesis was a better explanation for the CI effect. The authors found stronger support for the elaboration hypothesis.
Regardless of which hypothesis was used to explain the CI effect, there appeared to be significant evidence that the CI effect was present in studies involving laboratory motor tasks. However, when the CI effect was studied using applied sport skills, the results have been mixed. In the case where a positive effect from the high interference practice schedules were not found, it has been suggested that the mitigating factor could be the complexity of the sports skills practiced (e.g., Jones and French, 2007; Landin et al., 2003; Zetou et al., 2007). A moderate practice schedule was proposed as a solution to the problem but attempts at manipulating the amount of interference of practice schedules still failed to provide a clear trend pertaining to the CI effect.
As such, is it possible that there is another way to reduce the difficulty of the sports skills being practiced? Most previous research addressing the contextual interference (CI) effect in applied sport settings have focused on multiple skills practiced independent of one another (e.g., Farrow and Maschette, 1997; Fialho et al., 2006; Granda Vera et al., 2008; Jones and French, 2007; Zetou et al., 2007) and in a closed skill manner (e.g., Brady, 1997; Landin et al., 2003; Meira and Tani, 2003; Porter and Magill, 2010; Wrisberg and Liu, 1991). In the majority of team environments, practicing a skill in isolation or independently in a closed skill environment does not represent the real-world setting of team sports. In a typical game setting, several skills (both discrete and continuous) often need to be executed one after another, and a combination skill is performed in order to achieve a particular outcome. In addition, an important aspect of a typical game is that it occurs in an unpredictable environment, whereby the type of skill a player executes is dependent upon the regulatory features (in particular: teammate and opponent movements) of the environment. While a number of studies that have attempted to bring CI research out of the laboratory by investigating applied sport skills and activities of daily living, there remains no pertinent literature examining combination skills. Furthermore, it appeared that only one study has investigated the CI effect with open sports skills. In that study, Granda Vera and colleagues (2008) compared three groups (blocked, alternating and combined) of children that practiced two soccer skills, kicking and dribbling.
Therefore, the purpose of this study was twofold. The first aim was to investigate the effects of three practice schedules located on the contextual interference continuum on the learning of combination skills. Practicing a set of skills in combination creates a functional skill that mirrors the way skills are executed in game play. A second purpose of this study was to investigate whether practicing skills randomly in an open skills environment could elicit the CI effect. A game-based training protocol was chosen to represent a random schedule with an unpredictable environment. As such, a more specific aim of this second purpose was to examine if a game-based training protocol is an effective form of high interference practice for skill learning. A review by Gabbett et al., (2009) found that while game-based training appeared to be a valuable tool for improving skill execution in team sports, the number of studies investigating its effectiveness was quite small and only focused on immediate skill execution but not retention performance. There have been no studies that had investigated the use of real-world game-based training (without conditioning or other activities) to assess acquisition and learning of sports skills in relation to the CI effect.
It was expected that the CI effect would be present when several sports skills were practiced in combination. Furthermore, practicing sports skills according to the game-based training protocol representing a random practice schedule in an unpredictable environment would be superior to the blocked and random group because of their exposure to the demands of a game and practicing in a similar environment. At the very least, the game-based schedule should be no worse than the random practice schedule characterised by a stable environment.
A total of 48 male and 22 female undergraduate students with a mean age of 21.56 and standard deviation of 1.23 (range between 19.17 to 26.67 years) volunteered to participate. The participants were first screened to determine that they had no prior experience in field hockey, had never received field hockey skills coaching and never played a competitive hockey match. All participants were given a copy of the information sheet and returned the signed informed consent form in accordance with the ethical guidelines of the Human Ethics Committee.
Two combinations of basic field hockey skills were practiced. In combination 1, participants were required to (1) stop the ball that was heading in their direction, then (2) close dribble and move with the ball in a straight line with the ball positioned next to the hockey stick at all times and then (3) push the ball as fast and as accurately as possible toward another participant. For combination 2, participants were required to simply stop the ball that was heading in their direction before pushing the ball as fast and as accurately as possible toward another participant.
Measures and test instruments Skill performance test
The skill performance test was used for the pre-test, acquisition and retention tests, whereby the close dribble and the push pass were assessed. For the close dribble, the speed of the participant dribbling with the ball over a distance of 10 m was captured while for the push pass, the speed and accuracy of the ball toward a target was recorded.
Figure 1 illustrates the layout for the skill performance test that was used in the pre-test, acquisition test and both retention tests. A speed gun (Bushnell Speedster II) quantified ball speed in km/h for the push pass. In addition, two four-foot long, two by three inch thick blocks of wood was used as the target. Scoring ranged from one to five points.
Game performance test
The game performance test was used as a transfer test whereby a pre and posttest was carried out. A four versus four game was played for seven minutes with specific rules introduced for the game. All participants played against four of five state-level field hockey players. The game play observational instrument designed by Turner and Martinek (1999) was adapted to assess motor execution. Two categories of behaviour was coded, one for control and the other execution (see Table 1).
The game performance test was coded according to the recommendations by Turner and Martinek (1992) which included observing one player at...