Effects of Different Observational Angles in Learner-Chosen Video Self-Modeling on Task Acquisition and Retention.

This study aimed to examine the influence of different observational angles in video self-modeling on task acquisition and retention. We randomly assigned 42 Japanese university students to three camera-angle groups, i.e., a front-angle, a rear-angle, and a control group. The participants performed a 3 × 6 × 3 cup-stacking task with three sequential laps. The front- and rear-angle groups viewed video self-modeling created from previously self-chosen videos. The retention phase was conducted 1 week after the acquisition phase. The rear-angle group demonstrated the fastest movement times in the acquisition phase. Our findings indicate that viewing learner-chosen video self-modeling from a rear angle enhances motor skill acquisition but does not contribute to motor skill learning.

Effects on modeling sequential body movements when viewed from the front or rear.

This study investigated the effect of having a model demonstration viewed from the rear and/or front on the subsequent acquisition of sequential gross-movement patterns, and further examined how participants who observed the bi-angle model directed their attention toward the rear view or the front view in mirror. The movement pattern consisted of seven pauses. A total of 36 participants was divided into three groups: the rear-angle group, which observed the rear view; the front-angle group, which observed from the front view and had to change the motions into their mirror opposites; and the bi-angle group, which observed the rear view and the front view in the mirror. The results showed that (1) all groups acquired the movement pattern, (2) the bi-angle and the rear-angle groups reproduced the demonstrated movement more accurately than the front-angle group, and (3) the bi-angle group tended to focus gaze on viewing the model from the rear. These results suggest that rear viewing was more effective than front viewing, because the participants could simply copy the motion, the bi-angle group members directed their visual attention to the view from the rear without any instruction about observational strategy, and modeling effect was the same for the rear-angle group and the bi-angle group.

Effects of vision on head-putter coordination in golf.

Low-skill golfers coordinate the movements of their head and putter with an allocentric, isodirectional coupling, which is opposite to the allocentric, antidirectional coordination pattern used by experts (Lee, Ishikura, Kegel, Gonzalez, & Passmore, 2008). The present study investigated the effects of four vision conditions (full vision, no vision, target focus, and ball focus) on head-putter coupling in low-skill golfers. Performance in the absence of vision resulted in a level of high isodirectional coupling that was similar to the full vision condition. However, when instructed to focus on the target during the putt, or focus on the ball through a restricted viewing angle, low-skill golfers significantly decoupled the head--putter coordination pattern. However, outcome measures demonstrated that target focus resulted in poorer performance compared with the other visual conditions, thereby providing overall support for use of a ball focus strategy to enhance coordination and outcome performance. Focus of attention and reduced visual tracking were hypothesized as potential reasons for the decoupling.

The use of knowledge of results based on the stability of performance during acquisition of timing skill: a validity study.

The goal was to examine the effect of changing knowledge-of-results bandwidth based on a participant's stable performance during acquisition of a timing skill. 36 university students experienced one of three conditions: (1) 100% KR condition during which information on errors was provided after each trial during practice, (2) fluctuation-of-range condition, wherein KR bandwidth was based on standard deviation of five trials, and (3) 10% KR bandwidth condition (10%), wherein the KR bandwidth was 810-990 msec. Variable error in the fluctuation-of-range condition at posttest and retention was significantly smaller than that with the 100% KR. Conditions in which range of KR was allowed to fluctuate were more effective for stabilizing performance.

Head-putter coordination patterns in expert and less skilled golfers.

The authors examined the patterns of expert and less skilled golfers in putting on an indoor surface to 1 of 3 circular targets (1, 3, and 5 m away) in trials with a ball present (and putted) or not present (a practice stroke). As expected, the experts performed better than the less skilled golfers on a large number of outcome and kinematic measures. Displacement and velocity profiles of the head and putter revealed high positive correlations for the less skilled golfers, indicating a dominant allocentric coordination pattern, but high negative correlations for the expert golfers, indicating a dominant egocentric coordination pattern. The observed coordination patterns did not interact with the distance of the intended putt or the presence/absence of a ball. These findings offer preliminary evidence that, although contrary to traditional beliefs, fundamental differences exist in putting coordination modes between expert and less skilled golfers.

Reduced relative frequency of knowledge of results without visual feedback in learning a golf-putting task.

This study examined the effects of reduced relative frequency of knowledge of results (KR) on learning to putt in golf. Participants (19 men and 15 women) putted a golf ball, stopping the ball on a line at a distance of 3.5 m from the starting position, which included an uphill portion. After a pretest, participants were assigned as they arrived in balanced order by sex to one of two groups (100% KR, 33% KR) and practiced 60 trials. Those in the 100% KR group performed the task in its natural context, while others assigned to the 33% KR were shown the location of the putted ball after every third trial. All participants then performed a posttest and two retention tests, done 10 min. and 24 hr. after the posttest. Analysis at posttest showed each group had a constant error and an absolute constant error (/CE/) less than those at pretest. Also, in the retention test conducted the following day, the constant error of the 33% KR group was less than that of the 100% KR group. Third, in the posttest and both retention tests, the /CE/ of the 100% KR group was larger than that of the 33% KR group. These results suggest that reduced relative frequency of knowledge of results is effective in learning the accuracy of the golf putt.

Average KR schedule in learning of timing: influence of length for summary knowledge of results and task complexity.

This experiment investigated the influence of length for average Knowledge of Results (KR) and task complexity on learning of timing in a barrier knock-down task. Participants (30 men and 30 women) attempted to press a goal button in 1200 msec. after pressing a start button. The participant was assigned into one of six groups by two tasks (simple and complex) and three feedback groups (100% KR, Average 3, Average 5). The simple and complex tasks required a participant to knock down one or three barriers before pressing a goal button. After a pretest without KR, participants practiced 60 trials of physical practice with one of the three following groups as a practice phase: one given the result of movement time after every trial (100% KR), a second given the average movement time after every third trial (Average 3), a third given the average movement time after every fifth trial (Average 5). Participants then performed a posttest with no-KR and two retention tests, taken 10 min. and 24 hr. after the posttest without KR. Analysis gave several findings. (1) On the complex task, the absolute constant error (/CE/) and the variable error (VE) were less than those on the simple task. (2) The /CE/ and the VE of the 100% KR and the Average 3 groups were less than those of the Average 5 group in the practice phase, and the VE of the 100% KR and the Average 3 group were less than those of the Average 5 group on the retention tests. (3) In the practice phase, the /CE/ and the VE on Blocks 1 and 2 were higher than on Blocks 5 and 6. (4) On the retention tests, the /CE/ of the posttest was less than retention tests 1 and 2. And, the VE of the 100% KR and the Average 3 groups were less than that of the Average 5 group. These results suggest that the average feedback length of three trials and the given feedback information after every trial are advantageous to learning timing on this barrier knock-down task.