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John B. Cronin, Eadric Bressel and Loren Finn

Context:

Frequency and magnitude of ground reaction forces (GRF) have been implicated in causing injuries such as “jumpers knee.”

Objective:

To investigate whether a single session of augmented feedback concerning landing technique would decrease GRF.

Design:

Pretest posttest experimental design.

Setting:

University biomechanics laboratory.

Participants:

Fifteen female Division 1 intercollegiate volleyball players.

Intervention:

Participants were required to land on a force platform after spiking a volleyball from a four-step approach before and after an intervention involving visual and aural augmented feedback on correct jumping and landing technique.

Main Outcome Measures:

Mediolateral (ML), anterioposterior (AP), and vertical (V) GRF normalized to body weight (BW).

Results:

Augmented feedback was found to significantly (P = 0.01) decrease VGRF by 23.6% but not ML (25%, P = 0.16) and AP (4.9%, P = 0.40) peak GRF.

Conclusions:

A single session of augmented feedback may be effective in reducing VGRF in collegiate athletes.

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Alexander T. Latinjak, Miguel Torregrosa and Jordi Renom

The main purpose of this study was to examine the efficacy of a strategy that combined self talk and performance feedback. Therefore, three groups of adult tennis players performed a forehand groundstroke task. The first group (n = 16) applied an instructional self talk and self feedback combination, the second (n = 16) used regular instructional self talk, and the third (n = 16) performed without any specific aid. The hypothesis was that the performance and concentration scores of both self talk groups would improve from the pretest to the posttest, while the scores from the control group would remain unchanged. The analysis of variance with repeated measures confirmed this hypothesis. Further, the players who used self feedback perceived the effectiveness of their intervention to be significantly higher compared with the other intervention group. Overall, the combination of self talk and feedback seems to be an alternative to the original instructional self talk intervention.

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Andrea Hazen, Carolyn Johnstone, Garry L. Martin and Suja Srikameswaran

A videotaping feedback package was developed for improving skills of youth competitive swimmers. Experiment 1 examined the videotaping package for improving freestyle and backstroke racing turns of young competitive swimmers. Positive results were obtained in a multiple-baseline design across subjects. Experiment 2 compared the videotaping feedback package to a group videotaping procedure (that the coach had been using at the time of this research) for improving freestyle swimming strokes of young competitive swimmers. The videotaping feedback package was effective whereas the group videotaping procedure had little or no effect. For most subjects in the two studies, improvements were maintained with minimal prompting and feedback under normal practice conditions. Suggestions for future research are discussed.

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Zoe Butcher, Stuart Fairclough, Gareth Stratton and David Richardson

This study examined whether feedback or feedback plus physical activity information could increase the number of pedometer steps taken during 1 school week. One hundred seventy-seven students (mean age 9.124 ± 1.11 years) in three elementary schools participated. Schools were randomly assigned to control (CON), feedback (FB), or feedback plus information (FB+I) groups. Children wore pedometers during school time for 5 consecutive weekdays. The total steps of the groups were recorded at the end of each school day, with students in the FB and FB+I groups free to view their step counts. In addition, the FB+I group received information and ideas about how they could increase their daily steps. The CON group received no step-count feedback or information. Students in the FB+I group achieved significantly more steps per minute (17.17 ± 4.87) than those in the FB (13.77 ± 4.06, p = 0.003) and CON (12.41 ± 3.12, p = 0.0001) groups. Information, as well as step-count feedback, increased elementary students’ school-based physical activity (number of steps) in the short term. A longer intervention period is necessary to assess the sustained impact of this type of approach.

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Howard K. Hall, Mobert S. Weinberg and Allen Jackson

The purpose of the present investigation was twofold: first, to examine the relationship between goal difficulty, goal specificity, and endurance performance in a physical activity setting, and second, to determine the relationship between different types of information feedback, goals, and performance. Subjects (N = 94) performed on a hand dynamometer endurance task, being asked to hold a one-third maximum contraction for as long as possible. The subjects were randomly assigned to one of the following goal-setting conditions: (a) Do your best, (b) improve by 40 s, or (c) improve by 70 s. They were provided with either concurrent or terminal feedback in a 2 x 3 x 2 (feedback x goals x trials) design. Performance results indicated a significant goals-by-trials interaction with the 40- and 70-s goal groups exhibiting significantly more improvement than the "do your best" group. No significant performance differences were found between the two feedback groups. However, significant differences in the performance-associated cognitions of the feedback groups indicated a preference for concurrent feedback as an adjunct to goals. Results are discussed in terms of Locke's goal-setting theory as well as some recent field research investigating the goal-setting performance relationship in physical education settings.

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Benjamin W. Stroube, Gregory D. Myer, Jensen L. Brent, Kevin R. Ford, Robert S. Heidt Jr. and Timothy E. Hewett

Context:

Anterior cruciate ligament (ACL) injuries are prevalent in female athletes. Specific factors have possible links to increasing a female athlete’s chances of suffering an ACL injury. However, it is unclear if augmented feedback may be able to decrease possible risk factors.

Objective:

To compare the effects of task-specific feedback on a repeated tuck-jump maneuver.

Design:

Double-blind randomized controlled trial.

Setting:

Sports-medicine biodynamics center.

Patients:

37 female subjects (14.7 ± 1.5 y, 160.9 ± 6.8 cm, 54.5 ± 7.2 kg).

Intervention:

All athletes received standard off-season training consisting of strength training, plyometrics, and conditioning. They were also videotaped during each session while running on a treadmill at a standardized speed (8 miles/h) and while performing a repeated tuck-jump maneuver for 10 s. The augmented feedback group (AF) received feedback on deficiencies present in a 10-s tuck jump, while the control group (CTRL) received feedback on 10-s treadmill running.

Main Outcome Measures:

Outcome measurements of tuck-jump deficits were scored by a blinded rater to determine the effects of group (CTRL vs AF) and time (pre- vs posttesting) on changes in measured deficits.

Results:

A significant interaction of time by group was noted with the task-specific feedback training (P = .03). The AF group reduced deficits measured during the tuck-jump assessment by 23.6%, while the CTRL training reduced deficits by 10.6%.

Conclusions:

The results of the current study indicate that task-specific feedback is effective for reducing biomechanical risk factors associated with ACL injury. The data also indicate that specific components of the tuck-jump assessment are potentially more modifiable than others.

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Bevan C. Grant, Keith D. Ballard and Ted L. Glynn

A multiple baseline research design across teachers was used to evaluate the effects of feedback to teachers of behavioral data gathered in baseline lessons. Two teachers received such feedback while a third teacher served as a control. Both teachers who received feedback increased the amount of time students spent in motor-on-task behavior (+15%). Increases in motor-on-task behavior did not occur at the expense of any other student behavior. While this increase provided the students with more learning trials, only one of the two intervention teachers was able to increase the percentage of success of all student achievement groups when performing the learning trials. There were no substantial differences in student behavior between the three classes taught by the teacher who did not receive feedback. The study showed that although there were considerable differences in how physical education lessons were implemented, the two intervention teachers were able to respond to feedback and to modify their lessons so that the amount of student participation was increased.

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Arthur D. Kuo

A simple pendulum model is used to study how feedforward and feedback can be combined to control rhythmic limb movements. I show that a purely feedforward central pattern generator (CPG) is highly sensitive to unexpected disturbances. Pure feedback control analogous to reflex pathways can compensate for disturbances but is sensitive to imperfect sensors. I demonstrate that for systems subject to both unexpected disturbances and sensor noise, a combination of feedforward and feedback can improve performance. This combination is achieved by using a state estimation interpretation, in which a neural oscillator acts as an internal model of limb motion that predicts the state of the limb, and by using alpha-gamma coactivation or its equivalent to generate a sensory error signal that is fed back to entrain the neural oscillator. Such a hybrid feedforward/feedback system can optimally compensate for both disturbances and sensor noise, yet it can also produce fictive locomotion when sensory output is removed, as is observed biologically. CPG behavior arises due to the interaction of the internal model and a feedback control that uses the predicted state. I propose an interpretation of the neural oscillator as a filter for processing sensory information rather than as a generator of commands.

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Regina Markland and Thomas J. Martinek

This study examined the nature and amount of feedback that more successful and less successful high school varsity volleyball coaches gave to their starting and nonstarting volleyball players. Two of the four coaches studied were considered more successful and two were considered less successful, based on previous regular season win-loss percentages. Players of all the coaches (N=41) were also used as subjects and identified as having either a starting or nonstarting role on the team. All subjects were observed on three occasions for 30 minutes per observation during regular season practice. The Cole Descriptive Analysis System (Cole-DAS) was used to observe coach augmented feedback as it was given to individual players in response to skilled performance. A 2 × 2 multivariate analysis of variance was used to describe the effects of (a) success of the coach, (b) role of the player, and (c) both success of the coach and role of the player on the dependent variables of coach augmented feedback. Results indicated that successful coaches varied considerably from less successful coaches in the types of feedback given to their players. Starting players were also found to receive significantly more audio, audiovisual, and immediate terminal feedback than nonstarting players.

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Lisa Silliman-French, Ron French, Claudine Sherrill and Barbara Gench

The purpose was to determine the effectiveness of three feedback conditions (aversive tone, preferred music, and no feedback) on time-on-task of correct upper body postural alignment in adults with profound mental retardation (PMR). Participants were seven adults (3 males and 4 females), ages 25 to 34. A randomized multiple-treatment design with generalization and follow-up phases was used. Participants received three randomly assigned conditions each day for a total of 45 sessions over 15 days. Five of the participants increased time-on-task in response to preferred music, whereas two participants increased time-on-task in response to both aversive tone and preferred music. Friedman two-way analysis of variance indicated that music was significantly more effective than other conditions. It was concluded that preferred music feedback is, at least minimally, effective in improving time-on-task of upper body postural alignment of adults with PMR.