Jeffrey T. Fairbrother

Self-Controlled Amount of Practice Benefits Learning of a Motor Skill

Abstract Self-control over factors involving task-related information (e.g., feedback) can enhance motor learning. It is unknown if these benefits extend to manipulations that do not directly affect such information. The purpose of this study was to determine if self-control over the amount of practice would also facilitate learning. Participants learned to throw a dart using their nonpreferred hand. The self-control (SC) group decided when to stop practice. The yoked group completed the same number of trials as their SC counterparts. Results revealed the SC group was more accurate during transfer and in recalling the number of trials completed. These findings indicate that self-control benefits extend to factors that do not directly alter task-related information.

The effects of self-controlled video feedback on the learning of the basketball set shot

Allowing learners to control some aspect of instructional support (e.g., augmented feedback) appears to facilitate motor skill acquisition. No studies, however, have examined self-controlled (SC) video feedback without the provision of additional attentional cueing. The purpose of this study was to extend previous SC research using video feedback about movement form for the basketball set shot without explicitly directing attention to specific aspects of the movement. The SC group requested video feedback of their performance following any trial during the acquisition phase. The yoked group received feedback according to a schedule created by a SC counterpart. During acquisition participants were also allowed to view written instructional cues at any time. Results revealed that the SC group had significantly higher form scores during the transfer phase and utilized the instructional cues more frequently during acquisition. Post-training questionnaire responses indicated no preference for requesting or receiving feedback following good trials as reported by Chiviacowsky and Wulf (2002, 2005). The nature of the task was such that participants could have assigned both positive and negative evaluations to different aspects of the movement during the same trial. Thus, the lack of preferences along with the similarity in scores for feedback and no-feedback trials may simply have reflected this complexity. Importantly, however, the results indicated that SC video feedback conferred a learning benefit without the provision of explicit additional attentional cueing.

Self-Controlled Feedback Facilitates Motor Learning in Both High and Low Activity Individuals

The purpose of this study was to determine if high and low activity individuals differed in terms of the effects of self-controlled feedback on the performance and learning of a movement skill. The task consisted of a blindfolded beanbag toss using the non-preferred arm. Participants were pre-screened according to their physical activity level using the International Physical Activity Questionnaire. An equal number of high activity (HA) and low activity (LA) participants were assigned to self-control (SC) and yoked (YK) feedback conditions, creating four groups: Self-Control-High Activity; Self-Control-Low Activity; Yoked-High Activity; and Yoked-Low Activity. SC condition participants were provided feedback whenever they requested it, while YK condition participants received feedback according to a schedule created by their SC counterpart. Results indicated that the SC condition was more accurate than the YK condition during acquisition and transfer phases, and the HA condition was more accurate than the LA condition during all phases of the experiment. A post-training questionnaire indicated that participants in the SC condition asked for feedback mostly after what they perceived to be “good” trials; those in the YK condition indicated that they would have preferred to receive feedback after “good” trials. This study provided further support for the advantages of self-controlled feedback when learning motor skills, additionally showing benefits for both active and less active individuals. The results suggested that the provision of self-controlled feedback to less active learners may be a potential avenue to teaching motor skills necessary to engage in greater amounts of physical activity.

Simple verbal instruction improves knee biomechanics during landing in female athletes

Knee injuries are highly prevalent in athletic populations, particularly among female athletes. Many of these injuries occur during landing from a jump. Various comprehensive knee injury prevention programs have been developed to date. However, there is a need to determine which components of these programs contribute directly to changes in knee biomechanics. Therefore, the purpose of this study was to investigate the immediate effect of three different simple verbal instructions on knee biomechanics during landing in adult female recreational athletes. Three-dimensional kinematic and kinetic analysis of landing from a countermovement jump was conducted in a counterbalanced cross-over repeated measures design. Results indicated that the instruction to land with equal weight distribution reduced the asymmetry of peak vertical ground reaction force compared to the control condition. The instruction to land softly reduced peak vertical ground reaction force and increased peak knee flexion compared to the control condition. The instruction to land with knees over toes increased peak knee flexion compared to the control condition. These findings indicate that verbal instruction may be a key component of the effects seen in previous research studies that have investigated the benefits of more complex training programs designed to reduce knee injury risk in female athletes.

Effects of increased step width on frontal plane knee biomechanics in healthy older adults during stair descent.

BACKGROUND Peak internal knee abduction moment is a common surrogate variable associated with medial compartment knee loading. Stair descent has been shown to yield a greater peak knee abduction moment compared to level-walking. Changes in step width (SW) may lead to changes in frontal plane lower extremity limb alignment in the frontal plane and alter peak knee abduction moment. The purpose of this study was to investigate the effects of increased SW on frontal plane knee biomechanics during stair descent in healthy older adults. METHODS Twenty healthy adults were recruited for the study. A motion analysis system was used to obtain three-dimensional lower limb kinematics during testing. An instrumented 3-step staircase with two additional customized wooden steps was used to collect ground reaction forces (GRF) data during stair descent trials. Participants performed five stair descent trials at their self-selected speed using preferred, wide (26% leg length), and wider (39% leg length) SW. RESULTS The preferred normalized SW in older adults during stair descent was 20% of leg length. Wide and wider SW during stair descent reduced both first and second peak knee adduction angles and abduction moments compared to preferred SW in healthy adults. CONCLUSIONS Increased SW reduced peak knee adduction angles and abduction moments. The reductions in knee abduction moments may have implications in reducing medial compartment knee loads during stair descent.

Prediction of 1500-m Freestyle Swimming Times for Older Masters All-American Swimmers

Age-related changes in times of elite swimmers have indicated marked slowing at about age 70—suggesting a discontinuity in aging processes related to physical performance. Overrepresentation of younger swimmers in United States Masters Swimming (USMS) data may also explain this shift. This study determined if age representation in USMS All-American records influenced predicted swimming times for older ages in 1500-m freestyle. Results indicated no influence. Thus, age-related changes in swimming times were predicted accurately using data from either all swimmers or just older swimmers, suggesting that different rates of slowing before and after age 70 represent biological or behavioral factors affecting physical performance and not simply a problem related to disproportionate sampling across age groups.

Too Much of a Good Thing: Random Practice Scheduling and Self-Control of Feedback Lead to Unique but Not Additive Learning Benefits

We examined the impact of self-controlled knowledge of results on the acquisition, retention, and transfer of anticipation timing skill as a function of random and blocked practice schedules. Forty-eight undergraduate students were divided into experimental groups that practiced under varying combinations of random or blocked as well as self-controlled or yoked practice conditions. Anticipation timing performance (5, 13, and 21 mph) was recorded during acquisition and during a short term no-feedback retention test. A transfer test, administered 24 h after the retention test, consisted of two novel anticipation timing speeds (9, 17 mph). Absolute error (AE) and variable error (VE) of timing served as the dependent measures. All participants improved their accuracy and consistency across acquisition blocks; however, those who practiced under blocked rather than random conditions had greater accuracy (lower AE) regardless of feedback delivery. During retention and transfer, those who practiced under random conditions showed greater consistency (lower VE) compared to their blocked counterparts. Finally, participants who controlled their feedback schedule were more accurate (lower AE) and less variable (lower VE) during transfer compared to yoked participants, regardless of practice scheduling. Our findings indicate that practicing under a random schedule improves retention and transfer consistency, while self-control of feedback is advantageous to both the accuracy and consistency with which anticipation timing skill transfers to novel task demands. The combination of these learning manipulations, however, does not improve skill retention or transfer above and beyond their orthogonal effects.

Age-Related Changes in Top-Ten Men's U.S. Masters 50-M Freestyle Swim Times as a Function of Finishing Place

This study described age-related changes in swim time as a function of top-ten finishing place for Masters swimmers. Previous research has documented increases in 50-m freestyle swim times for men beyond age 35 using aggregated top-ten times. The present study examined the relationship between age and swim time, taking into account the potential influence of finishing place in the top-ten. Data were retrieved from the United States Masters Swimming database for male top-ten finishers in the 50-m short course freestyle for the years from 1993 to 2002. Data from each year were analyzed using linear regression procedures with Age, Square of age, and Finishing place as predictor variables and Swim time as the dependent variable. Analysis indicated that, when Finishing place was considered, a more gradual increase in Swim time as a function of age was seen for finishing places closer to first place than for those closer to tenth place.

Self-control behaviors during the learning of a cascade juggling task

This study examined the self-control behaviors of participants learning a 3-ball cascade juggle. Participants chose when they would receive one of four types of instructional assistance: (a) instructions; (b) video demonstration; (c) knowledge of performance (KP); and (d) knowledge of results (KR). Juggling proficiency was divided into three categories based on catches per attempt during retention and transfer testing. In general, participants decreased their requests for instructions and video demonstration throughout acquisition. For the most proficient performers, requests for KR increased over practice. Post-experimental interviews revealed that participants requested KR after primarily good attempts and KP after both good and bad attempts. Participant-reported reasons for requesting feedback included the confirmation of success (KR) and identification of technique flaws (KP). Overall, the findings suggest that self-control behaviors are more complex than previously demonstrated and that participants use self-control differently depending upon the type of assistance available, individual preferences, and learning needs.

The Effects of a Home-Based Instructional Program Aimed at Improving Frontal Plane Knee Biomechanics During a Jump-Landing Task

STUDY DESIGN Randomized controlled trial. OBJECTIVES To determine the effects of instruction to improve frontal plane knee biomechanics during a jump-landing task. BACKGROUND Technique training is a common component of knee injury-prevention programs. In developing programs that minimize time commitment and increase the likelihood of adoption by target groups, there is a need to evaluate individual program components. METHODS A total of 26 female recreational athletes (average age, 21.2 years), who presented with medial knee displacement during a jump-landing task, completed the study protocol. Participants were randomly placed into 1 of 2 groups, an experimental or control group. The experimental group received instructions aimed at improving knee abduction during jump landings. The control group received a sham training. Prior to training, baseline kinematics and kinetics (peak knee abduction angle, peak internal knee adductor moment, knee flexion excursion, peak internal knee extensor moment, and peak vertical ground reaction force) were obtained from participants while performing a basketball rebound task. Immediate (5 minutes postinstruction) and delayed (15-20 minutes postinstruction) retention tests were performed within the instructional session. Two additional retention tests were performed following home-based training (1 and 2 weeks following the initial training). RESULTS The initial instructional session resulted in greater knee flexion excursion (9°) and a 20% reduction in the peak internal knee adductor moment in the experimental group. Following home-based training, the experimental group continued to exhibit increased knee flexion excursion, along with decreased peak vertical ground reaction forces. No biomechanical changes were observed in the control group for any of the retention tests when compared to baseline. CONCLUSION The jump-training instructions employed in the current study resulted in kinematic and kinetic changes in the sagittal plane as opposed to the frontal plane. LEVEL OF EVIDENCE Prevention, level 2b-.