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1.
Three experiments examined repeated retention testing effects in a contextual interference (CI) protocol. Retention was assessed at 10 min and 24 hr following acquisition or at just 24-hr for the one-test conditions. Experiments 1 and 2 used speeded-response key-pressing tasks. Dependent measures were total time and errors. Experiment 3 used sequential-timing tasks. Dependent measures were absolute error and absolute constant error Results revealed CI effects in each experiment. Repeated retention testing effects were not found in Experiments 1 and 3. Experiment 2 revealed superior performance by the two-test condition compared to the one-test condition. This result was qualified by possible practice effects during the 10-min test. It was concluded that repeated retention testing does not present problems for most studies of CI.  相似文献   

2.
This experiment investigates the recent proposal of Schmidt, Young, Swinnen, and Shapiro (1989) that summary knowledge of results (KR) improves skill retention. In Schmidt et al.'s experiment, however, summary length varied concomitantly with the frequency of KR presentation. The current investigation held KR presentation frequency constant while manipulating the number of trials seen in the summary KR display. Subjects were required to perform a timing task on a linear slide. Five groups (n = 12) of subjects participated in acquisition trials then in 10-min and 2-day delayed no-KR retention tests. In 4 conditions, subjects completed each acquisition block without any KR, but following each block they received KR on either 15, 7, 3, or 1 of the 15 trials performed in that block. In the final condition subjects received immediate KR. Analysis of the absolute constant error (magnitude of CE) data for acquisition revealed all groups improved with practice and the immediate KR group performed better than all the summary groups which in turn did not differ significantly. Analysis of the magnitude of CE retention data found performance to be worse on the 2-day retention test for all groups. The effect of condition was significant. The 1/1 group had lower error scores than all other groups, which in turn were not significantly different. Analyses of variable error (VE) revealed only that VE decreased with practice. These findings suggest frequency of KR presentation may be the basis for the summary KR effect found by Schmidt et al. (1989).  相似文献   

3.
Two experiments are reported that examined the usefulness of observational learning for acquiring both error detection and movement production capabilities. In both experiments, individuals were assigned to a no-practice, physical-practice, or observational practice condition. Those assigned to a physical-practice condition acted as models for those assigned as observers. In both experiments, models were administered a random practice of three serial key-press tasks that had the same spatial pattern and same relative timing requirement but differed in the overall time goal. During the retention test, individuals provided estimates of their overall time after each trial. Data from these experiments revealed that error detection and overall time specification were similar following observation and physical practice. However, data from Experiment 2 indicated that physical practice offered an advantage beyond that afforded via observation, with regard to acquiring the appropriate relative time pattern. These data are discussed with respect to the role of observation for learning movement recognition and production processes.  相似文献   

4.
Abstract

Two studies investigated the effects of delayed visual feedback on manual tracking. In Experiment 1, individuals practiced with visual feedback provided either immediately (0 delay) or with a 333-ms delay. During acquisition, the 0 delay group performed with less error than the 333-ms delay group. A retention test with 0 delay feedback was performed with the least error by the 0 delay group. A transfer test using a different 0 delay tracking pattern, was performed with the least error by the 333-ms delay group. In Experiment 2, individuals practiced at six different delays. Error increased as training feedback delay increased. For retention there were no differences between the delay groups during the 0 delay retention. At a 417-ms retention, test error decreased as training feedback delay increased. Results indicate that error during acquisition does not necessarily impair learning and that feedback delays can be beneficial for learning.  相似文献   

5.
Two experiments investigated the effects of a single reminder trial on immediate and delayed retention. Experiment 1 determined if beneficial effects of a reminder trial were a function of task order immediate retention performance benefited only when the reminder trial was practiced in the first block of trials. Experiment 2 added a 24-hr delayed retention test to examine the long-term benefits of a reminder trial. Retention performance was enhanced over both delay intervals. The long-term effect extended previous research (Shea & Titzer, 1993) that documented effects after 10 min. The use of a single reminder trial established that intertask comparisons between multiple reminder trials were not a precondition for the reminder trial effect as postulated by Shea and Titzer.  相似文献   

6.
Abstract

The decay of the memory trace for intervals of 1/2 min., 1 1/2 min., and 4 min. between the test stimulus and the reproduction trial was studied for a force reproduction task in which the amount of movement was very small, .13 in. The subject pushed against a handle attached to the top of a steel bar with the preferred hand. Sixty-three women volunteers from college physical education classes performed the experiment. For Part A all subjects first had four trials in which the reproduction was immediate (the control condition). Then they were divided randomly into three subgroups of 21, and each subgroup was assigned to one of the three retention intervals (experimental conditions) for four more trials. In Part B the whole experiment was repeated. For both absolute and algebraic error, analysis of covariance indicated no significant differences at the .05 level among the experimental conditons. Also, no significant differences were found comparing a condition in Part A with its respective condition in Part B. While there were no significant differences between control and experimental conditions for absolute error, significant differences were found for algebraic error. The algebraic error changed from considerable overestimation upon immediate reproduction to only slight overestimation after a 1/2-min. retention interval.  相似文献   

7.
Abstract

Because manipulations of knowledge of results (KR) are critical to motor learning, researchers have attempted to establish an optimal length for summary KR. Experiment 1 of the present study investigated the option that optimal summary length may be dependent on a subject's task-related experience. Participants in a summary 1, 5, or 15 condition practiced a simple striking task for one session on three consecutive days with each day followed by a 24-hour no KR retention test. The retention test results indicated that optimal summary length is dependent on task-related experience. Experiment 2 investigated the nature of the relationship between task-related experience and complexity and optimal summary length (summary 1, 5, or 15). Again, striking tasks (simple and complex) were used. There was one practice session with either a simple or complex striking task for either novice or experienced performers, followed by a 24-hour no KR retention test. Data from the two experiments suggest that task complexity and performer experience interact in determining optimal summary length.  相似文献   

8.

Two experiments investigated the effects of a single reminder trial on immediate and delayed retention. Experiment 1 determined if beneficial effects of a reminder trial were a function of task order. Immediate retention performance benefited only when the reminder trial was practiced in the first block of trials. Experiment 2 added a 24-hr delayed retention test to examine the long-term benefits of a reminder trial. Retention performance was enhanced over both delay intervals. The long-term effect extended previous research (Shea & Titzer, 1993) that documented effects after 10 min. The use of a single reminder trial established that intertask comparisons between multiple reminder trials were not a precondition for the reminder trial effect as postulated by Shea and Titzer.  相似文献   

9.
Wearable activity trackers have become popular for tracking individual’s daily physical activity, but little information is available to substantiate the validity of these devices in step counts. Thirty-five healthy individuals completed three conditions of activity tracker measurement: walking/jogging on a treadmill, walking over-ground on an indoor track, and a 24-hour free-living condition. Participants wore 10 activity trackers at the same time for both treadmill and over-ground protocol. Of these 10 activity trackers three were randomly given for 24-hour free-living condition. Correlations of steps measured to steps observed were r?=?0.84 and r?=?0.67 on a treadmill and over-ground protocol, respectively. The mean MAPE (mean absolute percentage error) score for all devices and speeds on a treadmill was 8.2% against manually counted steps. The MAPE value was higher for over-ground walking (9.9%) and even higher for the 24-hour free-living period (18.48%) on step counts. Equivalence testing for step count measurement resulted in a significant level within ±5% for the Fitbit Zip, Withings Pulse, and Jawbone UP24 and within ±10% for the Basis B1 band, Garmin VivoFit, and SenseWear Armband Mini. The results show that the Fitbit Zip and Withings Pulse provided the most accurate measures of step count under all three different conditions (i.e. treadmill, over-ground, and 24-hour condition), and considerable variability in accuracy across monitors and also by speeds and conditions.  相似文献   

10.
This study assessed the effects of stride length on symptoms of exercise-induced muscle damage after downhill running and whether the extent of the symptoms sustained in a repeated bout of downhill running are influenced by stride length manipulation in the first bout. Eighteen males aged 21.1 - 0.6 years (mean - s) were allocated to one of three groups for bout one: preferred stride frequency, overstride and understride. Bout two was performed 2 weeks later at the participants' preferred stride frequency. Maximal isometric force and perceived muscle soreness were assessed pre-test and 30 min, 24, 48 and 72 h post-exercise for each downhill run. Threefactor analyses of variance with repeated measures on time and bout were used for analysis. Results revealed a three-way interaction for soreness (F 8,60 = 3.56, P ? 0.05) and relative isometric strength (F 5.0,37.8 = 3.2, P ? 0.05). Post-hoc analyses revealed that, after bout one, the overstride group perceived most soreness and the understride group retained most strength. After the second bout, the overstride and preferred stride frequency groups perceived less soreness than the preferred stride frequency group in bout one. Strength retention was greater after bout two for all groups. In conclusion, strength retention after a repeated bout appears to be independent of the damage experienced in the initial bout of downhill running. However, understriding may provide least protection against soreness in a subsequent bout.  相似文献   

11.
Abstract

The effects of grip and forearm position on two tests of upper body muscular endurance were investigated in 109 male subjects 18–21 years of age. Subjects were systematically presented 12 tasks: six pull-up and six straight-arm hang grip and forearm variations. Each of the six tasks for both endurance tests represented a different combination of grip (thumb over bar and thumb under bar) and forearm position (pronated, supinated and semi-pronated). Task results were analyzed utilizing 2 × 3 (grip × forearm) ANOVA with repeated measures on the two factors. Analysis of pull-up data revealed that the semi-pronated and supinated forearm positions were not statistically different from each other, but superior to the pronated condition. Results of straight-arm hang performance revealed a significant difference between grips at the semi-pronated position, with the “thumb under bar” being superior. Results for forearm positions at grips indicated a significant difference for the “thumb under bar,” with the pronated and semi-pronated positions being superior to the supinated position. For forearm positions at “thumb over bar,” the pronated condition was significantly different from the semi-pronated and supinated positions. Thumb position trends and kinesiological mechanical analysis did foster general recommendations for use of the “thumb over bar” for pull-ups and the “thumb under bar” position for the straight-arm hang.  相似文献   

12.
This study assessed the effects of stride length on symptoms of exercise-induced muscle damage after downhill running and whether the extent of the symptoms sustained in a repeated bout of downhill running are influenced by stride length manipulation in the first bout. Eighteen males aged 21.1 +/- 0.6 years (mean +/- s) were allocated to one of three groups for bout one: preferred stride frequency, overstride and understride. Bout two was performed 2 weeks later at the participants' preferred stride frequency. Maximal isometric force and perceived muscle soreness were assessed pre-test and 30 min, 24, 48 and 72 h post-exercise for each downhill run. Three-factor analyses of variance with repeated measures on time and bout were used for analysis. Results revealed a three-way interaction for soreness (F8,60 = 3.56, P < 0.05) and relative isometric strength (F5.0,37.8 = 3.2, P < 0.05). Post-hoc analyses revealed that, after bout one, the overstride group perceived most soreness and the understride group retained most strength. After the second bout, the overstride and preferred stride frequency groups perceived less soreness than the preferred stride frequency group in bout one. Strength retention was greater after bout two for all groups. In conclusion, strength retention after a repeated bout appears to be independent of the damage experienced in the initial bout of downhill running. However, understriding may provide least protection against soreness in a subsequent bout.  相似文献   

13.
The purpose of these experiments was to investigate further the variable practice effect found by Shea and Kohl (1990). Experiment 1 was an initial attempt to determine the locus of the retention benefits demonstrated by subjects provided variable practice experiences. All groups received 20 acquisition blocks consisting of five test trials per block at a target of 150 N. The interval between test trials was either unfilled or filled, with additional trials consisting of the same target force, variable target forces, or practice on an unrelated motor task. The results indicated retention was not incremented (relative to an unfilled interval) by requiring subjects to perform an unrelated motor task in the intertest-trial interval. However, when the interest-trial interval was filled with practice on related motor tasks, retention was significantly improved. Experiment 2 assessed the impact of increasing the number of related motor tasks interpolated between test trials. The results indicated filling the intertest-trial interval with one motor task resulted in large retention benefits relative to an unfilled interval. Further increases in the number of related motor tasks (3) interpolated between test trials resulted in only modest increments to retention. The results were consistent with the elaboration perspective proposed by Shea and Zimny (1983). The elaboration perspective proposes that the simultaneous presence of related items in working memory facilitates interitem elaborative and distinctive processing that ultimately results in retention benefits.  相似文献   

14.
Abstract

The purpose of these experiments was to investigate further the variable practice effect found by Shea and Kohl (1990). Experiment 1 was an initial attempt to determine the locus of the retention benefits demonstrated by subjects provided variable practice experiences. All groups received 20 acquisition blocks consisting of five test trials per block at a target of 150 N. The interval between test trials was either unfilled or filled, with additional trials consisting of the same target force, variable target forces, or practice on an unrelated motor task. The results indicated retention was not incremented (relative to an unfilled interval) by requiring subjects to perform an unrelated motor task in the intertest–trial interval. However, when the intertest–trial interval was filled with practice on related motor tasks, retention was significantly improved. Experiment 2 assessed the impact of increasing the number of related motor tasks interpolated between test trials. The results indicated filling the intertest–trial interval with one motor task resulted in large retention benefits relative to an unfilled interval. Further increases in the number of related motor tasks (3) interpolated between test trials resulted in only modest increments to retention. The results were consistent with the elaboration perspective proposed by Shea and Zimny (1983). The elaboration perspective proposes that the simultaneous presence of related items in working memory facilitates interitem elaborative and distinctive processing that ultimately results in retention benefits.  相似文献   

15.
The persistence and generality of the contextual interference (CI) effect was tested using a rapid sequential aiming task. Participants (N=48) practiced three movement patterns for three blocks of 18 trials under a blocked (BL) or random (RA) schedule. Movement patterns were displayed and KR provided throughout practice and testing. A 24-hr delayed knowledge of results (KR) retention test included three blocks of 18 trials, followed by a transfer test of a single new movement pattern. In contradiction of the CI effect, RA practice provided an advantage for RA retention only, not BL retention. Furthermore, group differences at transfer were not persistent. Hence, RA practice does not necessarily provide enhanced, context-free learning, but it is essential training for task switching. Overall the findings reveal limited persistence and generality of the CI effect.  相似文献   

16.
The specificity of practice hypothesis was examined using a tracking task. In Experiment 1, visual or auditory feedback about performance was provided. Vision was more useful than audition early in acquisition. Performance gains found in acquisition were maintained during retention, but learning was specific only if the acquisition modality was visual. Specificity did not increase with the amount of practice. In Experiment 2, visual and auditory information were combined. Again, the specificity of practice hypothesis was supported. Also, instructing participants to attend to one information source allowed us to demonstrate that information can be explicitly or implicitly processed. Further, specificity effects may occur because of different rates of development for error detection and correction processes.  相似文献   

17.
For this study, we investigated the effects of self-controlled practice on learning multiple motor skills. Thirty participants were randomly assigned to self-control or yoked conditions. Participants learned a three-keystroke pattern with three different relative time structures. Those in the self-control group chose one of three relative time structures before each of 90 practice trials; yoked participants were not allowed to choose but were yoked to a self-control participant and followed that individual's sequence of practice trials. Results of the 24-hr serial transfer test revealed the self-control group exhibited significantly lower relative timing error, absolute error, and total error than the yoked group. Findings further support the efficacy of self-controlled learning  相似文献   

18.
Abstract

Despite the widespread use of isokinetic eccentric muscle endurance protocols, no research has examined the absolute and relative reliability of such tests. The aim of this study was to examine the reliability of an isokinetic eccentric knee muscle endurance task. Fifteen healthy untrained males volunteered to take part in the study and written informed consent was obtained. The procedures received approval from the University Research Ethics Committee. Participants visited the laboratory on three separate occasions: 2 weeks before testing to familiarize them with the experimental procedures, and on two separate occasions, 2 weeks apart and at the same time of day. Isokinetic eccentric knee extension and flexion movements of the dominant limb were performed using a calibrated dynamometer (Biodex System 3). Range of motion during testing was set using voluntary maximal full extension (0 rad) to 1.57 rad of knee flexion and testing was conducted at 1.56 rad · s?1. Participants performed four maximal efforts to determine maximal peak torque. After 2 min rest, participants completed the all-out endurance test of 50 continuous eccentric repetitions. Data were gravity corrected and windowed to only include constant velocity periods. Repeated-measures analyses of variance were used to examine differences in maximal peak extension and flexion torque and the maximal torque measurement recorded during the endurance test. Absolute and relative reliability of the torque fatigue index, work fatigue index, and total work were assessed through calculation of intra-class correlation coefficients, coefficients of variation, and absolute 95% limits of agreement using the methods described by Bland and Altman (1986). Differences between the strength test and the endurance trial for peak torque were found to be non-significant for both quadriceps (323 vs. 323 N · m) and hamstrings (183 vs. 178 N · m). The intra-class correlation coefficients revealed significant (P<0.05) positive moderate to strong correlations (r=0.44–0.94) across repeated trials for all parameters except hamstring torque fatigue (P=0.11) and hamstring work fatigue index (P=0.08). Coefficients of variation ranged from 6% to 48% and were large for the work fatigue index and torque fatigue index but acceptable for total work for both the extensors and flexors. The 95% limits of agreement indicated systematic bias in repeated trials for both the work fatigue index and torque fatigue index for extensors and flexors, ranging from ?3% to ?10%, with less fatigue evident in the second test. There was also systematic bias for total work, with more work being performed during the second than the first test for both extensors and flexors. The random error was large for all variables and there was greater random error in the hamstrings compared with the quadriceps. Together with moderate to strong intra-class correlation coefficients and large coefficients of variation, the data suggest that there is small systematic bias in repeated eccentric muscle actions for both the quadriceps and hamstrings, although the random error was large despite habituation procedures. Therefore, data from an isokinetic eccentric muscle endurance task should be viewed with some caution even when participants receive considerable habituation before assessment.  相似文献   

19.
In this study, we investigated the effects of acute post-exercise alcohol consumption on measures of physical performance, creatine kinase, and immunoendocrine function in the 48 h following a rugby game simulation. Ten male senior rugby union players completed a rugby game simulation after which they consumed either 1 g of alcohol per kilogram of body mass or a non-alcoholic control beverage. Agility, 15 m sprint, countermovement jump, and srummaging performance were assessed pre-simulation and 24 and 48 h post-simulation. White blood cell count, testosterone, cortisol, and creatine kinase were measured before the simulation and 30 min, 12, 24, 36, and 48 h after the simulation. One week after the first trial, participants completed the second simulation after which the other beverage was consumed. The acute consumption of alcohol after a rugby game simulation negatively affected countermovement jump performance in the days following the simulation (P = 0.028). No differences between treatments were observed for the other criterion measures made in this study. In conclusion, after 80 min of a simulated rugby game, the consumption of 1 g of alcohol per kg body mass negatively impacts lower body vertical power output. However, performance of tasks requiring repeated maximal muscular effort is not affected.  相似文献   

20.
The assessment of sprint velocity is useful for evaluating performance and guiding training interventions. In this paper, we describe an adaptive filtering algorithm to estimate sprint velocity using a single, sacrum-worn magneto-inertial measurement unit. Estimated instantaneous velocity, average 10 m interval velocity, and peak velocity during 40 m sprints from the proposed method were compared to a reference method using photocell position-time data. Concurrent validity of the proposed method was assessed using mean absolute error and mean absolute percent error for all velocity estimates. The significance of the mean error was assessed using a factorial ANOVA for average interval velocity and a paired-samples t test for peak velocity. Reliability was assessed using Bland–Altman 95% limits of agreement for repeated measures. Average interval velocity was underestimated early in the sprint (??0.25 to ??0.05 m/s) and overestimated later (0.13 m/s) with mean absolute error between 0.20 m/s (3.95%) and 0.62 m/s (7.78%). The average mean absolute error was 0.45 m/s (7.02%) for instantaneous velocity and 0.63 m/s (7.84%) for peak velocity. The limits of agreement grew progressively wider at greater distances (??0.59 to 0.34 m/s for 0–10 m and ??1.32 to 1.59 m/s for 30–40 m). The estimation error from the proposed method is comparable to other wearable sensor-based methods and suggests its potential use to assess sprint performance.  相似文献   

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