ARTICLE INFO

Article Type

Original Research

Authors

Ahar   S. (*)
Aslankhani   M.A. (1)
Zareian   E. (2)






(*) Department of Motor Behavior, Physical Education & Sport Sciences Faculty, Allameh Tabataba'i University, Tehran, Iran
(1) Department of Motor Behavior, Physical Education & Sport Sciences Faculty, Shahid Beheshti University, Tehran, Iran
(2) Department of Motor Behavior, Physical Education & Sport Sciences Faculty, Allameh Tabataba'i University, Tehran, Iran

Correspondence

Address: Physical Education & Sport Sciences Faculty, Allameh Tabataba'i University, Shahid Fahmide Highway, Tehran, Iran. Postal Code: 1464785581
Phone: +982144118632
Fax: +982144118629
saeid.ahar@atu.ac.ir

Article History

Received:  April  5, 2016
Accepted:  June 9, 2016
ePublished:  June 18, 2016

BRIEF TEXT


Underlying processes of new memories are first unstable and then they consolidate over time [1].

... [2-4]. Consolidation is divided into two different categories to be based on improvement and stability. Stability is related to maintaining the performance of motor skill over time and without additional practice after the interference in which the memory becomes stable due to the interference caused by performing the second task (retroactive interference) [5]. Robertson et al. indicated in their study that even if there is a 24-hour interval of exercise easement, the procedural memory does not consolidate and retroactive interference occurs. They suggest that the procedural memory may never consolidate [5]. ... [6-15].

This study aimed to investigate the effect of different intervals of exercise easement on the consolidation process based on stability in hidden motor memories of disabled athletes and veterans.

This study is semi-experimental.

45 disabled male athletes and veterans with physical-movement problems were studied during summer, 2015 in Yazd among the athletes of provincial teams who were preparing themselves for national competitions and Olympiads.

The sampling was done based on convenience sampling.

These athletes did not have any neurologic and cognitive disabilities and were regularly trained three times a week. After confirmation of having the inclusion criteria, these people were randomly divided into three experimental groups (15 people in each group). Data collection tools were questionnaires for demographic features, Goldberg`s General Health Test (GHQ-28), Petersburg`s sleep quality, Mini–Mental State Examination Test (MMSE) and Wechsler`s Memory Scale (third version). Goldberg General Health Questionnaire (GHQ-28) contains 28 questions in four components of anxiety, depression, social function and physical symptoms, its validity has been approved by experts and its reliability has been reported 0.85 to 0.91 using Cronbach's alpha [16]. Petersburg`s sleep quality questionnaire includes seven components: an individual`s general description of sleep quality, latency in falling asleep, duration of a good sleep, sleep sufficiency, sleep disorders, the amount of consumed hypnotic drugs and morning performance, and is measured from zero to 3 scores in each component. Its validity has also been confirmed and the reliability has been reported 0.78 to 0.82 [17]. The Mini–Mental State Examination test (MMSE) comprises components of memory and navigation, attention and concentration, assessment of linguistic skills, perception, and visual-spatial ability. Those with a score less than 23 in this test are regarded as being suspected to disorders. The test`s validity has been confirmed, and its reliability has been reported 0.78 [18]. Wechsler Memory Scale, third version (WMS_III) constitutes 18 subscale (11 items form among the initial ones and 7 items of optional ones), its validity has been verified by experts and its reliability in the subscales has been reported 0.75 to 0.86 [19]. After administrating the above tests, the subjects were randomly put into three groups of 6-hours, 24 hours and 72 hours; all groups accomplished the first or chief task (alternative chain reaction time) in the first session. The first, second and third group performed the second or intervening task (the task of chain Color matching reaction time) each 6, 24 and 72 hours later, respectively and all groups attended the retention test of main task 24 hours after performing the second task . In the acquisition phase (learning the skill), subjects received the Alternative Serial Reaction Time Task (ASRTT) which was generated under the researcher`s order and in Sina Behavioral Sciences Research Institute (mental equipment), in a selected 8-item pattern of 1R4R2R3R. This pattern was repeated 10 times sequentially in each block, and in 25 training blocks (5 training packs) which every training block involved 88 attempts; the first 8 attempts were omitted without any specific rules and for introducing and warming up, and the total number of the attempts was 2000. This is the modified version of serial reaction time task which has been designed on specific software. To ensure the establishment of the hidden motor memory, a pilot study was conducted on 10 people other than subjects of the study. The subject sits in front of the computer screen and responds to stimuli with his/her dominant hand. In each trial attempt of this task, four white solid circles appear on the screen and then suddenly one of the circles goes black. . From the time one circle gets black (presenting the stimulus) until the subject responses to that stimulus by pressing the related key on the computer keyboard, is calculated as the subject's reaction time. An 8-item pattern was deployed in this study of which four stimuli were presented according to the researcher`s sequence and other four stimuli, appearing among the stimuli of the pattern, were presented randomly. There was an interval of 120 ml seconds between each trial attempt and at the end of each pack there was a 20-second rest. The acquisition phase lasted about 37 to 40 minutes. Subjects of the first, second and third group performed 160 attempts of the interfering task which was Serial Color Matching Task (SCMT) each, 6, 24 and 72 hours after the acquisition stage of the first skill, respectively, and in order to examine the consolidation process based on stability, they participated in the retention test 24 hours after receiving the intervening task. Retention test involved performing a training block (400 attempts) of alternative serial reaction time task which had been administered in the first session (learning the skill). Besides, retention test was accomplished in about 10 minutes. At the end of the test, participants were given the Knowledge Questionnaire as a recognition test in order to evaluate the explicit knowledge of sequence. This questionnaire consists of three options that should be responded by the participants. If the subjects are proved to have the knowledge sequence in this test, they will be omitted from the study. The acquisition session for all the experimental groups was held during 8 to 11 am and the retention test was administered according to the group with a space intended for each one. Descriptive statistics including the mean and standard deviation were used to describe the characteristics of the subjects. The time difference of serial reaction of the repeating and random patterns was used as the main analysis. The time of median reactions for every random stage and 80-trial sequence were calculated for each subject and the mean of separate sequences` medians for the block was also measured. Then the time difference of serial reaction between the repeating and random patterns was obtained. To determine the normality of data distribution, Shapiro – Wilk Test was used and for analyzing the data and comparing the performance of experimental groups in the fifth pack of acquisition stage and retention pack, the analysis of two-factor variance with repeated measures in the training packs was applied so as ANOVA to examine the difference between experimental groups in general variables and Bonferroni post hoc and Duncan test to compare the performance in the experimental groups.

The mean age of participants was 35.1 ± 12.3 years. 24 subjects (8 people in each group) were veterans. In terms of injury percentage, the highest and the lowest frequency related to injury percentage was 25% (with a frequency of 17.8 %) and 30% (with a frequency of 2.2%), respectively. The majority of the subjects (34.4%) had Diplomas. In addition, traffic accidents (with a frequency of 25.5%) were the most common causes of disability among disabled athletes. There was not any significant differences in general variables ( age, disability percentage, general health, sleep quality, visual memory, verbal memory, delayed retention, cognitive test, attention and focus, and common memory) among the subjects of the three experimental groups (p>0.05). In the learning stage, the main effect of the training pack (p=0.58) and the interactive effect of the training pack and the group (p=0.42) were not significant, unlike main effect of the training pack (p=0.001). The reduction in the difference of the mean of alternative serial reaction time in repetitive and random sequences was significant from the first pack to the second, third, fourth and fifth ones, from the second pack to the third, fourth and fifth ones, from the third pack to the fourth and fifth ones, and from the fourth to the fifth pack. The subjects` process had improved by the increasing of the number of trial attempts and the subjects were able to establish the hidden motor memory and to learn the motor skills regardless of their groups. In the retention phase, the main effect of the training pack was significant (p=0.001). The mean of chain reaction time in the retention stage`s pack was significantly better than the reaction time of acquisition stage`s fifth pack. Furthermore, the main effect of the group (p=0.048) and the interactive effect of the training group and pack were significant (p=0.001). As followed, it was found that in groups with 24 and 72-hour intervals of exercise easement, the consolidation process based on stability has occurred, but there was no significant difference in their performance (p=0.61). However, in the group with 6 hours of exercise easement, retroactive interference was caused and consolidation process based on stability was not observed. The difference of performance in groups with 24 and 72-hour intervals of exercise easement was also significant compared to the group with 6 hours of exercise easement (p<0.05).

… [20]. The results of this study in the acquisition stage are in line with the findings of researchers who have showed that with the implementation of the skill in the acquisition phase (skill learning session), the transformation process in the difference of the mean of serial reaction time increases and that skill acquisition boosts [6, 7, 12, 21-23]. The results of this phase of the study are on the contrary with the findings of researchers who have indicated that consolidation process based on stability would not happen with exercise easement interval (albeit this duration is 24 or 72 hours) and that retroactive interference would occur in the motor memory [10, 11 13]. ... [24-29].

Reconsolidation process is one of the most important and controversial issues for the experts of behavioral sciences and conducting researches is recommended regarding the effect of intervals of exercise easement on this process in hidden motor memories of disabled athletes and veterans.

One of the limitations of this research was the selection of samples merely amongst male athletes.

Establishing intervals of 24 and 72 hours for exercise easement affects the consolidation process based on stability in hidden motor memories of disabled athletes and veterans.

Special regards are addressed to those who have assisted us in this research as well as the disables athletes and veterans who have devoted their precious time to this study.

Non-declared

Forms of agreement were distributed to and collected from subjects for participating in this study. Information related to each individual was confidentially maintained and subjects who were willing to receive the results of the study got informed via e-mail.

This study is part of MA thesis of movement behavior of Faculty of Physical Education and Sport Sciences, University of Allameh Tabatabai.


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