Although one-repetition maximum repetition tests 1-RM are widely employed to evaluate the muscular power, the lack of previous familiarization with the test procedures may cause erroneous interpretations. Thus, the purpose of this study was to analyze the behavior of the muscular strength in prepubescent children during 1-RM repetitive tests.
For this, nine boys 9. Three trials with minutes of resting interval were performed by subjects in each of the chosen exercises. It was observed significant increases of These results indicate that the number of sessions necessary to stabilize the muscular strength in 1-RM tests seems to depend upon the motor task performed, and possibly upon the size of the agonist muscular group involved in performing the motor task. Therefore, the results suggest that to attain a more accurate evaluation on the muscular strength Mas muchachos greater quantity legal age teenagers prepubescent boys by means of 1-RM tests, it is necessary to perform three to five familiarization sessions.
Tres esfuerzos, intervalados durante minutos de descanso, fueron ejecutados por los chicos en cada uno de los ejercicios escogidos. Ejercicios con los pesos.
The one-repetition maximum test 1-RM has been widely used as reference pattern to evaluate the muscular strength in different populations, and based on the results obtained, it is possible to analyze the behavior of the muscular strength in different muscular groups, in order to evaluate whether regular programs of physical activities are effective or not to increase the muscular strength or even to prescribe the ideal intensity to be applied in weight exercises.
The main advantages brought by the use of 1-RM tests are related to the easiness to interpret the information produced at a low operational cost, and the possibility to apply it to populations of quite different trainability levels. Despite of this, several researches are still resistant to use such 1-RM tests to evaluate the muscular strength levels in some populations, mainly children and adolescents, choosing to apply sub-maximal 3, 8 or RM tests.
Thus, the ability to produce maximal strength in prepubescent children has not been evaluated in the majority of the studies available in the literature, once the execution of a higher number of repetitions is much more connected to the strength resistance than to the maximal strength 1. The decision to use multiple repetition tests rather than 1-RM tests to evaluate the muscular strength in children and adolescents is supported by the lack of a higher amount of information on the existence or not of injuries or structural damages to the musculoskeletal system growth cartilage, and bone epiphysis associated to the execution of the 1-RM tests specifically in Mas muchachos greater quantity legal age teenagers populations.
In such sense, Faigenbaum et al.
On the other hand, some factors may sensitively interfere in the quality of the information attained through the 1-RM Mas muchachos greater quantity legal age teenagers, and this has generated strong discussions, particularly in the academic mean, on the confidence of the information produced by the use of such kind of test.
The lack of previous familiarization with the test procedures may Mas muchachos greater quantity legal age teenagers the most important of all these factors, once recent researches performed with young and elder adults has indicated that both inexperienced and those individuals with previous experience in weight exercises 3but with no specific training for at least six months 4,5 may have their muscular strength underestimated by the 1-RM tests performed by individuals with no previous familiarization.
This fact may compromise in a very sensitive way the muscular power evaluation as well as the prescription of the training overload, mainly in weight exercise programs that follow the intensity reference loads set through 1-RM values. Searching in the research performed on the major database available in the literature in May,it was found no study on the familiarization process using 1-RM tests in children and adolescents.
Therefore, the initial purpose of this study was to analyze the behavior of the muscular strength in prepubescent children in repetitive 1-RM tests, and next, using weight exercises in different body portions, seeking to achieve a more accurate evaluation on the muscular strength specifically among that population.
It was selected initially 15 boys to participate in this study, after being widely divulged at an Application School of the Londrina State University.
Every subject was classified as prepubescent according to the criteria proposed by Tanner 6. From that initial number, only nine boys were effectively present in every testing session, and it was included in every analysis.
None of the individuals reported any previous skills in weighted exercises or even the participation in systematic programs of regular physical activity with a higher than two sessions per week periodicity in the six previous months to the beginning of this investigation.
Before the beginning of the study, every child and their respective caretakers were clarified on the purpose of this investigation, as well as to the procedures adopted. Next, the children's caretakers signed a Mas muchachos greater quantity legal age teenagers and clarified consent term.
The body mass was attained through a 0. The body composition was determined by the skinfold thicknesses technique. For this, the triceps and subscapular skinfold thicknesses were measured by a sole researcher using a Lange scientific caliper Cambridge Scientific Industries Inc.
The test-retest coefficient was higher than 0. Every measurement was rotationally taken, with a three time repetition, and the mean value was recorded. Based on the skinfold thickenesses values, the relative body fat was estimated by means of the equations proposed by Slaughter et al.
Due to the fact that all participants had no previous experience in weight exercises, a previous familiarization process was adopted as to the technical gestures demanded by the leg extension and arm curl exercises.
For that purpose, it was performed four sessions, each of them composed by three sets of repetitions with no overloading in each exercise. The rest interval between series was approximately of 90 seconds, while the interval between sessions was of 48 hours. After that period, all individuals were submitted to eight 1-RM test sessions in the leg extension and arm Mas muchachos greater quantity legal age teenagers exercises, with a 48 hours interval between each session.
Three tries of each exercise were performed with a minutes resting interval.
The order of execution was arranged according to the size of the higher agonist muscular group involved, i. The transition interval between exercises was five minutes. The exercises were chosen because they are quite often used in studies searching for the effects of the weight training on prepubescent children.
The execution form and technique were standardized 9 and individually monitored. After a two minute rest, the test began. Individuals were guided to try to complete two repetitions. When two repetitions were completed in the first try, or even when it was completed no repetition, a second try was performed after a three to five minutes rest interval with a higher load first possibility or a lower load second possibility to the one employed in the previous try.
This procedure was repeated in a third last try in the event the individual did not complete a single maximal repetition. The load recorded as 1-RM was the one in which each individual was successful in completing a Mas muchachos greater quantity legal age teenagers maximal repetition The analysis of variance ANOVA for repeated measurements was used to make a comparison between the scores attained in different 1-RM test sessions in the leg extension and arm curl exercises.
Table 1 presents information on the age, body mass, height, relative body mass, lean body mass, and fat mass of the individuals investigated. According to the concordance limits, the mean differences and the confidence interval have shown to be reduced in both analyzed exercises in the sessions where the stabilization of the 1-RM values occurred compared to the other tries.
Figures 1 and 2 illustrate the plottage between sessions 1 and 8 for both studied exercises fig. The analysis is set by the relationship between the mean values between the moments confronted x axisand the individual difference of each subject between two 1-RM tests y axis. Although the application of the 1-RM tests in children and adolescents is a matter for several discussions, the hypothesis that this type of strength may cause structural damages in the muscle-skeletal system or injuries in the growth portions of the bone epiphysis in those populations still does not find up to this moment scientific support in the available literature.
On the other hand, Mas muchachos greater quantity legal age teenagers the last decade some researchers, have indicated that besides the 1-RM tests are able to be safely applied in young individuals, the demanded strength may be quite well physiologically tolerate by children and adolescents 1,2. This information was confirmed in this study, since no apparent discomfort or any injuries was observed or reported by all individuals investigated.
It is believed that the rest interval to be adopted between multiple sets of 1-RM tests in children and adolescents shall be relatively the same ones adopted to the adult population minutesonce the intramuscular concentrations of resting ATP and PCr are similar to those found in adult individuals Upon the establishment of the experimental outline to be used in this investigation, we believed it would demand a previous familiarization process as to the necessary technical gesture to perform the leg extension and arm curl exercises, having in mind that all participants had no previous experience in weight exercises.
However, the hypothesis that that procedure may have some effect on the results found cannot be despised, although the use of reduced workloads and a relatively high number of repetitions in multiple sets seem to affect mainly the physical ability of strength resistance, while the most demanded physical ability to the 1-RM tests is the maximal strength.
Despite the stabilization process of the muscular strength on the extensor table has been already identified in the third 1-RM test application session figure 1it was verified an increase in the loads lifted with no statistical significance in the subsequent sessions, and the peak values were attained in the seventh session. Thus, from the On the other hand, the stabilization of the muscular strength in the arm curl exercise occurred more lately fifth test session.
This fact may be used as one of the main criteria to the establishment of the Mas muchachos greater quantity legal age teenagers sessions in 1-RM tests. According to what was reported by those researches, both young and elder women with Mas muchachos greater quantity legal age teenagers previous experience in weight exercises had an increase in the maximal lifted load of about The discrepancy in the number of sessions necessary to the familiarization with the 1-RM test among prepubescent boys and elder women can be probably explained by the fall in the neuromuscular performance caused by the major presynaptic inhibition of the motor units occurred along with the aging, mainly after years 3.
It is worthy to mention that the neuromuscular activation capability recruitment and frequency of the motor units' activation is not yet completed in prepubescent children 13and this can affect the speed of the familiarization process in the 1-RM test for that population.
Unfortunately, in order to assert whether such hypothesis is confirmed or not needs the use of more sophisticated techniques, such as electromyography, which was not employed in this study.
When Dias et al. In absolute values, such difference may be attributed at least in part due to different age levels analyzed in both studies, to the higher number of 1-RM tests applied in the present investigation eight x fouror even to the lack of experience as to the practice of weighted exercises of the studied children, once the contribution of the natural factors to the increasing muscular strength is inversely proportional to the previous experience related to the demanded motor task The findings show that the muscular strength in the lying squat exercise in the equipment increased along the whole period of the study, while the muscular strength in the bench press exercise reached its plateau between the second and third session.
The researches attributed the different behavior observed between exercises to the upper and lower limbs mainly to the complexity of the technique involved in the lifting, and to the amount of muscular mass.
However, such hypothesis was not possible Mas muchachos greater quantity legal age teenagers be confirmed in the present study, and this may be justified by the simple lifting techniques used in the exercises adopted in this investigation single-joint Mas muchachos greater quantity legal age teenagers.