The results of a study examining the physique and performance of adolescent female judo athletes from the perspective of the presence or absence of menarche and the age of menarche were reported. Post-menarche athletes have significantly better indicators than pre-menarche, and age can explain many of their performance levels.
Examination by 19 adolescent female judo athletes
During puberty, which is the transition period from childhood to adulthood, the body grows and develops rapidly, and especially in girls, major biological changes occur with the onset of menarche. Changes in physique and performance of adolescent female athletes due to menarche have been investigated mainly by aesthetic sports athletes, and less by contact sports that require high-intensity action. Therefore, the authors of this paper examined this point for adolescent female judo athletes.
Evaluate general performance and judo-specific performance (SJFT)
The subjects of research are 19 female judo athletes. The age is 13.9 ± 2.3 years. All had at least two years of formal judo training experience, with 10 purple and 9 brown belts competing at the Brazilian state or national level. In the country, 39 female athletes of this age group participated in the 2021 competition, and 48.7% of them were considered in this study.
A female researcher conducts individual interviews with the subjects to obtain information on menarche. As a result, 7 out of 19 were before the onset of menarche and 12 were after the onset of menarche.
Evaluation items include height and weight, general sports performance, and judo-specific performance. Typical tests included a standing long jump, a medicine ball slow test (a test in which a 3 kg ball is thrown in a sitting position to evaluate distance), and grip strength. Judo-specific tests were evaluated by the Special Judo Fitness Test (SJFT) and the gripping force of judo clothing.
Menarche age can explain many of the performance levels
As a result, let’s first look at the data comparing the physique and performance between the group before the onset of menarche and the group after the onset of menarche. The age of menarche in the group after the onset of menarche was 11.8 ± 1.2 years.
Comparison of physique and performance before / after menarche
The age was 11.5 ± 0.9 years in the premenarche group, 15.4 ± 1.5 years in the postmenarche group (p <0.01, effect size = 2.98), and the training history was 4.0 ± 2.2 years, 6.4 ± 2.5 years (p) in the same order. = 0.03, ES = 1.01), and the weight and height were significantly higher in the postmenarche group.
In a general performance test, the standing long jump was 177 ± 15 cm and 213 ± 45 cm (p = 0.04, ES = 0.90) in the same order, which was also significantly higher in the postmenarche group. However, in the medicine ball slow test, there was no significant difference at 277 ± 19 cm and 309 ± 71 cm (p = 0.15), and there was no significant difference in grip strength at 29.7 ± 6.9 kg and 34.8 ± 7.6 kg (p = 0.085).
The results of the Judo-specific performance test (SJFT) show that the number of throwing techniques within a predetermined time is 20 ± 1 times, 23 ± 3 times (p = 0.01, ES = 1.13), and the number of throwing techniques ends immediately after the end of the throwing technique 1. The SJFT indexes calculated from the difference in heart rate up to minutes were 16.7 ± 1.1 and 14.9 ± 1.9 (p = 0.02, ES = 1.08), both of which were significantly better in the postmenarche group. The gripping force of the judo suit was 33.7 ± 9.8 seconds and 43.9 ± 15.7 seconds, which were better in the postmenarche group, but the difference between the groups did not reach a significant level (p = 0.07).
40 to 70% of performance indicators can be explained by menarche, actual age, physique, etc.
As a result of statistical analysis, the explanatory factors for each performance index were clarified below.
Standing long jump
The standing long jump was significantly associated with higher levels as the actual age increased (β = 0.526, p = 0.04). In addition, the longer the training history, the higher the level (β = 0.476, p = 0.05). On the other hand, the higher the age of menarche, the lower the level tended to be (β = -0.382, p = 0.10). It was calculated that these three factors could explain 70% of the standing long jump performance.
Medicine ball slow test
The medicine ball slow test was significantly associated with higher levels as the actual age increased (β = 0.731, p = 0.01). On the other hand, the higher the age of menarche, the lower the level tended to be (β = -0.449, p = 0.10). It was calculated that these two factors could explain 40% of the results of the medicine ball slow test.
Grip strength
There was a significant association that grip strength was stronger as the actual age increased (β = 0.585, p = 0.02). In addition, the taller the person, the stronger the grip strength tended to be (β = 0.446, p = 0.06). It was calculated that these two factors could explain 52% of grip strength.
Gripping power of judo wear
There was a significant association that the gripping force of judo clothing was stronger as the actual age increased (β = 0.783, p <0.01). On the other hand, there was a significant association that the older the menarche was, the weaker it was (β = -0.788, p <0.01). It was calculated that 70% of the judo wear gripping force could be explained by these two factors and the three factors including the body weight. Since the judo wear gripping force is measured by suspension, heavy weight is a negative factor, and a negative correlation is also observed in this study (β = -0.803, p <0.01).
Based on these results, the authors write that “menarche age and growth variables such as height and weight explain a certain percentage of judo-related physical abilities, so these indicators are for adolescent women. It can be a key performance indicator for judo athletes. ”
Documentary information
原題のタイトルは、「Body Size Measurements and Physical Performance of Youth Female Judo Athletes with Differing Menarcheal Status」。〔Int J Environ Res Public Health. 2021 Dec 5;18(23):12829〕
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