As a method of agility measurement under wide current use, the repeated side step is well-known. At present in Japan, a duration of 20 seconds is employed to test agility ; but it is often reported that the factor of endurance is included in this. When a diagnosis involving agility is made based on the performance of exercise, the duration of the time of measurement was controlled in order to avoid the mixing of other factors and to ensure measurement of as few factors as possible. The distance of step was made flexible according to the age. Since a constant distance makes the longitudinal tracing easier, the distance of step was also studied.
Side steps were tested and duration of measurement was examined based on determinations in 1857 subjects, Junior and Senior school boys and girls and male university students. During the 20 seconds of measurement, scores were recorded every 5 seconds to study the time course of the fluctuations of scores. Taking into consideration factors of endurance such as the endurance of the lower extremity system, the knee test was conducted to see the relationship between scores of the repeated side step and knee test values. As to the distance of the step, 200 high school girls were tested over a distance of 100cm ×2 and 120cm ×2, for 10 seconds each.
As to the time of measurement, the average score during the first 10-15 seconds after start tended to decrease. In the time course of fluctuations of the scores in each subject, a decrease in the fall of scorse was seen about 10 seconds after the start in approximately 55% of the test subjects.
Based on the assumption that the endurance of the lower extremity system participates in this, high and low groups with a significant difference in the endurance of the lower extremity at the level of P<0.001 were compared. While no difference was seen in the slope of the score increase over a 10-second period from the start, changes of scores were distinctly different between 10 and 20 seconds, the lower values in the low group being obvious. The endurance of the lower extremity system was then studied in the two groups with high and low scores in the side step between 10 and 20 seconds. In the group with high scores, the endurance of the lower extremity was high : and a significant difference at P<0.01 was noted in this index.
These results would definitely indicate that mixing of other factors is unavoidable under the current measurement duration of 20 seconds
As to the distance of the step, scores are apparently different even in the same test subject, depending upon the distance of the step. The scores are also different depending upon the body length.
In both of the two groups, however, the scores for each different distance of the step showed a high correlation between each other, giving a correlation coefficient of γ= 0.88 in the group with high body length and γ= 0.82 in the group with low body length, indicating a high correlation.
Based on the diagnosis of agility and performance of exercise, in order to obtain the results of measurement of as simple a factor as possible, the agility time measurement is corrected to 10 seconds ; and the distance of the step is made constant at 100cm×2 regardless of the age, to a distance without unnatural effort even by a primary school pupil, in order to obtain a better diagnosis and tolerance for exercise for the desirable development and maintenance of agility.
The influence of body height on the score should be studied in the future.