Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, Chiba, 260-8670, Japan.
Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, Chiba, 260-8670, Japan.
J Orthop Sci. 2024 May;29(3):891-896. doi: 10.1016/j.jos.2023.03.015. Epub 2023 Apr 11.
Lower limb flexibility (LLF) is an essential motor function. However, assessing LLF during adolescence is difficult because of the influence of marked physical changes. We, therefore, assessed LLF and investigated the relationship between LLF and sex and age in healthy children and adolescents.
We conducted a five-year cross-sectional study with students aged 8-14 years at a single school in Japan. We evaluated the heel-buttock distance (HBD), straight leg raising angle (SLRA), and dorsiflexion angle of the ankle joint (DFA) at the beginning of each year. We conducted a comparative analysis on the performance of the HBD, SLRA, and DFA techniques, stratified by both sex and age. The statistical significance of observed differences was assessed through the application of Mann-Whitney U and Kruskal-Wallis tests. Furthermore, we analyzed the effects of sex, age, height, and weight on LLF using a multivariable linear regression model.
Of the 4221 initial study participants, 3370 were analyzed. Mean HBD, SLRA, and DFA values were 1.6 cm, 77.0°, and 15.7°, respectively. Girls showed significantly higher HBD and lower SLRA and DFA values than boys and 14-year-olds (p < 0.01). Median HBD value for girls was 0 cm, whereas for boys, it exceeded 0 cm after age 13. The median SLRA value for girls was 80-85°, while for boys, it was 70-75°. The median DFA value for girls was 15-19°, and for boys, it was 12-15°. A multivariable linear regression model indicated that boys had significantly greater tightness than girls (p < 0.01).
The reference values of HBD, SLRA, and DFA differed according to age and sex. Furthermore, we showed that sex differences were significantly associated with LLF. Data in this study provide the reference value for assessing LLF in children and adolescents.
下肢灵活性（LLF）是一项基本的运动功能。然而，由于青少年身体变化显著，评估 LLF 较为困难。因此，我们评估了健康儿童和青少年的 LLF，并研究了 LLF 与性别和年龄之间的关系。
我们在日本的一所学校进行了一项为期五年的横断面研究，研究对象为 8-14 岁的学生。我们在每年开始时评估跟臀距离（HBD）、直腿抬高角度（SLRA）和踝关节背屈角度（DFA）。我们对 HBD、SLRA 和 DFA 技术的表现进行了比较分析，并按性别和年龄进行分层。通过应用 Mann-Whitney U 和 Kruskal-Wallis 检验评估观察到的差异的统计学意义。此外，我们使用多变量线性回归模型分析了性别、年龄、身高和体重对 LLF 的影响。
在最初的 4221 名研究参与者中，有 3370 名被分析。HBD、SLRA 和 DFA 的平均数值分别为 1.6 厘米、77.0 度和 15.7 度。与男孩和 14 岁的孩子相比，女孩的 HBD 明显较高，SLRA 和 DFA 值较低（p<0.01）。女孩的 HBD 中位数为 0 厘米，而男孩的 HBD 中位数在 13 岁后超过 0 厘米。女孩的 SLRA 中位数为 80-85 度，而男孩的 SLRA 中位数为 70-75 度。女孩的 DFA 中位数为 15-19 度，男孩的 DFA 中位数为 12-15 度。多变量线性回归模型表明，男孩的紧张程度明显大于女孩（p<0.01）。
HBD、SLRA 和 DFA 的参考值因年龄和性别而异。此外，我们表明性别差异与 LLF 显著相关。本研究的数据为评估儿童和青少年的 LLF 提供了参考值。
