To understand the association between weight-adjusted-waist index (WWI) and cardiopulmonary endurance among middle school students, so as to provide references for the improvement of cardiopulmonary endurance levels in adolescents.
From June 2015 to December 2018 by using the method of purposive sampling, height, weight, waist circumference, and 20 m shuttle-run tests were measured among 44 870 adolescents aged 13-18 from Northeast, North, East, South, Southwest and Northwest of China. The WWI of the adolescents and the maximum oxygen uptake (VO2max) were calculated indirectly. The t-test and one-way analysis of variance were used for comparison, and the curve regression analysis method was adopted to analyze the relationship between WWI and VO2max.
For Chinese middle school students aged 13-18, the WWI was (9.35±1.02), the number of 20 m shuttle-run was (38.89±18.14) times, and VO2max was (39.96±5.88) mL/(kg ·min-1). The differences of VO2max between WWI quartile arrays of boys aged 13-18 were statistically significant (F=15.19, 9.00, 14.97, 20.48, 28.13, 10.13, P < 0.01), girls had the same trend (F=23.36, 16.61, 33.45, 32.96, 18.23, 19.36, P < 0.01). There was an inverted U-shaped curve relationship between WWI and cardiopulmonary endurance. When WWI was 8.5, the VO2max level reached the highest, which was 40.07 mL/(kg ·min-1). Compared with girls, WWI in boys had a more significant impact on cardiopulmonary endurance.
Maintaining optimal WWI levels may enhance adolescents' cardiopulmonary endurance.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |