Table 3 Percent changes, standardized effect sizes and 95% confidence intervals of changes per decade in 1-minute sit-ups performance, body height, mass, body mass index among urban Chinese girls from 1985 to 2019 by age and period*.

From: Population-based trends and distributional characteristics in sit-ups performance among school-aged girls in urban China over three decades

Tests

Age categories (yrs)

Change in means per decade (95% CI)

Percent (%)

Standardized ES

1985–1990

1991–2000

2001–2010

2011–2019

1985–1990

1991–2000

2001–2010

2011–2019

1-minute sit-ups (reps.)

7 to 9

33.8 (26.1, 41.4)

0.7 (−4.7, 6.2)

−8.3 (−10.6,−5.9)

21.8 (13.0, 30.6)

0.70 (0.54, 0.86)

0.01 (−0.10, 0.12)

−0.18 (−0.23,−0.13)

0.45 (0.27, 0.64)

 

10 to 12

30.9 (22.7, 39.2)

−4.5 (−10.3, 1.2)

−13.3 (−16.1,−10.5)

20.9 (11.0, 30.7)

0.87 (0.64, 1.10)

−0.13 (−0.29, 0.03)

−0.37 (−0.45,−0.30)

0.58 (0.31, 0.86)

 

13 to 15

41.6 (32.6, 50.6)

1.8 (−4.9, 8.5)

−11.9 (−14.0,−9.9)

18.4 (9.1, 27.6)

1.23 (0.96, 1.49)

0.05 (−0.15, 0.25)

−0.35 (−0.41,−0.29)

0.54 (0.27, 0.82)

 

16 to 18

47.2 (38.2, 56.2)

6.5 (−0.6, 13.6)

−11.3 (−12.5,−10.1)

11.9 (4.2, 19.6)

1.40 (1.13, 1.67)

0.19 (−0.02, 0.40)

−0.34 (−0.37,−0.30)

0.35 (0.12, 0.58)

 

Total

38.6 (30.1, 47.0)

1.3 (−5.0, 7.6)

−11.1 (−13.2,−9.1)

18.1 (9.2, 27.0)

1.05 (0.82, 1.28)

0.04 (−0.13, 0.21)

−0.31 (−0.36,−0.25)

0.48 (0.24, 0.72)

Height (cm)

7 to 9

2.1 (2.0, 2.2)

1.7 (1.6, 1.8)

1.4 (1.3, 1.4)

1.2 (1.2, 1.2)

0.43 (0.42, 0.45)

0.35 (0.34, 0.37)

0.28 (0.27, 0.29)

0.24 (0.23, 0.24)

 

10 to 12

2.8 (2.5, 3.0)

1.6 (1.4, 1.8)

1.2 (1.1, 1.2)

2.0 (1.7, 2.2)

0.54 (0.49, 0.59)

0.31 (0.27, 0.35)

0.23 (0.22, 0.24)

0.39 (0.34, 0.44)

 

13 to 15

1.3 (1.2, 1.5)

0.7 (0.6, 0.8)

0.6 (0.5, 0.6)

1.2 (1.0, 1.4)

0.35 (0.31, 0.39)

0.18 (0.16, 0.21)

0.15 (0.14, 0.17)

0.33 (0.28, 0.38)

 

16 to 18

0.6 (0.6, 0.6)

0.4 (0.4, 0.5)

0.5 (0.5, 0.5)

0.8 (0.7, 0.9)

0.17 (0.16, 0.18)

0.13 (0.12, 0.13)

0.14 (0.13, 0.15)

0.23 (0.21, 0.25)

 

Total

1.7 (1.5, 1.8)

1.1 (1.0, 1.2)

0.9 (0.9, 0.9)

1.3 (1.2, 1.4)

0.37 (0.34, 0.39)

0.24 (0.22, 0.26)

0.199 (0.19, 0.21)

0.29 (0.26, 0.32)

Mass (kg)

7 to 9

7.9 (7.8, 8.0)

8.1 (8.0, 8.1)

7.0 (6.6, 7.3)

4.4 (3.8, 5.0)

0.39 (0.38, 0.39)

0.40 (0.39, 0.40)

0.34 (0.32, 0.36)

0.21 (0.18, 0.24)

 

10 to 12

11.0 (10.4, 11.7)

8.2 (7.7, 8.7)

7.1 (7.0, 7.3)

9.1 (8.5, 9.8)

0.48 (0.45, 0.51)

0.35 (0.33, 0.37)

0.31 (0.30, 0.31)

0.40 (0.37, 0.42)

 

13 to 15

5.9 (5.5, 6.3)

4.2 (4.0, 4.4)

4.6 (4.2, 5.0)

8.0 (7.1, 8.8)

0.34 (0.31, 0.36)

0.24 (0.23, 0.25)

0.26 (0.24, 0.28)

0.45 (0.40, 0.50)

 

16 to 18

3.5 (3.2, 3.9)

2.4 (2.2, 2.5)

3.1 (2.7, 3.4)

6.2 (5.5, 7.0)

0.24 (0.21, 0.26)

0.16 (0.15, 0.17)

0.21 (0.18, 0.23)

0.42 (0.37, 0.47)

 

Total

7.0 (6.7, 7.3)

5.7 (5.4, 5.9)

5.4 (5.3, 5.5)

6.8 (6.4, 7.2)

0.35 (0.34, 0.37)

0.28 (0.27, 0.30)

0.28 (0.27, 0.29)

0.37 (0.34, 0.39)

Body mass index (kg/m2)*

7 to 9

-

-

3.3 (3.0, 3.5)

2.3 (1.7, 2.8)

-

-

0.22 (0.20, 0.23)

0.15 (0.12, 0.19)

 

10 to 12

-

-

3.9 (3.6, 4.2)

4.9 (4.8, 5.0)

-

-

0.23 (0.21, 0.24)

0.29 (0.28, 0.29)

 

13 to 15

-

-

2.9 (2.5, 3.3)

5.3 (4.8, 5.7)

-

-

0.18 (0.16, 0.21)

0.33 (0.30, 0.37)

 

16 to 18

-

-

1.2 (0.6, 1.8)

4.9 (4.2, 5.7)

-

-

0.08 (0.04, 0.13)

0.35 (0.30, 0.40)

 

Total

-

-

2.8 (2.4, 3.1)

4.3 (4.1, 4.5)

-

-

0.18 (0.15, 0.20)

0.28 (0.27, 0.29)

  1. Positive trends indicated temporal increases in means and negative trends indicated temporal declines in means. Trends in mean were estimated in each test-age-specific group by best-fitting/most parsimonious regressions (linear or quadratic or cubic regressions). Population-weighted average changes were calculated by combining test-age-specific changes using stratified population weighting. The population weighting was derived from the sex-region-age-specific population data from the 2020 Population Census in China. CI is confidence interval and ES is effect size. Bold represented significant changes. * Body mass index data were reported only after 2000.
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