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Table 4 Associations between independent variables (TV, computer/game time, age, sex, physical activity, and BMI) and strength measures

From: Screen-based sedentary behavior and associations with functional strength in 6–15 year-old children in the United States

 

TV change in strength per 1 hr increase

Computer change in strength per 1 hr increase

Age change in strength per 1 year increase

Sex Males - Females

Physical Activity change in strength per 1 day increase

BMI-Z-Score change in strength per 1 z-score increase

 

Beta (95 % CI)

Beta (95 % CI)

Beta (95 % CI)

Beta (95 % CI)

Beta (95 % CI)

Beta (95 % CI)

   

Absolute strength

Gripa (kg)

−0.31* (−0.56, −0.06)

0.05 (−0.12, 0.22)

2.79*** (2.69, 2.89)

3.16*** (2.53, 3.79)

0.02 (−0.11, 0.15)

1.58*** (1.30, 1.86)

Leg Extensionsa (kg)

−0.99** (−1.70, −0.28)

0.35 (−0.42, 1.13)

3.31*** (2.75, 3.86)

1.35* (0.091, 2.62)

−0.14 (−0.57, 0.29)

3.22*** (2.46, 3.98)

   

Relative strength

Gripa (kg per kg of body weight)

−0.006* (−0.011, −0.001)

−0.002 (−0.006, 0.002)

0.009*** (0.007, 0.011)

0.049*** (0.039, 0.060)

0.003** (0.001, 0.005)

−0.058*** (−0.064, −0.053)

Leg Extensionsa (kg per kg of body weight)

−0.018* (−0.033, −0.004)

0.001 (−0.013, 0.015)

0.009** (0.004, 0.014)

0.001 (−0.021, 0.024)

0.001 (−0.007, 0.010)

−0.048*** (−0.064, −0.033)

Planka (seconds)

−3.49*** (−5.18, −1.18)

−2.04 (−4.22, 0.13)

6.19*** (5.00, 7.39)

7.45 (−0.10, 15.01)

1.76** (0.67, 2.86)

−12.39*** (−14.53, −10.26)

Pull-upsbc (odds ratio for completing ≥1 pull-ups)

0.83*** (0.76, 0.92)

0.86** (0.78, 0.94)

0.99 (0.94, 1.05)

3.41*** (2.36, 4.93)

1.05 (0.99, 1.12)

0.40*** (0.31, 0.51)

Pull-upsb (# of pull-ups for children with ≥1 pull-ups)

−0.34 (−0.84, 0.15)

−0.23 (−0.61, 0.14)

0.72*** (0.53, 0.90)

2.63*** (1.77, 3.49)

0.31** (0.12, 0.49)

−1.18*** (−1.48, −0.88)

  1. a Coefficients were estimated from linear regression models including all covariates in the table
  2. b Due to the large number of children unable to complete one modified pull-up, two types of models were used to analyze the data. The first model estimated the association of the covariates with the ability of a child to complete at least one modified pull-up using a logistic regression model. The second model estimated the association of the covariates with the number of modified pull-ups completed only among children that completed at least one modified pull-up using a linear regression model. Both types of models included all covariates listed
  3. c Females were coded as the reference group (denominator) for the logistic regression model
  4. *p < 0.05, **p < 0.01, ***p < 0.001