Table 4 Mean, standard deviation and p-value of backpack and total load expressing in kilograms and normalizing for body mass by gender, physical education participation, BMI, afternoon with classes and lunch spot

 M

4.87 (1.42)

0.129 (0.046)

3.75 (1.25)

0.064 (0.022)

5.27 (1.57)

0.139 (0.050)

4.08 (1.47)

0.072 (0.027)

 F

5.13 (1.42)

0.131 (0.042)

4.29 (1.13)

0.087 (0.026)

5.56 (1.48)

0.141 (0.046)

4.64 (1.39)

0.095 (0.032)

 p

0.064

0.546

< 0.001

< 0.001

0.040

0.513

< 0.001

< 0.001

 Normal

5.05 (1.28)

4.09 (1.14)

5.45 (1.37)

4.46 (1.43)

 Overw.

5.19 (1.50)

4.48 (1.25)

5.66 (1.67)

4.86 (1.43)

 p

0.730

0.027

0.467

0.044

 Yes

4.63 (1.12)

0.123 (0.037)

4.00 (1.25)

0.080 (0.026)

5.64 (1.42)

0.148 (0.047)

4.83 (1.64)

0.097 (0.035)

 No

5.20 (1.55)

0.134 (0.048)

4.10 (1.19)

0.076 (0.028)

5.26 (1.59)

0.136 (0.049)

4.14 (1.23)

0.077 (0.028)

 p

0.003

0.057

0.651

0.163

0.018

0.061

< 0.001

< 0.001

 Yes

5.39 (1.49)

0.132 (0.046)

4.13 (1.24)

0.080 (0.028)

5.87 (1.50)

0.153 (0.049)

4.56 (1.49)

0.089 (0.034)

 No

4.33 (1.02)

0.114 (0.036)

3.80 (1.07)

0.069 (0.021)

4.64 (1.26)

0.120 (0.040)

3.82 (1.07)

0.069 (0.021)

 p

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

 Home

4.31 (1.03)

0.112 (0.035)

3.60 (1.04)

0.065 (0.019)

4.63 (1.23)

0.120 (0.040)

3.70 (1.04)

0.068 (0.020)

 School

5.25 (1.48)

0.137 (0.046)

4.38 (1.22)

0.084 (0.028)

5.69 (1.55)

0.149 (0.050)

4.90 (1.48)

0.094 (0.034)

 p

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001