Changes in children’s physical fitness, BMI and health-related quality of life after the first 2020 COVID-19 lockdown in England: A longitudinal study

Figures & data

Table 1. Changes in anthropometry and physical fitness variables from baseline to follow-up (means, standard deviation (SD) and 95% confidence intervals (95% CI))

	Baseline		Follow-up		Difference		Effect size (Cohen’s d; 95%CI)
Variable (n)	Mean	SD	Mean	SD	Mean (SD; 95% CI)	p
Anthropometry
Age (y) (163)	9.1	0.6	10.2	0.5	1.1 (0.03; 1.1,1.1)	<0.001	-
BMI (kg · m^−2) (146)	18.3	3.3	19.8	4.0	1.5 (1.5; 1.2,1.7)	<0.001	0.99; 0.79,1.19
BMI z-score* (146)	0.71	1.19	0.95	1.22	0.25 (0.47; 0.17,0.32)	<0.001	0.52; 0.35,0.69
Physical fitness
20mSRT (total shuttles run) (141)	23	13.6	21	12.6	−3^# (9.1; −4.3,-1.3)	<0.001	−0.30; −0.47,-0.13
Standing Broad Jump (cm) (149)	122	23	129	24	6.8 (13.1; 4.7,9.0)	<0.001	0.52; 0.35,0.69
Handgrip strength (right hand, kg) (146)	13.2	3.1	14.7	3.3	1.5 (2.2; 1.1,1.8)	<0.001	0.66; 0.48,0.84
Handgrip strength (left hand, kg) (144)	13.1	3.0	14.4	3.1	1.3 (1.9; 1.0,1.6)	<0.001	0.67; 0.49,0.85
Sit-and-reach (cm) (148)	15.3	7.7	13.5	7.9	−1.8 (3.6; −2.4,-1.2)	<0.001	−0.50; −0.67,-0.33
Kidscreen-27 domains (T score**)
Physical Wellbeing (137)	52.2	10.8	50.6	9.7	−1.6 (10.7; −3.4,0.2)	0.080	−0.15; −0.32,0.02
Psychological Wellbeing (138)	50.3	10.6	50.3	10.9	0.04 (10.8; −1.8,1.9)	0.965	0.00; −0.16,0.17
Parents & Autonomy (136)	49.9	10.4	51.3	10.5	1.4 (11.2; −0.4,3.3)	0.132	0.13; −0.04,0.30
Social Support & Peers (141)	51.6	11.0	53.7	10.4	2.0 (14.1; −0.4,4.3)	0.099	0.14; −0.03,0.31
School Environment (139)	52.0	10.8	52.0	9.9	0.07 (12.3; −2.0,2.1)	0.950	0.01; −0.16,0.17

*Assessed against UK90 data (Cole et al. 1995) . ^# Not −2 due to rounding. BMI – body mass index kg · m⁻², 20mSRT = 20m shuttle run test. **Within each dimension, item scores were summed and transformed to T-scores with a mean ≈ 50 and SD ≈10. Higher scores indicated higher HRQoL.

Cole TJ, Freeman J, Preece M. Body mass index reference curves for the UK, 1990. Arch Dis Child. 1995;73

Table 2. Change in weight status from baseline to follow-up

		Baseline categories of weight status*, n					Total
		Underweight	Healthy weight	Overweight	Obese	Severely obese
Follow-up categories of weight status*, n	Underweight	-	-	-	-	-	-
	Healthy weight	2	76	-	-	-	78
	Overweight	-	15	9	2	-	26
	Obese	-	5	8	15	1	29
	Severely obese	-	-	-	3	10	13
Total		2	96	17	20	11	146

*Assessed against UK90 data (Cole et al., 1995) “underweight” (≤2nd centile or below), “healthy weight” (>2nd <85th centile) “overweight” (≥85th <95th centile) “obese” (≥95th <99.6th centile) or “severely obese” (≥99.6th centile and above). “-“ indicates no children in this cell. Shaded cells indicate the number of individuals who have stayed in the same category.

Cole TJ, Freeman J, Preece M. Body mass index reference curves for the UK, 1990. Arch Dis Child. 1995;73

Table 3. Summary of linear regression models predicting change in fitness variables by change in anthropometry variables

	Dependent variable: change in fitness variable Unstandardized B (95% CI)
Independent variable	Change in total shuttles	p	Change in max jump distance (cm)	p	Change in right max handgrip (kg)	p	Change in left max handgrip (kg)	p	Change in max sit-and-reach (cm)	p
Constant	−11.46 (−36.38, 13.45)	0.364	22.63 (−9.23, 54.49)	0.162	−1.38 (−7.22, 4.45)	0.640	−0.76 (−6.10, 4.58)	0.779	−7.75 (−17.53, 2.02)-	0.119
Sex (male = 1, female = 2)	0.98 (−2.03, 3.99)	0.519	2.73 (−1.21, 6.67)	0.173	0.45 (−0.27, 1.16)	0.220	0.24 (−0.42, 0.89)	0.479	−0.07 (−1.27, 1.13)	0.909
Baseline age (y)	0.99 (−1.64, 3.62)	0.458	−1.70 (−5.08, 1.68)	0.321	0.22 (−0.40, 0.85)	0.477	0.19 (−0.38, 0.76)	0.507	0.67 (−0.37, 1.71)	0.203
Change in BMI z-score	−5.69 (−8.88, −2.50)	0.001	−8.37 (−12.51, −4.22)	<0.001	0.30 (−0.44, 1.05)	0.421	0.24 (−0.45, 0.93)	0.499	0.17 (−1.08, 1.42)	0.789
Baseline BMI z-score	−0.10 (−1.35, 1.16)	0.878	−3.2 (−4.84, −1.56)	<0.001	−0.01 (−0.31, 0.29)	0.963	−0.15 (−0.43, 0.13)	0.292	−0.15 (−0.65, 0.35)	0.554
Final model Adjusted R^2	6.8%		16.5%		−0.11%		−0.10%		−1.3%

Table 4. Summary of linear regression models predicting change in health-related quality of life (HRQoL) by change in anthropometry and fitness variables

	Dependent variable: change HRQoL domain Unstandardized B (95% CI)
Independent variable	Change in Physical Wellbeing	p	Change in Psychological Wellbeing	p	Change in Parents & Autonomy	p	Change in Social Support & Peers	p	Change in School Environment	p
Block 1: Anthropometry (forced entry)
Constant	−40.95 (−71.34,-10.56)	0.009	10.59 (−23.00,44.17)	0.534	11.84 (−23.75,47.42)	0.511	−32.69 (−73.50,8.12)	0.115	−60.34 (−97.06,-23.62)	0.001
Sex^a	−1.80 (−5.42,1.83)	0.328	−6.03 (−9.94,-2.12)	0.003	−3.73 (−7.96,0.51)	0.084	−0.57 (−5.42,4.72)	0.816	−3.75 (−8.09,0.60)	0.090
Baseline age (y)	4.53 (1.34,7.72)	0.006	0.01 (−3.50,3.5)	0.997	−0.68 (−4.40,3.04)	0.718	3.75 (−0.54,8.03)	0.086	7.08 (3.23,10.92)	<0.001
Baseline BMI z-score	2.45 (0.84,4.06)	0.003	0.37 (−1.35,2.09)	0.673	0.41 (−1.46,2.27)	0.667	2.63 (0.48,4.78)	0.017	1.09 (−0.83,3.01)	0.263
Change BMI z-score	−4.66 (−8.43,-0.89)	0.016	−3.38 (−7.47,0.71)	0.104	−0.69 (−5.35,3.98)	0.772	−2.21 (−7.30,2.89)	0.393	0.78 (−3.77,5.33)	0.734
Block 2: fitness^b (forward stepwise)
Change in sit-and-reach (cm)	-	-	0.70 (0.16,0.13)	0.012	-	-	-	-	-	-
Final model adjusted R^2	16.8%		10.4%^c		−0.01%		5.4%		12.6%

^aMale = 1, female = 2; ^bonly significant (p < 0.05) change fitness variables are put forward through the analysis, and thus presented; ^cBlock 1 only Adjusted R² = 6%.

Cole, T. J., Freeman, J., & Preece, M. (1995). Body mass index reference curves for the UK, 1990. Archives of Disease in Childhood, 73(1), 25–29. https://doi.org/10.1136/adc.73.1.25

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Data availability statement

Data are available from the corresponding author upon request