Table 2.

Correlation between accelerometer measures and clinical measures (Spearmen coefficient)

		Age	Height	BMI	6MWT	4SC	RRF	10MW	Distance	SV50C	SV95C	SL50C	SL95C
Age	5–17 y		0.927**	0.667**	0.122	0.184	0.418**	− 0.143	− 0.083*	0.513**	− 0.609**	0.829**	− 0.099*
	≥ 18 y
Height	5–17 y	0.909**		0.620**	0.157	0.137	0.389**	− 0.149	− 0.135	0.499**	− 0.598**	0.883**	− 0.037
	≥ 18 y	− 0.134
BMI	5–17 y	0.363**	0.356**		− 0.204	0.057	0.390**	0.065	− 0.091	0.321**	− 0.575**	0.510**	− 0.363**
	≥ 18 y	0.627**	0.189
6MWD	5–17 y	0.6**	0.538**	− 0.015		− 0.135	− 0.334**	− 0.565**	0.101	0.336**	0.271*	0.212	0.465**
	≥ 18 y	− 0.703**	0.061	− 0.559*
4SC	5–17 y	− 0.142	− 0.163	− 0.303*	− 0.033		0.607**	0.256*	− 0.285**	− 0.077	− 0.3**	0.057	− 0.224*
	≥ 18 y	0.14	− 0.288	0.181	0.054
RFF	5–17 y	− 0.011	0.028	− 0.008	− 0.183	0.515**		0.181	− 0.298**	− 0.01	− 0.631**	0.289**	− 0.494**
	≥ 18 y	0.447	0.01	0.432	− 0.409	0.63**
10MW	5–17 y	− 0.479**	− 0.407**	− 0.113	− 0.595**	0.155	0.089		− 0.362**	− 0.377**	− 0.203	− 0.276*	− 0.328**
	≥ 18 y	0.434	− 0.326	0.225	− 0.373	0.415	0.362
Distance	5–17 y	0.03	− 0.036	0.013	0.11	− 0.232	− 0.263*	− 0.426**		0.455**	0.389**	0.081	0.289**
	≥ 18 y	0.115	0.108	0.174	− 0.078	− 0.43	− 0.241	− 0.201
SV50C	5–17 y	0.621**	0.552**	0.292*	0.454**	− 0.219	− 0.222	− 0.477**	0.451**		− 0.053	0.74**	0.293**
	≥ 18 y	− 0.206	0.116	− 0.113	0.444	− 0.087	− 0.018	− 0.331	0.691**
SV95C	5–17 y	− 0.231	− 0.269*	− 0.207	0.034	− 0.117	− 0.418**	− 0.09	0.437**	0.114		− 0.414**	0.734**
	≥ 18 y	− 0.738*	0.254	− 0.397	0.858**	0.05	− 0.385	− 0.306	0.157	0.542*
SL50C	5–17 y	0.869**	0.876**	0.285	0.518**	− 0.163	− 0.1	− 0.493**	0.148	0.786**	− 0.098		0.16
	≥ 18 y	− 0.091	0.678**	− 0.145	0.103	− 0.27	0	− 0.331	0.659**	0.684**	0.417
SL95C	5–17 y	0.312*	0.274*	− 0.142	0.374**	− 0.144	− 0.405**	− 0.298*	0.281*	0.418**	0.728**	0.455**
	≥ 18 y	− 0.561*	0.668**	− 0.093	0.485*	− 0.187	− 0.256	− 0.319	0.252	0.449	0.748**	0.721**

Significance level p ≤ 0.01**, p ≤ 0.05*. Upper part: correlation on the whole sample. Lower part: correlation on the two age groups. BMI body mass index, 6MWT 6-min walk distance, 4SC 4-stair climb; RFF rise from floor; 10MW 10-m walk test; SV50C 50th centile stride velocity; SV95C 95th centile stride velocity; SL50C 50th centile stride length; SL95C 95th centile stride length