I'm writing up my masters dissertation in biomechanics. I have carried out a study where 6 racehorses jumped over a hurdle on a synthetic (riding school) surface and a week later over the hurdle on a grass surface. I measured all the appropriate joint angles (marked on the horses for the computer to measure- I won't bore you with it too much!). With the resulting data I carried out non-parametric tests- one Wilcoxon signed rank to test differences and one spearman's coefficient to test correlation. The problem i'm having is this: where P=<0.05 and the initial hypothesis is retained (I hypothesised the horses do jump differently on turf compared to synthetic surface) on the spearman's the two sets of data correlate (r=> 0.6). So how can they be significantly different but also correlate? Its probably really obvious and I've massively overthought it but any help would be much appreciated!!

Many thanks,

Sara