Fig. 5.

Relationship between femur length and wheel-running distance. A: voluntary wheel usage varied from 5 to 25 km/day, but there was no significant difference in average distance between cold and warm groups. There was a slight positive correlation between distance run and femur length (Pearson's r = 0.3, P = 0.03, outliers excluded as denoted by # and ##), suggesting that the amount of wheel running could be related to degree of limb lengthening. This 5-fold range in average daily distance may also account for increased variation in other data collected (see Figs. 2 and 4). #Mice with unusually long femurs; ##mouse with extremely high running activity.