It's a statistically significant finding, but that doesn't mean it's one of meaningful magnitude. If you're not trained in statistics, that basically means there's a difference that's correlated to relative limb length, but doesn't say anything about the magnitude of difference. Also, a correlation in the .6 to .7 range that they've found, only accounts for 4-5% of the variance that they found, if I remember my statistics.

Basically, it could be a very small difference (can't tell from what's reported), and the limb length (relative to body mass) only accounts for 4-5% of that variance.