You have to think about that one image a bit for what it means to sink in:
You read that Neanderthals were normally around 5-6 and there's a tendency to wonder how strong somebody 5-6 could be since we think in human terms. But the human in that figure at 5-6 would be ballpark for the size and weight of a lightweight or junior welter prizefighter i.e. around 140 lbs and the Neanderthal appears to be at least double that so that you're looking at a creature which was typically around 5-6 and 300 lbs without being fat or overweight; the human race doesn't include anything like that.