Having a kettlebell is essentially halfway to having all the exercise equipment you need. From swings to deadlifts, presses, cleans, snatches and goblet squats, grabbing a kettlebell can help you unlock a near-limitless amount of full-body exercises that can string together a monster HIIT workout. If you plan to purchase just one, our advice is to chose a weight according to an exercise that you might find more challenging. You want a KB that's heavy enough to tax you with moves your efficient with but light enough that you can still move it without compromising your form.
$ for a 17-pounder at
The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".   Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.  The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.  Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.