*The following is excerpted from an online article from Science World Report.
Boys will be boys, as they say, but a new study shows that more aggressive adolescents are likely to develop into stronger teenagers.
A new study published in the journal Psychological Science supports a link between male upper-body strength and aggressive tendencies. However, researchers are still looking to understand why the two are connected.
"Very little is known about how this association unfolds developmentally," said psychological scientist Joshua Isen of the University of Minnesota, Minneapolis, in a news release. "Our study is unique because we used a prospective longitudinal design to examine whether male-typical behavioral tendencies are related to pubertal change in physical strength."
For the study, they examined data from two large samples of twins collected as part of the Minnesota Twin Family Study. The twins began participating in the study at age 11 and were followed up with every 3 years.
Researchers specifically monitored their strength levels at 11, 14 and 17. Aggressive-antisocial tendencies were also monitored when using a combination of teacher and self-reported ratings, while strength was measured with a hand-grip strength, which is a good way to assess muscular strength. For hand grip strength, the children were instructed to squeeze a dynamometer as hard as possible with both their left and right hands.
Findings showed that boys with high aggression and those who had low levels of aggression were equally strong at age 11. However, over time, this was not the case. Adolescence changed that, which may be contributed to a number of factors, including weight, height, etc.
The same aggressive-antisocial tendencies and development of physical strength, however, was not seen in girls.
"Our findings indicate that other aggression-related characteristics -- including deceit, risk taking, and lack of empathy -- predict future development of strength in males," said Isen.