I've written and presented on ACL injury prevention/ reduction for years but, as always, the more you coach, the more you learn.
I think a lot of prevention/reduction is simple. Install a good year-round training program and have a more intelligent approach to play and practice. (ACL Injury Prevention is Just Good Training)
However, as we have trained more females I have noticed a trend that gets overlooked.
Young females moving through puberty gain what is best described as "non propulsive mass". The size and consequent weight gains in a young females' body can drastically change their strength to bodyweight ratio in an unfavorable way.
As young men (statistically less prone to ACL tears) go through puberty we generally see gains in size and increases in weight in the form of lean tissue. Of course young males can gain bodyfat through puberty but, from an observation standpoint this does not seems to happen. The increase in male testosterone generally causes an increase in muscle mass and, in strength.
On the other hand, the body changes in females often also result in weight gain but, this weight is often “non propulsive”.
This means that for females, strength training through puberty is critical to learn to control the added mass.
It's funny. Some people immediately get what I'm talking about when I say "non propulsive mass" others look puzzled.
It's a tough topic to tackle because the effects of puberty on two groups is almost athletically opposite.
Working with my son and his friends from age 12-15 and having one female in our group has been really eye opening.
Our one female member is clearly the best athlete. At 12 she was as fast and as strong as the strongest and fastest male in the group. She was also average height for the group.
Fast forward three years and she is
- the shortest (she has not grown at all)
- still near the top in speed but most of the boys have caught up to her or are very close.
- She is still above average in strength. Only her bench pressing strength has obviously lagged behind the boys.
She has gained 15 lbs but, not the muscle mass and additional length that the boys have gained.
During the same time period most of boys have grown from 3-7 inches and gained 20-30 lbs of primarily lean body mass.
Thankfully, our one female member has continued to train on a consistent basis this whole time.
My guess is that young females who are playing sports but, not doing strength and speed training go through a significant loss of speed during puberty. I'm not sure if there have been studies on this but, I would bet my bottom dollar on it. It would be interesting to see some studies on speed changes and weight gain as females move through puberty.
In any case, the maturation process of the female body really reinforces the need for young female athletes to begin the strength training process sooner and stick with it.