Fair enough and very good correction. It's not about *any* weight training, it's about *excessive* weight training or *heavy loads*.
What's excessive? That's where the trick is and I think that generated the "rule of thumb" with "body weight", if someone's not doing this "by the book".
It would be interesting to know if in those studies, the 6 year olds lifted more than their body weight... or if, at the end, the weight lifters were faster than swimmers...
A serious strength training program for ski racers will require testing of several parameters and fine-tuning the program accordingly. Testing of PHV, hormones, testosterone, bone mineral density etc. Tests of
coordination and flexibility to ensure they're not affected etc.
These all play a role. The "growth plates" are especially vulnerable apparently, during the growth spurts - which makes sense logically and why you're supposed to test for growth spurts every 3 mths (i.e. PHV). Here's some of the actual warnings in the manual.
"Adult forms of training which emphasize heavy load repetition maximum and heavy eccentric type training may cause damage to these growth plates. Supervision is critical to ensure appropriate load and execution."
and
"[...] in their growth spurt: • The growth plates (discussed in lesson 4) are at their most vulnerable. Supervise your athletes – adolescent males in particular will be tempted to lift larger weights with improper technique"
In fact, if you look at general age guidelines, body weight only is up to 12-15, next is 13-17 to learn lifting techniques with limited weights and after 18, when the athlete mastered lifting technique,
"the coach can then introduce repetition maximum and advanced lifting. The focus remains on maintaining form and range of motion."
I don't mean to throw the book at you - just to add more detail to an admittedly over-simplified "rule of thumb"... and thanks for the opportunity to refresh my memory on this topic!
Disclaimer: I am totally not qualified to teach lifting technique and maybe my athletic development manual is dated... I know there are other posters here much more qualified to talk about that... I think the most important take-away for skiing is the focus on maintaining coordination, speed. flexibility
and range of motion, while developing some strength, stamina and endurance... alpine ski racing is widely recognized as the hardest sport to train well, from this point of view, among others. It's not just about not messing with the growth, but also about not impacting overall athlete development, especially in the early teen years, when different features develop at different rates.
cheers
p.s.
At the same time, my own skiing is now limited by strength... (but given that I'm not a teen, avoiding weights is not an excuse! Damn it!
).