how young is too young?

My 6yo son has raced three triathlons (3rd, 1st, 1st - that's what's up!) and swims in 7/8 on his swim team.  He freakin' loves it.  The time is now - assuming they are interested and it's fun.  Get her off those training wheels.

I don't think there is too young!  My 4 and 7 year old run with us, and my 7 year old wants to run her first 5k by the end of the summer, and her first kids triathlon in October.  

My 2 year old loves to be active, so I am sure as soon as he can get out there and run, he will be there too! 

No age is really "too young" until ...

... the distances start to increase (i.e., sprint distance, olympic distance, the 70.3, and beyond).

Many elite running coaches, for proper development as a human and as an athlete, do not recommend doing a 26.2 marathon until beyond 25 years of age (we're talking just a marathon by itself). Many triathlons take as long or longer to complete than a marathon.

The typical human skeleton does not fully ossify (change to bone from cartilage) until somewhere after 25 years of age. In addition to detrimental health effects, if you push too much distance too soon, what you'll get is a youngster who quits the sport early and never returns.

At 5, I was a gymnast, swimmer, and t-ball player!

Read up on kids and running (here's a start: http://www.runnersworld.com/article/0,7120,s6-238-267--11828-0,00.html)... and if she gets really into it, find a coach or youth team - as much to insure a lifelong ability to do the sport safely as to improve skill. USAT certifies youth coaches.

Be very careful here.  Growth plates are nothing to mess with.  Pound them enough and you'll ruin your kid.  Let them explore many sports and activities.  If you REALLY want to get  the most bang  for THEIR buck.....swimming!!!  

Build the engine without wrecking the machine.

My son has swam since he was 4.....he didn't run until he was 13....he is now 14 and runs a sub 18 5K....easily....he'll enter High School next year and run a sub 5 mile....easily. He won his middle school mile in 5:03. Virtually every kid that is competitive (top 15) on a national level in ITU youth triathlon has a swim background.

Take any advice you want....but if your kid enjoys it (THAT'S the biggest thing)......get him/her on a swim club.....a competitive swim club.  If they don't enjoy it....follow their lead (with HUGE guidance on overdoing it).  I've got kids who dance, play softball, basketball, whatever.  BUT....if you think you have a kid who wants to get into endurance sports...see if they want to SWIM.

Help them build the engine.....and then let them decide what to do with it.

There is wisdom here. ^^

One of my family members started as an Iron Kid.  She is now in her 30's and trying to qualify for Hawaii.  In my opinion, the only thing they are too young for is weight training.  I think kids need to go through puberty before hitting the weights.  Cardio type stuff like tri sports should be ok.  I'm no expert, but just my opinion.

Oh, and I got beat bya 12 year old a couple of weeks ago in a sprint tri (I'm 43).

A word of caution about swimming as well.  Though it doesn't pound the joints, it can ruin shoulders.  My team had four seniors blow out shoulders while trying for scholarships (I think the coach over-worked them).  Good coaching is very important for kids, no matter the sport.  If you can't find one, time to get to reading and cruising well respected web sites so you can protect your kids health as much as possible.

^^yep

We could discuss it all day when it comes to our kids.....but I bet at the end of the day we'd all agree on CAUTION.  They're kids, and growing.  That's why, as a sub 4:30 miler as a kid...a very young kid, I would urge an abundance of caution on running too much too young...it takes a big toll.  I was wrecked by the time I was 20....others may not have the same experience, but I have to use mine.

ETA: I was 20 over 30 years ago....there is now an abundance of knowledge and expertise on training kids that wasn't available for me....find it....it's there.

I echo these sentiments.  A competitive swim club is the way to go with the kids 12 and under.  Let your daughter run for fun in the backyard or around the block.  Take of the training wheels.  Encourage her to be active.  

I'd say if your child expresses an interest in participating in a triathlon, then by all means encourage it!  I won't seek it out for my kids until they tell me they want to do one.  

My oldest is 7 and he just started in the 7/8 group in a competitive swim club.  He goes 2-3 times per week for 1 hour each session.  He also has swim lessons at sports camp every day.  I don't want to push him to do the swim team 5 days per week even though I know that would be best for his development as a swimmer, because I know firsthand how burned out a kid can get from that.  I want him to love swimming.  Of course, the second he tells me he wants to go every day (or once he's moved up to the 9/10 or coach demands it), I will support that.     

I've been a competitive swimmer since age 5. I'm now 26.

Swimming 5x a week for the summer session isn't necessarily a recipe for burn out. I swam 5x a week every summer. I didn't swim in the winter until high school - and then, I swam summer and winter. I went on to swim in college. I've competed in masters a few times since then. I love every single season! Senior year of college I started to feel the twinges of being burnt out - I worked with my coach on keeping me sane and happy for my last season, and I was competing in Masters Nationals by the year after graduation.

Swimming also isn't guaranteed to ruin your shoulders. I struggled a bit in high school and college with some pain - never really found the cause, but found ways to manage it (stretches, chiropractor, ice). I wouldn't for a second trade one of those swim seasons for anything. My shoulders are function and fine, with the exception of an occasional ache after a long (3500+ yd) swim session.

The big thing my parents did was let me choose. Every year it was "Elaine, are you sure you want to swim this year?" and I answered yes. 

So, please don't be discouraged by what people are saying. Let your kid guide her athletics - just be certain that who is coaching her has some idea what they are doing. 

I love swimming. Some of my proudest moments happened on a pool deck

Right there (in bold) are the operative words.

But finding someone to coach your child who really knows what they're doing is not so easy, trust me.

I agree that swimming 5 x per week will not lead to burn out in all kids.  When I said that, I was speaking of my son, specifically.  He goes to sports camp from 9-4 every day, and then he swims 2-3 evenings per week.  I think if he swam every single night after going to camp for that long, where they play sports all day (including 1 hour of swim lessons), then there is a possibility he might burn and fade.  I don't want that for him, especially when he's expressed that he doesn't want to do swim team every evening.  

I have spoken to lots of swimmers who felt that they were under a lot of pressure as youngsters on the swim team (we are talking competitive swim clubs...not summer swim), so there is a fine line.  Pressure isn't necessarily a bad thing, but it can lead to burn out.   

Short distances a few times a week is great. Our girls 10, 8 & 5 love running but we limit the 5 year old to a mile.

I think the original post answered itself.  You have a 6-year old who loves doing something active and is having fun doing it.  Let her do a race or three during the year, make sure that they aren't overdoing it (a very common problem with any youth sport around here, at least), and make sure that they are having fun the whole time.  When it stops being fun, its time for something else. 

Semi-related anecdote:  Just a few weeks back, my 9-yr old competed in his first soap box derby.  There were probably 30 or so racers there, the organization sucked, and it was hot as all get out.  Many of the kids had parents that were definitely "helping"...like a mobile pit crew or something.  My son was convinced before the race that he was winning everything in sight, but once I saw some of the involvement of the parents in this thing I was pretty sure it wasn't in the cards.  So, I made sure and reminded him that smiles are, indeed, more aerodynamic and put all my efforts into making sure he was having fun.  He may want to do it again next year, and he may not.  I won't be bothered either way, and if he decides to next year I will at least know it was because he had fun doing it and not for any thoughts of quenching his desire for competition (which he has a LOT of).

Our family Ortho Doc would disagree with you....and he's a good one.  Osgood-Schlatter disease is one of the biggest knee problems in children.  One of our girls suffered with it for years.  Any sport that entails continuous running for kids carries a risk.  And while the condition itself may not cause any permanent damage....there is always a cost somewhere when it comes to injury.  My son had problems with the heel growth plate when he first started running.....we had him quit for a year. 

 I think you are spot on with your starting age though......12-13 is right for kids to start handling some "training".