Many of us are or will be parents with kids participating in sports. They'll participate for fun. For fitness. To develop character and build resiliency. Maybe even get college paid for.
Here are some things to consider:
Travel select teams. Year round baseball, basketball, volleyball and soccer. Going all in on a sport at age 9. These are increasingly common aspects of youth sports and it's a bad trend. Meanwhile, free play and informal pick up games are becoming less common. The dominant form of exercise for little kids should be free play. Sadly, kids self-organizing and playing sports or games together is less frequent in today's over structured and over scheduled youth. A valuable element of experimentation, emotional intelligence, courage and independence is being sacrificed under the false concern of safety.
The science on the subject and the opinion of every performance coach I value (a group as diverse as Louie Simmons, Dan John, the Soviet sports scientists, Pavel, Kelly Starrett, Eric Cressey, Mike Boyle etc) tells us that kids who play a variety of sports end up better at overall physical skill acquisition, are far less likely to burn out or experience mental health issues, have broader overall athletic qualities that actually make them better in their specialized sport down the road, make better teammates, are mentally tougher and experience significantly fewer overuse injuries (Tommy John surgery for young pitchers is epidemic).
All-or-nothing Select Elite coaches make their living playing on parental insecurities about scholarship procurement and your fear of short-changing little Billy's future, touting genetic elites as products of their system and convincing everyone that a 11 year old is "behind" because he or she is not committing to year round baseball or volleyball. These coaches are too often financially self-interested blowhards and are nowhere to be found when junior hates your guts at age 16 after getting rotator cuff surgery while joylessly pursuing a sport he no longer wants to play because you're chasing seven years of sunk costs. The fact is that the professional leagues and Olympics are full of athletes who didn't decide on their "primary" team sport well into high school, if not occasionally college. When a 17 year old "mysteriously" blows out her ACL "landing like she has a thousand times before" after eight years of year round volleyball-only training on hard surfaces, we shouldn't be all that puzzled.
Elite youth coaches dismiss lots of sports as GPP (or general physical preparedness) as "soft parenting" which doesn't value "the pursuit of excellence" confusing the need for specialization in adult athletes with the same need in kids.
Let's examine that...
The Soviet sports programs of the 70s and 80s were single-minded in their pursuit of excellence, athletic success their only propaganda polish on a garbage system. Few would describe the Soviet sports system as coddling or overly interested in the needs of the individual. Yet, in their elite sports academies, youths were exposed to a wide program of general physical preparedness for years before being funneled to any sport (even though early phenotype made it clear where some of these kids were headed). This GPP included running (distance, sprints), obstacle courses, balance games, rope climbs, old fashioned kid's games, dodgeball, cycling, jumping, gymnastics, multiple ball sports, judo, body weight strength training, Olympic lifting with PVC pipes and so forth. Little Alexander Karelin did the same stuff as a future gold medalist ice skater. Children were encouraged to experience what Russians call "muscle joy." After three years of this GPP training, these tweens were evaluated for specialization. The next round of specialization was still fairly general by our standards - it simply eliminated antagonistic training (no more five miles runs for Olympic lifters) but there was still plenty of calisthenics, gymnastics and strength training. In their teen years, there were clear off seasons and wide swathes of time dedicated to "de-loading" and non-sports specific supportive training. The Soviets did this because that's where the science and results led them.
The law of accommodation is a primary reason. When you train the same identical motor patterns or "solve" the same athletic problems over and over to the point of diminishing returns, you don't just level out. You get worse. YOU. GET. WORSE. This law is too often explained as fragile psychology, but the athlete's nervous breakdown or descent into drug abuse is just the side effect of having few tools to overcome new athletic problems in an environment of all-eggs-in-one-basket pressure. The abusive tennis parent with early burn out/drug addict kid is a cliche for a reason. Children engrained with multiple pathways for neural plasticity solve the athletic problems posed by the law of accommodation effortlessly. Those who lack that plasticity peak quickly and rarely recover.
But, but my kids need 10,000 hours!
Sadly, Gladwell's popularization of the "10,000 hour rule", what he termed "the magic number of greatness", is the most-cited support for early specialization. The notion that Gladwell's arbitrary rule (he's infatuated with the tipping point idea and he's settled on 10,000 hours for this one) is meaningfully generalizable from an anecdotal micro-study of Berlin violinists to athletes is absurd. Not to mention that the original researcher Gladwell bastardized responded to him in an article with the scathing title The Danger of Delegating Education to Journalists. Ouch.
Gladwell's argument rests on retrospective data that came from one study of a small number of elite violinists who were already pre-selected for talent selecting for a relatively narrow trait (violin playing) rather than the wide swathe of characteristics and skills needed for more complex interactive activity. The study is also a classic case in survivor bias. Thousands of violinists on track for an early >10,000 hours washed out as they realized that their time would be better spent on the guitar, playing Nintendo or started dressing like Marilyn Manson to protest their parents prodding. Indeed, the most elite musicians from this school averaged under 10,000 hours of practice. It also relied on estimations of time spent practicing in lieu of objective data. 10,000 was the average of their best guesses. A mean. Which doesn't represent a more important data point - the range. 10,000 hours is a marketing device bordering on active deception. The data don't even make a particularly interesting anecdote.
Here's an interesting anecdote. Steve Nash's fingers didn't touch a basketball until he was 12 years old. Good ball-handler? Hakeem Olajuwon waited until he was 15 to handle his first Spalding. Decent low post game? Was this ideal for optimal development of an athlete in their sport? No. We would have preferred both athletes handle a basketball earlier. Useful information though? You bet. Talented athletes with a broad sporting base can acquire skills quickly when the physical attributes are present. Broad athletic traits have immense carryover. Trey Hardee is the best decathlete on the planet. An event that calls for a broad array of physical attributes and learned skills. He first attempted a track event as a junior in high school and didn't attempt 8 of the 10 events in the decathlon until he was in college. 10,000 minutes, anyone?
Neural plasticity & proprioception.
Little kids benefit from all sports and movements but early exposure to gymnastics, martial arts & dance have inordinate lifetime benefits. Specifically in improved body control, proprioception, discipline, injury prevention, kinesthetic awareness, less fear of contact. Even if Junior clearly isn't cut out for gymnastics long-term, a couple of years basic tumbling and mastering his own body in space has benefits. I'll add swimming as well, mostly because it's a necessary skill for saving your own life and opens up lifelong recreational opportunities.
Strength training doesn't stunt growth, but it should be done correctly.
That old yarn about smashing growth plates is something you'll still hear from doctors who should know better. Gymnastics, push-ups, medicine ball work, body weight exercises, chores, pulling a sled or pushing a Prowler are all good things for kids. I'd wait until 13-15 to initiate barbell training as a wide base of sports and Soviet style GPP (General Physical Preparedness) must form the necessary platform for progression. You don't want to develop muscles ahead of joint and connective tissues ability to handle them. Some kids will blow up on weights before their bodies can catch up to the hypertrophy. Keep them on push-ups and pull ups until you're satisfied they have the necessary base. If the 7th grade football coach in your local Texas Football Suburb System disagrees, show him this article and ask him to explain how tendons and ligaments work.
Talent transfer and big fishes in small ponds.
Highly specialized sports with regional, cultural or financial barriers and limited participation levels are ripe opportunities for exploitation. A potentially useful springboard to get into an elite school, discover a late ability or get school paid for. A pretty good athlete in a popular sport dominated by great athletes has a limited athletic future, but may become dominant in a niche sport very quickly, particularly if the skill outputs aren't prohibitive. When Australia and England hosted the Olympic games, they approached several lower tier national athletes in wide participation sports with no hope of qualifying or placing and encouraged them to take up more esoteric ones. A year and half later, several of them were on the medal stand and each country recorded their largest medal counts in history. China does this so routinely it's in their state athletic protocols. Third tier gymnasts are forced to try Olympic lifting, ribbon dancing, platform diving and other sports. They understand that certain athletic traits are generalizable and that many sports have easily acquired skills.
At the risk of offending some readers - Crossfit, fencing, lacrosse, rugby, American Olympic lifting, field hockey, water polo, cross country, most paddling sports, numerous winter aerial and push sports, speed skating, diving, time trial cycling are all examples of sports ripe for interlopers. Even the less glamorous events in track & field are invaded all of the time by athletes from other events. A marginal sprinter at a DIII college trained high jump for eight months and won the world championships. 10,000 hours? Try 400. The form that he won with has been described as "offensive." A marginal Australian gymnast who had never seen snow competed in aerial skiing in the Winter Olympics after the Australian Sports Institute asked her to give it a go. Her training began with an instructional of how to put on skis. Gold medalist.
Want to get your kid into Princeton or see if he/she might thrive in a niche sport? Promote general athletic ability in lots of sports and then see if they like a sport with some participative or financial barriers to entry. If their body type fits and they get obsessed with improving, they'll catch up to and exceed the small pond lifers fairly quickly.
Don't have kids specialize early.
Let 'em play. Early organized athletics should optimally include some element of gymnastics, dance, martial arts and swimming. Encourage wide sports participation and develop generalizable athletic qualities (speed, endurance, mental toughness, strength, coordination, body control, fearlessness) over intense skill drill downs in one narrow sport (hello, law of accommodation). When/if your teenager does specialize later, create artificial offseasons if they won't play another sport. During that offseason, do something with athletic carryover with different movement patterns and/or surfaces to preserve joints, increase athletic traits and avoid the law of accommodation. Young football players get better at football by wrestling, powerlifting, running track and playing basketball - not operating in a perpetual season or off-season program.