I love it when sports show growth. Any sport, any level, for any age, for any gender. It's just good, and it makes for a nice balance to all the ink given to childhood obesity and so forth.

Recently, two reports came across my desk. They describe two different sports that are on the upswing, and they're growing for very different reasons.

The first is a sport we're going to be seeing a lot of in the next few weeks, given the upcoming U.S. Open: tennis.

According to the State of the Industry report released by the Tennis Industry Association, the tennis economy is growing. It's already a $5.57 billion business, according to TIA.

The report (available for purchase, here) states there has been a 10 percent growth in the number of "frequent" tennis players (those who play at least 21 times a year), up to 5.31 million. Frequent players account for more than 70 percent of all expenditures in tennis, including buying equipment, paying for lessons and court time, and playing league tennis.

The best news? These core players are the people who come to your club and spend money. And we're not talking about Federer or the Williams sisters here. We're talking about everyday joes - people like you and me (who in my opinion, are the people sports industries should be paying attention to, since we actually drive the industry by doing most of the buying of clothing and equipment.)

Tennis is also showing gains in other areas including a 4 percent increase in overall participation, growth in sales of youth tennis equipment and increased tennis TV coverage.

The reason for all this growth can be traced back to a proactive approach across the entire industry. New growth initiatives meant to recruit children to tennis started with new rules for the sport pertaining to that age group.

Another growth initiative was Tennis On Campus, a team-based intramural program designed to keep kids in the game, even if they weren't a part of their college's varsity team. It helps them stay active through their college years and emerge into the working world wanting to continue playing by joining clubs and leagues.

All that leads to more people playing (and from a club standpoint, more people joining.) It's good to see growth, particularly when the industry is taking the lead rather than simply decrying a lack of participation.

Another sport that is growing is perhaps the oldest on Earth: running. According to a report released recently by Running USA, running seems to be entering its "second boom" in the U.S. The report notes:

Millions of Americans, from young to old, serious to novice, thrill-seeker to the color-inspired, spent billions of dollars for shoes, apparel, gear and event expenses while participating in running events at record levels.

According to the National Sporting Goods Association (NSGA), running/jogging continues to show strong and consistent growth annually as running total participation was up nearly 4% overall in the last year. The Sports & Fitness Industry Association (SFIA) survey indicates similar growth for the general running population as well as explosive growth in the category of adventure racing.

Running has grown steadily in popularity since 1990. And while admittedly, race directors are thinking outside the box in order to design fun and creative races to attract runners (really, having to outdistance zombies is such a cool idea), industry experts are saying that's not the only force at work here. Running is popular because it is a good workout that costs very little. The roads are free and no professional instruction is needed. Essentially, it requires only appropriate shoes and clothing. Participation in races is voluntary and generally represents less of a financial commitment than joining a health club. It's a winner for those who want to stay fit in a down economy.

The full report can be purchased from Running USA, but a synopsis available here also shows significant growth in women's and half marathon participation, as well as in non-traditional races (color runs and obstacle races, for example). The appeal of the 'bucket list' is also seen as a popular incentive, since first-time marathon participation remains strong.

Tennis and running are flourishing. Whether fueled by intensive professional growth initiatives or by a simple wish to spend less on fitness, it's growth and it's good. Let's see some other sports take their own cues and grow too.