Keeping active in the 21st century costs money.

Even in Honolulu, where free outdoor alternatives are easy to find, many residents maintain a gym membership. For working adults with families, simply finding the time to go out to exercise can be a challenge.

The solution for some is the build-it-yourself route, where upfront costs are higher but the end result provides a convenient workout solution for the whole family.

Here are three examples of local families who enhanced the fitness possibilities offered by their garage or backyard.

Build a batting cage

Despite thousands of youth baseball and softball players on Oahu, there remains a dearth of commercial batting cages on the island. For generations, young athletes have turned to structures erected in the yards of private residences to work on their swing.

Aiea Heights resident Ray Sakurai built his backyard batting cage with a buddy as a weekend project some 25 years ago, recalled his son, Jonny. He used metal poles to create a framework approximately 15 feet high and 60 feet long, then attached nylon netting to complete the cage. His home soon became a regular destination for the younger Sakurai’s youth league and high school teammates looking for a place to practice.

“When we were growing up, anyone our age or on our teams would come up and he’d open it up to others who needed help,” said Jonny Sakurai, a 30-year-old Aiea High School graduate who was a member of three Oahu Interscholastic League championship teams and played college baseball at Chicago State University and California State University Northridge. He is now an assistant coach at Mililani High School.

“I live right down the street, and almost every weekend I’m up there working with some kids. My brother also uses it a lot now because he’s playing in college. My nephew, who just started ninth grade at Moanalua High School, always comes up.”

Sakurai said his dad, an assistant junior varsity baseball coach at Mid-Pacific Institute, knew at the outset he wasn’t building the batting cage for just his family.

“That’s one of the biggest things I appreciate about my dad, him giving back to the next generation. People took care of us, so we have to go back and take care of others,” he said.

Building a home batting cage can cost anywhere from $500 using materials from home improvement stores, to $1,000 or more to purchase a kit. Expect to spend at least $600 to $800 on bats, baseballs, protective helmets and a protective screen for the pitcher.

Build a climbing wall

Kids have an innate desire to explore, which often includes the urge to climb stuff they’re not supposed to.

“To me it’s already instilled in you,” said Justin Ridgely, owner of Volcanic Rock Gym in Kailua and Volcanic Climbing & Fitness on Punahou Street. “You grow up, and as a kid you climb a tree. We’re naturally climbers.”

He said he sees kids of all ages at his Kapaa Quarry facility. But you’ve got to pay to play, which can make it costly as a family outing, and it takes a ride over to the Windward side to access the fun. Ridgely, 33, has a 7-year-old son of his own, so he also understands that child-care responsibilities sometime trump working out. His solution was to install a pair of wooden climbing panels in the garage of his Salt Lake home.

The setup allows him to spend time with son Ronin and stay sharp, even when he can’t make it to the gym.

“The more experience you get, the more confident you feel,” said Ridgely. “Climbing is a lot more mental than some might think.”

One of the panels, called a campus board, is attached at an overhanging angle so that climbers use only their hands and arms to move up the rungs. The other is a hangboard, or fingerboard, which is mounted horizontally on a wall and used much like a chin-up bar — one that requires you to rely on only your fingertips while at a dead hang.

Using the boards improves grip strength and finger dexterity and builds muscles in the neck, shoulders, arms and back.

Larger boards can cover an entire wall. Expect to pay about $200 for a setup similar to the one in Ridgely’s garage, which includes a mix of grips he made himself or purchased from climbing equipment manufacturers.

Falls are inevitable with this type of activity, so Ridgely made sure to provide strategically placed foam pads for cushioning.

“Pads run about $200 each,” he said. “You can get a pad for $99 but go for the best you can afford. Pay the price. It’s better than getting a broken ankle.”

Ridgely said anyone interested in building their own climbing wall at home can contact him for free advice at Volcanic Rock Gym, 201 Kapaa Quarry Road, from 3 to 10 p.m. weekdays and noon to 8 p.m. weekends, or call 397-0095.

Build your own gym

Dr. Donald Gaucher has three sons ages 9, 10 and 11, who, like him, practice Brazilian jiujitsu. Despite paying monthly training fees for the four of them, the 42-year-old anesthesiologist transformed his Mariners Ridge home’s garage into a mixed martial arts gym last summer.

“They go and they train Brazilian jiujitsu,” said Gaucher, who also has a background in taekwondo, Japanese jiujitsu, krav maga and amateur MMA fighting. “But that doesn’t involve kicking, punching, knife defense, gun defense and all those other things.”

Gaucher said he spent approximately $3,000 to transform his garage into a space that allows him to hold weekly classes for his kids and their friends, while also providing enough room for surf racks, shelving for tools and a beer fridge along with all the protective gear and homemade fighting implements used during the workouts.

Gaucher said the biggest expense was 10 protective mats that cost about $200 each and are held in place by a frame bolted into the garage floor.

“Too many dads don’t have things in common with their kids,” said Gaucher. “A lot of times I’ll do stuff at the adult jiujitsu class and then I’ll come home and we’ll all try it.“