nly an hour after leaving Rock Spot Climbing, I could barely flex my fingers enough to type this. Despite the early signs of spring, I had headed indoors to learn what traditionally is an outdoor sport: rock climbing. And while I'd climbed with my brother twice before—once indoors and once actually out in nature—it had been long enough ago that I definitely needed a refresher.

Since it's often easier to work out when you have someone to motivate you and hold you accountable (or in this case, hold the ropes so you don't plummet to the ground), I called on one of my fit friends to join me. Greenbean (like any good teammate, I use nicknames) is a twenty-something female who generally prefers to do her exercising outdoors. A hiker, cyclist, and runner, she practices a lot of yoga in the winter months. Her current yoga goal is to perform something called Scorpion Pose, which I don't understand and makes me fear for her life.

Tucked inside an industrial park close to the Readville commuter rail station on the Dedham-Boston line, Rock Spot Climbing is easy to miss, and, at first, we did. But the gym's location in a cluster of warehouse-like buildings made sense once we walked inside. Beyond a small retail area and a couple of vending machines sits 9,000 square feet of textured rock wall. With numerous brightly marked climbing routes spread across areas for bouldering and top-roping, as well as a few cardio machines, the gym offers plenty of ways to break a sweat. Thirty-six dollars apiece got us day passes, harnesses, rock shoes, and a full lesson for beginners taught by Sam, an able young, instructor.

After getting us set up with gear, Sam taught us how to tie in both as climbers and belayers on one of the easier top-roping routes. Being somewhat spatially challenged, I asked him to show me how to replicate the double-figure-eight knot several times before I could do it myself. Fortunately, he didn't seem to mind. Either that or he was still disoriented by the inappropriate jokes Greenbean and I had fired off while tightening our harnesses (it was almost too easy to make him blush).

Following a five-point inspection of each others' equipment, Greenbean and I got down to business. She went first, climbing up the 24-foot top-roping wall. I stayed on the ground, hooked into an anchor to belay for her as she ascended. Back on solid ground she gave me an unexpected hug for not allowing her to die. What are friends for?

As I made my own first few stretches up the wall, I quickly understood her gratitude. Though I knew the harness, rope, Greenbean, and Sam were protecting me, a feeling of unease grew with each successive hand and foothold. Before I'd even looked down, I knew I was at a height I'd normally see through a window or over a railing. These practice runs over, Sam had us try several announced and unannounced falls to test each other. Listening to the nearby thuds as the men bouldering beside us dropped to the mats made the experience that much more interesting.

After several more ascents, we were ready to climb on our own, and Sam left us to trust what we’d learned (and that the gym’s liability policy was in order). While he moved on to belay for a children's birthday party, we attempted some tougher routes so as not to get shown up by the kids.

A route's difficulty is marked on the wall, ranging from about 5.4 (Greenbean and I scrambled up these with relative ease) to about 5.11 (we looked up, looked at each other, and kept moving). After nearly two hours of climbing, our arms gave out before our legs, even with Sam’s instruction to “push yourself up the wall rather than pull yourself up it.” To reassure myself, I considered that Greenbean's arms were tired too, despite being jacked from yoga (never mind the fact that I normally beat her in arm wrestling).

Rock Spot Climbing is open daily from 10 a.m. to midnight and offers specials including outdoor climbing trips, ladies' nights, family time, and competitions. Members can also take advantage of the sister Rhode Island Rock Gym in Lincoln, Rhode Island. On the North Shore? Try MetroRock in Everett and Newburyport. Or here's a great place to climb outdoors—for free!