When was the last time you used a Bowflex or ate a PowerBar? That is the thing about consumer appetite for sports fads: insatiable one day, fleeting the next.

Investors last year rushed to quench their thirst for stay-at-home stocks with the connected-fitness company Peloton. Valued at around $8 billion as of its initial public offering pricing in 2019, Peloton cycled up to a $49 billion market value in January. Shares have since backpedaled rapidly, shedding nearly half their value as vaccines rolled out and gyms reopened.

This week Peloton saw its hardware lineup temporarily cut in half. The company said Wednesday it was voluntarily recalling its treadmill products after the U.S. Consumer Product and Safety Commission reported one death and many injuries resulting from Peloton’s Tread+, as well as injury risk from the potential detachment of the touch screen on its lower-priced Tread. In addition to treadmills, Peloton sells two models of a stationary bike.

Recalls aside, recent business has been thriving. Peloton on Thursday reported results for the March quarter that showed revenue surged 141% year on year. Connected-fitness subscriptions grew 135% in the quarter, which showed a 12-month retention rate of 92%.

Some analysts see rough terrain ahead. BMO analyst Simeon Siegel said Peloton’s market value has been driven by its marketing department rather than by its engineers or instructors. With the recalls, he worries that the stock will start trading on numbers rather than investor theses. He cited multiplying competition in connected fitness, adding that Peloton’s days in a one-company playing field are behind it.

Peloton brands its products as beautiful, powerful fixtures meant to be placed in idyllic spaces. The technology is for everyone, according to the company’s website, painting an image that, after a year holed up with family, children and pets, likely appeals to a lot of people. But consider the image of a child being sucked under a Peloton product, and reality sets in quickly. If Peloton was trading on the dream, it has now seen some of that fantasy tarnished.

For investors, the reality is that Peloton was a multiproduct company that, besides much smaller subscriptions, accessories and apparel businesses, only sells bikes for now. On top of managing the logistics of having to handle returns and moves for those who want them, the company will be offering full refunds as desired. The sum could be sizable: The Tread+, for example, runs for over $4,000, and the recall of that product applies to roughly 125,000 machines alone.

But the bigger risk now is the loss of potential new customers who are needed to support Peloton’s expected growth trajectory. Even as the world increasingly opens back up, analysts are forecasting that Peloton will increase revenue of its connected-fitness products by a quarterly average of nearly 40% year over year for the next three quarters, according to FactSet.

Bullish analysts are still sticking with the stock. In a recent note, Stifel’s Scott Devitt called the treadmill recalls a gift to patient investors. In the years ahead, he wrote, using the company’s stock ticker, “we will recall this moment in PTON history as the proverbial buying opportunity.”

Peloton has certainly developed a cult following of customers enamored with the technology. The company said Thursday that its users are averaging 26 monthly workouts per connected-fitness subscription. That is a Peloton workout nearly every day.

That hype won’t die overnight, but it could easily fade as more people embrace the great outdoors, become too busy to work out, or opt for competitor products, often at cheaper prices.

Those factors should continue to weigh on Peloton’s stock in the coming quarters. Already, data from Similarweb shows total traffic in April at onepeloton.com was down nearly 8% from March, with unique visitors declining more than 10% over the same period.

“Recommend the bike, worried about the shares,” BMO’s Mr. Siegel wrote.

Write to Laura Forman at laura.forman@wsj.com

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