A swimmer with a heart-wrenching history is about to race at the Olympics, so of course NBC will first air a slickly produced feature full of teary interviews and stirring music.

Not next year. Not enough time.

With the 2016 Summer Games taking place in Rio de Janeiro, which is just an hour ahead of the United States' Eastern time zone, the network can broadcast many high-profile events live in prime time. Make no mistake, NBC executives are thrilled about that prospect, but it means tweaking a formula that has worked so well in recent Olympics.

"People still react to live," NBC Sports Group Chairman Mark Lazarus said Wednesday, a year before the start of the Rio Games. "While we've been very successful in delayed coverage because the Olympics are so unique, live is still better."

There will be plenty of those trademark features, though some may need to appear at other times of day or online instead of on the centerpiece prime-time telecasts.

It will be "less that polished presentation the time delay affords you," said executive producer Jim Bell, "and more rock and roll sports event."

Swimming and track and field will air almost entirely live in prime time. Beach volleyball, with some matches starting at 11 p.m. Eastern time, will be a late-night staple. But one of the Summer Games' biggest sports will still get that polished presentation.

Gymnastics, which will take place in the late afternoon and early evening, will be shown on tape delay that night with a quick turnaround. Fans will be able to watch live on streaming video but not on TV.

"It's frankly a better show packaged," Lazarus said.

Live, the trouble is that multiple gymnasts compete on different apparatus at the same time, and there are long delays. The network had a hit televising figure skating live on cable network NBCSN with commentators Johnny Weir and Tara Lipinski during the 2014 Winter Games from Russia. But that sport's format fits much better on live TV with skaters competing one after another, Lazarus said.

NBC was able to show many events live in prime time during the 2010 Winter Olympics in Vancouver, which drew strong ratings. During the 2008 Summer Games, the finals in some high-profile sports were held in the morning in Beijing, which meant they were at night in the U.S. That proved particularly successful when Michael Phelps chased his record eight gold medals on live TV.

But then NBC unexpectedly attracted larger audiences for the London Olympics four years later even though all the competition in prime time was previously recorded. Viewers who already knew who won through social media or live streaming seemed even more motivated to watch the neatly packaged presentation each night. It helped that American athletes performed well.

The familiar rhythm of the London broadcasts — the welcome from Bob Costas, the feature setting up an easily digestible chunk of competition — will be replaced by a quicker, choppier pace in Rio.

Breaking news or delays in events can always wreak havoc with the schedule. Bell has yet to decide whether NBC will stick with entirely live coverage in that scenario when tape delay is an option.

"There is part of me that thinks we may tend to overestimate the value of it," he said. "But then there's part of me as a fan, with regard to an actual sports event, that thinks there's value in it."

Even if NBC can't air as many features in prime time, it won't abandon its formula of chronicling athletes' stories. The burden will fall to the announcers at the venue to squeeze those tales in before a race starts.

"Almost like a live profile," Bell said, "as opposed to a treated 2 1/2, 3-minute lovingly crafted feature with music."