Commentary: NBC is counting on some momentum as the Games enter second week on TV

Momentum carries such clout in sports that it is sometimes anthropomorphized with a nickname: Big Mo.

Just as athletes and teams in the Summer Olympics seek the acquaintance of Big Mo in their medals quest, so does the televising network with high ratings. Interest in Rio, as reflected by the numbers for NBC programming, was slow to start but has picked up steam.

No secret why.

Because our lives are busier than ever — and the sports calendar more crowded — the contemporary Games tend to unexpectedly creep up on us. We are increasingly inclined to wake up one morning to the realization that the opening ceremony is a few days away but we’ve already planned a Friday night out or a summer weekend getaway.

The eyeball count on NBC’s main telecasts initially fell well below expectations, perhaps tamped further by alarm-sounding from the media that framed the Games as a disaster-in-waiting.

Then the peacock network got lucky.

Team USA starts kicking tail in the center-stage sports of swimming and women’s gymnastics, which almost monopolize prime-time airings in the first week.

Michael Phelps, less than two years removed from rehab and seemingly washed up, finds athletic resurrection in astonishing fashion. Katie Ledecky rules the pool like no woman in ages.

The Simones — Manuel, the first black woman to win a swimming gold, and Biles, the African American gymnast who staked a claim as the greatest of any ethnicity — effectively invite in a more diverse audience.

Nostalgia was injected into the picture by swimmer Lilly King, whose finger-wag at the image of Russian rival Yulia Efimova, tainted by positive drug tests, evoked the Cold War era. Nothing like stirred memories of animosity toward the former Soviet Union to raise some patriotic dander.

As a result, viewership has risen by ... well, who really knows? Ah, such a simpler time it was, before the sports bar was invented, when all Nielsen had to do was attach devices to living room Zenith or Panasonic consoles in designated households and compute who was watching which shows.

Comparing the ratings methodology for Rio to past Olympics is apples to ... a very large fruit. As laptops and smartphones become bodily appendages, watching televised sports on an actual TV screen is so “aughts,” right? Measuring audience size is such an inexact science.

But darned if NBC isn’t trying. It has redefined ratings as consumption of the Games across over-the-air and cable networks, plus digital via live streaming. The sum is described in corporate-speak: total audience delivery. Of course, the network has concluded that viewing is up, by at least 6% nightly through Thursday, over the impressive figures from London.

Less precise but just as persuasive is the volume and breadth of buzz about the Games. Eavesdrop on conversations, and you will hear references to Phelps and Ledecky and the Simones and the finger-wagger — along with complaints about the frequency of commercials that interrupts an event’s ... momentum.

The surge could be sustained as gymnastics winds down and swimming gives way to the second week’s prime-time staple of track and field, but it won’t come easy. As riveting as Biles has been, we might be ready to move on, while prospects for a continued U.S. medals harvest in the truest of Olympic sports are dimmer.

Even if the national anthem no longer plays in some arenas on a seemingly endless loop, interest in the Games could hold steady as the charismatic Jamaican sprinter Usain Bolt, whose popularity transcends nations’ borders, guns for gold in three events.

Elsewhere, the countdown to the closing ceremony is driven by buildups to gold-medal games and matches in team sports, many of which are the province of Team USA. NBC can do without more early ousters such as Friday’s buzz-killing calamity with the women’s soccer squad.

The network needs Big Mo to stay by its side.