Thursday’s major events

The senior competition gets underway Thursday with the pairs and women’s short programs at Xcel Energy Center. Here’s a primer on some of the skaters and stories to watch:

WOMEN’S SHORT PROGRAM

When: 7:30 p.m.

Defending champion: Ashley Wagner

Other top contenders: 2014 champion Gracie Gold, who has been first or second at the past three national championships; 2014 silver medalist Polina Edmunds; Courtney Hicks, second and sixth in two Grand Prix events this season; Karen Chen, bronze medalist at the 2015 nationals and a two-time top-five finisher on the Grand Prix circuit.

The big rivalry: Wagner and Gold are evenly matched skaters who between them have won the past four U.S. titles. Wagner, the champ in 2012, 2013 and 2015, said both have improved by pushing each other technically and artistically. Wagner finished fourth at the Grand Prix Final this season, rallying from a poor short program with a personal-best score in the free skate; Gold finished fifth and was sorely disappointed by her uneven performance. Gold was runner-up to Wagner at the 2013 and 2015 U.S. championships.

Gracie under pressure: Like Wagner, Gold mixes moments of brilliance with inexplicable lapses. She finished fifth of six skaters at the Grand Prix Final after a flurry of mistakes, despite excellent preparation. “I just choked,’’ she said. “I got in my own head and freaked myself out.’’ Gold said she is determined to avoid that fate at nationals; she has been training extremely well and plans to attack her programs with everything she has. “I’m tired of going down without a fight,’’ Gold said. “I want to at least go down guns blazing.’’

PAIRS SHORT PROGRAM

When: 2:45 p.m.

Defending champions: Alexa Scimeca and Chris Knierim

Other top contenders: 2015 bronze medalists Tarah Kayne and Danny O’Shea; Marissa Castelli and Mervin Tran.

Starting fresh: Scimeca and Knierim, who have skated together since 2012, won silver and bronze medals at their two Grand Prix events last fall. But they were seventh in the Grand Prix Final after falling on their quadruple twist, one of their signature elements. They worked to solidify that as they trained toward nationals; they also retooled their free skate, adding a tempo change by inserting some slower music. The pair is engaged, with their wedding planned for this summer.

On the rise: Kayne and O’Shea, partners since 2012, won the bronze medal at last year’s nationals despite an injury to Kayne that cut short their training and competition schedule. They followed up with top-six finishes at four international events last fall and set a personal-best score for their free skate at the Rostelecom Cup. Castelli won national championships in 2013 and 2014 with former partner Simon Shnapir before teaming with Tran in 2014. The pair finished fourth and sixth in their Grand Prix debuts this year.

RACHEL BLOUNT