Fred Bronson reports on chart feats of Terror Squad, Kimberley Locke, Los Lonely Boys, Usher and Alicia Keys.

'LEAN' MACHINE: Simply by remaining No. 1 on Billboard's Hot 100 for a third week, "Lean Back" (SRC/Universal) by Terror Squad becomes the longest-running non-Usher chart-topper of 2004.

Take away the 12-week reign of Usher's "Yeah!" and the eight-week rule of his "Burn," and "Lean Back" has more weeks in pole position than any other song that has advanced to No. 1 this calendar year.

The eight songs that have moved into the No. 1 spot in 2004, in order of how long they dominated the chart, are:

"Yeah!" Usher featuring Lil Jon and Ludacris (12 weeks)
"Burn," Usher (eight weeks)
"Lean Back," Terror Squad (three weeks)
"Confessions Part II," Usher (two weeks)
"Slow Motion," Juvenile featuring Soulja Slim (two weeks)
"The Way You Move," OutKast featuring Sleepy Brown (one week)
"Slow Jamz," Twista featuring Kanye West and Jamie Foxx (one week)
"I Believe," Fantasia (one week)

THE 'WONDER' WEEKS: There are two new entries in the top 10 of Billboard's Adult Contemporary chart, and both make chart news in different ways.

Kimberley Locke's "8th World Wonder" (Curb) entered this chart the week of April 17, and now, in its 21st chart week, moves 12-10. That's the longest climb to the top 10 since the chart dated March 29, 2003, when Norah Jones' "Don't Know Why" achieved top 10 status in its 31st chart week.

The longest AC climb to the top 10 was 49 weeks. That's how long it took Train's "Drops of Jupiter (Tell Me)" to reach the top 10 in 2002.

While Locke reaches the top 10 with her first single, her follow-up, "Wrong," debuts at No. 39 on Billboard's Mainstream Top 40 tally.

The other new entry in the AC top 10 this week is "Heaven" (Or/Epic) by Los Lonely Boys. "Heaven" ascends to the top 10 in its 11th chart week, a fairly rapid rise in a format that normally moves at a snail's pace. The upward movement of "Heaven" is the fastest climb into the top 10 for a debut AC artist since Kelly Clarkson's "A Moment Like This" took four weeks to reach No. 10 in October 2002.

'BOO' WHO: During the rock era, there have been some superstar pairings that just scream "No. 1" when you hear them -- like duets by Paul McCartney and Stevie Wonder or Barbra Streisand and Donna Summer.

This week's highest debut on Billboard's Hot R&B/Hip-Hop Singles & Tracks is yelling pretty loud. "My Boo" (LaFace) by Usher and Alicia Keys is the highest new entry, bowing at No. 41.

It's the second highest debut of 2004 on this chart. The only song to open in a higher position was "Burn," also by Usher. That song debuted at No. 35.