The solution to the 49ers’ offensive issues is simple: Run. The. Ball.

I mean, right?

From 2011 to 2013, the 49ers had the most rushing attempts in the NFL, made power-running their offensive identity and three straight trips to the NFC Championship Game followed.

This season, they are on pace for their fewest rushing attempts (462) of the Jim Harbaugh era, rank 22nd in total yards per game and already have their most regular-season losses since 2010.

So, again: Run. The. Ball.

Right?

Um, wrong.

The problem with the just-run-it theory is the 49ers aren’t running very well.

They are averaging 3.97 yards a carry, which would be their lowest figure since they averaged 3.94 yards per attempt in 2005. That 2005 offense ranked last in the NFL in total offense (224.2 yards per game) and 30th in points.

What’s happened to their ground game?

It’s possible, of course, age is chasing down Frank Gore, 31, who is averaging 3.9 per attempts after he had a career-worst figure (4.1) last year. Still, fresh-legged rookie Carlos Hyde, who has earned mostly positive reviews, is averaging 3.7 yards a carry.

That leads to the offensive line, which has lacked the continuity it enjoyed in recent seasons. From 2012-13, 49ers’ offensive linemen combined to miss just four starts (all by Mike Iupati in 2013). In 2014, left tackle Joe Staley is the only lineman to start all 12 games and the other four starters have combined to miss 14 starts.

In last week’s 19-3 loss to Seattle, rookie center Marcus Martin made his fifth straight start in place of Daniel Kilore, who is on season-ending injured reserve. In addition, right tackle Jonathan Martin made his seventh start in place of Anthony Davis, who has been sidelined by three different injuries this season.

Another possible factor: right guard Alex Boone missed the entire offseason in a contract holdout. Boone’s run-blocking grade of +1.4, according to Pro Football Focus, is well below his grade in 2012 (+25.4) and 2013 (+5.3).

Here are the 49ers’ rushing totals since 2005:

2014: 347 attempts, 1,378 yards, 6 TD, 3.97 yards per rush

2013: 505-2,201-18-4.4

2012: 492-2,491-17-5.1

2011: 498-2,044-14-4.1

2010: 401-1,657-10-4.1

2009: 371-1,600-12-4.3

2008: 397-1,599-10-4.0 (4.02)

2007: 357-1,477-8-4.1

2006: 439-2,172-12-4.9

2005: 428-1,689-9-3.9 (3.94)

Twitter: @Eric_Branch