At age 34, Justin Smith has taken thousands of hits. In his 13th NFL season, Smith's body has absorbed week after week of physical punishment. And, going into this season, there were questions about whether the 49ers' All-Pro defensive end would regain the form he had last season before he suffered a partially torn triceps and essentially had to play one-armed through the postseason.Yet 10 games into the 2013 season, it's obvious Smith is as good now as he's ever been. There are other areas to find fault with on the 6-4 Niners – who now are relegated to fighting for a wild-card playoff spot – but right defensive end in San Francisco's 3-4 defense isn't one of them.Smith has been terrific against the run, again drawing double teams and getting push against opposing offensive lines. He has 34 tackles and 2½ sacks and has helped the 49ers be one of the NFL's best defensive units. San Francisco ranks No. 7 in total defense, is No. 3 in points allowed (just 17.8 points per game) and is 12th against the run, giving up just 3.9 yards per carry.This past week in New Orleans, where the 49ers lost 23-20 on the final play of the game, Smith was a mauler. On one play in the...