Coach Mike Singletary continues to put his stamp on this team with his no-nonsense approach. There is no denying who is running the show. Singletary demands a lot out of his players, no question. Today was the fourth consecutive day of practice. The club also has organized team activities schedules for Tuesday, Wednesday and Thursday.

Toward the end of the scheduled workout on this day, things were getting mighty ragged. The 49ers' first teams (offense and defense) were taking part in a two-minute drill in which the offense had to move 62 yards in 98 seconds for a touchdown.

On a second-down play, defensive end Parys Haralson (the defense was in its nickel package) took off before the snap and right tackle Adam Snyder immediately came out of his stance. There was an animated debate about which player should get penalized.

Singletary loudly declared how things happen in the NFL. He said if it's a home game for the offense, the call is offside; if it's a road game, he said, it's a false start. He then announced it was a home game, causing the offense to erupt in cheers while the defense grumbled.

On the next play, there was more sloppiness. Some players moved at the snap, others did not. Hill and receiver Josh Morgan were not on the same page, leading to an Allen Rossum interception at the sideline. Singletary decided the team would redo that sequence. On the next play, Takeo Spikes jumped a route and nearly picked off a Hill pass intended for tight end Vernon Davis, who never turned around.

Singletary brought the team together for a chat.

Two plays later, on a fourth-down play, safety Dashon Goldson broke up Hill's pass deep down the middle to Davis when all the team needed was a 2-yard gain to keep the chains moving.

Unhappy with what he saw - apparently he thought more than a few players were going through the motions - Singletary again brought the team together. This time, he was clearly angered.

At a time when the 90-minute practice should have been nearing its conclusion, Singletary ordered the team to run six sideline-to-sidelines. (That's 53 1/3 yards each time, for those keeping score at home.) It might not sound like much, but for players who have already gone through nearly an full practice, it was pretty difficult.

Interestingly, rookie receiver Michael Crabtree, who is rehabbing his right foot after March surgery to repair a stress fracture, took part in this conditioning/discipline exercise. Crabtree had earlier done some running on the artificial turf field adjacent to the 49ers' main grass practice fields.

After the players ran, the team returned to practice. Instead of concluding on schedule at around 11:30, the 49ers' practice lasted until 11:57 a.m.

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GM Scot McCloughan said Alex Smith's performance over the weekend at minicamp was as good as he has seen from the No. 1 overall pick of the 2005 draft. That reinforces the opinion I developed after watching Smith throw the ball over those three days.

McCloughan noted Smith's accuracy, velocity and tightness on his spiral. He also said it's encouraging that Smith has not experienced any problems with his shoulder.

Smith said he can definitely feel the difference from a year ago. But he said he can also see the difference on film.

"Just for me, thinking back to where I was last year, going through surgery and rehab, and not being where I knew I should be, was frustrating," Smith said. "It was frustrating to see in the film room that it's your shoulder that's not allowing you to do something.

"And now to get back to where I feel like I can do everything on the field right now, I can really focus on getting into the offense and being a better quarterback and not have it sit in the back of my head that my shoulder is not feeling very good."

I spoke with Smith at length today on the topic of leadership. I will share his thoughts on the subject a little later.

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Corrnerback Nate Clements, who sat out the minicamp with a "mild case of pneumonia," has not been re-evaluated. He did not take part in today's workout.

Veteran receiver Isaac Bruce and guard Chilo Rachal also did not practice. Bruce generally does not take part in voluntary team gatherings. Rachal was excused from the mandatory minicamp Friday afternoon for a personal matter.

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