4 YO agressive behavior

My 4 YO son has recently become physically aggressive towards me.  It has been going on for about 1 month.  Prior to this, when he was around 18-24 months he did hit and bite and have fits lasting 30 minutes - 1 hr in which he would be completely uncontrollable but has since outgrown these so I took them as part of a normal developmental stage.  Now, at 4.5 years he has started getting physically violent towards me about twice a week.  It is always initiated by me trying to discipline him for something he shouldn't be doing, or to get him to do something he doesn't want (e.g. we need to go inside now because you ran out in the street when I told you not to). He is typically well behaved, he is not violent towards other children or adults.  When he gets violent with me I stay calm and put him in his bedroom so he can't hurt me or my other two children and eventually he calms down.  Once he's calm he says he's sorry and is tearful about what he did, but it takes sometimes 30 minutes or more for him to snap out of it.  I'm concerned that this behavior is a sign of a bigger problem that will worsen as he get older.  Do I need to seek further help?

[Kevin Kennedy, Ph.D.]

At this point not specialized help is warranted. Continue to set a very firm limit (i.e., absoultely no aggressive behavior) and discipline him with time out immediately on the occurrence of any aggressive behavior.