Michael John DeSarno, a former high school wrestling coach, was sentenced to four years in prison yesterday after a Prince George's County jury found him guilty of sexual child abuse for forcing a student to perform a sex act during a coaching session.

It was the second time a jury in the county Circuit Court convicted DeSarno of the charge.

DeSarno, 47, of Beltsville, was charged with two counts of child abuse last December after two teen-agers told police that he had forced them in separate incidents to perform sex acts at DeSarno's home in 1983 and 1984. One of the youths was 16 years old at the time of his coaching sessions and the other was 15.

In separate trials in July, DeSarno was found guilty in the case of the 16-year-old and not guilty in the case of the 15-year-old. Circuit Judge G.R. Hovey Johnson later granted DeSarno's request for a new trial in the 16-year-old's case because one of the state's chief witnesses was the 15-year-old, who provided what the judge called "devastating" testimony.

That second youth did not testify in this trial, and neither did DeSarno, who had testified in the July trial.

However, Assistant State's Attorney Thomas McManus was able to get a statement DeSarno had given to county police introduced as evidence. The judge in the July trial did not allow the statement to be used as evidence because of a dispute between DeSarno's attorney and the prosecutor.

DeSarno denied in the statement that he had sexual contact with the 16-year-old youth. But the statement backed up most of the teen-ager's testimony and said DeSarno had hypnotized the youth and had him disrobe. DeSarno argued that was part of his efforts to make the youth a more aggressive wrestler.

The teen-ager, a former wrestler at Hammond High School in Howard County, testified early in the trial this week that he had sought help from DeSarno, a former coach at St. John's College High School in Northwest Washington and at Hammond, to improve his wrestling techniques. At one coaching session in DeSarno's apartment, the youth testified, DeSarno hypnotized him, told him to disrobe and perform a sex act.

Joseph DePaul, DeSarno's attorney, said during closing arguments on Wednesday that the youth attended about 50 more sessions with DeSarno after the incident and gave DeSarno Christmas and birthday gifts.

DePaul said that the teen-ager made up the story "to get even" with DeSarno for dropping him from the coach's wrestling program. "The boy had to get off the hook, he had to somehow explain to his family why the man everyone wanted to coach him suddenly dropped him," he said.

Judge Howard Chasanow, at DeSarno's request, delayed the start of DeSarno's sentence until Jan. 2. A condition of the delay is that DeSarno not be alone with anyone under the age of 18.