Receiving Serial Data from Kinect to control two DC motor speeds

Ok.. 'Sometime after' meaning still within my loop. Would I make this an if statement or can I go ahead and write my constraint from the read function? See below.

void loop(){
  if(Serial.available())
  motorForward();
  motorBackward();
  
  if(Serial.read()){
     for(int=0; i<=n; i++)   //accel. Motor from 0 to 255
	{ analogWrite(pwmB, i);
 	   analogWrite(pwmA, i);
	  delay(10);}
}