The distance from the back point of home plate to the pitching rubber in slow pitch softball is 50 feet for men's, women's and co-ed league play. The fast pitch distance varies with the age of the players. Girls who are age 10 and under throw from 35 feet out. The distance increases to 40 feet for players between 11 and 16 and then to 43 feet for adults and teenage girls older than 16.
Boys fast pitch leagues set the rubber at 40 feet for boys up to age 12, and then it moves out to 46 feet for boys 13 and older.
Slow Pitch Delivery
Slow pitch softball pitchers have the option of releasing the pitch from the pitching slab or from an area defined as the pitching area, which is a six-foot area directly behind the slab. The slab and the pitching area are both two feet wide. When he releases the pitch, the pitcher must have one foot on the ground either on the slab or within that six-foot deep box.
The pitch must come out underhand, from below the pitcher's waist, and must have an arc to its trajectory. The USSSA rule book states that the ball must go up at least three feet from the point at which it leaves the pitcher's hand and can not go higher then 10 feet above the ground.
To be called a strike, the pitch must pass the batter between the level of the highest shoulder and the front knee.
Fast Pitch Delivery
The fast pitch pitcher must start her pitching delivery with her shoulders squared up to home plate, her hands separated with the ball in either the hand or the glove, her pivot foot on the pitching slab and her other foot either on or behind the slab. The pitcher is allowed just one step once she starts into her motion, and it must be towards home plate. The pivot foot must stay in contact with the slab until she releases the ball. The pitching motion must come from below the waist, in an underhanded style.
The strike zone in fast pitch softball is defined by USSSA as the area over the plate and between the armpits and the knees.