The practice of kata with the makiwara as a target/opponent develops mai (awareness of distance and surroundings especially as applied to an opponent). This is a most important aspect of physical and mental karate training. Kata/makiwara practice develops this principal while allowing one to actually strike an object from different postures with multiple offensive and defensive techniques as found in the kata. The makiwara remains stationary while the practitioner positions, sets up the distance and stance, and attacks according to the dictates of the kata. The attacks/blocks are delivered to the rear, sides or straight ahead then one re-positions oneself after each move. This takes concentration at first but becomes rote or second nature after time. The ultimate objective is to eventually hit with maximum force into the makiwara (or heavy bag,etc.) skillfully employing balance (rooting down), co-ordination, focus and all aspects of every movement of the kata.
Consult your Sensei for more explanation, we have practiced this, at times,
in class over the past years. However, once understood, it is best done on
your own. Arigato, Kyoshi Robert Scaglione.