A multi-purpose fitness apparatus. The apparatus includes an extendable base, a height-adjustable weight-supporting frame, a resistance assembly providing adjustable resistance, an exercise mechanism, a detachable bench assembly, and a connecting mechanism connecting the exercise mechanism to the resistance assembly. The resistance assembly includes a supporting frame having a lower resistance support and an upper resistance support that is slidably coupled to the lower resistance support. A top spring-attachment member is mounted on the top end portion of the upper resistance support. A bottom spring-attachment member is moveably coupled to a vertical track member mounted on the lower resistance support. The movement of the bottom spring-attachment member is resisted by resistance from one or more resilient resistance members detachably affixed to the spring-attachment members. The amount of resistance is adjustable by selecting the number of the resistance members affixed.