The Alternate Preacher Curl Machine is a machine that reproduces the spider curl exercise for training the elbow flexor muscles, with the advantages of optimal tension over the entire ROM, ensured by CAM, and greater safety compared to the use of free weights such as dumbbells and barbells. The independent height adjustments of the seat and chest support allow correct positioning on the machine for users of all builds and size.

The working setup, with the shoulder flexed approximately 45°, places the two heads of the biceps brachii in partial shortening, while the underlying brachialis muscle maintains, due to its mono-articular nature, its full range of motion, acting as the main executor of the gesture.

The position with the torso resting on the padding significantly limits cheating during execution, such as the classic oscillations of the torso; while the inward inclined trajectory and the absence of constraints on the elbows avoid forcing and potential criticalities on these joints.

The peculiarity of the Alternate Preacher Curl Machine lies in the presence of the two independent weight packs on the two sides, which allow very high loads to be handled safely and, if necessary, even diversified between the right and left arms. The two CAMs not only provide, as mentioned above, optimal tension over the entire ROM that cannot be reproduced with free weights (dumbbells or barbells), but also guarantee an effective peak contraction.

Variations in execution: thanks to the two independent weight packs, the exercise can be performed either bilaterally or unilaterally, in alternating mode or with only one arm at a time, in this case using the fixed central support as a support. Lastly, the handles, which, in addition to being jointed and rotating for maximum freedom and adaptability of movement, are equipped with two adjustable angles, for supine or semi-supine grip.