Which of the following is a correct list of possible matwork variations that could be taught on the reformer with arms in straps?

The choice of possible matwork variations that can be taught on the reformer with arms in straps is accurately represented by the selection that includes Single leg stretch, Double leg stretch, Lower and lift, Scissors, Helicopters, Criss-Cross, and Frogs. This selection showcases exercises that not only utilize the reformer's unique setup but also keep the arms active in straps, allowing for a full range of motion and engagement of core stability.

Specifically, these exercises are designed to promote flexibility, core strength, and coordination. For example, Single leg stretch focuses on core engagement with leg movement, while Double leg stretch continues this theme but allows for dual leg coordination. Lower and lift, Scissors, and Helicopters all emphasize control and stability, utilizing the resistance of the straps to enhance muscular engagement throughout the movements. Lastly, Criss-Cross adds a rotational component, which is beneficial for oblique strength, and Frogs incorporate the lower body in a way that emphasizes hip mobility.

The other choices present exercises that either do not comprehensively incorporate the use of arms in straps or do not include a varied enough range of movements typically performed on the reformer. Therefore, the selected answer is not only appropriate but also represents the integrated use of the