Challenge Your Core 🔥🔥🔥 ⁣ Here are 3 moves to challenge your core by focusing on your abs with the use of the J METHOD MiniBand. By using the MiniBand you are able to effectively train your entire core musculature. Done properly exercises should force your entire core to work together as a unified whole. They should recruit a much wider group of muscles, extending into your hips, thighs and glutes, as well as the erector muscles which reach to your upper back. This kind of integral approach t