Start on all fours (hands under shoulders, knees under hips) with a neutral spine and core engaged. Gently draw your belly button up toward your spine to activate your deep core muscles. Without arching your back, lift one arm forward and the opposite leg backward in a straight line, keeping hips level. Pause briefly, return to the starting position, then repeat on the other side. Focus on controlled movement and stability throughout the exercise.
Log your abdominal 4 points sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.