The line down your back is just the seperation between the muscles. Th, back workouts

Back Day Workout - Full Back Workout for Men

Best Back Exercises to Build Muscle and Prevent Injury

Diastasis Recti Exercises: How to Fix Diastasis Recti

How to Do Negative Pullups and Progress on Your Pullup Goals

17 Best Lat Exercises and Workouts to Build a Stronger Back

The 10 Best Dumbbell Lat Exercises to Build Your Back

Back and Triceps Workout Routine (8 Exercises) – StrengthLog

Middle back pain: Causes, treatment, and exercises

Build an Abdominal V From 'Sex Lines' Workouts

the line on your back aka the erector spinae! lots of questions surrou, Back Exercises

20 Best Oblique Exercises For Core Strength - Side Abs Workouts