The physical therapy world calls this bird dog. The Pilates world calls it spinal balance. Either way, it is a great core (abdominals AND back) strengthener and stabilizer! Move with awareness and intention.
Related workouts
Lateral Shoulder Raise with Resistance Band
The 10 Minute Upper Body Circuit
Squat Row
5 Min Standing Leg Lift Series
Plank with Shifting Forward & Back
Lat Pull Down with Resistance Band
Deadbug (Core)
TK Fit : Lower Body Jolt!
Stationary Lunges