Set the bar on a Smith machine at shoulder height and stand under it with it resting across your upper back. Step one leg diagonally behind and across the other leg (like a curtsey), lowering your hips until your front thigh is about parallel to the floor. Push through your front heel to return to standing. Repeat on one side before switching to work both legs, focusing on controlled movement and hip stability throughout.
Log your smith rear lunge sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.