CrossFit is a strength and conditioning program that uses a wide variety of functional exercises to create the workouts. A common exercise is the back extension that is used to strengthen the posterior chain muscles including the lower back, glutes and hamstrings. The prescribed way to perform back extensions within a CrossFit workout is to use a glute-ham extension machine. But, if you don't have the specific equipment, or can't physically perform the back extension as a result of an injury, there are several ways to scale the exercise to meet your fitness and strength level.
Good mornings use a movement that resembles a CrossFit back extension without using a glute-ham extension machine. You can perform good mornings with or without weight. To perform good mornings with weight, place a barbell on the top of your back, similar to performing a back squat. Stand with your feet shoulder-width apart and slowly bend at the waist until your torso is parallel to the ground. Feel a slight stretch in your hamstrings and slowly return to the starting position. Complete the total number of repetitions as prescribed in the CrossFit workout.
Deadlifts are one of the most commonly performed exercises in CrossFit workouts, and it can also be used as a substitute for back extensions. The deadlift and back extensions focus on the similar movement patterns and train similar muscle groups. According to Greg Glassman, founder of CrossFit, the deadlift creates head-to-toe strength. To perform the deadlift, grab a barbell or dumbbells with your feet hip-width apart. Lift the weight off the ground as you extend your hips and shoulders. Slowly return the weight to the ground and perform the recommended number of repetitions.
Supermans are a scaled substitute for back extensions if you don't have a glute-ham machine or need to avoid excessive back extension. The superman exercise also trains your entire core and is performed while lying face down with your arms and legs extended. Start the movement by exhaling and lifting your arms and legs as high as possible. The goal is to create a "U" with your body. Hold the movement at the top for two to five seconds, inhale and slowly return to the starting position. Do the recommended number of repetitions.
Stability ball back extensions are the closest substitution to CrossFit back extensions without actually using a glute-ham machine. The movements are nearly identical in both exercises. Start by placing your belly button on a stability ball and hooking your feet under a bench or bar. Straighten your legs so your weight shifts to the ball and bend at your waist to raise and lower your torso. Pause at the top as your squeeze your lower back and glutes. Continue for the prescribed number of repetitions in the CrossFit workout.