45-Degree Back Extension – Hyperextension

The 45-degree back extension (incline back hyperextension) is a great lower back exercise in which you flex your body around your hip joints while keeping your spine neutral. Hamstring flexibility will determine the degree of flexion you can achieve. Just about every gym has a back extension bench (incline version) usually set at 45 degrees.

Incline Back Extension Exercise Instructions

STARTING POSITION (SETUP): Adjust the apparatus so that the top of the leg pad is just below your waist. Secure your feet in front of the ankle pads and place your thighs against the thigh pads, with your legs straight. Begin with your upper body aligned with your lower body and your arms crossed over your chest. In other words, your torso should form a straight line from head to toe, with your spine in a neutral position.

MOVEMENT (ACTION): Bend at the waist to lower your torso toward the floor. When your waist reaches roughly a 90-degree angle, contract your lower-back muscles to lift your torso back to the start position.

The 45-Degree Back Extension (Hyperextension) Tips & Tricks

• Keep your feet flat on the support.
• Maintain straight legs.
• Position your thighs on the pads of the chair so that your hips are free to flex.
• As an alternative, you can clasp your hands behind your head (instead of crossing your arms over your chest) to keep your upper body steady.
• Keep your movement slow and controlled.
• Do not extend back beyond the start position as you may injure your back.
• Look for your body to move forwards from the lower gluteal, not your back or spine.
• Avoid improper positioning  (your hip bones should be in direct contact with the pads).
• Don’t jerk your torso as you raise it back up to the starting position.

Muscles Engaged in the 45-Degree Back Extension

The back extension (formerly known as hyperextension) belongs in the isolating exercise category because only the hip joint is mobilized. Nevertheless, it does recruit large muscle groups such as the lumbar muscles, the glutes, and the hamstrings. Unlike the deadlift, which tends to compress the intervertebral discs, the back extension is safer for the lower back but less effective in terms of overall strengthening. However, if your lower back is fragile, we recommend this isolating exercise over the deadlift.

• MAIN MUSCLES: spinal erectors, longissimus dorsi, quadratus lumborum, iliocostalis, latissimus dorsi, spinalis, multifidi, gluteus maximus, hamstrings (semimembranosus, semitendinosus and long head of the biceps femoris);
• SECONDARY MUSCLES: serratus posterior inferior, gluteus medius (rear fibers), adductor magnus, piriformis;
• ANTAGONISTS: rectus abdominis, iliopsoas, obliques, front quadriceps, tensor fasciae latae, pectineus, sartorius;

Back Extension Variations

• Upright bench back extension. The leg pad and foot platforms on most back extension apparatuses are slanted at a 45-degree angle. You can perform the back extension on apparatuses on which the leg pad is parallel with the floor and in line with the ankle pads. Exercises on both versions are effective. By lying on a flat bench, you will make the exercise even harder.

• Weighted 45-degree back extension. The technique is the same as the basic exercise. For added resistance, hold a weight plate against your chest while you perform the movement.

Alternative Exercises (Substitutes)

If you don’t like this exercise, you can easily replace it with any other lower back exercise (erector spinae exercise) from the list below:

• Good Morning Lift
• Traditional Deadlift
• Romanian Deadlift
• Roman Chair Back Extension (90-degree back extension)
• Machine Lumbar Extension

Closing Thoughts About The 45-Degree Back Extension

The 45-degree back extension (incline back extension) is an isolation exercise for the back muscles (entire lower back and the muscles along the spine), buttocks, and hamstrings. Like dips and chin-ups, this lower back exercise (erector spinae exercise) uses only your body weight for resistance.

The two main kinds of lumbar benches are the upright bench and the 45-degree incline bench (described in this post). Your choice will depend on the availability of each type in the gym and your personal preference. Performing the movement at an incline with the hips supported high and the ankles closer to the floor makes the exercise easier.

However, the 45-degree incline bench has one disadvantage. It does not effectively stretch the erector spinae or the spine at the bottom of the movement. Because of the particular type of the resistance provided by 45-degree incline benches, these benches are better for hamstring work than lumbar work.

Finally, the spinal erectors are directly trained using back extension exercises and indirectly with rowing and deadlift movements.