The hack squat is a machine-based, compound exercise that adds strength and size to the lower body. While it’s often used as an accessory to the barbell back squat, the hack squat also serves as an alternative because it places greater demand on the quads, is safer to train to failure, and requires less mobility.
Although there are some hack squat variations, this article will cover the muscles the machine hack squat works and some of its primary benefits.
Hack Squat Muscles Worked
- Quadriceps
- Hamstrings
- Glutes
- Calves
- Abdominals
Quadriceps
The quadriceps consist of four individual muscles, including the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. This muscle group is located on the front of the upper thigh. The quads collectively work together to flex the hips and extend the knee.
Since the hack squat machine is more upright, it targets the quads more than the glutes or hamstrings. Position the feet lower on the platform and closer together to further emphasize the quads while performing a hack squat. The quads play an important role in jumping, running, and walking.
Hamstrings
The hamstrings consist of four muscles: the semimembranosus, semitendinosus, and biceps femoris long and short head. This muscle group is located on the back of the upper thigh. Its main actions are knee flexion and hip extension. The hamstrings are considered an antagonist muscle group to the quads because they perform opposite actions.
Since the hack squat is a compound movement, it engages the hamstrings on the concentric portion of the lift. In other words, the transition from squat to standing recruits the hamstrings to assist with the full hip extension. Stronger hamstrings may reduce the risk of anterior cruciate ligament tears because they help prevent the tibia from traveling too far.
Glutes
The glutes consist of three muscles: the gluteus maximus, gluteus medius, and gluteus minimus. They are all located on the back of the pelvic bone most commonly called the butt. The gluteus maximus is the largest and most superficial of the three glute muscles.
They are responsible for hip extension, whereas the other two perform hip abduction. During a hack squat, the glutes help complete the lockout portion of the lift by performing hip extension. This muscle group is crucial for nearly all lower body movements.
The glutes are collectively known for being the body’s largest and strongest muscle group. Place your feet wider and higher up on the platform to emphasize the glutes and hamstrings while performing a hack squat.
Calves
The calves consist of two muscles: the gastrocnemius and soleus. They are located on the back of the lower leg. The gastrocnemius is larger and more superficial than the soleus. It has two heads, the medial and lateral, which run from the femur to the Achilles tendon at the ankle.
Since the gastrocnemius crosses the knee joint, it assists with knee flexion and ankle plantar flexion. The soleus is a wider, flat muscle located just underneath the gastrocnemius. It doesn’t cross the knee joint and only performs plantar flexion.
If someone struggles with reaching full depth on a squat, meaning their hips pass below parallel, it’s likely due to poor ankle mobility. Increasing the flexibility and strength of the calves will help improve the range of motion in any squat variation, including the hack squat. The hack squat isn’t the most effective movement for building the calves, but they are engaged.
Abdominals
The abdominals, also known as the core, consist of four muscles: the rectus abdominus, external obliques, internal obliques, and transverse abdominis. This muscle group is primarily located on the front of the lower torso and wraps around the lower back. The external and internal obliques assist with the rotation of the trunk. So they are important for any movement that involves rotation, such as a baseball swing or golf swing.
The rectus abdominus, also known as the six-pack, performs trunk flexion. The transverse abdominis is active during breathing and helps create intra-abdominal pressure which is important for spinal stabilization during most compound movements.
While performing a hack squat, the core primarily stabilizes your torso. Since this exercise is machine-based, the core is not as active as during a barbell back squat but still plays an important role.
Hack Squat Benefits
- Increases lower body strength and muscle mass
- Places less load on the spine
- Great accessory movement for the barbell back squat
- Good for beginners
- Beneficial for those with poor shoulder mobility
Here are the top five hack squat benefits:
Increases lower body strength and muscle mass
The hack squat is a compound movement, training multiple muscle groups simultaneously. Due to the angle and weight distribution, this exercise targets the quads more than other squat variations.
Since this is a machine-based exercise, lifting heavier and training closer to failure is safer than a free-weight exercise. Built-in safety mechanisms reduces the need for a spotter, and the fixed load path lowers injury risk.
Furthermore, fewer stabilizer muscles are involved which results in less systemic fatigue and greater localized fatigue, as the platform allows for stance variations for muscle group targeting.
Places less load on the spine
The angle and fixed movement path engages more of the core and the torso and shoulders are braced against a back pad and shoulder pads, which increases external stability.
This feature also places less tension on the spine by limiting the torso’s movement. The hack squat may be a better alternative for those with a previous back injury or who experience lower back pain while barbell squatting.
Great accessory movement for the barbell back squat
Although the barbell back squat is often referred to as the king of all exercises, it can result in a greater systemic fatigue because it engages many muscle groups. To increase total training volume for the lower body, it’s a good idea to use other movements that carry over to the back squat, such as the hack squat.
Since the hack squat has a similar movement pattern to the barbell squat, it can further help build and strengthen the lower body without taxing the shoulders, core, or lower back. This allows trainees to recover better between sessions and may reduce injury risk by performing slightly different exercises.
Good for beginner lifters
Since the hack squat is less technical than the barbell squat, has built-in safety features, and uses a fixed path of motion, it could be a better option for beginners. This exercise would be beneficial for learning how to squat, build lower body strength, and practice proper bracing.
Form and technique are extremely important when it comes to squatting, so using a nearly fool-proof machine is a good place to start.
Beneficial for those with poor shoulder or wrist mobility
Nearly all barbell squat variations, such as the back and front squat, require decent shoulder and/or wrist mobility. The shoulders play an important role in stabilizing the barbell while performing a free-weight squat. Another limiting factor for most people when performing front squats is wrist mobility.
Fortunately, the hack squat is an option for those with limited shoulder mobility due to any reason. The hand grips on a hack squat have a neutral grip slightly in front of the body, so no major external rotation is involved. A good free-weight option resembling the hack squat would be a safety-bar squat, which is more common in powerlifting gyms.
Frequently Asked Questions
The answer to this question depends on the person. Back squats are superior for overall strength and muscular hypertrophy because they engage more muscle groups simultaneously. They are also more functional than hack squats.
However, hack squats are better for targeting the quads and have less systemic fatigue. Both exercises are effective for building lower body strength and size. Barbell back squats are a requirement for competitive powerlifting.
If you want to learn more about the differences between back squats and hack squats, check out this article: Hack Squats vs. Back Squats: Pros and Cons
Here are some cons of hack squats: Not every gym has a hack squat machine; It’s not very practical for a home gym set-up; They are not as functional as a barbell squat; Hack squats have less carry-over to other movements; The fixed path of motion may limit the range of motion; They don’t engage as many muscles as free-weight squats; Not ideal for glute and hamstring hypertrophy; Hack squat machines vary depending on the brand.
The hack squat is better for overall strength and hypertrophy than the leg press because it engages more muscles simultaneously. Since the hack squat resembles a barbell squat more than a leg press, it also has greater carry-over to other movements.
Ideally, you would perform both movements rather than just one. With that said, hack squats would be the best choice if you can only perform one. If you want to learn more about the differences between hack squats and leg press, check out this article: Leg Press vs Hack Squat: Differences & Benefits
Here are some common hack squat variations and alternatives: Reverse hack squat; Barbell hack squat; Barbell squat; Front squat; Safety bar squat; Lunges; Leg press; Bulgarian split squat
