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10 Body Parts You Didn't Know You Had

author image Raquelle Ross
Raquelle Ross is a yogi, lover of real, healthy food & unabashed coffee addict. She's a believer in finding time to break a sweat daily and is a fan of yoga, running, hiking, circuit training and Pilates. On her healthy lifestyle blog,, Raquelle share recipes made with heathy, clean ingredients and geeks out over all-things fitness.

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10 Body Parts You Didn't Know You Had

As a fitness instructor, I use proper anatomical terms in class to make sure my students maximize their performance and stay injury-free. But as a student, I know what it's like being the person who's always a step (or three!) behind because they have no idea what the instructor is talking about. To help you get with the program, here are 10 of the most common body parts and their official names. It's a win-win: You get to expand your knowledge of body lingo AND you become the person who the newbies follow!

1. Powerhouse

1 Powerhouse

This refers to your core: the three layers of muscle in your midsection -- from the abdominal and back muscles to the muscles around the pelvis. The powerhouse is the most important muscle group to work because it's the foundation for all movement. Engaging your core is more than working your abs: Your core stabilizes your body because it uses all your midsection muscles. Here are three steps to make sure you’re engaging your powerhouse the next time your instructor tells you to “activate” it: 1. Squeeze and tighten your pelvic floor muscle. 2. Pull your navel in toward your spine. 3. Lift your abs up and along your spine toward your ribcage.

Related: The 41 Hardest Ab Exercises

2. Floating Ribs

2 Floating Ribs

The lower ribs that aren't directly attached to the sternum (breast bone) or another rib are known as floating ribs or floaters. Most of us have at least one set: To find them, place your palms on your lower back and inhale deeply. Do you notice a subtle movement through your muscles? This is the area into which floating ribs extend. Floaters are important to protect and maintain a healthy low back, lungs, liver, colon and kidneys, says Francine Tseng, an osteopathic therapist. A few reasons an instructor may use the term “floating rib” is to help draw awareness to your lower ribcage, optimize breathing or encourage you to recognize that region softening naturally as you straighten your spine.

3. Psoas Muscle

3 Psoas Muscle

Pronounced “so-az,” this is the thick muscle deep behind your abs that runs through your hips to connect your lower back to your upper thigh. It's at the very center of your core and is your strongest hip flexor muscle. Have a hard time firing up your glutes when you do squats? If so, it’s likely you’ve got a tight psoas. It plays a key role in proper posture, moving your hip joints and spine stabilization and acts as a shelf for major organs. If the psoas is too tight, it can cause overarching in your lumbar spine, unbalanced movements and pain in your lower back and pelvis. An instructor may refer to the psoas to increase your awareness of your core, hip flexors and body alignment to help prevent injury and stiffness.

4. Neutral Spine

4 Neutral Spine

This refers to the natural position of the spine. Many instructors encourage their students to be aware of maintaining a neutral spine to protect it. Being constantly aware of the spine’s natural alignment is crucial to prevent strain, maintain balance, increase energy, activate the right muscles and improve breathing and circulation of bodily fluids. Not only will your instructor direct you to “come to a neutral spine,” but they may also talk about the three natural curves to help with proper alignment: cervical spine (neck area), thoracic spine (middle of the back) and lumbar spine (lower back).

5. Deltoids

5 Deltoids

These are the muscles at the tops of your shoulders; also known as your “delts.” Upper-body training day? Don’t forget your delts! Well-defined deltoids are a telltale sign that someone is athletically fit. It’s crucial to exercise this muscle because it plays a key role in upper-body movement and supporting the arms and shoulders when lifting heavy loads. Your instructor will refer to this area any time you’re doing an arm or shoulder abduction exercise.

Related: 6 Moves for Strong Shoulders

6. Sitz Bones

6 Sitz Bones

These are the two bones that protrude from under the flesh of your rear end; also known as “sitting bones” or “ischium bones.” Calling attention to your sitz bones helps you balance your weight evenly when you’re seated or help you visualize yourself lifting your upper body up to straighten your spine. When your instructor cues you to “sit on your sitz bones,” don’t round or arch your lower back. Tuck this area in and sit up straight. And always make sure you feel the two protrusions under your flesh touch the ground.

7. Trapezius

7 Trapezius

This is the triangular-shape muscle that starts along the back of your neck and shoulders, then connects with the spine down to your mid-back region; also known as your “traps.” This muscle plays a key role in developing upper-body strength. You use it to move, rotate and stabilize your shoulder blades. You have two symmetrical trapezius muscles: one on the right and left of your the spine. Instructors may target the upper, middle and lower muscles of your midsection when they have you work this area. Building strong traps increases your upper-body strength and helps sculpt your upper torso symmetrically.

8. Latissimus Dorsi

8 Latissimus Dorsi

This is your largest back muscle, attached to the pelvis, lower back, middle back and inside of the upper arm; also known as “lats.” Want to power through plenty of pull-ups? Then you may need to strengthen those lats. This large muscle group is responsible for extension, adduction, transverse extension and internal rotation of the shoulder joint. Instructors want you to work your lats because they help you burn more calories, boost overall strength, improve posture and align the symmetry of your upper body.

9. Sacrum

9 Sacrum

This is a triangular-shaped bone below your lower back forms the base of the spine and intersects the hip bones to form the pelvis. Your sacrum is a very strong bone that acts as a keystone to the pelvis and supports the weight of your entire upper body. Instructors refer to this region often because it plays an important role in preventing injury and joint pain. Your instructors are likely to do stretches for the sacral area during your cooldown -- bending forward while seated or bringing your knees in toward your chest while on your back -- to reduce tension in the lower back and legs that you just worked out.

10. Opposing Muscles

10 Opposing Muscles

When you move, one muscle relaxes while its opposing muscle is working; also known as antagonist muscles. This action occurs naturally during any movement your body makes. According to Harvard Health, the body never allows opposing muscles to work at the same time, so when the agonist muscle contracts, the antagonist muscle will relax. For example, your glutes are the antagonist muscle to your psoas. So when you’re working your glutes, your psoas is relaxing.

What Do YOU Think?

What Do YOU Think?

What anatomical lingo has stopped you in your tracks during a class? What body parts or cues have instructors said that confused you? Do you think trainers should stick with technical terms or use layman’s terms? Leave a comment below and let us know!

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