Enfuse Fitness
(860) 253-9111
786 Enfield St - Enfield, CT 06082
Contact Us

Core Isometrics

EnFuse Institute For Learning

Category: Strength & Rehabilitation

Core Belt

What is the Core?

The human body is composed of over 600 muscles. These muscles are used for everything from locomotion to grasping your coffee mug. Our core is made up of the muscles our body uses to stabilize our trunk, and the visceral contents contained within.. Some of the muscles are located in the stomach area, while others are part of the musculature of the back. The primary core muscles involved in trunk stability include:

  • Transveres abdominus
  • Multifides
  • Rectus abdominus
  • Erector spinae
  • Internal/ External obliques

Your glutes also contribute to core stability, and will be included in the next article regarding hip isometrics.

What Does the Core Do?

The core is the unseen weight belt that we use when our trunk needs bracing for an activity. It is responsible for stabilizing our mid-section when performing everyday movements like sitting upright, walking, and running. Maintaining a strong core is important regardless of employment or activity level as it helps us to avoid developing impairments like bowel and urinary incontinence, and chronic low back pain later in life. A weak core, if it persists for many years, can lead to postural deficits such as protracted shoulders or decreased lumbar curvature (lumbar lordosis).

Strength & Conditioning Implications

The core is a muscle group that must be targeted when partaking in physical exercise. In weight training, yoga, plyometrics, or any of the other fields of fitness, core engagement is key. when we are squatting, we are primarily working on strengthening the muscles in your lower extremity, but we also should be engaging your core for a more stable, and safer lift.

Another example is the traditional plank. This exercise can help give us a leaner stomach, but can also reinforce core stability for all of the other exercises we are performing during our workouts. Overhead presses and exercises done in prone (on our stomachs) and in supine (on our backs) all require extensive core support.

Why Isometrics?

Previous articles in this series went into depth on the details and science behind isometric training. Core isometrics, specifically, are helpful because they teach us controlled breathing while contracting the abdominals and surrounding core musculature. Core muscles are not designed for power; they are designed for endurance. The trunk musculature is constantly active while we move about our days. Isometric exercises reinforce the stamina of these muscles, which the carries over into our everyday lives.

Physical Rehabilitation

Think about the structure of a tree. The roots anchor it while the trunk provides support to its vertical structure. Without a strong trunk, the tree is unable to grow high and fully blossom. The muscles in our core are our trunk. A weak core can lead to comorbidities in the human body. In physical therapy, there is a phrase that embodies a certain thought process and treatment approach: proximal stability for distal mobility. Proximal means close to midline, like our spine. Distal refers to the point farthest away from midline, like our shoulders, wrists, and fingers. To have mobile limbs, our core, and thus the joints close to our midline, must be stable.

Low back pain is a common diagnosis that is seen in orthopedic clinics. Generalized core instability is often a cause of this pain. Physical therapists will target the trunk musculature and try to strengthen it in order for the patient to achieve stability and resolve the pain.

Furthermore, physical rehabilitation will target the core even if the impairments are distal (for example: weak rotator cuff, weak scapular retractors). Many exercises can be executed while activating the core as a secondary muscle group (such as band scapular retraction). This is essentially done to treat patients using a holistic approach.


Exercises to increase core strength should be performed with proper breathing technique. It can be difficult to contract the abdomen and maintain a normal breathing pattern. This can create what is called valsalva maneuver, a conscious exhaling of breath against a closed airway.

Furthermore, some of the core isometrics exercises mentioned can be painful to body parts in contact with the floor/table. You may want to perform these exercises on foam mats or towels to avoid irritation or bruising to your skin.


Core Protocol


Plank on elbows

Plank On Elbows
  • Your body should be in the push-up position. Transition from weight bearing through your hands to weight bearing on both forearms.
  • Remember to keep your forearms parallel to each other and DO NOT clasp your hands.
  • Tighten your core and maintain a moderately flat back.
  • Your hips should not be on the ground or high in the air.
  • Feet shoulder width apart.
  • Squeeze your gluts
  • Maintain a neutral position with your head.
  • Hold this position for 15- 30 second increments.
Progress this exercise: As this becomes less challenging, you can repeat the exercise while extending an arm or leg (or both, just make sure they are opposite of each other).

Transverse Abdominis with Ball

Transverse Abdominis With Ball
  • Lying on your back (supine), hold an exercise ball on your stomach with both arms.
  • Bring both legs up to the ball until your knees are touching it.
  • Contract your core and squeeze the ball, pressing with both hands and both knees.
  • Make sure your head remains in a neutral position, to avoid any unnecessary stresses to non-target areas.
  • Hold this position for 15- 30 second increments.
Progress this exercise: You will be in the same starting position as previously mentioned. From here, lower one arm keeping it straight over your head (as if you were raising your hand in a classroom) and lower the contralateral (opposite) leg. Be sure to keep both of the lowered limbs off of the ground about six inches.


  • Lying flat on your stomach (prone), keep both arms at 90 degrees abduction and the both elbows in 90 degrees flexion.
  • Lift your arms and legs off of the floor.
  • Your trunk and some of your pelvis will still be in contact with the floor.
  • Maintain a neutral position for your head.
  • Hold this position for 15- 30 second increments.
  • This exercise can be uncomfortable if done on a hard surface. Using a mat may help decrease this irritation.
Progress this exercise: In order to make this exercise more difficult, you can extend your arms and reach out over your head. You can later hold weights in your hands to increase the load.

Quadruped Alternating Hand & Leg

Quadruped Alternating Hand and Leg
  • The starting position for this exercise is on your hands and knees.
  • Again, you may want to lay a mat down to relieve some pressure from your knees.
  • Raise one arm out in front of you and hold it there.
  • Likewise, you can raise one leg out straight behind you keeping both hands on the ground.
  • Hold this position for 15- 30 second increments.
  • Keep your head in a neutral position.
Progress this exercise: You can make this exercise more challenging by raising an arm and the opposite leg at the same time.

Ball sits with band resistance

  • Sit on an exercise ball with your right or left shoulder facing the wall.
  • Tie a resistance band to a hook or handle.
  • Hold the band with both hands and tighten your core to prevent your body from rotating towards the wall.
  • Hold this position for 15- 30 second increments.
  • Switch sides and repeat this exercise.
  • Keep both feet flat on the floor to maintain your base of support.
Progress this exercise: Extend your arms out straight in front of you to add greater rotational stresses to your core.

Supine Alternating Arm & Leg

Supine Alternating
  • Lying flat on your back, raise both arms all the way above your head (again, as if you were in a classroom).
  • Extend your legs so they are flat on the floor with your heels in contact with the ground.
  • Raise one arm and the opposite leg off of the ground.
  • Eliminate your low back curvature through initiating your abs.
  • You should not have any space under your low back when performing this exercise.
  • Hold this position for 15- 30 second increments.
Progress this exercise: You can progress this exercise buy holding a weight in your hands or ball between your feet.




Lee BCY, Mcgill SM. Effect of Long-term Isometric Training on Core/Torso Stiffness. Journal of Strength and Conditioning Research. 2015;29(6):1515-1526. doi:10.1519/jsc.0000000000000740.

Motte SJDL, Gribbin TC, Lisman P, Murphy K, Deuster PA. A Systematic Review of the Association Between Physical Fitness and Musculoskeletal Injury Risk. Journal of Strength and Conditioning Research. 2017:1. doi:10.1519/jsc.0000000000002174.

Pourahmadi MR, Takamjani IE, Jaberzadeh S, et al. The Effect of Core Stabilization Exercise on the Kinematics and Joint Coordination of the Lumbar Spine and Hip During Sit-to-Stand and Stand-to-Sit in Patients With Chronic Nonspecific Low Back Pain (COSCIOUS): Study Protocol for a Randomized Double-Blind Controlled Trial. JMIR Research Protocols. 2017;6(6). doi:10.2196/resprot.7378.




If you would like help and or guidance developing a hand-tailored fitness program that considers your own unique needs, please contact our team - support@EnFuseFitness.com

We hope that you find this article helpful!

In Health,
Team EnFuse


Contact Our Team


EnFuse Fitness, located in Enfield, Connecticut, is a veteran and family-owned private personal training studio that offers Pilates, yoga, deep tissue & sports massage, meal prep, and nutritional counseling services.

Proudly serving residents of western Massachusetts and northern Connecticut since 2010.

Copyright 2017 EnFuse Fitness

All rights reserved



Medical Disclaimer

THIS SITE DOES NOT PROVIDE MEDICAL ADVICE: None of the information on this site is intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images and information, contained on or available through this web site is for general information purposes only. EnFuse Fitness makes no representation and assumes no responsibility for the accuracy of information contained on or available through this web site, and such information is subject to change without notice. You are encouraged to confirm any information obtained from or through this web site with other sources, and review all information regarding any medical condition or treatment with your physician. Reliance on any information provided by EnFuse Fitness, its employees, others appearing on the site at the invitation of EnFuse Fitness, or other visitors to the site is solely at your own risk. NEVER DISREGARD PROFESSIONAL MEDICAL ADVICE OR DELAY SEEKING MEDICAL TREATMENT BECAUSE OF SOMETHING YOU HAVE READ ON OR ACCESSED THROUGH THIS WEB SITE.


Share this: