Killer Core

Reprinted with permission from the Aquatic Exercise Association (AEA) This article first appeared in the April/May 2019 issue of Akwa magazine.

IAFC 2019 Land Workshop Highlight
Killer Core
By Lauren Eirk, MS

We all know that it is important to incorporate core training into our exercise regime, and our clients ask for it regularly. Training muscles that work spinal, hip, and shoulder joints are essential to any fitness program, whether on land or in the water. These exercises are the foundation of Hatha Yoga, which is thought to date back as far as 6,000 B.C.

Muscles of the trunk and spine have several functions:
• Support, move, and stabilize the intervertebral joints in order to adequately distribute forces through the spine.
• Transfer force from the lower body to the upper body and vice versa.
• Assist in respiration.
• Protect the spinal cord.

The muscles of the trunk move the vertebral column, form the thoracic and abdominal walls, cover the pelvic outlet, and help the complex shoulder and hip joints to innervate with the trunk and spine to move our extremities. Having a strong, stable core helps us to prevent injuries and allows us to perform at our best. Our function truly depends on the strength of the core.

Why Trunk-Related Injuries Are So Common
Injuries to the spine tend to come from a combination of bending forward, side to side or rotating excessively. Back injuries are not usually linked to one specific incident (lifting something heavy), but rather to a history of excessive load with bad mechanics. Injuries can only be explained when we consider our neuromuscular health from head to toe. We simply adapt to the positions and joint ranges that we spend our time participating in during the day.

We get comfortable being in mid-ranges, but most people are not strong in the “extreme” or “end” ranges of our joints. In the practice of yoga, the muscles in our hips, torso and shoulders work together. Not only that, there is a huge importance placed on ground forces coming up through the foot without the input from shoes. Yoga should be taught as a form of resistance training, with the idea that being inflexible is largely due to muscles not being able to fully contract and respond to our environment.

In the practice of land-based Hatha Yoga, there are positions that are sequenced from a combination of standing, upright sitting, prone, supine, and sometimes inverted poses. One learns to develop strength in the trunk and spine against the force of gravity while moving surrounding joints into various positions and maintaining one’s center of mass.

Control is the theme of yoga, as one not only learns to control the thoughts, but also to move in a precise manner that mirrors one’s current level of overall joint function. In the IAFC 2019 land workshop, Killer Core, we will be looking at several yoga sequences that build on specific movements of the trunk and spine. Yoga poses should be sequenced in a logical, progressive manner from isolated to integrated joint isometric resistance scenarios as we learn to achieve better muscle contractions and responsivity. As joint stability increases, so will our range of motion. Since humans are rooted in the trunk and spine as our foundation, we will be prioritizing trunk rotation, trunk flexion, hip flexion, hip rotation, lateral trunk flexion, and trunk extension.

Teaching and Sequencing Yoga with a Core Focus
Aquatic programs may be chosen for those who need a gentler approach to fitness, as the water provides a buoyant environment that is therapeutic for joints. When transitioning to land-based exercise, yoga is a logical next step in the progression. It is isometric in nature, deals with the body itself, and is designed to move in a slow, controlled manner with a mindful, breath-based approach.

In this workshop, we will be taking a look at some progressive trunk-themed sequences that aquatic participants will find helpful. We need core strength in the water just as much as we do on land. Since the forces are different on land, with gravitational compressive loads, we must safely and effectively cue our participants to take their time and always observe their active range of motion.

In a progressive core-strengthening yoga sequence, we could start with a single plane of motion, a specific joint motion, or sequence many joint motions for a full-body approach. For example, if we desire to improve our forward bend in yoga (trunk and hip flexion), we will want to first look at which joints are involved around the hip and trunk. On land, if we want to target forward bending poses, we may want to first sequence poses that strengthen the abdominal muscles such as plank, boat, and active downward facing dog pose (focusing on tightening the abdominals), possibly working on the floor so that gravity is opposing our joint actions and muscles can get stronger.

We will also want to couple these with poses that strengthen the hip flexor muscles such as the chair pose (squat), warrior poses (lunges) and the supine extended big toe pose called “Utthita Hasta Padangusthasana”. These may be better suited from a standing position as gravity runs through our body in a straight line opposing our joint actions. Direct load will be placed on the joints of the hip, foot, and ankle. Developing strength in these areas will translate for better trunk mobility, as the foot influences the mobility of the hip joints and the hip joints attach directly into the spine via the pelvis and sacrum.

Sequencing a mixture of rotation, lateral flexion, trunk and hip extension/flexion will help to improve hip and core strength and over time allow for greater mobility and stability. In the workshop, we will discuss how these could translate in the water, as the buoyant forces are in a different direction from the force of gravity. A land-based yoga practice will make your students better suited to deal with the aquatic environment as well as help them keep the skeleton strong and supple on land by training specific muscle groups. It is not an accident that yogis can develop amazing mobility, as this is a practice rooted in muscular balance!


camel pose

Photo by Megan Resch

Lauren Eirk, MS, is the Founder and Director of the Yoga Integrated Science™ Wellness Studio in Louisville. She is a certified E-RYT 500 level Yoga Instructor with Yoga Alliance® with over 30 years of teaching experience, Yoga Alliance® Continuing Education Provider (YACEP), developer of the 500- hour Registered Hatha Yoga School Yoga Integrated Science™, Certified Yoga Therapist C-IAYT, and Master Level MAT / Muscle Activation Techniques™ Certified and MATRx Full Body Specialist, making her a leading expert in the treatment of muscular Imbalances. Find more information at or contact her at