This is a two part research article on How to Train the Core
Part 1- What is the Core? Evolving Concepts
Part 2- Exercises for the Core
Please note the video links I have added in the text. Copy link into your browser if needed. I picked these videos among many others on YouTube because they give valuable information on important core exercises.
CORE PART 1
- WHAT IS THE CORE? EVOLVING CONCEPTS
Most exercisers agree that core training is very important. Yet many don't really know what the core is or how it works. If your answer was to point out to your abs, this is only a very small part of the core. Yes, since ancient times having nice abdominal muscles has been an ideal for strength and looks for exercisers, but you will see that there is more to core than the abs.
It was scientific research on back pain that lead to the discovery of the functional core. Researchers found many muscles responsible for "lumbar pelvic stability" or the ability of the neuromuscular system to maintain appropriate support around the lumbar spine and pelvis during movement.
This core stability is essential for good posture and to prevent back problems. it is vital in our everyday activities like walking, working, yoga, exercising and even more so in athletic performance.
The core includes all muscles from the neck to the base of the gluteus. There are 29 pairs of muscles that support the lumbo pelvic hip complex (LPHC) to support the spine, pelvis, and kinetic chains during functional movements. These muscles work together mostly to stop movement (segmental stabilization) and then to produce movements.
The core can be divided in two three functional systems.
1- The Local Stabilization System. These deep core muscles attach directly onto the spinal vertebrae and provide segmental stability. They includes: Transverse abdominis (TVA), Multifidus, pelvic floor muscles, diaphragm, Toracolumbar Fascia, Rotares, Interspinales, Intertransversarii.
2- The Global Stabilization System are muscles attached from pelvis to the spine. They transfer loads between upper extremity and lower extremity, provide stability between pelvis and spine, and provide stabilization and eccentric control of the core during functional movements. They generate torque, act like guy ropes to control spinal orientation and work in co-contraction to control spinal motion in the application of external loads.
Global muscles include: quadratus lumborum, psoas major, external obliques, portions of the internal oblique, rectus abdominis, gluteus medius, and adductor complex.
3- The Movement System includes muscles that attach the spine and/or pelvis to the extremities. These muscles are primarily responsible for concentric force production and eccentric deceleration during dynamic activities. Primary muscles that make up movement system include latissimus dorsi, hip flexors, hamstring complex, and quadriceps.
Collectively all muscles within each system provide dynamic stabilization and neuromuscular control of the entire core (Lumbo Pelvic Hip Complex or LPHC). They produce force (concentric), reduce force (eccentric), and provide dynamic stabilization in all planes of movement during functional activities.
In isolation, these muscles do not effectively achieve stabilization of LPHC; rather it is through their synergistic interdependent functioning that they enhance stability and neuromuscular control.
EVOLVING CORE CONCEPTS
The old style of core training was to do sit-ups and crunches. I remember doing hundreds of them as a teen in pre-skiing seasons clinics. Unfortunately many athlete and exercisers suffered spinal disk compression injuries caused by endless repetitions of sit-ups, crunches, Russian twist and other abdominal flexion exercises. This is why planks gained popularity as they do not bend the spine.
A few years ago Australian researchers working on back pain therapies developed a technique that isolates the Transverse abdominus (TVA)". Physical therapists started cueing their patients to " hollow" or "pull in" the lower abs. This technique trickled down from physical therapy to fitness training and very soon a lot of trainers were doing the same hollowing technique with their healthy clients. Many other core training have become popular such as instability training and many strength exercises for overall core.
As core is getting more popular and trendy it is also getting more confusing. New scientific studies show that instability exercises are not necessarily better for your core, abdominal work does not always improve core stability (only the anterior core) and hollowing of TVA may even weaken your stability.
Furthermore jumping into advance core exercises without any knowledge of proper progressions is counterproductive and even lead to injuries, just like with the sit-ups.
More recently, Stuart McGill, foremost authority in the world on low back pain and rehab and professor of spine biomechanics at the University of Waterloo found that isolation of TA is not natural and does not serve core stability well. He did multiple studies showing that "bracing" the entire trunk is better than pulling the lower abs in. The trunk muscles, diaphragm and pelvic floor create a type of cylinder of internal pressure or " super stiffness".
What is the difference between hollowing and bracing ( McGill)
Core bracing (Muscle & Motion)
Note that it is important to match the intensity of bracing to the effort required. Bracing can very light for endurance exercises like bird dog or standing from a chair, or it can be more extreme as in a power lift. It can be a quick pulsing and release as in a golf swing and sports moves
CORE PART 2
- EXERCISES FOR THE CORE
Did you know core stability starts with breathing?
Breathing has a dual purpose, first it is to bring oxygen to the cells and secondly it activates our core. The diaphragm initiates cores stability through its influence on intra-abdominal pressure, it works with the transverse abdominis, multifidus and pelvic floor muscles to provide support to the spine. Proper diaphragmatic function provides us with the basic postural stability that is required for complex movements as well.
The problem is that many of us are interfering with natural breathing. Studies say 50 % of the population are chest breathers, meaning the breath action is located in upper chest instead of mid and lower trunk.
"Apical breathing" or chest breathing depends mostly on muscles of the neck upper chest and ribs (accessory breathing muscles) while the diaphragm muscle is not doing much. Since the inhalation is shallow, the body has to compensate by breathing more frequently and working harder.
If you add exercising vigorously along with apical breathing, accessory muscles will fatigue quickly and the work of the diaphragm muscle as a stabilizer is compromised.
A good core program should start by practicing proper diaphragmatic breathing followed by foundation bracing exercises.
Diaphragmatic breathing is similar to deep yogic breathing. The breath starts from the lower belly then goes up to the chest. Diaphragmatic breathing is explained in the first video in link below. Second video shows dead bug progressions.
This is the same diaphragmatic breathing but done in a prone position. Gray Cook, renowned strength Coach, Physical Therapist and creator of FMS developed this exercise as a way to feel belly breathing better in fitness and sports training.
CORE BRACING EXERCISES
How to brace the core
With good diaphragmatic breathing you can start to activate the Local Core with the bracing technique. Bracing is a simple tightening of the abs and trunk, think as if anticipating a little slap to your stomach. Once the core is brace, emphasize breathing in side ribs to facilitate work of diaphragm.
This video gives another good trick on how to get the bracing technique.
McGill " Big 3
Modified crunch - bird dog - elbow side planks; as well as "stir the pot" an elbow plank on the ball which is intermediate level core exercise and good alternative for abs crunches on the ball.
Stuart McGill, world renown biomechanics professor demonstrates these exercises (copy link):
Everyone should learn "McGill 3 Big" basic core exercises to work the anterior, lateral and posterior core.
Keep a light bracing as you do them. Work toward doing sets of 10 seconds each and increase reps.
Descending pyramid sets are great for developing core endurance.
Example: One round of 5/4/3/2/1 reps. 10 sec hold each rep.
Front plank is also good for learning basic core stiffness. Remember that side is more functional because in real life the core is mostly activated to resist rotation and side planks are ideal for training anti-rotation.
Rotary stability rolling The Local core system should always activate prior to the global core. If a person cannot keep their balance in "bird dog" variations it could be a rotary stability issue. This simple rolling on the floor exercise is a developmental stage movement that can help reset the natural triggering of local core.
Paloff Press Pushing a cable or resistance band at 90 degree angle is a great basic core exercise.
Variations: kneeling and half kneeling press are a good progression; You can also do a Paloff press facing in or away from attachment to activate anterior and posterior core.
Dead bug progressions See second video in same link as for Diaphragmatic breathing.
GLOBAL AND MOVEMENT CORE SYTEM
When you do any full body exercises and athletic movements ( as opposed to isolating muscles like sitting on an exercise machine) you are activating all three systems of the core: the Local, Global and Movement core systems. Full body movement activate important muscle chains connected to the core. The main muscle chains or muscle slings are explained in "Muscle Sling" link in reference below. Fitness Trainers should incorporate exercises for all main muscle chains.
In sports and high speed movement the core must be able to quickly turn on and off to relax the body for best performance. This "Reflexive Core" can be trained with medicine ball rotation throws, DVRT press out rotation, DVRT around the world and other sports specific exercises.
List of effective core exercises
Rotary stability rolling
McGill Big 3
Dead bug variations
Kneeling and standing cable chops and lifts.
Plank variations (yoga has many)
Stir the pot
TRX planks (with hip flexion, TRX elbows or high planks, TRX crunch, TRX pike, TRX dynamic plank (roll out)
Angle barbell rainbow
Farmer walk and carries
Crunch variations (in moderation)
Overhead press (with rotation)
Squats/deadlifts with various holding
Medicine ball exercises
Single leg exercises
DVRT Core Training
"Dynamic Variable Resistance Training" (DVRT Ultimate Sandbag) offers amazing core work exercises with progressions and regressions.
First, the core is activated by the instability of shifting sand inside the sandbag. The implement is very versatile and works really well for moving in different planes of motions. The bag has about 6 different holding positions, including suitcase handle, clean handle and snatch handles. You can also pull handles apart during an exercise to increase connection in latissimus dorsi and other trunk muscles. DVRT core work is great for anti-rotation, ant-flexion, anti-extension and cross sling activation.
In short you get great core activation, a lot of movement and the implement gives superior feedback to feel which muscles you are suppose to fire up and activate.
DVRT foundation core exercises
Hands and knees lateral drag
Plank lateral drag
supine leg lowering (dead bug)
Bear crawl and X man drag
DVRT get ups
kneeling arc press
Around the world
Shin box variations
Chops and lifts
Farmer walks and carries (front loaded, shouldering, overhead)
REFERENCES / ARTICLES
Core Performance/ Core Performance Endurance - mark Verstegen
Blog and training with Josh Henkins and Jessica Bento Ultimate sandbag
How to integrate core work in strength training - Josh Henkins Modern Core Training
Core work in functional training.
core stability https://www.physio-pedia.com/Core_stabilitycore training concept
Core Training: Evidence translating to better performance and injury prevention by Stuart McGill, PhD Spine Biomechanics, Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
Why everyone need core training - Stuart McGill
DVRT ultimate sandbag Training - Josh Henkins - MUSCLE SLINGS
Advantages of abdominal breathing
Role of breathing and PT
Studies on breathing pattern disorder and functional movement
Core Training, evidence translating to better performance and injury prevention - McGill
Rotary stability FMS breakdown of rotary exercises: