BASE OF STREGNTH FOR THE TRUNK AND SPINE REGION

This is obviously a highly controversial and well-discussed topic in the Medical and Sports Performance industry.  Many people refer to it as “core training” or “abdominal training.”  It is probably more appropriate to refer to strengthening muscles in the trunk simply as “trunk strengthening.”  With the trunk simply being defined the region between the pelvis and the rib cage; which can encompass some of the muscles that attach to the pelvis, rib cage and/or spinal columns in that region.  Now there are exceptions – obviously muscles that attach higher than the rib cage that will cause motion in this defined “trunk” region.  For simplicity purposes, this aforementioned definition of trunk can be used as a standard.  There are so many variations of what “core” can actually mean, that many times it’s not as specific as strengthening the motions in the trunk.  For example, many muscles will attach to the pelvis, but not the rib cage or spine.  These play an important role in stabilizing the pelvis during trunk motion; but not be active trunk movers.  Those muscles could be considered into what is commonly referred to as core training.  So for definition purposes, core training is more global, while trunk development is more specific to strengthening the motions of the specific region.  The motions of the trunk can be simply categorized as flexion, extension, rotation, and lateral flexion (or side bending).

It is definitely important to know each of the individual muscles, the attachment sites, and the integrated function of each.  Having a full understanding of anatomical functions (specifically how it relates to muscles that attach to the pelvis, rib cage, and spine) is an essential part of being a true professional as a medical and/or performance professional.  However, this is not an article to dazzle advanced science on anatomy, biomechanics, and joint forces.  This is intended to simplify the understanding of the motions of this loosely defined trunk area, and exercises that assist with the strengthening and development of this area.  Like anything in the industry, there is advanced scientific basis – and intelligent application methods that is easy to implement with the clients.  This is definitely a key point – many times there is a ton of advanced scientific literature without any good follow up of implantation strategies.  Other times there is a mass of exercises in a database based on what “feels the burn in the abdominals” without any real scientific basis on whether or not it’s appropriate.  Many times, the best way to approach applied science is to simplify concepts – and the exercises can be advanced over time as the practitioner gains more anatomy and biomechanics education.  And that can be an issue.  Contrary to what many believe, there is nothing wrong with a trainer with limited anatomical knowledge to implement basic strategies – as long as he/she is committed to advanced education, and implementing advanced strategies as the education reaches a level that is appropriate for these advanced strategies.

ISOMETRIC VERSUS CONCENTRIC/ECCENTRIC ACTION

This is going to be a key point that is referenced to constantly.  It’s absolutely crucial to get isometric focus when combining trunk motions.  It’s obvious the combining motions will occur in sport.  However, that doesn’t make it necessarily appropriate to attempt to “re-create” the motions in training.  What can be appropriate is simultaneously developing the combination of motions, with one focus being on the concentric/eccentric action, and the other motion being developed isometrically.  It’s always important to remember that we are Performance Coaches – our job is to develop the muscles by improving the contraction and raising the threshold.  The muscles developed will then be able to withstand the forces that occur during sport – thus raising the performance and minimizing injury.  This concept is exemplified in the following examples, which is demonstrated in the BPS University Exercise Database:

1. Basic Crunch versus Single Sided Weight Crunch

Basic Crunch – goal of this exercise is trunk flexion.  Forget the whole “draw in versus the abdominal brace” argument.  It’s been argued to death.  Think in basic terms – the trunk MUST flex, so the cue is to bring the rib cage towards the pelvis (use ASIS as a landmark if necessary).  One of the best cues?  Basic Crunch – Resisted.  Both are in the BPSU database.  Note that the cue is to push into the manual resistance, which will force the rib cage towards the hips, creating basic trunk flexion.

Single Sided Weight Crunch – goal of this exercise is combining trunk flexion with trunk rotation.  Note that the trunk flexion is the exact same as the Basic Crunch – creating the same concentric/eccentric action.  With the weight on one side of the body, the Trunk Rotators are working isometrically.  The cue is to have the exact same Basic Crunch action, with the shoulder blades leaving the ground simultaneously, and coming back to the ground simultaneously.  If the weight is on the right side – when the trunk starts to go into flexion, the weight is “trying to pull” the trunk into right rotation.   If the trunk flexes WITHOUT rotation to the right however, the left side trunk rotators are being developed isometrically during the action.

Considerations of these exercises as an appropriate alternative

This sequence can be much more appropriate than a “Rotational Crunch” where there is a combination of flexion and rotation from a concentric/eccentric action in both motions.  Understanding the anatomy of the spinal columns in this region, this might not be appropriate in many cases due to the structure of the facet joints. 

Note that on BPSU, this concept is shown with many variations of hip flexion angles. Trunk flexion and combination of trunk flexion / trunk rotation needs to be developed at various hip flexion angles, in a supported (feet on ground), and unsupported (foot or feet off ground). 

2. Supine Hip Bridge versus Supine Hip Bridge (Side Band)

Supine Hip Bridge – goal of this exercise is hip extension and trunk extension.  While the primary action is hip extension, there is subtle trunk extension involved in this action – from a concentric/eccentric action and isometric action.  Note on the BPSU Exercise Database, there are many variations of leg position, and additional variations of isometric dorsiflexion or plantarflexion.  All of it is important, as the varying leg positions will put a different emphasis and challenge across the pelvis during the action.

Supine Hip Bridge (Side Band) – goal of this exercise is combining hip/trunk extension with trunk lateral flexion.  Note that the hip/trunk extension is the exact same as the Supine Hip Bridge – creating the same concentric/eccentric action.  With band pulling to one side, the trunk lateral flexors (side benders) are being developed isometrically.  If the band is around the left hip with the force being pulled to the right, the band resistance is “trying to pull” the trunk into left side lateral flexion.  If the exercise repetition is completed WITHOUT lateral flexion to the left, the right side trunk lateral flexors are being developed isometrically.

Considerations of these exercises as an appropriate alternative

This is the same concept as shown in the previous example of flexion and rotation.  It may not be appropriate to work the lateral flexors in a concentric/eccentric action (especially with combining other trunk motions) because of the anatomical structure of the spinal columns in that region – to limit inappropriate stress on the facet joints. 

3. Pushup Series Leg Extension versus Pushup Series Leg Extension Fan

Pushup Series Leg Extension – goal of this exercise is trunk flexion and rotation, with hip extension.  In the pushup position, the hands and feet are obviously on the ground.  Gravity is “trying to pull” the trunk into extension.  If the pushup position is held WITHOUT trunk extension, the trunk flexors are working isometrically.  When the right leg leaves the ground for concentric hip extension, gravity is now “trying to pull” the pelvis to the left (which is turn is “trying to pull” into right side trunk rotation).  If the hip extension occurs WITHOUT rotating the trunk to the right, the left side trunk rotators are now developing isometrically. 

Pushup Series Leg Extension Fan – goal of this exercise is combining trunk flexion, trunk rotation, hip extension, and trunk lateral flexion.  Note that the exercise is the exact same as the Pushup Position Leg Extension.  The main difference is at the top of the hip extension, the leg is “fanned out” (hip abduction), then returned to the original position (hip adduction), and then returned to the ground.  Using the right leg action example again – when the leg is “fanned out”, the force is “trying to pull” the trunk into right side lateral flexion.  If the exercise repetition is completed WITHOUT right side lateral flexion, the left side lateral flexors are developing isometrically. 

Considerations of these exercises as an appropriate alternative

This entire sequence is really a phenomenal example of training the entire system.  This exercise sequence is a great way to combine 3 different trunk motions simultaneously in a safe and highly effective manner.  Take the examples of a baseball pitcher throwing a baseball, a volleyball player spiking a ball, or a tennis player serving.  A case can be made that all of these actions involves some type of combination of trunk flexion/rotation/lateral flexion.  While it might not be appropriate to “recreate the action” of this exact sport motion during training – safely and effectively training the muscles that are involved in the action is very appropriate.

Putting the Plan into Action

When focusing on the trunk strengthening, there can be three primary categories:

  • Basic strength – as demonstrated in this article, and referenced in the BPSU Exercise Database
  • Isometric development – pillar bridges, planks, and isometric band work (demonstrated repeatedly in the BPSU Webinar on Overhead Throwing Athlete)
  • Integrated function – Sled march series (BPSU Exercise of the Week), Keiser and Band Power Endurance Series (BPSU Webinar) and Various Landmine Exercises

A progressive overload is necessary to developing the trunk, just like with any other type of resistance training.  The following plan can be a great example of how to intensify exercises and increase the specificity once the base foundation of strength and stability is achieved. 

Early in the macrocycle:

Day 1 – Pillar Isometrics

  • 2×30 sec each

Day 2 – Basic Strength (232 tempo)

  • Trunk Flexion exercise 2×8
  • Trunk Flexion/Rotation exercise 2x8e 
  • Trunk Extension exercise 2×8

Day 3 – Band Isometrics (Seated)

  • 2×30 sec each

Day 4 – Integrated Function Band Power Endurance (212 tempo)

  • 2-3 exercises; 10 reps each side

Middle of the macrocycle:

Day 1 – Basic Strength (212 tempo) – add weight where applicable

  • Trunk Flexion (unsupported hip angles) 2x12e
  • Trunk Flexion/Rotation exercise (unsupported hip angles) 2x12ee
  • Trunk Extension/Lateral Flexion exercise 2x12e

Day 2 – Band Isometrics (Kneeling Aligned) or Weighted Pillars

  • 2×30 sec each

Day 3 – Basic Strength (101 tempo)

  • Trunk Flexion (weight) 2×15-20
  • Trunk Rotation exercise (unsupported hip angles) 2x8e
  • Trunk Extension/Lateral Flexion exercise 2x15e

Day 4 – Integrated Function Landmine Rotation Series (101 tempo)

  • Linear Rotation 2x5ee
  • Lateral Rotation 2x12e
  • Reverse Rotation 2x8e

End of the macrocycle:

Day 1 – Basic Strength (311 tempo) – add weight where applicable

  • Trunk Flexion/Rotation 2x8e
  • Lateral Flexion 2x12e
  • Trunk Flexion/Rotation/Lateral Flexion 2x10ee

Day 2 – Integrated Function – Keiser/Band Power Endurance (XXX tempo)

  • 2-3 exercises; 15 reps each side

Day 3 – Band Isometrics (Kneeling Align, Unsupported)

  • 2×20 sec each align, each direction (8 total)

Day 4 – Integrated Function – MB Power or Landmine Bar Toss/Drop Series

  • 2-3 exercises; 6-10 reps each side