9 Month High Oblique Shoulder Sliders | Advanced Shoulder Stability | Life in Motion Chiropractic Livonia MI
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9 Month High Oblique
Shoulder Sliders

An advanced integrated shoulder stability exercise prescribed by Dr. Dockery that combines the 9 month high oblique position with slider-based arm reaches — simultaneously training eccentric latissimus dorsi control, scapular stability, rotational trunk control, and glute activation in a single coordinated movement pattern.

5–10 min/day Advanced level Sliders or smooth surface Livonia, MI
Book an Appointment 734-427-6333
Shoulder stability muscles anatomy — rotator cuff, serratus anterior, trapezius, lat — Life in Motion Chiropractic Livonia MI
What Is It?

What Is the 9 Month High Oblique Shoulder Slider?

The 9 Month High Oblique Shoulder Slider is an advanced shoulder stability and integrated movement exercise that uses slider pads (or a smooth surface) to create controlled eccentric loading of the shoulder, lat, and trunk as the arms slide outward from a specific rotational body position — and then demand active concentric pulling back to the start.

The name breaks into two components. The “9 month high oblique” position is a specific half-kneeling stance derived from Postural Restoration Institute (PRI) principles, in which the body is rotated and positioned to create an asymmetric challenge to the trunk, pelvis, and shoulder — mimicking the position a fetus occupies at approximately nine months gestation. This position loads the obliques, lats, and hip stabilizers in an integrated, rotationally biased way that flat bilateral exercises cannot replicate. The “slider” component then adds controlled eccentric and concentric shoulder loading through this asymmetric position, demanding that the rotator cuff, serratus anterior, lower trapezius, and latissimus dorsi work together to control the sliding arm while the trunk resists collapse.

According to Physiopedia’s review of shoulder complex rehabilitation, exercises that integrate scapular control with trunk rotation and distal limb loading are among the most clinically effective for restoring overhead mechanics, reducing impingement recurrence, and improving functional shoulder resilience — exactly what the 9 Month High Oblique Slider is designed to do.

Primary muscles trained: Latissimus dorsi (eccentric and concentric through the slide and return), serratus anterior (scapular protraction and upward rotation control), lower and mid trapezius (scapular stabilization during reach), obliques (anti-rotation trunk control in the asymmetric position), and gluteus medius/maximus on the down-side hip (maintaining pelvic position throughout). The rotator cuff co-activates throughout as dynamic shoulder joint stabilizers.

Clinical note: This is a progression exercise — it requires solid foundational shoulder stability before it delivers the intended training effect. Patients are typically working through the Scapular Push-Up, the TWL Exercise, and the 3 Month Supine Overhead Extension before advancing to this exercise. Dr. Dockery will confirm when the progression is appropriate based on your current shoulder mechanics and symptom presentation.

Who It Helps

Common Conditions & Goals This Exercise Addresses

Shoulder impingement syndrome
Overhead movement deficits
Rotator cuff rehabilitation
Scapular dyskinesis
Rotational trunk weakness
Advanced shoulder stability
Athletic overhead performance
Lat & posterior chain integration
Understanding the Position

The 9 Month High Oblique Setup

What is the “9 Month High Oblique” position?

This is a specific rotational half-kneeling stance: one knee is on the ground and the opposite foot is forward, creating a rotationally asymmetric position between the pelvis, trunk, and shoulder girdle. The term “high oblique” refers to the orientation of the trunk — the torso is slightly rotated and the ribs are elevated on one side, loading the obliques and lat in a way that bilateral positions don’t achieve. The slider arms then reach out from this rotated starting point, extending the reach of the lat eccentrically while the trunk obliques work to resist the rotation the slider movement would otherwise create.

Dr. Dockery demonstrating the 9 Month High Oblique Shoulder Slider mid-movement — Life in Motion Chiropractic Livonia MI
Dr. Dockery mid-movement on the 9 Month High Oblique Shoulder Slider at Life in Motion Chiropractic, Livonia MI — note the rotational trunk position and shoulder blade engagement throughout the slide
Prerequisites

Build These First

This is an advanced exercise. Foundational shoulder stability should be established through these exercises before progressing here:

Scapular Push-Up
Serratus anterior base
TWL Exercise
Lower trap activation
3 Month Supine Overhead
Lat & lower trap non-WB
How To Do It

Step-by-Step Instructions

1

Set up slider pads and the 9 month high oblique position

Place slider pads (or furniture sliders) on a smooth floor surface. Come to a half-kneeling position — one knee down, the opposite foot forward. Rotate the trunk slightly so it is oriented toward the forward leg side, creating the asymmetric “high oblique” position. Place both hands on the sliders in front of you, arms relatively straight but not locked.

2

Establish shoulder blade position and abdominal pre-tension

Before sliding, press firmly through both hands to engage the serratus anterior and activate the shoulder stabilizers — feel the shoulder blades spread slightly away from the spine (protraction) and become solid rather than winging. Create gentle abdominal pressure to stabilize the trunk. Drive the down knee gently into the floor to activate the glute on that side and maintain pelvic position.

3

Slide the arms forward with eccentric lat control

Slowly slide both arms forward — reaching out in front of you while maintaining shoulder blade engagement and trunk position. The latissimus dorsi will lengthen eccentrically as the arms extend; this is the primary training stimulus. Move only as far as you can control the position without the shoulders collapsing inward, the lower back arching, or the trunk rotating further than the starting position. This is not a race to reach maximum distance.

4

Hold briefly and feel the integrated activation

At the end-range position (within your controlled range), hold for 1–2 seconds. This is where the shoulder stabilizers, lats, obliques, and hip stabilizers all load simultaneously in the integrated position. The pause before the return also trains the nervous system to recognize and stabilize this shoulder position before the concentric demand of pulling back.

5

Pull back to the starting position with concentric control

Draw the arms back to the start by pulling through the lats and rear shoulder musculature — think of initiating the return from the armpits and posterior shoulder rather than from the hands. This concentric phase trains the lats and lower traps to actively load the shoulder back into a stable position after an extended reach — the functional pattern most relevant to throwing, pressing, and overhead activities.

6

Perform the prescribed reps, then switch sides

Complete the prescribed repetitions on one side before switching to the opposite half-kneeling position. Because the 9 month position is asymmetric by design, both sides must be trained — but they may feel different and have different ranges of comfortable control, which is expected and clinically meaningful information for Dr. Dockery’s assessment.

Stop if you notice: the shoulder blade winging away from the ribcage during the slide, the lower back arching excessively at end range, the trunk rotating beyond the starting position as the arms extend, or the neck tensing and the upper trap substituting. Any of these indicates the range is beyond current shoulder stability capacity — reduce the sliding distance until control is restored throughout the full arc.

Equipment

What You Need

Slider pads designed for exercise work best and can be found at most sports retailers. Furniture sliders (the felt or plastic discs used under furniture legs) work on hardwood, tile, or laminate floors. On carpet, sliders may not glide freely — in that case, smooth plastic plates or even paper plates can substitute. The key is a surface that allows controlled, low-friction sliding without sticking or catching mid-movement.

Form Cues

Key Technique Points

Press through the hands before sliding — creating shoulder blade engagement before any movement begins prevents the serratus from switching off partway through the reach; think “spread and stabilize” before “slide”
Initiate the return from the armpit and posterior shoulder — not from the hands; if you feel the arms pulling back from the wrists or forearms, the lats are not initiating the movement and a compensatory pattern has taken over
Keep the trunk rotation stable throughout the slide — the oblique demand is anti-rotation; the trunk should not continue to rotate as the arms extend further; if it does, reduce range
Down knee drives into the floor — this activates the glute on the down side and stabilizes the pelvis during the asymmetric trunk position; losing this cue causes the pelvis to shift and the position loses its intended loading
Neck long and relaxed throughout — if the upper trap is engaging or the neck shortens as the arms slide forward, shoulder blade control has been lost and the upper trap is substituting
Smaller range with full control beats larger range with compensation — this is the rule on every rep; build range progressively as the shoulder stability improves rather than forcing distance at the expense of position
Video Demonstration

Watch the Technique

9 Month High Oblique Shoulder Sliders — Life in Motion Chiropractic

Dr. Dockery demonstrates the 9 month high oblique setup, shoulder blade pre-engagement, the controlled eccentric slide, the pause at end range, and the concentric lat-driven return — including how to identify and correct the most common compensations.

Benefits

Why This Exercise Works

Trains the full shoulder stabilizer chain in an integrated position — the serratus anterior, rotator cuff, lower trapezius, and latissimus dorsi must all co-activate simultaneously through the slide, which is far more demanding and functional than training each in isolation
Provides eccentric lat loading rarely achieved in standard exercises — the latissimus dorsi is one of the largest and most powerful muscles involved in shoulder stability; its eccentric control during reaching is critical for overhead athletes and desk workers alike, yet most standard exercises train it concentrically
Trains anti-rotation trunk control in a functional rotational stance — the 9 month oblique position places the trunk in a rotationally biased stance that mimics real movement patterns; the obliques must resist further rotation throughout the slide, building the functional core stability that transfers to sport and daily tasks
Addresses shoulder asymmetries that bilateral exercises miss — because the exercise is performed asymmetrically, differences between sides in shoulder stability, lat length, or oblique control become immediately apparent and can be specifically targeted during the rehabilitation program
Builds the integrated shoulder-trunk-hip connection — the down-knee glute activation, trunk anti-rotation demand, and shoulder slider challenge all occur simultaneously, training the kind of full-body integrated coordination that functional shoulder performance depends on
Progressively loadable and scalable — range of motion, speed of movement, pause duration at end range, and surface resistance can all be modified to adjust difficulty; as shoulder stability improves, range increases naturally without requiring equipment changes
Further reading
Physiopedia — Scapular dyskinesis and integrated shoulder rehabilitation NIH — Shoulder stabilizer activation in advanced rehabilitation exercises Mayo Clinic — Rotator cuff injuries and advanced rehabilitation Cleveland Clinic — Advanced shoulder strengthening and stability exercises
Common Questions

Frequently Asked Questions

What exactly is the “9 month high oblique” position and why does it matter?
The 9 month position refers to the rotational, asymmetric body orientation that places the trunk in an oblique bias — similar to how the body might position itself to carry a weight on one side. The “high” component refers to the rib positioning. This position is used because it creates an asymmetric challenge to the shoulder, lat, and oblique on each side individually — unlike symmetric bilateral exercises, which allow stronger sides to compensate for weaker ones. By performing the slider in this position, the exercise targets the specific shoulder-trunk integration pattern that is most commonly disrupted in patients with chronic shoulder pain or impingement.
I feel this mostly in my upper trap, not the shoulder blade muscles. What’s wrong?
Upper trap substitution during the slider is the most common compensation and means the serratus anterior is not maintaining shoulder blade control through the slide. The most common causes are insufficient shoulder blade pre-engagement before the movement starts, sliding too far and exceeding current serratus and lower trap capacity, or lacking the prerequisite shoulder stability for this level of exercise. Try pressing more firmly through the hands at the starting position before any movement, reducing the range of the slide by 30–40%, and focusing on feeling the shoulder blades spread and stabilize before sliding. If upper trap substitution persists, Dr. Dockery may regress the exercise to the Scapular Push-Up or TWL Exercise to build the prerequisite activation before returning to the slider.
How is this different from a standard plank slider exercise?
A standard plank slider is typically performed in a symmetric prone or tall-plank position and primarily trains anterior core stability with some shoulder loading. The 9 Month High Oblique Slider differs in three important ways: the asymmetric rotational body position adds anti-rotation oblique demand that a plank cannot provide; the half-kneeling stance integrates hip and glute stability into the shoulder challenge; and the specific PRI-influenced trunk position targets the shoulder-lat-oblique integration pattern that is most relevant to real-world shoulder mechanics, overhead performance, and impingement prevention.
Is this safe with a rotator cuff issue?
The 9 Month High Oblique Slider is generally prescribed during the later stages of rotator cuff rehabilitation rather than the early stages, because it requires sufficient rotator cuff stability to control the shoulder through the eccentric slide range. If you are in early recovery from a rotator cuff injury or surgical repair, this exercise is not appropriate yet — the foundational progression (Scapular Push-Up, TWL, 3 Month Supine) should be completed first. Dr. Dockery will determine when this exercise is appropriate based on your specific presentation, pain levels, and shoulder mechanics assessment.
The two sides feel very different — is that normal?
Yes, and it is actually one of the most valuable pieces of clinical information this exercise generates. Asymmetric shoulder stability, lat flexibility, or oblique control is extremely common and is one of the primary drivers of unilateral shoulder pain, impingement, and performance deficits. The fact that one side feels more restricted or that one side’s shoulder blade loses control at a shorter slide distance tells Dr. Dockery exactly where the asymmetry exists and informs the specific side-biased training needed. Document which side feels different and share it at your next visit.
What does the slider exercise have to do with my shoulder pain?
Shoulder pain — particularly impingement and rotator cuff presentations — is most commonly driven not by an isolated muscle weakness but by a failure of the integrated system: the shoulder blade isn’t stabilizing properly, the lat isn’t controlling the humeral head eccentrically, and the trunk isn’t providing a stable base for the shoulder to work from. This exercise trains all three of those deficits simultaneously in an integrated, asymmetric position that requires the whole system to work together. The goal is not just to strengthen individual muscles but to restore the coordinated movement pattern that allows pain-free shoulder mechanics.

This is an advanced exercise. Stop if shoulder pain, winging of the shoulder blade, or lower back discomfort develops, and consult Dr. Dockery before proceeding if you are unsure whether this exercise is appropriate for your current level of rehabilitation.

Shoulder Pain or Impingement?

Dr. Dockery will assess your shoulder blade mechanics, lat control, and rotational trunk stability — then build a progressive shoulder rehabilitation plan tailored to your presentation.

Book an Appointment Call 734-427-6333

Shoulder stability progression

Scapular Push-Up
Step 1 — serratus foundation
TWL Exercise
Step 2 — lower trap activation
3 Month Supine Overhead
Step 3 — lat & lower trap
90/90 Breathing
Rib & trunk foundation

Related conditions

Shoulder Pain
Conditions we treat
Sports Injuries
Athletic shoulder rehab
Neck Pain
Upper trap / shoulder connection
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Advanced Shoulder Rehabilitation in Livonia, MI

The 9 Month High Oblique Shoulder Slider is most effective as part of a progressive shoulder stabilization program. Dr. Dockery serves patients throughout Livonia, Farmington Hills, Redford, Plymouth, and greater Wayne County.

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