Core SET

Fundamentals of Core Training and Exercise Classification

• Beginning core exercises represent a specific repertoire of movements designed to challenge all parts of the core at an introductory level.

• Exercise Classification and Mechanics

  • Core exercises are unique in that the majority involve an isometric contraction, also referred to as a non-moving contraction or bracing.

  • Because there is no joint movement during many of these exercises, they are technically classified as isolation or single-joint exercises, though they often sit in their own specific grouping as "core exercises."

  • While joints do not move, core exercises involve an isometric contraction or bracing of multiple muscle groups simultaneously, including the abdominal wall, the lower back region, and the glutes.

  • These muscles frequently cross multiple joints, making the movement complex in terms of stabilization even if static.

• Role of the Core in Complex and Explosive Movements

  • The core is essential for complex vertical loading. For example, a weightlifter locking out a bar above their head requires significant abdominal and lower back bracing.

  • Specific weight loads example: A female bar of $15\,kg$ combined with additional plates might reach significant totals, such as weights above $72.5\,kg$ or $75\,kg$. Maintaining a skeletal lockout with arms fully extended requires a high level of core activation.

Adaptations of the Seven Classic Training Rules for Core Training

• Breathing and Repetitions

  • In core training, a "repetition" is often held for time rather than movement cycles.

  • Holding durations may range from $15\,s$, $25\,s$, $30\,s$, and $45\,s$, up to $90\,s$ or even $2\,min$.

  • Clients must be taught to breathe with control throughout the entire duration of the hold.

• Range of Motion

  • For bracing-based exercises, there is effectively no range of motion. The goal is to lock muscle groups to prevent joint movement.

• Posture and Alignment

  • Posture is vitally important for core exercises. Developing the core in suboptimal or faulty alignments can lead to faulty movement patterns and is a primary cause of lower back pain.

  • Correct alignment ensures the core is developed for its intended functional purpose: stabilizing the spine.

• Progression and Load

  • Difficulty is progressed through duration rather than just external weight.

  • There is a significant functional difference between a $15\,s$ hold and a $25\,s$ hold. A client might perform a quality $15\,s$ rep but lapse into a suboptimal faulty movement pattern if forced to go to $25\,s$. Quality of movement must always supersede duration.

The Principle of Muscular Stiffness and Core Stability

• Definition of Core stiffness

  • The core consists of deep muscles whose primary role is to provide stiffness or tightness around the spine.

  • Appropriate muscular stiffness is obtained through coordinated muscular activation, which reduces the likelihood of subsequent injury and pain.

• Proximal Stiffness for Distal Mobility

  • Moving the appendicular skeleton (the arms and legs) effectively requires stiffness in the axial skeleton (the pelvis, spine, cranium, and rib cage).

  • Whether running, squatting, jumping, or lifting, the lumbar spine requires a stable base protected by musculature to perform its function without being overloaded.

  • Failure to meet stability demands leads to two outcomes: parts of the spine are overloaded with forces (increasing injury risk), and performance suffers due to technical sloppiness.

Categorization of Core Musculature

• Primary Stabilizers (Deepest Layer)

  • Transverse Abdominis (TVA): Deep abdominal muscle essential for bracing.

  • Multifidus: Small, deep muscles along the lumbar vertebrae.

  • Function: These provide direct stability to the lumbar vertebrae.

• Secondary Layer (Lateral and Rotational Stability)

  • Internal and External Obliques: Familiar muscles for rotational stability.

  • Quadratus Lumborum (QL): A posterior muscle that fills the gap between the bottom rib and the top of the pelvis. It exists on both the left and right sides of the spine.

  • QL Function: It stabilizes the spine when moving from side to side (lateral stability). For example, standing on one leg requires the QL to stabilize the pelvis near a horizontal level.

• Mobilizers (Surface Layer)

  • Rectus Abdominis: The "six-pack" muscle.

  • Erector Spinae: Muscles used in back extensions.

  • External Obliques (partial function): Also contributes to movement.

  • Note: These are frequently trained in "ab workouts" (crunches, extensions) but are categorized as mobilizers because they create movement rather than purely providing stabilization.

Technical Execution: The Prone Bridge

• Aliases: Prone Plank, Plank, or Hover.

• Variations and Loading

  • From the Knees: This is a beginner level. It places approximately $60\%$ of body weight through the shoulder girdle.

  • From the Toes: This is a progression. It increases the load to approximately $75\%$ of body weight, representing a $15\%$ increase in stimulation over the knee variation.

• Key Performance Indicators (KPIs)

  • Head/Neck: Must be in a neutral position (aligned with the spine). Avoid neck extension (looking up).

  • Hands: Neutral position with palms facing each other.

  • Shoulder/Elbow Alignment: The elbow should be positioned vertically directly under the shoulder.

  • Spine: The lumbar spine (lower back) must be in a neutral position. Avoid hiking the hips too high or allowing the lower back to sag (excessive lordosis).

  • Ankles: In the toe variation, the ankles should be at roughly a $90^\circ$ angle. Avoid excessive dorsiflexion where the client loads too far back into the heels.

Technical Execution: The Supine Bridge

• Aliases: Glute Bridge, Hip Bridge, or rarely, Supine Plank.

• Key Performance Indicators (KPIs)

  • Foot Placement: Heels should be pulled back toward the glutes so the shins (tibia/fibula) are close to vertical.

  • Hip Extension: The goal is full gluteal contraction to achieve a flat line through the front of the quadriceps and the lower abdominal region. Any "crease" at the hip indicates incomplete extension.

  • Hand Position: Palms should face UP (supinated).

  • Correction: Having palms down (pronated) internally rotates the shoulders. During long holds ($45\,s$ to $90\,s$), this can cause unwanted tension and gripping in the shoulders, which is problematic for clients with shoulder issues.

  • Variation: Hands can be placed out to the sides for better stability, but they should never be used to "hold" the hips, as this turns the exercise into a weight-bearing arm movement and encourages internal shoulder rotation.

Technical Execution: The Side Bridge

• Aliases: Side Plank.

• Variations

  • Knees (beginner), Toes (intermediate), or unstable surfaces like a Swiss ball (advanced/unstable shoulder).

• Key Performance Indicators (KPIs)

  • Stacking: Knees or feet should be stacked.

  • Body Line: A straight line should be visible between the knee, hip, shoulder, and earlobe.

  • Muscular Focus: This heavily challenges the Quadratus Lumborum and the Obliques for lateral stability.

  • Upper Hand Position: The top hand can be on the hip or resting on the side of the thigh. It should not touch the opposite shoulder, as this encourages the torso to rotate forward, creating a faulty movement pattern.

  • Ankle Safety in Split Stance: If a client has a history of ligament damage (lateral collateral ligament/LCL), stacking the ankles might be too aggressive because the bottom leg might sag. A split stance (top leg forward, bottom leg back) spreads the load more evenly.

  • Progression Alternative: Instead of moving to the toes, a client can stay on the knees and hold a medicine ball on the top hip to increase resistance while protecting the ankles and knees.

Technical Execution: The Russian Twist

• Floor Variation Mechanism

  • Often performed sitting at a $45^\circ$ angle.

  • Faulty Pattern: This position is usually held by the hip flexors rather than the core. When hip flexors pull on the spine, they pull the lumbar-thoracic region into a forward curve (flexion). This can lead to lower back pain.

• Swiss Ball Variation (Preferred Course Model)

  • Hips must remain extended with glutes contracted. This helps keep the hip flexors out of the movement.

  • The exercise involves rotating and rolling in the tightest possible circle.

  • Target Range: Aim for a rotation where the arms reach a horizontal position (parallel to the floor).

  • Mistakes: Allowing the hips to drop or the knees to open up and move at varying angles indicates a loss of stability.

• Overload Options

  • Resistance can be added using a weighted plate (e.g., a white plate), a medicine ball, or a 7-foot bar.