Touching Hands Behind Your Back: Biomechanics, Assessment, and Improvement Strategies

How do you touch your hands behind your back?

Touching your hands behind your back is a common assessment of shoulder mobility, requiring a complex interplay of glenohumeral joint rotation, scapular movement, and muscle flexibility, primarily involving the rotator cuff and surrounding musculature.

Understanding the Biomechanics: Anatomy of the Shoulder Girdle

The ability to touch your hands behind your back is a testament to the intricate mobility of the shoulder girdle, a complex region composed of several joints and numerous muscles. Understanding these components is crucial:

• Glenohumeral Joint: The primary shoulder joint, where the head of the humerus (upper arm bone) meets the glenoid fossa of the scapula (shoulder blade). This ball-and-socket joint allows for the greatest range of motion in the body, including flexion, extension, abduction, adduction, and internal/external rotation.
• Scapulothoracic Joint: While not a true anatomical joint, this functional articulation between the scapula and the posterior rib cage is vital. Scapular movements (protraction, retraction, elevation, depression, upward rotation, downward rotation) are essential for optimal glenohumeral rhythm and overall shoulder health.
• Rotator Cuff Muscles: A group of four muscles (Supraspinatus, Infraspinatus, Teres Minor, Subscapularis - SITS muscles) that originate on the scapula and insert on the humerus. They are critical for stabilizing the glenohumeral joint and facilitating its various rotations.
• Other Key Muscles: The latissimus dorsi, pectoralis major/minor, deltoids, and various upper back muscles (e.g., rhomboids, trapezius) also play significant roles in controlling shoulder and scapular movement and can restrict range of motion if tight.

The "Hands Behind Back" Movement Explained

This seemingly simple action actually involves two distinct movements, each assessing different aspects of shoulder mobility:

• Superior Reach (Overhead Approach): Involves reaching one hand over the shoulder and down the back. This primarily assesses:

  • Shoulder External Rotation: The humerus rotates outwards from the body's midline.
  • Shoulder Abduction: The arm moves away from the body.
  • Scapular Upward Rotation: The shoulder blade rotates upwards, allowing the arm to elevate.
  • Flexibility of Internal Rotators and Adductors: Such as the latissimus dorsi and subscapularis.

• Inferior Reach (Underhand Approach): Involves reaching the other hand under the arm and up the back. This primarily assesses:

  • Shoulder Internal Rotation: The humerus rotates inwards towards the body's midline.
  • Shoulder Adduction: The arm moves towards the body.
  • Scapular Downward Rotation: The shoulder blade rotates downwards.
  • Flexibility of External Rotators and Abductors: Such as the infraspinatus, teres minor, and posterior deltoid.

The goal is typically to touch the fingertips of both hands, or even overlap them, indicating a healthy range of motion in both directions.

Why is This Movement Important? Assessing Shoulder Mobility

The ability to touch your hands behind your back serves as a practical, functional assessment of shoulder mobility, often referred to as the Apley Scratch Test. This test provides insight into the flexibility of the glenohumeral joint capsule and the surrounding musculature.

• Indicator of Joint Health: Good mobility in this test suggests healthy joint mechanics and adequate flexibility of the muscles and ligaments that cross the shoulder.
• Injury Risk Assessment: Limited range of motion, particularly in internal or external rotation, can indicate muscle tightness, joint capsule stiffness, or underlying pathology. This restriction can predispose individuals to common shoulder injuries such as impingement syndrome, rotator cuff tears, or biceps tendinopathy, as the joint may be forced into compromised positions during daily activities or exercise.
• Functional Movement Capacity: Optimal shoulder mobility is crucial for a vast array of daily activities (e.g., dressing, reaching for objects, personal hygiene) and athletic endeavors (e.g., throwing, swimming, overhead lifting, gymnastics). Deficiencies can limit performance and increase compensatory movements.

Common Limitations and Contributing Factors

Several factors can restrict your ability to touch your hands behind your back:

• Muscle Tightness:
  • Latissimus Dorsi: A large back muscle that internally rotates, extends, and adducts the arm. Tightness here severely limits overhead reach and external rotation.
  • Pectoralis Major/Minor: Chest muscles that internally rotate and adduct the arm. Tightness can pull the shoulders forward, restricting external rotation and scapular movement.
  • Subscapularis: One of the rotator cuff muscles, primarily an internal rotator. Tightness limits external rotation.
  • Infraspinatus/Teres Minor: Rotator cuff muscles primarily responsible for external rotation. Tightness limits internal rotation.
• Joint Capsule Stiffness: The fibrous capsule surrounding the glenohumeral joint can become tight, especially the posterior capsule (limiting internal rotation) or anterior capsule (limiting external rotation). This is common after prolonged immobilization or in conditions like adhesive capsulitis ("frozen shoulder").
• Poor Scapular Control/Dyskinesis: If the scapula doesn't move optimally with the humerus (e.g., not upwardly rotating enough during overhead reach), it can restrict glenohumeral motion and lead to impingement.
• Posture: Chronic rounded shoulders or forward head posture can shorten anterior muscles and lengthen posterior muscles, leading to imbalances that restrict shoulder mobility.
• Previous Injury or Surgery: Any trauma, surgery, or inflammatory condition affecting the shoulder can lead to scar tissue formation, adhesions, and reduced range of motion.

Strategies to Improve "Hands Behind Back" Mobility

Improving this specific range of motion requires a multifaceted approach focusing on flexibility, strength, and motor control. Consistency is key, and movements should always be pain-free.

• Dynamic Warm-up:
  • Arm Circles: Forward and backward, gradually increasing range.
  • Shoulder Rolls: Backward and forward.
  • Thoracic Spine Rotations: Improving mid-back mobility, which directly impacts shoulder range of motion.
• Targeted Stretching (Static Holds for 20-30 seconds):
  • For Superior Reach (External Rotation/Abduction Focus):
    • Doorway Stretch: Targets pectoralis major/minor. Stand in a doorway, place forearms on the frame, and lean forward.
    • Latissimus Dorsi Stretch: Kneel or stand, reach arms overhead, grasp a stable object (e.g., pull-up bar), and lean back/down, feeling the stretch along your lats.
    • Sleeper Stretch: Targets posterior capsule and external rotators. Lie on your side with the target arm bent 90 degrees at the shoulder and elbow. Use your other hand to gently push your forearm down towards the floor.
  • For Inferior Reach (Internal Rotation/Adduction Focus):
    • Cross-Body Arm Stretch: Targets posterior deltoid and external rotators. Pull one arm across your body with the other hand.
    • Internal Rotation Stretch with Stick/Towel: Hold a stick or towel behind your back with both hands. Use the upper hand to gently pull the lower hand higher up the back.
    • Pectoralis Minor Stretch: Similar to the doorway stretch, but focus on keeping the elbows slightly lower than the shoulders to target the smaller pec minor.
• Scapular Stability Exercises:
  • Scapular Push-ups: In a plank position, depress and elevate only your scapulae, keeping arms straight.
  • Band Pull-Aparts: Hold a resistance band with outstretched arms, pull it apart, squeezing shoulder blades together.
  • YTWL Exercises: Lying prone or standing, perform arm movements to form Y, T, W, and L shapes, focusing on scapular retraction and depression.
• Rotator Cuff Strengthening: Light resistance band exercises for internal and external rotation can improve joint stability and muscle balance.
• Foam Rolling/Myofascial Release: Address tightness in the upper back (thoracic spine), latissimus dorsi, and pectorals.

When to Seek Professional Guidance

While improving shoulder mobility through self-care is often effective, it's important to know when to consult a professional:

• Persistent Pain: If stretching or movement causes sharp or persistent pain.
• Significant Asymmetry: If one side is significantly more restricted than the other, or if there's a sudden loss of range of motion.
• History of Injury: If you have a history of shoulder dislocation, surgery, or chronic conditions like arthritis.
• Lack of Progress: If consistent effort doesn't yield improvement over several weeks.

A physical therapist, kinesiologist, or sports medicine physician can accurately diagnose the underlying cause of limited mobility and provide a tailored program including manual therapy, specific exercises, and education to safely improve your shoulder health and functional movement.