Active Isolated Stretching (AIS) is a dynamic, targeted approach to flexibility and mobility training that differs from traditional static stretching. Developed by Aaron Mattes, AIS is designed to safely lengthen muscles and connective tissues while respecting the body’s natural protective reflexes. Unlike long-held static stretches, AIS uses short, repeated holds—typically 1–2 seconds—allowing muscles to gradually release without triggering resistance or strain.
The methodology is simple yet highly effective. Each stretch is performed actively, meaning the working muscles engage to support the movement, while the opposing muscles relax. Repeating this process several times helps increase range of motion, improve circulation, and enhance muscle recovery. It’s a system that works for beginners, athletes, yoga practitioners, and anyone looking to maintain or restore functional mobility.
Historically, AIS gained recognition in the 1980s as a rehabilitative and performance-enhancing technique. Its gentle, precise approach makes it relevant for both everyday fitness and specialized disciplines like yoga, martial arts, dance, and sports. By combining anatomical understanding with mindful execution, AIS not only improves flexibility but also encourages body awareness and safe movement patterns.
Below, you’ll find a series of video tutorials demonstrating AIS for different body parts—shoulders, hips, spine, wrists, and more—so you can explore the method hands-on and integrate it into your daily practice.
Psoas Sequence
Activate:
- Iliopsoas
- Rectus femoris
- Transverse abdominis
- Lower abdominals
- Hip flexors (general)
Stretch:
- Iliopsoas
- Rectus femoris
- Tensor fasciae latae (TFL)
- Quadriceps
- Anterior hip capsule
The psoas plays a key role in hip flexion, spinal stability, and gait, so restoring its normal range of motion is essential. In healthy movement, the hip should comfortably extend behind the body without compressing the lower back or tipping the pelvis forward. As you work through this sequence, you should feel a gentle, lengthening stretch across the front of the hip, not pressure in the lumbar spine.
Aim for a smooth, easy sensation—not strain. If the pelvis stays level and the breath stays soft, you’re in the right zone. Over time, this sequence helps free the hip flexors, reduce back tension, and improve posture and movement efficiency.
Rotator Cuff Sequence (External & Internal Rotation)
Activate:
- Infraspinatus (external rotation)
- Teres minor (external rotation)
- Subscapularis (internal rotation)
- Deltoid (anterior and posterior fibers)
- Scapular stabilizers (serratus anterior, lower trapezius)
Stretch:
- Posterior shoulder capsule
- Infraspinatus / teres minor (internal rotation stretch)
- Subscapularis (external rotation stretch)
- Pectoralis major & minor
- Latissimus dorsi (as it influences internal rotation)
Healthy shoulder function requires a balanced range of internal and external rotation, typically around 70–90° of external rotation and 60–70° of internal rotation, depending on individual structure. In this sequence, aim for a sensation of gentle rotation inside the joint, not pinching at the front of the shoulder or strain in the neck.
When performed correctly, you’ll feel a smooth, targeted stretch across the back of the shoulder during internal rotation work, and a broad opening through the chest and front-shoulder during external rotation work. Keep the ribcage quiet and the breath steady—this helps the rotator cuff muscles engage precisely and protects the joint.
Wrist, Hands & Fingers Sequence
Activate:
- Forearm flexors (flexor digitorum profundus & superficialis)
- Forearm extensors (extensor digitorum, extensor carpi group)
- Intrinsic hand muscles (lumbricals, interossei)
- Thenar and hypothenar muscles
- Grip and pinch stabilizers
Stretch:
- Wrist flexors (flexor carpi radialis & ulnaris)
- Wrist extensors (extensor carpi radialis & ulnaris)
- Finger flexors and extensors
- Palm fascia and intrinsic hand muscles
- Thumb flexors/extensors (thenar group)
Healthy hand and wrist function depends on maintaining balanced strength and mobility through both the forearm muscles and the small intrinsic muscles of the hand. A normal range of motion includes approximately 70–90° wrist extension, 70–80° wrist flexion, and smooth, pain-free movement through finger opening and closing.
As you work through this sequence, look for a gentle, lengthening stretch across the palm or forearm, without numbness, tingling, or compression at the wrist. You should feel activation in the small muscles that support grip and dexterity, and a sense of spaciousness returning to the joints.
This sequence is especially helpful for anyone practicing yoga, handstands, typing frequently, or dealing with stiff or overworked hands.
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Calf, Shin, Foot Sequence
Activate:
- Gastrocnemius
- Soleus
- Tibialis anterior
- Extensor digitorum longus
- Flexor hallucis longus and brevis
- Flexor digitorum longus and brevis
- Intrinsic foot stabilizers (lumbricals, interossei)
- Peroneals (longus and brevis)
- Tibialis posterior
Stretch:
- Gastrocnemius (knee straight)
- Soleus (knee bent)
- Achilles tendon
- Tibialis anterior (during plantar flexion stretch)
- Peroneals
- Plantar fascia
- Toe flexors and extensors
- Intrinsic foot musculature
Normal Range of Motion & What to Feel For
Ankle Dorsiflexion
Normal: 10–20° with knee straight; up to 20–30° with knee bent.
Feel for: A lengthening sensation in the calf, especially gastrocnemius with straight-knee stretching. No sharp pulling behind the knee.
Notes: Limited dorsiflexion often shows up as tight calves, stiff Achilles, or restricted soleus. You should feel the stretch more centrally than at the tendon insertion.
Ankle Plantar Flexion
Normal: 40–50°.
Feel for: A gentle pull across the front of the ankle and shin. The stretch should feel diffuse—not like a jam at the front of the ankle joint.
Notes: This helps balance the tibialis anterior and prevents “shin splint”–type stress.
Inversion & Eversion
Normal:
Inversion: 30–35°
Eversion: 15–20°
Feel for:
Inversion stretch: Along the outer shin and peroneals.
Eversion stretch: Along the inner shin and tibialis posterior.
Notes: The goal is to recondition the ankle stabilizers to fire in short pulses—vital for balance and gait.
Toe Flexion & Extension
Normal:
MTP joint extension: 60–90° (big toe ideally closer to 90°)
Toe flexion: 30–50°
Feel for: A smooth opening along the plantar fascia when extending the toes, and a mild stretch across the top of the foot during toe flexion stretches.
Notes: Good toe mobility improves overall foot mechanics and reduces strain on calf and Achilles.
What Healthy Movement Should Feel Like
Gentle, rhythmic activation in small pulses—never forcing range.
A sense of warmth in the feet and lower legs as circulation improves.
The arch feels alive and responsive; the toes articulate more independently.
Calves feel long and supple rather than dense or ropy.
After the sequence, gait should feel lighter, springier, and more evenly distributed across the foot.
Piriformis Sequence
Activate:
- Piriformis
- Deep external hip rotators (gemellus superior/inferior, obturator internus/externus, quadratus femoris)
- Gluteus medius and minimus
- Gluteus maximus
- Tensor fasciae latae (as stabilizer)
- Hip flexors (as counter-activation)
Stretch:
- Piriformis
- Deep lateral rotators
- Gluteus maximus and medius
- Posterior hip capsule
- Slight influence on hamstrings depending on position
Normal Range of Motion & What to Feel For
Hip External Rotation
Normal: 40–60° depending on hip structure.
Feel for: A broad, deep stretch in the outer hip—not a sharp pinch in the groin or SI joint.
Notes: Healthy external rotation helps protect the knees during seated postures, lotus work, and Ashtanga’s half-lotus transitions.
Hip Internal Rotation (as counterbalance)
Normal: 30–45°.
Feel for: Mild lengthening in the back of the hip near the piriformis.
Notes: Internal rotation helps decompress the posterior hip capsule and keeps the rotators from becoming over-dominant.
What Healthy Piriformis Movement Should Feel Like
A smooth gliding sensation deep in the outer hip—not sharp, burning, or nervy.
The stretch should feel muscular, not like tendon tugging or compression.
With proper activation, the glutes should feel switched on, providing stability for the pelvis.
After the sequence, the hip often feels:
lighter
less “grippy”
more stable during walking, standing, and yoga transitions
Sciatic irritation should decrease as the deep rotators become balanced and supple.
Full Neck Sequence
Activate:
- Sternocleidomastoid (SCM)
- Scalenes (anterior, middle, posterior)
- Longus colli & longus capitis (deep neck flexors)
- Upper trapezius
- Levator scapulae
- Splenius capitis & cervicis
- Suboccipital muscles
- Erector spinae (cervical portion)
Stretch:
- Upper trapezius
- Levator scapulae
- SCM
- Scalenes
- Suboccipitals
- Paraspinal/erector muscles of the neck
- Posterior cervical fascia
- Lateral fascial lines (scalenes, levator)
Normal Range of Motion & What to Feel For
Neck Flexion (chin to chest)
Normal: 45–60°.
Feel for: A gentle lengthening along the back of the neck—not a jam at the throat.
Notes: The stretch should come from the upper cervical spine (suboccipitals), not the mid-back rounding.
Neck Extension (looking up)
Normal: 45–70°.
Feel for: A broad opening across the front of the throat and chest—not a sharp compression in the back of the neck.
Notes: Keep the lift long and spacious, avoiding “crunching” into C5–C7.
Rotation (turning right/left)
Normal: 60–80° each direction.
Feel for: A diagonal stretch from jaw to collarbone or along the side of the neck.
Notes: Rotation highlights asymmetries—AIS helps restore balance between SCM and deep rotators.
Lateral Flexion (ear toward shoulder)
Normal: 40–45°.
Feel for: A clean stretch along the opposite side of the neck.
Notes: You may feel levator scapulae or upper trapezius stretching depending on shoulder position.
Oblique Flexion (diagonal angles)
Normal: Variable, but generally 30–40°.
Feel for:
Toward front corner: SCM and anterior scalene stretch.
Toward back corner: Levator scapulae and upper traps.
Notes: These are some of the most useful angles for releasing tech-neck tension and restoring balanced posture.
What Healthy Neck Movement Should Feel Like
Smooth, controlled pulses without bracing or gripping.
Stretch sensations should remain muscular, not nerve-like or sharp.
You should notice:
Easier breathing (scalene release)
Less jaw tension
Clearer head and reduced headaches (suboccipital decompression)
Better posture—especially after computer work
After the sequence, the neck should feel light, long, and more mobile in every direction.
Hamstrings Sequence
(Semitendinosus • Semimembranosus • Biceps Femoris)
Activate:
- Semitendinosus
- Semimembranosus
- Biceps femoris (long & short head)
- Gastrocnemius (as synergist during hip flexion with straight knee)
- Hip flexors (iliopsoas, rectus femoris)
- Tibialis anterior (to assist dorsiflexion during activation)
- Gluteus maximus & medius (as stabilizers)
Stretch:
- Biceps femoris (lateral hamstring)
- Semitendinosus (medial, superficial)
- Semimembranosus (medial, deep)
- Proximal attachment at the ischial tuberosity
- Distal attachments near the tibia & fibula
- Fascial lines connected to calves and posterior chain
Normal Range of Motion & What to Feel For
Straight-Leg Hip Flexion (SLR)
Normal: 70–90° for most healthy adults.
Feel for: A broad, smooth stretch from the sit bone (ischial tuberosity) down the back of the thigh—not a sharp tug behind the knee.
Notes:
If you feel it only behind the knee → the distal hamstring attachments are tight.
If you feel it high in the glute → proximal hamstring tension near the sit bone.
Medial Hamstring Emphasis (internal rotation of the leg)
Normal: Same as SLR—70–90°, depending on structure.
Feel for: A deeper stretch along the inner thigh line (semis & adductors).
Notes: Essential for postures like Janu Sirsasana, Baddha Konasana, and transitions requiring internal rotation.
Lateral Hamstring Emphasis (external rotation of the leg)
Normal: Slightly less range is common—60–80°.
Feel for: A stronger stretch along the outer hamstring and IT-band line.
Notes: Targeting the biceps femoris reduces strain on the low back and knees during forward bends.
Bent-Knee Stretch (isolating proximal attachments)
Normal: Knee can flex to 120–135° with hip flexed.
Feel for: A specific stretch high near the sit bone—perfect for releasing “gluteal gripping” and sit-bone adhesions.
Notes: Excellent for runners, cyclists, and Ashtanga practitioners who feel tightness in Marichyasana or seated forward bends.
What Healthy Hamstring Movement Should Feel Like
Pulsing activation without shaking or gripping the hip flexors.
A balanced stretch along the entire posterior chain, not just behind the knee.
Improved pelvic tilt—your pelvis moves more freely into anterior tilt, which helps all forward bends.
Relief from “pulling” at the sit bones and reduced risk of proximal hamstring strain.
After the sequence, forward folds feel smoother, deeper, and more integrated.
Chest Sequence
(Pectoralis Major • Pectoralis Minor • Anterior Deltoid • Intercostals)
Activate:
- Rhomboids
- Middle and lower trapezius
- Posterior deltoid
- Rotator cuff (external rotators)
- Serratus anterior
- Thoracic extensors
- Scapular stabilizers (to maintain neutral shoulder position)
Stretch:
- Pectoralis major (sternal and clavicular fibers)
- Pectoralis minor
- Anterior deltoid
- Subclavius
- Intercostals (upper ribs)
- Fascial connections across the anterior shoulder and arm line
Normal Range of Motion & What to Feel For
Horizontal Abduction (opening the arms outward)
Normal: 30–45° past neutral.
Feel for: A spreading sensation across the front of the chest—not pressure at the shoulder joint.
Notes: This is the most direct stretch for the pectoralis major, especially the horizontal fibers.
External Rotation (upper arm rotating outward)
Normal: 80–90° (with arm at 90° abduction).
Feel for: A deep stretch across the front delt and chest, without pinching in the AC joint.
Notes: Helps restore balance between internal and external rotators—key for posture and overhead work.
Overhead Reach (isolating pec minor)
Normal: Full shoulder flexion is 160–180°.
Feel for: A lengthening under the collarbone and along the upper ribs—a “front body lift.”
Notes: Pec minor restrictions are a primary cause of rounded shoulders and forward head posture.
Diagonal Chest Opener (functional stretch)
Normal: Variable, typically 30–60° depending on angle.
Feel for: A tension line that follows the upper or lower chest, depending on arm angle.
Notes: This helps target the sternal vs. clavicular fibers more precisely.
What Healthy Chest Movement Should Feel Like
A gentle opening sensation across the collarbones and sternum.
No pinching in the front of the shoulder—stretch should be muscular and broad.
Improved ability to retract and depress the shoulder blades.
Freedom in:
deep breathing (intercostal mobility)
backbends (less compression in the lumbar spine)
overhead movements (reduced impingement)
After the sequence, posture naturally shifts to:
shoulders back and down
chest open
neck long and aligned
Psoas Side Sequence
(Iliopsoas • Iliacus • Psoas Major • Psoas Minor)
Activate:
- Gluteus maximus (hip extension)
- Gluteus medius & minimus (hip stabilization)
- Obliques (to stabilize rib cage)
- Quadratus lumborum (as stabilizer when side-lying)
- Hamstrings (secondary assistance in hip extension)
- Deep spinal stabilizers (multifidi)
Stretch:
- Psoas major (primary)
- Iliacus (deep pelvic component)
- Psoas minor (if present)
- Rectus femoris (secondary when knee is bent)
- Fascial line across the front body and lower abdomen
- Anterior hip capsule
Normal Range of Motion & What to Feel For
Hip Extension (side-lying AIS psoas stretch)
- Normal: 10–20° of clean hip extension without lumbar arching.
- Feel for:
- A deep, subtle stretch at the front of the hip—not in the low back.
- The sensation is often felt low and deep, near the inner pelvis.
- The pelvis stays neutral; the stretch should not cause rolling or twisting.
Hip Extension with Slight External Rotation
- Normal: Similar range, 10–20°.
- Feel for: A diagonal stretch that targets iliacus and the lateral fibers of psoas major.
- Notes: Excellent for releasing rotational imbalances that show up in standing poses and backbends.
Bent-Knee Variation (rectus femoris included)
- Normal: Heel comfortably approaches the glute without hip hiking.
- Feel for:
- Dual stretch through psoas + rectus femoris.
- No knee pain or compression.
- Notes: This version is ideal for improving lunge depth and easing anterior pelvic tilt.
What Healthy Psoas Movement Should Feel Like
Many people notice immediate relief from chronic hip-tightness, anterior pelvic tilt, and back stiffness.
A subtle but deep sensation—much less surface-level than quad stretching.
No pulling in the low back; the lumbar spine should feel long and neutral.
The hip opens without the pelvis rotating or the ribs flaring.
After the sequence, you should feel:
lighter in the lower back
freer in standing and walking
more spacious in the front body
improved hip extension in poses like Warrior I, Ustrasana, and Up Dog
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Ilio-Tibial Band (IT Band) Sequence
(Tensor Fasciae Latae • IT Band Fascia • Gluteus Maximus Lateral Fibers)
Activate:
- Gluteus medius
- Gluteus minimus
- Gluteus maximus (lateral fibers)
- External hip rotators (piriformis, gemelli, obturators)
- Quadriceps—especially vastus medialis (as counterbalance to the ITB)
- Tibialis anterior and peroneals (lower-leg stabilizers)
Stretch:
- Tensor fasciae latae (TFL)
- Lateral gluteus maximus fibers
- IT Band fascial sheath (indirect stretch—ITB is dense fascia, not contractile tissue)
- Lateral quadriceps (vastus lateralis)
- Lateral hip and thigh fascial lines
Note:
The IT Band itself does not “stretch” much, but AIS can decompress, lengthen surrounding muscles, and improve gliding between tissues—resulting in major relief.
Normal Range of Motion & What to Feel For
Hip Adduction (leg crossing midline)
Normal: 20–30° past midline.
Feel for: A deep, broad tension along the outside of the hip and thigh—not sharp pressure at the knee.
Notes: This is the key AIS movement to decompress TFL and improve the slide of the IT band.
Hip Extension with Slight Adduction
Normal: 10–20° extension while lightly crossing the leg behind the standing leg.
Feel for:
A diagonal stretch from the front-lateral hip down toward the knee.
No low-back compression.
Notes: This angle targets TFL + lateral glutes simultaneously.
Side-Lying Adduction (bottom leg lifting toward ceiling)
Normal: 20–30° lift.
Feel for: A clean lengthening along the outer thigh, sometimes extending to the knee or upper calf.
Notes: Helps restore pelvic alignment and reduce lateral knee stress.
Diagonal AIS Sweep (cross + slight internal rotation)
Normal: Variable 10–20° depending on hip structure.
Feel for: A line of stretch that follows the TFL curve toward the ASIS (front hip bone).
Notes: Excellent for runners and cyclists who have ITB friction symptoms.
What Healthy IT Band Function Should Feel Like
A balanced, gliding sensation along the outer thigh—not tight, ropey, or tender.
Hip feels more stable during:
walking
running
squatting
lunging
Ashtanga transitions
Reduced strain in the lateral knee and improved tracking of the patella.
Pelvic alignment becomes more natural—less “hiking” or tilting.
After the sequence, standing postures feel more grounded and symmetrical.
Rhomboid/Rotator Cuff Sequence
(Cross-Body / Horizontal Adduction)
Activate:
- Posterior deltoid
- Infraspinatus
- Teres minor
- Upper and middle trapezius (light activation during arm assist)
Stretch:
- Rhomboids (major and minor)
- Middle trapezius
- Posterior shoulder capsule
- Rear deltoid fibers
Range of Motion & What to Feel For
Healthy horizontal adduction allows the arm to move comfortably 10–20° past the midline of the chest without shoulder elevation or rotation. As you bring the arm across the body, you should feel a broad, spreading stretch between the shoulder blade and the spine, sometimes extending into the back of the shoulder.
Look for:
- A gentle “opening” sensation in the mid-scapular region
- No pinching in the front of the shoulder
- Shoulder staying relaxed and low
- Smooth, easy breathing
Avoid:
- Shrugging the shoulder upward
- Twisting the torso to “cheat” the range
- Forcing the arm too far across the chest
Performed with the 1–2 second AIS rhythm, this stretch helps release tightness in the rhomboids while restoring balance to the posterior shoulder.

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