Muscle functions

1. postural stability
2. torque production for mvt (create + transmit)
3. Protection (back muscles = internal organs)
4. Fine mvt of head and neck (gaze)

Muscle general structure

• cross at multiple joints (spine muscles)
• vary in different
  • length
  • shape
  • fiber direction
  • cross-sectional area
  • leverage

Muscle organization

• Trunk
  • posterior, anterolateral, additional muscles
• craniovical region

"strength"

• produce force at torques/summation of torque + angles (mostly at spine)
  • force * moment arm (=> moment arm)
• ability to produce a lot of force
• 80 degree of force (verticle) = hulling you up

Special considerations

• muscles on both sides/sets activated
  • sagittal plane = flexion + extension
• muscle one activated
  • sagittal plane + multiplane (axial rotation or frontal plane motion)

Muscles of posterior trunk: SUPERFICIAL

• Traps, lats, rhomboids, levator scap, serratus anterior (shoulder + arm stuff)
  • Bilateral -> extension
  • Unilateral -> lateral flexion & sidebending

Muscles of posterior trunk: INTERMEDIATE

(ventilation & proprioception)

• low cross-sectional + body imaging/space
• Serratus posterior superior
• Serratus posterior inferior

Muscles of posterior trunk: DEEP

• WHAT MOVES YOU AROUND
• Erector spinae group
• Transversospinal group
• Short segmental group

Transversospinal group + short segmental

Muscles of trunk and craniocervical region

Erector Spinae group

• turn on both sides = pure extension
• turn on one side = rotation/sideband (unilaterally) + extension
• BIG MOVEMENTS (DL)
• Main move extension

Transversospinal group

• semispinalis (semi. thoracic/cervicis/captits) -> multifid -> rotatores (brevia/longus)
• low cross-sectional + many levels + lost strength
• fine motor mvts

Muscles of the anterolateral trunk (abs): function

• obliquus internus abdominis
• protective work of ab organs
• high intrabdominal + thoracic pressure

Muscles of the anterolateral trunk (abs) [specific]

• obliquus externus abdominis
• obliquus internus abdominis
• transverse abdominis

Short Segmental

• no force generation + lots of muscle spindle
  • tracks muscle length = proprioception
• supervisor muscles

Muscles of the anterolateral trunk (abs) [errector abdominous movement]

• both sides on(bilateral errector ab): trunk flexion
• 1 side on: flexion + lateral

Muscles of the anterolateral trunk (abs): external + internal oblique

• longest moment arm (rotation)
• large cross-sectional area (x2 of errectus abdominous)
• Turn left: right external obli on
• Turn right: right internal obliq on
• PSOAS = middle (does everything/depend on starting position)

Research Paper

• transverse abdominal work = helps create pressure, prevent distention/sweeting of guts (Olympic weight belt)
• external load application (dumbbell + barbel) = highest core application
  • EMG activation (on)

Superman vs. Deadlift: So which one creates more torque??

• not same activity
• superman increases use of deep muscles
  • more accessible, more better prescribed, low-load
• deadlift: bracing, depends on what muscles (erectus spinous)

Extension Torque > Flexion Torque

• Flexor-to-extensor torque (isometrically) is .45-.77
• Trunk flexors: greater leverage
• extensors: greater mass & better vertical orientation

Additional muscles: Iliopsoas & Quadratus Lumborum

• Iliopsoas: hip flexor with femur-on-pelvis (hang leg raise) or pelvis-on-femur (sit-ups), lateral flexion, vertical stabilizer (trunk)
• Quadratus Lumborum: dynamic control of pelvis, extensor of lumbar (bilaterally), flexor of LR (unilaterally)

Muscle interactions division

1. Intrinsic stabilizer
2. extrinsic stabilizer

Muscle interactions: Intrinsic stabilizer

• Transversospinals // short segmentals
• oriented completely verticle (telephone pole)
• stabilization, compression, no sliding
• prevent bowstringing (with big mvt) = generate stabilization (fine coordination)

Muscle interactions: extrinsic stabilizer

• Anterolateral (abs) // Erector Spinae // QL // Ilioposas // Hip muscles
• prevent bowstringing (with big mvt) = generate stabilization (deep muscles)

Sit ups

• causes hip flexor activation
• erectors abdominus/lats/pec/oblique/rectus+transverse abdominus/
• max flexion torque: turn all muscles north of spine
• max extension torque: turn all south of spine

sumo deadlift + squat

• hip extension + lumbar extension (knees/calf/back/legs)
• start position
• don't need flexors on = bracing automatic/trainned = ???

Cervical spine head (AT NEUTRAL)

• potential movement = depend on starting position
• not a lot of plantar movements
• more extensor + flexor

Sternocleuidomastoid

• neutral vs extensor start
  • extension
• unilateral + contralateral axial rotator (flex+extend)

Scalene muscles

• unilateral flexor
• both sides on: help with ventilation, raise thoracic spine up (COPD patients)

Deep muscles (right longus capitis, right rectus capitis anterior, right rectus capitis lateralis, left longus colli)

• dynamic anterior longitudinal ligament
• helps with flexion

large mover muscles (neck/head)

• multi-level movers
• splenius captitis: rotation + side bend
• splenius cervicis: side bend + ecternal + rotation
• levator spinae: side bend

small/single mover muscles (neck/head)

• precise control of occipital and axial joints
• provide neural feedback on position + rate of head movement (balance, equilibrium, eye-head coordination)

Cervical interactions

eye / fine movement / neck muscles

• allows the head to stay on the neck after car accident/collision
• vestibule system + neck muscles = control gaze
  • sends signals to each other
• balance, equilibrium, eye-head coordination