Muscular Considerations for Movements Flashcards

Question

Abdominal Muscles and Spine

Answer 1

Abdominals not good protective factor for the spine Transverse Abdominus has some benefits, deep, hard to train Ultrasound can be used to train transverse abdominis

Answer 2

Muscles largely act in combination VMO/VL Ratio Patellar tracking is influence by how these muscles work Very hard to selectively train one of these muscles Patella doesn't move in accordance with Rectus Femoris as it pulls from both sides Q angle has an influence in patellar tracking

Answer 3

ASIS to center of patella to tibial tuberosity Women have larger Q angle

Answer 4

* Muscles resting length will influence amount of tension developed * Elastic energy storage * Depends on type of muscle/tendon * Increased passive stiffness with stretch * Consider the effect of prestretching prior to active muscle * Ex: Jumping, need to bend knee deeper to be able to jump up rather than slight stretch * Surgical Implications * Releases, tenodese, transfers

Answer 5

* Pre-stretch (Some neurological but largely elastic) * Quick lengthening of a muscle before contraction * Generates greater force than contraction alone * Utilizes elastic component of muscle

Answer 6

* Conditioning protocol that utilizes pre-stretching * Single-leg bounds, depth jumps, stair hopping * Ex: Sport * Involves stretch shortening cycle

Answer 7

Sliding filament theory More stretched position, less ability for cross bridging to occur, less power output More overlap, more power output Can get to point of no more overlap possible

Answer 8

Begin when stretch is presented to the system

Answer 9

* Not great data on muscle lengths beyond ROM * Not all muscles shorten the same amount through a movement

Answer 10

* Passive insufficency * Multi-joint muscle **stretching** will not allow full ROM at each joint cross * Finger flexion during wrist flexion * Knee extension: Hamstring * Active insufficency * Multi joint muscle under **active tension** cannot produce full ROM at each joint crossed * Wrist Flexion not as strong * Knee extension: Quadriceps * Sarcomeres are maximumly shortened, sarcomeres run into each other * Why does this occur? * Active Insufficency: Muscle can't make cross bridges when too short

Answer 11

* Maximum tension (force) - not instantaneous (up to 300 ms) * Reaction time studies (Neurology side, muscle tendon proprioceptors) * Time to sense: 40-80ms * Electromechanical Delay (Mechanical side, actin-myosin crossbridges) * Time to develop tension: 7-120 ms * Seems to depend on tendon stretch or relaxed (Elastic elements: SEC and PEC) * Enough to prevent injury? * Maybe not * Expectations matter * Understanding what we need to turn on is important * Anything surprising will put us at risk for injury

Answer 12

* Eccentric (lengthen under tension) \> Isometric \> Concentric (shorten under tension) * The velocity of shortening of the muscle * Slower - the more cross bridges possible = more force

Answer 13

Depends on how the movement is performed

Answer 14

Muscle length Velocity Force Output

Answer 15

* Power = Force x Velocity * Concentric force of muscle x velocity = Power * Training for power don't want to train too fast or too slow * Sweet spot to properly train for power

Answer 16

* Torque (Moment) = Force \* Perpendicular distance * Perpendicular distance must be to vector * This distance is called the moment arm * Amount and location of resistance produce another vector * Mechanical Advantage (MA) * Describes the "potential" of the leverage system * MA = Force arm/ Resistance arm * Levers in the human body have poor MA * Rotary Arm is rotary torque

Answer 17

* Turning effect of muscles themselves * Largest moment arm has best chance of rotate joint (Brachiradialis)

Answer 18

* 125 Normal * \<125 Vara * Generates less muscle force * \>125 Valga * Generates more muscle force * Why? * Less force compressing the hip components in vara

Answer 19

* Directions of the moments about the joint * Which add? * Which subtract? * H = Hamstring * W = Weight (Comes from center of mass of LL) * T = Torque from PT * Sum of Torque = 0 * In isometric * TH, TW, TTH = 0

Answer 20

* Many different factors * Very complicated BUT all lead to specific adaptations imposed to demands * Get stronger relative to demands * Specificity of movement is important Muscles length influences isometric tension development

Answer 21

* Only ~20% of child's body mass is muscle tissue * Movements should not be limited * Body weight is enough resistance to create strength * Normal development is enough of a training stimulus * Muscle mass increases parallel to body mass * Children can perform resistance exercise * Heavy resistance is generally considered to be avoided * Don't want to damage injury to growth plate with high impact activities * Bone insertion stability is still happening

Answer 22

* Strength gains can occur rapidly, especially in male * Maturation, proportion of muscle mass in males * Males and females can be trained similarly * Muscle mass diverges by sex * Females 90% of males at 11-12 years, 85% at 13-14%, 75% at 15-16 years * Biological (hormonal) and societal (basis) * Some precautions. Skeletal growth not complete. Epiphyseal damage and insertion sites are a concern.

Answer 23

* Greatest potential 18-30 year period. * Most adaptable, tolerate high loads

Answer 24

* Begin to lose strength * 2 hours of training a week may positively influence strength

Answer 25

* Can reverse weakness in old age * Males lose strength at greater rate than females * Helps reduce symptoms of joint degenerative changes * Can train for power * Atrophy reflects disuse and not mere age-related changes

Answer 26

* Immobilization by plaster or fiberglass cast or suspension system (sling) \> strength reductions with bed rest * In 4 weeks, see loss in cross sectional area and torque when immobilized.