LECTURE 3: stretching

Question 1

what are the ROM limiting factors

Answer 1

Active structures
Passive structure
Viscosity
CNS
Discomfort

Question 2

active structures

Answer 2

muscle fascicles (structural proteins such as myosin, actin, titin, and others)

Question 3

passive structures

Answer 3

tendons, aponeuroses, joint capsules, and ligaments.

Question 4

viscosity

Answer 4

50% to 78% fluid (water), dependent on age, sex, hydration, and other factors.

Question 5

CNS

Answer 5

a highly activated central nervous system could increase muscle tonus.

Question 6

Discomfort

Answer 6

pushing a joint to its maximum ROM can be uncomfortable or painful

Question 7

biarticular

Answer 7

easily stretched e.g. hamstrings, gastrocnemius, rectus femoris

Question 8

monoarticular

Answer 8

anatomically impossible e.g. tibialis anterior, masseter, temporalis, brachialis

Question 9

acute effects

Answer 9

Thixotropic effects (muscle, tendons and fascia)

Tonic muscle reflexes

Static stretching = Disfacilitation of motor neuron from suppression of monosynaptic spinal reflex. Stress relaxation. Effect is global

Dynamic stretching = excitation of myotatic reflex (muscle spindles)

Question 10

chronic effects

Answer 10

Increased stretch tolerance
- Inhibition of E reflexes (cutaneous pain receptors)

Morphological Mechanisms

Question 11

stretching reduces risk of injury depending on

Answer 11

who, what, when + where

Question 12

injury for non athletes: poor flexibility has been associated with

Answer 12

Difficulty when performing your daily activities

Joint stiffness, muscle tightness, lower back pain and other postural, and health related problems.

Greater arterial stiffening. Arterial stiffening is called arteriosclerosis and it influences how hard your heart has to work to pump blood through your body. Myocardial infarction (heart attack) and stroke are both a direct consequence of atherosclerosis.

Question 13

static stretching has a negative impact on performance

Answer 13

Strength 
Power 
Speed 
Agility 
Balance 
Mean deficit 1% (<30s) to ~5% (60-120s)

Question 14

Stretching will (Acutely and Chronically) increase ROM in muscles that we can anatomically stretch by

Answer 14

Warming up fluids, inhibiting tonic muscle reflexes, increasing stretch tolerance.

Question 15

Stretching may plausibly reduce risk of injury in hamstring muscles in sprinting/field athletes.

Answer 15

No evidence of reduced injury risk in recreationally active people.

Question 16

Static stretching will not improve performance when done prior to event (i.e., in warm-up)

Answer 16

Particularly in power/speed based sports.

Question 17

why stretch

Answer 17

increases ROM

Question 18

who should stretch

Answer 18

Want to improve flexibility – general health

Athletes who require large ROM (e.g., gymnasts, Ice hockey goalies, dancer)

Potentially beneficial to field athletes as protection for hamstring (more evidence required)

Question 19

when should one stretch

Answer 19

Not before competition, unless other dynamic tasks are done to mitigate effects.

As part of normal training or as periodised as part of pre-season preparation.

Question 20

proposed mechanism link between stretching and ROM

Answer 20

The acute increase in range of motion (ROM) was thought to reduce resistance to movement, and to provide greater limb excursions which would be important for work output (work = force × linear or angular distance), running stride length, activities that need substantial flexibility (e.g. gymnastics, dance, figure skating, and others), and other movements.