Week 11 Flashcards
(174 cards)
Why do we consider muscle performance?
Strength: amount of force produced
Endurance: ability to sustain a specified output
Power: rate of force produced. Muscles with an increased % of type II fibers will generate more torque and power at a standard velocity compared to muscles with predominately type I fibers
Explain intervention ladder
1) What are the rules to initiate strengthening? 2) to initiate plyometric and complex task training?
1) The patient needs to have functional or relatively full, pain free range of motion prior to initiating strengthening at a level of > 60% MVC.
If they do not have functional pain free range of motion, we have to address these impairments first (inflammation, pain, and mobility restrictions) prior to introducing strengthening exercises.
2) You need full pain free range of motion, adequate muscle strength, and evidence of joint stability.
How to differentiate intensity, duration and frequency options for MIDF?
List individual factors that affect muscle performance
Explain 1) muscle cross sectional area, 2) muscle pennation and length, 3) fiber type and distribution
1) In general, the greater the muscle’s cross-sectional area with muscle fiber, the more force production the muscle is able to perform.
The “in general” note refers to the fact that certain muscles, in the presence of pain or dysfunction, get fatty infiltration in the muscles. Although the muscles may not loose cross-sectional area (CSA), they loose fibers within that CSA.
2) * Short fibers with increased pennation = high force production (quad, gastroc)
* Long, parallel fibers = less force production (sartorius, lumbricals), but more ROM through muscle excursion
3) * Mainly Type I fibers = low force production, slow rate of force development, high resistance of fatigue
* Mainly type IIA and IIB fibers = fast rate and large amount of force production; quickly fatiguable
Explain 1) type of muscle contraction, 2) changes in fiber type, 3) changes in the size of muscles
1) * Eccentric: The muscle is working while lengthening in a controlled manner.
* Isometric: The muscle is holding a set position.
* Concentric: Work is being done with the muscle shortening.
2) * There are various isoforms, but we’ll focus on 3 main isoforms.
* The percent of contribution of each fiber type within a muscle can theoretically be altered by exercise, inactivity, and age.
3) Hypertrophy
* An increase in cross sectional area closely correlated with increases in force production Results from accumulation of proteins through either an increased rate of synthesis or a decreased rate of degradation
Hyperplasia
* An increase in fiber number
How many MHC (myosin heavy chain) proteins can adult skeletal muscles express?
Explain reasons we lose strength
Define muscle atrophy
Explain sarcopenia
Explain forms of fatigue
(need to check when reestablishing muscle performance)
1) muscle fatigue: Considered to be a reduction in the force generating capacity of the neuromuscular system.
Involves both central and peripheral components.
* Central fatigue (inhibition) versus peripheral fatigue (metabolic)
Local muscle fatigue can include:
* Decrease in energy stores, insufficient 02, and build up of H+
* CNS inhibition
* Possible decrease in activity at the motor unit
2) cardiopulmonary fatigue: Diminished response as a result of prolonged activity
Caused by:
* Decrease in glucose levels
* Decrease in glycogen stores in the muscle and liver
* Decrease/depletion of potassium (K)
3) form fatigue: * local fatigue characterized by diminished force generating capacity of muscle
* Remember from motor control, we want to see if the patient can overcome this form fatigue. If they can’t, we pause the exercise until it can be done correctly so as not to feed into faulty movement patterns
What is the usual recovery time from a set of exercise?
What should you expect from the muscle tissue with mechanotransduction?
Why do we overload muscles?
Explain muscle strength vs endurance
Define resistance training
What do you expect to happen with resistance training?
What can the patient expect to see with gains?
Does resistance training cause tendon remodeling?
Define isometric, concentric, and eccentric contractions
isometric: The muscle contracts, but the body region does not change positions.
Strength gains are angle specific (# 10° although some studies have found a 30° transfer, and up to a 75° transfer if trained in a lengthened position) Advantage: contraction occurs without joint movement
Concentric: The muscle is producing positive work by shortening with an active muscle contraction.
In this exercise, you still have to consider where gravity is in relationship to the bony segment moving. For example, in a standing bicep curl, the biceps is contracting concentrically as the elbow is flexed, and the bicep acts eccentrically as the elbow returns to the extended position.
But what if the patient was supine? The biceps would contract concentrically until the elbow is flexed to 90 deg. Then, to complete elbow flexion, the triceps acts eccentrically through the rest of elbow flexion. When returning the elbow to the start position, the triceps acts concentrically until 90 deg of elbow flexion, then the biceps acts eccentrically for the rest of elbow extension.
Eccentric: The muscle contracts in a lengthening direction to control the load, usually to slow down the speed in the direction of gravity. This produces negative work.
Eccentric muscle contractions are characterized by greater force production an a given velocity, more neuromuscularly efficient, less metabolically demanding.
Not so good news: There is an increased incidence of delayed onset muscle soreness (DOMS).
What are the exercise volume protocols?
Explain Advantages and disadvantages
Explain Advantages and disadvantages
