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Exercise Science

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Topic updated on 06/12/16 4:31pm
Types of Contractions/Movements

Type
Definition
Example
Isotonic 

Force remains constant through range of motion 

-improves motor performance

Biceps curls using free weights
Isometric 

Constant muscle length and tension that is proportional to the external load

-Causes muscle hypertrophy

Pushing against an immovable object
Concentric post

Shortened muscle and tension that is proportional to the external load Biceps curl with elbow flexing
Eccentric post

Force remains constant as muscle lengthens.
Most efficient method of strengthening muscle 

Biceps curl with elbow extending  
Isokinetic   

Muscle contracts at a constant velocity through varied resistance.      

 -often used to objectively evaluate muscle strength during injury rehabilitation.

Require special machines (e.g, Cybex).

Plyometric Rapid eccentric-concentric shortening.
Good training for sports that require power.

Box jumps

Open chain   Distal end of extremity moves freely Seated leg extensions and curls
Closed chain  Distal end of extremity is fixed Squats with planted foot


Anaerobic vs. Aerobic 

 
Anaerobic
Glycolytic
Aerobic
Energy source
ATP-CP
Lactic acid
Oxidative phosphorylation (Krebs cycle)
Muscle type
Type II (A, B) muscle
-fast twitching
c
Type I muscle
-slow twitching
Exercise duration
10 seconds of high intensity
2-3 minutes
endurance
Note
-Type IIA: aerobic and anaerobic
-Type IIB: primarily anaerobic
-low ATP yield
-lactic acidosis after several minutes

-high yield ATP
-requires O2 
"slow red ox muscles"


Exercise Programs Definitions
  • Periodization 
    • strength and conditioning term for planned variation in intensity and duration of a specific workout over a predefined duration of time
  • Dynamic exercise improves cardiac output by increasing cardiac stroke volume 
  • Endurance (aerobic) Training
    • results in changes in circulation and muscle metabolism
    • contractile muscle adapts by increasing energy efficiency
    • increases in mitochondrial size, number, and density
    • increases in enzymes involved in Krebs cycle, fatty acid processing, and respiratory chain
    • over time, increased use of fatty acids > glycogen
    • over time, oxidative capacity of Type I, IIA, and IIB fibers increase
      • percentage of more highly oxygenated IIA fibers increases
    • Aerobic Threshold: level of effort at which anaerobic energy pathways become significant energy producer
    • Anaerobic (lactate) Threshold: level of effort at which lactate production > lactate removal
  • Strength Training
    • typically high-load, low-repetition activities
    • results in increased cross-sectional area of muscle due to muscle hypertrophy
      • hyperplasia (increased number of fibers) less likely
    • results in increased motor unit recruitment +/- improved synchronization of muscule activity
    • maximal force production is proportional to muscle physiologic cross-sectional area
    • adolescents can safely participate in appropriate strength training programs 
      • gains in strength largely due to improved neuromuscular activation and coordination rather than muscle hypertrophy
      • gains for adolescents are reversible if training is discontinued
Aquatic training
  • Benefits 
    • decreases joint stress by lowering vertical component of the ground reaction force through buoyancy  
    • unique advantages in cardiorespiratory fitness when compared to land training
    • less abrupt increases in heart rate
    • increased oxygen consumption
    • prevents secondary injuries to the lower limb
Exercise Induced Laryngeal Obstruction (EILO)
  • Commonly mistaken for exercise-induced bronchoconstriction in athletes
  • Epidemiology
    • gender - more common in females
  • Mechanism - unknown
  • Symptoms
    • dyspnoea
    • wheeze
  • Differential diagnoses
    • exercise-induced bronchoconstriction (EIB, or exercise-induced asthma)
    • hyperventilation
    • cardiac conditions
  • Diagnosis
    • negative bronchodilator reversibility test (with beta2-agonist)
      • positive in EIB
    • negative bronchoprovocation tests (e.g. methacholine challenge, mannitol challenge, eucapnic voluntary hyperventilation test)
      • positive in EIB
    • positive continuous larynvoscopy during exercise (CLE)
  • Types (anatomic location)   
    • supraglottic level
    • glottic level
  • Treatment
    • optimum treatment is being investigated
Weight training
  • Effects on muscles
    • increased cross-sectional area
    • increased strength
    • increased mitochondria
    • increased capillary density
    • thickened connective tissue
  • Adult strength gains are associated with muscle hypertrophy
  • Adolescent strength gains occur more from increased muscle firing efficiency and coordination
Nutritional training
  • Carbohydrate loading 
    • involve increase carbohydrates three days prior to an event and decreasing physical activity to build up carbohydrates stores
    • increases the stores of muscle glycogen to provide improved endurance, especially in events lasting > 90 minutes when the bodies normal supply of glycogen runs low
    • best technique for athlete is to instead maintain normal diet
  • Fluid loading and replacement
    • magnitude of core temperature and heart rate increase accompanying work are proportional to the magnitude of water debt at the onset of exercise 
    • best technique is to replace enough water to maintain prepractice weight
  • Fluid carbohydrate and electrolyte replacement
    • best done with low osmolarity (< 10%) fluids of carbohydrates and electrolyties which enhances absorption in the gut
      • glucose polymers decrease osmolarity
Muscle Injury
  • Muscles soreness
    • caused by edema and inflammation in the connective tissue
      • leads to increased intramuscular pressure
      • occurs primarily in Type IIB fibers
    • worse with unaccustomed eccentric exercise
    • often with delayed onset: Delayed-Onset Muscle Soreness (DOMS) 
      • peaks at 24-72 hours
    • elevated CK levels seen in serum
  • Muscles strain
    • occurs commonly at myotendinous junction (off during eccentric contraction which produces highest forces in skeletal muscle)
    • pathoanatomy in inflammation followed by fibrosis
  • Muscle contusion
    • non-penetrating blunt injury
    • leads to hematoma and inflammation
    • extracellular connective tissue forms within 2 days, peaks between 5-21 days
    • healing characterized by late scar formation, variable muscle regeneration
    • myositis ossificans (bone formation within the muscle tissue) 
      • most apparent 4 weeks post-injury
  • Muscle laceration (complete tear) 
    • typically occur near myotendinous junction
    • characterized by abnormal muscle countour
    • fragments heal by dense connective scar tissue
      • this process is mediated by myofibroblasts
        • TGF-Beta stimulates differentiation and proliferation of myofibroblasts 
    • regeneration and renervation: unpredictable and likely incomplete
Muscle Immobilization
  • Can result in shorter muscle position and atrophy
  • Leads to decreased ability to generate tension and increased fatigability
  • Results in fatty infiltration
  • Atrophy occurs faster in muscles crossing a single joint
  • Atrophy occurs at a non-linear rate
    • most changes occur during initial days of disuse
    • seen at cellular level: loss of myofibrils within the fibers
    • related to duration of immobilization
  • Atrophy is more prominent if immobilization occurs without tension
    • quadriceps atrophy greater than hamstrings with knee immobilization in extension
Treatment
  • Local treatments designed to assist with soft tissue recovery or rehabilitation
  • Goals of treatment
    • decrease inflammation
    • increase local blood flow
    • increase tissue compliance
  • Modalities include
    • cryo or heat treatments
    • massage
    • ultrasound
    • electrical stimulation
    • Iontophoresis  
      • use of an electrical current to drive charged molecules of medicine through the skin to the deep tissues
      • medications including steroids, local anesthetics, salicylates, and non-steroidal anti-inflammatory drugs

 

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Qbank (20 Questions)

TAG
(SBQ07.26) Which of the following best describes the use of closed chain kinetic exercises for shoulder rehabilitation? Topic Review Topic

1. Closed chain exercises are not used for upper extremity rehabilitation
2. Causes compression of the glenohumeral joint increasing the demand on the rotator cuff
3. Causes distraction of the glenohumeral joint reducing the demand on the rotator cuff
4. Allows for co-contraction of the periscapular and rotator cuff muscles
5. Involves extrinsic loads such as exercise tubing or hand weights

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TAG
(OBQ13.72) Which of the following cytokines has been shown to promote scar tissue formation in lacerated skeletal muscle? Topic Review Topic

1. Fibroblast growth factor (FGF)
2. IGF-1
3. Nerve growth factor (NGF)
4. VEGF
5. TGF-Beta

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TAG
(OBQ12.226) Regarding muscle biology, all of the following descriptions are correct EXCEPT? Topic Review Topic

1. Isotonic: constant tension as the muscle length changes
2. Isokinetic: constant effort through a variable speed
3. Isometric: contraction with no change in muscle length
4. Eccentric: muscle fibers lengthen as the muscle contracts
5. Concentric: muscle fibers shorten as the muscle contracts

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TAG
(OBQ11.23) Which of the following remains constant during an isotonic exercise? Topic Review Topic

1. Muscle tension
2. Muscle length
3. Contraction velocity
4. Muscle work
5. Contraction acceleration

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TAG
(OBQ10.31) Iontophoresis, as commonly used in physical therapy, is a modality best defined by which of the following descriptions? Topic Review Topic

1. Induction of muscle contraction facilitating metabolic byproduct removal
2. Transcutaneous delivery of medication with electrical current
3. Transmission of high frequency acoustic waves to soft tissues
4. A low level laser treatment
5. Utilization of pulsed magnetic fields for recalcitrant muscle pain

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TAG
(OBQ10.178) A 78-year-old male with a history of chronic low back pain and bilateral knee arthritis enrolls in an aquatic exercise program after land training has become too painful for him. Each of the following are true regarding aquatic exercises EXCEPT: Topic Review Topic

1. They function to minimize joint stress
2. Secondary injuries of the lower limb joints can be prevented
3. They are associated with lower maximal heart rates when matched against comparable land exercises
4. Oxygen consumption is increased when compared to equivalent exercises on land
5. The vertical component of the ground reaction forces increases compared to equivalent exercises on land

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TAG
(OBQ10.246) The exercises shown in Figure A are most appropriately described as which of the following? Topic Review Topic
FIGURES: A          

1. Isokinetic
2. Plyometric
3. Isometric
4. Open chain
5. Closed chain

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TAG
(OBQ07.264) Which term used in rehabilitiation describes a strengthening exercise performed at a constant speed? Topic Review Topic

1. Open chain
2. Closed chain
3. Isotonic
4. Isometric
5. Isokinetic

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TAG
(OBQ06.259) The strength and conditioning term for planned variation in intensity and duration of workouts over a predefined duration of time is? Topic Review Topic

1. Isokinetic modulation
2. Periodization
3. Static progressive exercise
4. Progressive overload
5. Stacking

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TAG
(OBQ05.22) A physical therapist asks whether "open chain" exercises may be used in rehabilitation after knee surgery. This term refers to what type of exercises? Topic Review Topic

1. Supine heel slides
2. Seated leg press
3. Recumbent bicycle riding
4. Standing leg press
5. Seated leg extensions

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TAG
(OBQ05.206) What is the term used to describe a treatment modality that uses galvanic current and medication? Topic Review Topic

1. Electromyography
2. Transcutaneous electrical nerve stimulations (TENS)
3. Photophoresis
4. Phonophoresis
5. Iontophoresis

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TAG
(OBQ04.32) Dynamic exercise training can increase an athlete's cardiac output through which of the following mechanisms? Topic Review Topic

1. Increased stroke volume
2. Increased resting heart rate
3. Increased aerobic capacity
4. Increased blood pressure
5. Increased red blood cell mass

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TAG
(OBQ04.55) Which of the following Figures represents the exercise type that strengthens muscle most efficiently? Topic Review Topic
FIGURES: A   B   C   D   E  

1. Figure A
2. Figure B
3. Figure C
4. Figure D
5. Figure E

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TAG
(OBQ04.72) Isokinetic refers to which of the following types of training? Topic Review Topic

1. Bicycling at a constant pedal velocity with varied resistance
2. Bicycling at a variable pedal velocity with constant resistance
3. Running a fixed distance with variable speeds (ie. intervals)
4. Running at variable speed to maintain a constant heart rate
5. Swimming the same distance each day at different speeds

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