Exercise Physiology Final

Concentric Muscle Action

Occurs when a muscle shortens while generating force, typically overcoming resistance.

Eccentric Muscle Action

Occurs when a muscle lengthens while maintaining tension, usually when resisting a force.

Isometric Muscle Action

Occurs when a muscle generates force without changing its length.

Sliding Filament Theory

Describes how muscle fibers contract by the sliding of actin and myosin filaments past each other.

Length-Tension Relationship

Indicates that muscle force generation depends on its length, with optimal overlap between actin and myosin enhancing force.

ATP-PCr Pathway Dominance Time

Dominates during the first 0-10 seconds of intense activity.

Glycolytic Pathway Dominance Time

Dominates from 10 seconds to 2 minutes of activity.

Oxidative Pathway Dominance Time

Dominates after 2 minutes of activity and increases over time.

Variable Determining Bio-Energy Pathway

The intensity and duration of the activity being performed.

Muscular Strength

The maximum amount of force a muscle or group of muscles can generate at one time.

Muscular Strength Assessment

Assessed using one-repetition maximum (1RM) tests.

Muscular Power

The ability to exert maximum force in the shortest amount of time.

Muscular Power Assessment

Measured using explosive movements like vertical jump or Olympic lifts.

Muscular Endurance

The ability to sustain repeated contractions over time.

Muscular Endurance Assessment

Assessed by performing exercises like push-ups or sit-ups in a set time.

MET Definition

1 MET is the energy cost of sitting quietly, approximately 3.5 mL of oxygen per kg of body weight per minute.

Q in Cardiorespiratory Function

Refers to cardiac output, the amount of blood the heart pumps per minute. HR x SV

SV (Stroke Volume) in relationship to HR

The amount of blood ejected by the heart in one contraction. As HR increases, SV will increase but may eventually plateau or decrease due to reduced filling time.

Max VO2

The maximum amount of oxygen the body can utilize during intense exercise. It is trainable with aerobic conditioning and endurance training

Importance of Max VO2 vs. Threshold

Max VO2 measures overall aerobic capacity, while threshold indicates lactic acid accumulation intensity. Endurance athletes improving threshold is more important

1st Class Lever Example

Neck, with fulcrum between force and load.

2nd Class Lever Example

Calf raise, with load between fulcrum and force.

3rd Class Lever Example

Bicep curl, with force between load and fulcrum.

Type I Muscle Fibers

Slow-twitch fibers that are endurance-oriented and fatigue-resistant.

Type IIa Muscle Fibers

Fast-twitch fibers with moderate endurance and high power.

Type IIb Muscle Fibers

Fast-twitch fibers with primarily anaerobic metabolism and low endurance.

Three aspects of a fitness program

Progressive overload: Continuously increasing demands on the musculoskeletal system for gains.

Variety of exercises

Recovery: allowing time to rest

Relative VO2

Volume of oxygen consumed per minute per kilogram of body weight.

Muscle Fiber Arrangements for Force Production

Pennate and fusiform muscle fibers

Type IIx Muscle Fiber

A hybrid fiber type that is more geared towards explosive movements than Type IIa but has better endurance than Type IIb, high intensity short-duration activity

Absolute VO2

total volume of oxygen consumed per minute typically expressed in L/min that is not adjusted for body weight

Strength Training Loading Sets, and Rep Scheme

75-90% 1Rm, 1-6 repetitions, 3-5 sets, 2-5 minutes between sets

Power Training Loading, Sets, and Rep Scheme

30-70% 1RM, 3-6 reps, 3-5 sests, 2-5minutes in between sets

Muscular Endurance Training Loading, Sets, and Rep Scheme

50-70% 1RM, 12-20 reps, 2-4 sets, 30-90 s of rest

Most Important Variable of increasing work capacity

progressive overload ensuring that the body will adapt to training, the intensity or volume needs to be increased

Training Adaptations that increase force production

neurogenic, myogenic, architectural

neurogenic adaptation

improved motor unit recruitment, increased fire rate, enhanced intermuscular coordination

myogenic adaptation

increased muscle cross-sectional area (hypertrophy), improved muscle type conversion, enzyme activity related to energy production increased

architectural adaptation

changes in increase of pennation angle, which can lead greater force generation capacity

pennate muscle fibers

arranged at an angle to the tendon allowing for great number of fibers to pack into a given muscle volume thus producing more force (quadriceps)

fusiform fibers

fibers run parallel to the muscle’s long axis allowing for greater contraction speed but not as much force (biceps brachii)

Golgi Tendon Organs (GTO)

sensory receptors located at the junctions of muscles and tendons. Prevent excessive force that can lead to injury by calling for muscle contraction when tension is too high

role of spindle fibers in muscular action

sensory receptors within the belly of the muscle that detects changes in length and the rate of change. Stretch reflex mechanism protects from excessive stretching