Sports and Exercise Physiology Flashcards
Strength of a muscle is determined mainly by its ___
Size
Maximal contractile force is computed as
muscle size in squared cm multiplied by 3.5
The holding strength of muscles is about ____ percent (greater or lesser?) than the contractile strength.
40
greater
This is the amount of force applied by the muscle multiplied by the distance over which the force is applied
Mechanical work
This is a measure of the total amount of work that the muscle performs in a unit period of time.
Power
At maximal load, the muscle cannot lift the load and hence cannot shorten. This is known as _________ velocity
zero velocity
The maximal isometric tension (i.e., force at which shortening
velocity is zero) is proportional to the:
number of active cross-bridges between actin and myosin (greatest with fast-twitch fibers
The maximal rate of work was done at a ________ load (namely, when the force of contraction was approximately 30% of the maximal tetanic tension)
submaximal
The velocity at which a muscle shortens is strongly dependent
on the:
amount of force that the muscle must develop
____ corresponds to the maximal cycling rate of the cross-bridges that occurs with the absence of any load
Maximal shortening velocity (V0)
Contraction in which muscle length is held constant, and the force generated during the contraction is then measured.
Isometric
Contraction in which the force (or tone) is held constant, and the change in length of the muscle is then measured
Isotonic
When a muscle at rest is stretched, it resists stretch by a force that increases slowly at first and then more rapidly as the extent of stretch increases. This purely passive property is due to the _____ of the muscle tissue.
elasticity
Contractile force increases as muscle length is increased up to a point known as:
Optimal length (Lo)
T/F: As the muscle is stretched beyond LO, contractile force decreases.
T
The adaptive response of skeletal muscle fibers to endurance exercise is mainly the result of:
an increase in the oxidative metabolic capacity of the motor units involved
Regular maximal-strength exercise, such as weightlifting, induces the synthesis of more ________ and hence hypertrophy of the active muscle cells
myofibrils
The prime factors that cause the pain during DOMS are _________ and ________ from injury to muscle cells, most commonly near the myotendinous junction.
swelling and inflammation
Type of motor units are affected more in the development of DOMS
Type II than type I motor units because the maximal force is highest in large cells
The source of energy actually used to cause muscle contraction is:
adenosine triphosphate (ATP)
Each high-energy bonds of ATP contains how much calories of energy?
7300 cal
The high-energy phosphate bond of phosphocreatine has how much calories of energy?
10,300
- higher than the bond of ATP: 10,300 calories per mole compared with 7300 for the ATP bond.
The combined amounts of cell ATP and cell phosphocreatine are called the:
phosphagen energy system
Which energy system is used for short burst of muscle power?
phosphagen energy system
