Exam 2 Flashcards
(108 cards)
What is important about muscular fitness?
- Burn some calories
- increase bone mineralization
- joint protection/lower back
- sports performance
- independent living as we age
Slow twitch characteristics:
- efficient in using oxygen
- delayed in muscle firing
- Do not fatigue easily
- Best suited for endurance sports, including cycling, marathon running, and long-distance triathlons.
Fast Twitch characteristics:
- do not burn oxygen efficiently
- fast to fire; best for explosive body movements
- tire out quickly
- best suited for short bursts of activity, including sprinting races, pole vaulting, and cross -fir style events
What does Muscular health include?
- Strength
- Endurance
- Flexibility
- Also includes: speed, power, agility, and balance
What are the factors that influence muscular strength:
Sex:
From 12 to 14, males are not much stronger than females, but changes occur afterward. Male hormones increase at puberty
Sex effect:
- College-aged women typically have 50 to 60
% of the arm/shoulder strength and 70 % of the leg strength as that of men - Higher % body fat and less lean tissue in women men
What are some factors that influence muscular strength?
Muscle Fiber Type, Genetics, and Training
What is Myostatin?
Growth factor released by the muscle that inhibits protein synthesis.
- The abnormal muscles have low proportions of mitochondria, which may
compromise force generation - Remember….mitochondria is where energy for contraction is generated
1 Rep Max:
Dynamic, Moving, and Isotonic
= maximum force generates during one repetition
Isometric Strength:
Same length of muscle fiber/joint movement, or no movement
Isokinetic Strength:
= Same speed
Maximum Torque
Muscular endurance:
- ability to keep going
- repetition of submaximal contractions or submaximal holding time ( static or isometric endurance).
- Essential for some sports performances
- Work/Activities of Daily Living
- Not to be confused with aerobic endurance
Speed/Power:
- requires rapid acceleration
- involves the contraction of fast-twitch muscle fibers
- speed of movement includes reaction time and movement time
- reaction time ( time from the stimulus until the beginning of the movement –> nervous system function)
- We can’t change the speed of nerve impulses, but we can change the speed of muscle fiber contraction.
Power:
combination of strength ( force) and velocity of the force production
Power equation:
force x ( distance/time)
Agility:
The ability to change position and direction rapidly, with precision, and without loss of balance.
*Composite of strength, speed, balance, and coordination.
* Helps to avoid injury in recreational activities and in potentially
dangerous situations
What are some factors to consider when accessing agility?
- excess weight hinders agility
- extreme strength or aerobic fitness are not prerequisites
- agility deteriorates with fatigue
- aerobic and muscular endurance can help maintain agility for extended periods.
Preload and Elastic Recoil:
A muscle exerts force when it is stretched ( preload) just before contraction
What is happening during reload and Elastic Recoil?
- aligns contractile elements ( cross-bridges) in muscle for maximal force
- stores elastic ( potential) E in the muscle-tendon complex
- contributes to the power and economy of movement
Force- Velocity Relationship:
- Resistance increases and the velocity of shortening decreases.
- strength training has little effect on the velocity of unloaded movements and vice versa.
-
Eccentric contraction:
Muscle lengthens- external force on the muscle is greater than the force that the muscle can generate, thus the muscle is forced to lengthen due to the high external load. (e.g., stretching)
Isometric contraction
No change in muscle length
because the external force on the muscle is the
same as the force being generated by the muscle-results in no movement.
Concentric contraction
- Muscle length is reduced and shortens because the external force on the muscle is
less than the force being generated by the muscle- results in movement.
Power training:
(15 to 25 repetitions at 30 to 60
percent of maximal strength, as fast as possible)