Strength and Flexibility Flashcards
What are strenfght and flexibilty?
Constraints to skilled performacne and everydady activity
Strength is a rate limiting constrain for infants standing
Flexibility is a constraint for many activities
Athletes are best when strong and supple
Training should emphasize a balance
What is strength?
The ability to exert force
Depends on number and size of fibres that are neurologically activated
How is strength assessed?
Force exerted against resistance -Isotonic -Isokinetic -Isometric Must specify muscle group, movement, speed and joint angle 1RM Dynamometer
What is taken into consideration during assessment?
The mechanical advantage the fibres gain based on where the force is applied in relation to axis of rotation
Neurologically, strength depends on degree of coordination in activating the fibres
Cannot assume that strength changes as muscle mass changes
Growth follows a sigmoid pattern
Force exertion depends on
-cross sectional area
-neurological factors
What are functional strength tests?
Chin up flexed arm hang Rope climbing Body weight is used as resistance Often require skill which affects test performance
What are developmental changes in strength for preadolescents?
Strength increases as children grow
boys and girls are similar until 13
Wood measured muscular strength and determined largest constributer was cross-sectional area
Strength increases steadily with growth
What was Asmussen and Heeboll-Nielson’s study?
Boys of same height into 2 age groups
Older group showed greater arm and leg strength (5-10% /yr)
Strength is not related to muscle size alone, there are neurological factors at play
Measured vertical jump and sprint
Practice aided performance
What are the neural factors that likely exert influence?
Myelination of nerve fibres
Muscle coordination
Relaxation of opposite muscles
Increase motor unit activation
What were the conclusions of Asmussen and Heebol-Nieson’s study?
FUnctional strength increases at faster rate than anticipated by muscle growth which emphasizes neurological growth
Peak strength increase follow peak muscle increase
Among same-size children of different ages, more mature children are stronger
What does strength look like in adolescence and young adulthood?
Clear general trend is that males demonstrate greater strength then women in adolescences
Boys gain more muscle mass
The average adult male is stronger than the average adult female
Women only produce 60-80% of the force
Other factors may account for the differences
What did shepard’s study show?
Over a period of 3 visits females improved on each subsequent visit, whereas males didn’t
What is habitual physical activity?
Traditional physical activity for boys promote strength development more than girls
How does muscle finer composition affect strength in adolescence and young adulthood?
Differnece in muscle fiber composition in boys and girls
Davies found no gender relationship between strength and muscle fiber composition
Males are generally stronger, especially in the arms and shoulders due to greater muscular hypertrophy
What iare strength changes after cessation in growth?
After growth stops, increases in muscle mass are associated with resistance training
Culturally this is an activity more acceptable for males
What does strength look like in middle and older adulthood?
Generally maintained in 20s and 30s
Generally declines after 30sGradual at first
After 50s 18-20% loss
Gardner reported a 45% loss of strength after 65
What are additional factors of strength in middle and older adulthood?
Young found 39% loss of strength but only 25% loss in cross-sectional area in quads
Loss of muscle mass does not parallel loss of strength
Changes in muscle fibers (shrinking of type II)
loss of motor neurone in spinal cord
Reduction in number of capillaries/muscle fibre
What are other considerations of adult strength?
Some older adults do not lose strength(effected by exercise)
Difficult to determine if loss of muscle mass and strength in older adults is related to aging of tissues or disuse
What is stregnth training consist of?
Prepubescents can increase strength
-increase neurological coordination
-monitored to avoid injury
Adolescents and adults can increase strength and muscle mass with appropriate resistance training
What is flexibilty?
Ability to move joints through full ROM
Benefits sport performance
Limited flexibility can be a factor in jury
Joint specific
What are ACSM recommendations for flexibility?
1) 2-3 days/wk
2) all major muscle /tendon groups
3) static or PNF
4) 10-30secnds hold
5) 4 repetitions/ muscle group
How is flexibility assessed?
Each joint muscle be assessed
Goniometer is used
(axis placed over joint, instrument aligned with limb at extreme movement range)
Sit adn reach is common
What are developmental changes in flexibility?
Infants and toddlers are very flexible
Studies shoew flexibilty declines in childhood
Can be maintained or improved
Girls as a group are more flexible
In adolescence flexibility is varianle, some peole lose a significant degree
What are changes in sit and reach over age in girls?
Upper % at young age increase
Lower % at young age tends to decrease
What does ?flexibility look like in adulthood?
Lose flexibility, especially in the little used joints after 50
Maintain training maintain levels
Each joints has its own ROM
