LECTURE 2 Flashcards
What exercises are good for bone health?
Tennis, Running, and Dancing
What type of loading do bones respond best to?
Uncustomary or unusual loading - heterogenity is key and triple jump is the best
What is Wolff’s Law? + Example
When the bone undergoes remodeling in response to mechanical stresses placed upon it, leading to changes in the external form and internal architecture of the bone
EX: Bones of Racquet-Playing Arm = Stronger than Opp. Arm
What happens with mechanical loading and unloding of bone?
- During growth and periods of loading = PERIOSTEAL EXPANSION
- During aging and period of unloading= ENDOSTEAL RESORPTION
What is the Mechanostat Theory?
Responsiveness to typical strains within a physiologically safe range
Bone adapts to forces via ______ in order to _____
Modeling and remodeling; keep typical strains within a physiologically safe range
Bone is altered to satisfy its _______ and _____
physiological need and create a structure that is appropriate for daily activites of individual
What does peak strain theory determine/
Whether bone is added, maintained, or is taken away of fails (fracture)
What is minimum effective strain and what happens if it is exceeded?
It is a threshold that if exceeded osteoblasts add bone and increase it’s strength so that the deformation is reduced below this value
What are the principles for adaption of bone to loading
Principle 1: Specificity
Principle 2: Overload
Principle 3: Initial Values
Principle 4: Reversibility
Principal 5: Diminishing returns
What is Specificity? + example
Major impact of the activity is the site of stress; ex: Bicep curls
What is overload?
to effect change or gain in bone mass, the exercise stimulus must exceed normal loading
What is initial values?
Individuals with the lowest BMD have the greatest capacity for improvement
What are the steps of reversibility?
- Positive effect of exercise will be lost if the exercise is discontinued
- Immobilization will result in loss of bone
- Loss of bone strength is rapid in comparison with its return
What are diminshing returns?
- Each person has an individual ceiling that determines the extent of a possible exercise training effect
- As the ceiling is approached, gains in bone mass will slow and eventually plateau
If loading increases, bone will remodel at the site of stress to become ___
stronger to withstand the load
If loadings decreases, bone will remodel at the site of stress and become___
weaker since it does not have the same load
What is Articular cartilage?
Smooth, white tissue that covers the surface of all the joints in the body
- During cyclinical exercises (jogging) the cartilage thickens
- Better able to dissipate force during the dynamic action
What is Synovial fluid?
Viscous fluid found in synovial joints that helps with joint lubrication; Exercise makes synovial fluid less viscous
How do Articular Cartilage and SF interact?
Articular cartilage soaks up SF – thickens the cartilage and improves the supply of nutrients and removal of metabolic waste products
What are ligaments?
Passive stabilizing structures of the joints that connects bone to bone; physical activity causes the ligaments to become stronger with increase in collagen synthesis and increase in cross-linking
What are tendons?
Attach muscle to bone
What is osetoarthritis?
Thinning of the articular cartilage but thickening of the thick layer of under the articular cartilage
Risk factors
- Genetics
- Age
- Obesity
What is the female athlete triad?
A clustering of health problems that affect
- Energy in the body
- Menstrual cycles
- Bone health
- Cardiovascular health
- Musculoskeletal injuries
- Performance
What is energy deficiency?
State of chronic under nutrition is usually because the athlete fails to eat enough food to meet all of the exercise expenditure needs
Energy Intake – Exercise Energy Expenditure = Energy Deficiency
Bone remodeling with poor estrogen status leads to…
increased bone breakdown (resorption)
Bone remodeling with poor energy status leads to…
decreased IGF-1 and decreased bone formation
What is eumennorhea and amenorrhea?
Eumenorrhea: regular menstrual cycles of 26-35 days
Amenorrhea: absence of menses for at least 3 months; NOT a normal response to exercise training it causes very low estrogen levels and poor bone health
What are stress fractures and factors that increase the risks?
Accumulation of microcracks within a bone often due to participation in repetitive activities within inadequate rest and poor nutrition
- amenorrhea, low bone density, 12 hours+ physical activity
Most common affects regrading the male athlete triad
Restrictive eating, dieting for thinness and body image disturbances
