Bone Flashcards
What is the impact of Estrogen on bone modelling?
It inhibits osteoclast resorption and periosteal formation
As we age, what happens to our bone in terms of the size?
The size increase via periosteal bone formation
But we lose endocardial bone via resorption
What cell can become an osteocyte
Osteoblasts
Osteoclasts take how long to eat away at bone?
3-4 weeks
Full osteoid mineralisation takes how long?
About a year
Over what timeframe does activation of osteoclasts occur?
10 days
A bones ability to resist mechanical load comes down to what three factors ?
- Quantity - mass and density
- Organisation - architecture
- Quality - mineral, micro damage, collagen
What are the 6 risk factors for RED-S
- BMD <1
- 12 hours or more of exercise a week
- BMI <21
- Oligo-amenorrhea
- Elevated dietary restraint
- Participation in “leanness” required sports
What was found to be an effective CMJ dosage program for improving bone density
20 jumps, 3 times a day and 3 times a week
What is the most common BSI region in basketball ?
MT
Three most common regions for BSI in long distance running ?
Tib/Fib
MT
Femur
Name 5 high risk BSI regions?
- Femoral neck
- Anterior tibial cortex
- Navicular
- Base of 2nd MT
- Proximal shaft of 5th MT
What is the first stage of imaging algorithm in a suspected BSI?
X-ray - if negative and not suspected at a high risk site, then crack on
What is the T vs Z score?
T = BMD compared to 30 year old healthy sex matched
Z = BMD COMPARED TO AGE AND sex matched individual
At what point does someone have OP
-2.5 points below where the should be
What does QCT stand for
Quantitative computer tomography
With bone loading, is volume or intensity more important ?
Intensity
Uphill and up stairs compared to flat, what’s the difference for born stress
Uphill is much less force through the bone
What loads the bone more, overground or treadmill running?
Overground
What loads the bone more, stair climber or treadmill?
Treadmill
What three factors reduce when increasing cadence ?
- Step length
- Vertical excursion
- Braking force
How does increasing cadence reduce braking forces
Leads to less overstriding, which results in a more vertical tibia = less eccentric loading through tibia
What is the leading hypothesis for how osteocytes sense mechanical load ?
Compression side of the bone cause fluid to flow to the tension side
What two exercise factors need to be high to induce adaption to bone cells?
Magnitude - think resistance training
Rate - think ploys
What’s the optimal dosage for bone loading programs
Bone goes deaf after around 20-30 loading cycles
Over what period of time do bones resensitise and therefore are able to be loaded again ?
4 hrs restores 75%
8 hrs restores 85%
When can you only develop bone size?
When young
When does periosteal absorption occur?
It never does. Your bone loses endocortical mass (from the inside) as you age
How well does bone size last through the life span if you’d played sport younger?
Size and strength generally remains throughout the life span, mass does not
Exercising during growth enhances what bone qualities ?
Mass and size
After developing a robust skeleton from adolescence, what qualities can remain into older age?
Size and strength
