LEC21: Osteoporosis and Physical Activity Flashcards
What is osteoporosis?
A condition where blood calcium levels (i.e. calcium in the extracellular fluid) are depleted which leads to a loss of mineral mass from bones
Osteoporosis: when bone resorption (blank) bone deposition
Exceeds
What is bone resorption controlled by?
Osteoclasts
What is bone deposition controlled by?
Osteoblasts
When someone has osteoporosis, they will…
have weak and fragile bones and an increased risk of bone fractures
When an individual has osteoporosis, they will have (blank) without any obvious symptoms (‘the silent thief’)
Bone loss occur
What is bone mass?
Refers to the weight of the skeleton
What is bone mineral density?
Refers to the ratio of weight to the volume or area of the bones
What is the basic assumption of heavier bones
It means stronger bones
Approximately (blank) Canadians have osteoporosis
2 million
(blank) women and (blank) men have osteoporosis
1 in 4, 1 in 8
Can osteoporosis strike at any age?
Yes
What are the most common sites for fractures?
Wrist, shoulder, hip, and spine
What are the areas most commonly affected by osteoporosis?
Spine, wrist, hip
What do vertebral fractures in advanced osteoporosis look like?
Bones become thinner and weaker with osteoporosis. Overtime, bones in the spine can become thin and collapse causing a person to hunch over
The line of gravity due to a kyphotic deformity
In a normal spine, the forces are distributed equally on the surface of the endplate avoiding stress peaks. The kyphotic deformity creates asymmetrical loading of the endplate which increases the risk of further fractures and increasing deformity
“wedge fractures”
“dowager’s hump”
What are factors affecting bone mineral density gains in childhood and adolescence
Genetics, mechanical forces, risk factors, nutrition, hormones, gender
Change peak bone mass (account for 60=80% of the peak bone mass variance)
Factors that affect calcium levels
- Dietary calcium
- Dietary vitamin D
- Alcohol intake
- Smoking
- Regular exercise
- Estrogen
Factors that affect calcium levels: dietary vitamin D
“Osteoporosis Canada’s new guidelines (July 2010)
- Recommended daily supplements of 400 to 1000 IU for adults under age 50 without osteoporosis
- For adults over 50, supplements of between 800 and 2000 IU are recommended.
- A daily supplement of 800 IU should be regarded as a minimum dose for all adults with osteoporosis.”
Factors that affect calcium levels: alcohol intake
A diuretic that causes calcium to be excreted in the urine
Factors that affect calcium levels: smoking
Decreases activity of osteoblasts
Factors that affect calcium levels: regular exercise
Weight bearing or resistance training makes bone respond (activates osteoblasts)
Factors that affect calcium levels: estrogen
- Lack of estrogen decreases the ability of the intestines to absorb dietary calcium
- Lack of estrogen decreases the ability of the kidneys to reabsorb calcium
- Post-menopausal women – calcium levels in the extracellular fluid (ECF) are low – bone resorption occurs to try to bring the ECF calcium levels back to normal
Effects of exercise and calcium intake on BMD in post-menopausal women
Most effective when taking calcium and having exercise
What is the purpose of physical activity for individuals with osteoporosis?
- Improve BMD: to decrease fracture risk
- Improve muscular strength: to decrease fall risk, to decrease fracture risk
- Improve balance and posture: to decrease fall risk, to decrease fracture risk
What will an improvement in bone mineral density (BMD) cause?
A decrease to fracture risk
What will an improvement in muscular strength cause?
A decrease in fall risk and fracture risk
What will an improvement to balance and posture cause?
A decrease in fall risk and fracture risk
How can you increase bone mineral density (BMD)?
You need to put stress on the skeletal system which can be done through activities
What two types of activities increase bone mineral density (BMD)
- Ground reaction forces (GRF)
e.g. walking, jogging, stair climbing) - Joint reaction forces (JRF)
e.g. weight lifting, rowing, cycling
What activities helped increase bone mineral density (BMD)?
Aerobic activity: higher intensities (85-90% of HRmax)
Resistance training: training with loads of > 80% 1 RM
Many of the studies that have looked at the effect of exercise on BMD in older adults have found (blank) changes in BMD.
no change or only very modest increases
(blank) is a more realistic outcome than increasing BMD.
Maintaining BMD
To decrease fracture risk, a better approach may be to focus on what?
Muscle strengthening and balance and postural
training
Decrease fall risk which will decrease fracture risk
What therapeutic goals should be targeted in individuals with osteoporosis?
- Fall prevention
- Safe movement or spine-sparing strategies
- Prevention of further bone loss
Prevent fractures via: fall prevention
Improve dynamic balance, mobility, muscle strength, posture
Prevent fractures via: safe movement or spine-sparing strategies
- Attention to posture during movement to protect the spine
- Train back extensor muscles to improve endurance
- Stretch muscles restricting optimal posture
Prevent fractures via: prevention of further bone loss
- Exercise may not have a certain effect on bone mineral density
- Muscle strengthening and weight-bearing dynamic exercise
What are recommendations for older adults with osteoporosis or osteoporotic vertebral fracture?
- Strongly recommend that individuals with osteoporosis engage in a multicomponent exercise program that includes resistance training in combination with balance training
- Recommend that individuals with osteoporosis do not engage in aerobic training to the exclusion of resistance or balance training
Exercise considerations for osteoporosis
- Weight bearing (stimulates bone growth)
a. Aerobic modalities: walking, jogging, low impact aerobics, stair climbing, weight bearing sports (bowling, tennis, badminton, volleyball, etc.)
b. Resistance training modalities: machine weights, free weights, body weight, resistive bands/tubing - Postural training: to strengthen muscles in trunk and those supporting the spine
a. Protraction and retraction of scapula
b. Consider training seated and standing posture
c. Consider isometric exercises to avoid compression of the vertebrae in the spine (see contraindications) - Balance training: to decrease fall risk (and therefore to decrease fracture risk)
Contraindicated movements for osteoporosis
- Large amounts of spinal flexion (forward) or extension (back)
- Large amounts of lateral flexion of the spine (side to side)
- Large amounts of twisting or rotation of spine
- Large amounts of loading through the spine (e.g. jumping)
End-range trunk flexion for individuals with osteoporosis:
instead of (blank), do (blank)
instead of: yoga/pilates movements that involve flexion
Do: supported flexion, not to end-range
eg. modified downward dog with hip hinge and chair
End-range trunk rotation for individuals with osteoporosis:
instead of (blank), do (blank)
Instead of: trunk rotation machine or twisting movements for abs
Do: side plank on wall or floor
Instead of: yoga/pilates twisting postures
Do: slow, controlled twisting in supine
Precarious balancing for individuals with osteoporosis:
instead of (blank), do (blank)
Instead of: standing on a chair
Do: use a step stool with a wide base of support and non-slip materials on the stepping surface and interface with floor
Bending or lifting for individuals with osteoporosis:
instead of (blank), do (blank)
Instead of: forward bending with spine, or lifting load away from body
Do: bend with knees and hips not spine. Use lower body to help lift. Stand close to load when bending, hold load close to body
Turning, with or without load in hand for individuals with osteoporosis:
instead of (blank), do (blank)
Instead of: twisting with feet planted
Do: step to turn, so that leading foot and torso face same direction
