Bone Study Questions

Question 1

1) Draw a labelled load-deformation curve for a hypothetical bone under compressive loading and indicate the elastic and plastic regions of the curve. Describe the differences between the mechanical events that occur within the elastic and plastic regions.

Answer 1

• it indicates that the elastic region is when tensile strength is placed on the bone as the load placed on the bone starts to increase. A minimal amount of deformation occurs in the elastic region because the strength of the bone can handle the certain load being placed.

Question 2

What are the basic differences between load-deformation and stress-strain curves and in what circumstances might you use each?

Answer 2

• The load-deformation curve is used to measures the amount of load that the bone can withstand until elastic compression becomes exceeded.
• The circumstances that can be used in the load-deformation curve is measuring overall bone strength based on its bone mineral density and bone mineral content, and how much load can the bone be placed under until the failure point is reached.
• .The circumstances that can be used in the stress-strain curve is measuring the amount of stress and strain is being applied

Question 3

Bone is said to behave in an anisotropic manner. What does this mean? What is the basis for this anisotropism?

Answer 3

Differences in strength depending on how we load the bone
- The basis for anisotropism is that the bones that are used for everyday human movements are becoming stronger based on the different types of loads that are experienced and the amount of stress and strain applied towards the bones.

Question 4

How does calf muscle activation affect the stresses applied to the tibia and fibula that are experiencing a bending force as a consequence of a skiing accident that involves sudden deceleration of the skis?

Answer 4

When a skiing accident occurs which causes a sudden deceleration of the skis, both the tibia and fibula experiences a large amount of force from the sudden impact and this then causes bending to be applied to the tibia within the ski boot which then creates compressive and tensile stresses. Then plantar flexor activity counters the tensile stresses otherwise experienced by the posterior cortex. The muscles that surround the tibia and fibula can help with redistributing the loads from the sudden impact that would otherwise be placed on the bones. The tension of the soleus muscles is the main contributor towards limiting tensile forces going to the bones and creating some damage to the bone structure of the tibia and fibula

Question 5

Describe the impact of loading rate on bone stress-strain curves, the effect that different loading rates have on the amount of energy absorbed before failure and the types of fractures that may occur.

Answer 5

During the slow loading rate, a low amount of stress is applied towards the bones because the bones are used to experiencing that sort of loading rate throughout everyday life. The slow loading rate also has a longer strain period. This is an ideal loading rate in order to reduce the chances on injury and bone fractures while performing a certain activity. The moderate loading rate has a medium amount of stress and a longer strain because there is a significant increase in stress towards the bones compared to the low loading rate. The fast loading rate has a high amount of stress towards the bones and a short amount of tension because there is a significant increase in stress and a significant decrease in strain towards the bones compared to the low and moderate loading rates. - The type of fracture that can occur as a result of the bone being under high stress and a shorter strain period is simple fracture. The type of fracture that can occur as a result of the bone being under low stress and a longer strain period is compound fractures

Question 6

) Growing bones and the surrounding musculoskeletal structures are more prone to certain injuries than the same structures in the adult. Describe (don’t just name!) one common epiphyseal injury that is known to occur in adolescent athletes and discuss the mechanism(s) (causative factors) of that injury.

Answer 6

• The one common epiphyseal injury that occurs within adolescent athletes is the Salter-Harris fracture.
• Salter-Harris fractures are fractures through a growth plate. These fractures are categorized according to the involvement of the physis, metaphysis, and epiphysis of the bone.
• A type 1 fracture is a transverse fracture through the hypertrophic zone of the physis. A type 2 fracture occurs through the physis and metaphysis; the epiphysis is not involved in the injury. A type 3 fracture is a fracture through the physis and epiphysis. A Type 4 fracture involves all 3 elements of the bone, passing through the epiphysis, physis, and metaphysisA type 5 injury is a compression or crush injury of the epiphyseal plate, with no associated epiphyseal or metaphyseal fracture.

Question 7

Describe the impact of aging (between 1 and 90 years) on bone’s mechanical properties and its responsiveness to exercise training.

Answer 7

bones can lose its mineral content and become less dense which then causes a minor reduction in stress tolerance and a significant decrease in strain tolerance to the bone when placed under load.

Question 8

What are the essential features of an exercise program that is designed to reduce the risk of osteoporosis? This answer must include information regarding the types of exercise and the frequency and intensity at which these exercises are optimally performed. It should also consider the optimal age groups that should be targeted most energetically when recruiting subjects for this program. (There should be ~1-1.5 A4 pages of answer here!).

Answer 8

• • weight-bearing aerobics exercise such as dancing.
• resistance training using free weights such as dumbbells and barbells, elastic band resistance, body-weight resistance or weight-training machines.
• exercises to improve posture, balance and body strength, such as tai chi.