Injury Zoe

Question 1

What are the considerations of injury

Answer 1

Type:

• Contact vs Non-contact
• Elite vs non-elite
• Knee vs other injuries

Implications

• Physical
• Psychological
• Societal
• Economic

Question 2

Early phases of injury

Answer 2

• Complete limb immobilisation (6-12 weeks)
• Total state of disuse (local)
• Elite athletes may experience muscle-tendon atrophy

Question 3

How much muscle tissue do we lose when inactive?

Answer 3

• 1 week single leg immobilisation- 200-300g muscle

- 1 week whole body bed rest- 1.5-2kg muscle

Question 4

Studies performed to examine disuse

Answer 4

Animal (rodent)- hindlimb suspension

Human models:

• Limb immobilisation
• Bed rest

Question 5

Dietary adaptions to minimise tissue loss during injury

Answer 5

• Fall in activity levels = fall in energy expenditure
• Continuation of normal eating habits = overeating (fat gain)
• Undereating = acceleration of muscle atrophy
• Recommendation is to maintain energy balance

Question 6

Energy balance in athletes (evidence for diet adaptions)

Answer 6

Biolo et al (2007)

• Calorie restriction accelerates the catabolism of lean body mass during two weeks bed rest
• Average -0.3kg/14d difference using eucaloric diet compared with 1.1kg/14d using hypocaloric diet

Question 7

Impact of macronutrient intake when trying to maintain energy balance

Answer 7

• Dietary protein is key to maintaining muscle mass in all circumstances
• General recommendation for athletes to maintain muscle mass and aid reconditioning is 1.6g/kg body mass of protein

Question 8

Other macronutrient recommendations when injured

Answer 8

Carb and fat can be reduced to allow for increased protein consumption

Question 9

Fractional muscle protein turnover during disuse

Answer 9

1-2% per day

0.04 - 0.14%/h breakdown/synthesis

Question 10

Protein intake in the injured athlete

Answer 10

• At least 20-30g dietary protein with each meal
• Meals should contain high leucine content (2-3g)
• Type of protein affects post-meal muscle protein synthesis rates

Question 11

Timing of ingestion?:

Answer 11

• Consume smaller, frequent meals (4-6 a day) containing adequate protein
• Protein ingestion prior to sleep can help achieve this

Question 12

Why care about muscle atrophy in injury?

Answer 12

• Strong predictor of severity and length of rehab/recovery process until full functionality
• Severe injury recovery process can last 12 weeks to over a year

Question 13

Wall et al (2013)- Disuse Atrophy:

Answer 13

Loss of CSA%, lean leg mass, and strength all higher after 14 days compared with 5

Question 14

Consequences of disuse:

Answer 14

• Reduced strength
• Reduced endurance
• Reduced Specific functional capacities
• Reduced insulin sensitivity
• Reduced Energy expenditure
• Increased fat deposition

Question 15

Can muscle disuse atrophy be prevented using neuromuscular electronic stimulation? (NMES)

Answer 15

Daily NMES prevented significant decreases in quad CSA vs control group (-0.8% vs -3.5%)