Detraining

Question 1

What is detraining

Answer 1

• Ceasing training or reducing training volume decreases physiological and performance capacities
• Short term detraining (<4 weeks) can result in significant decreases in endurance and strength performance
• Detraining is at least as rapid in elite populations

Question 2

What aerobic changes occur after 0-12 days

Answer 2

• 4% decrease VO2 max in 4 days
• 6-7% decrease in 12 days
• Due to decrease in SV associated with 6-7% decrease of PV
• HR and a-vO2 difference remained unchanged
• One week of bed rest can result in 6-7% decrease in VO2 max, 6-7% decreases in total haemoglobin and 6-7% decrease in blood volume

Question 3

What aerobic changes occur after 21-84 days

Answer 3

• Most training benefits are lost within 4 weeks of cessation of training
• 14% decrease in VO2 max in 4 weeks
• 20% decrease VO2 max in 8 weeks
• Complete detraining effect may take several months and decreases Q, SV, ventricular mass, a-vO2 difference, capillary density, fibre CSA and oxidative enzyme capacity
• Increase in sub-maximal HR

Question 4

What strength and power changes occur in first 4 weeks

Answer 4

• 15% decrease in power
• 6-10% decrease 1RM
• 14-17% decrease peak power output, due to decrease EMG activity, atrophy in Type II (fast-twitch) fibres and decreased neural drive (motor unit recruitment)

Question 5

What strength and power changes occur following 12 weeks - 30 weeks

Answer 5

• 12 weeks cessation resulted in 68% decrease in strength

- 30 weeks sees 31% decrease in strength

Question 6

What aspects of adaptations are able to be maintained over time with reduced training load

Answer 6

• Decreasing frequency from 3 to 2 days per week while maintaining intensity, maintains VO2 max for 10 weeks
• Decreasing from 3 to 1 days per week does not totally prevent a decline in VO2 max
• Decreasing to 1 day per week results in a 7% decline in VO2 max over 10 weeks
• Reducing training time from 40 minutes per day to 26 can maintain training benefits (35% decrease in time)
• Reduce to 13 minutes is not sufficient to maintain long term benefits for 15 weeks (~68% decrease in time)

Question 7

What is retraining

Answer 7

• There appears to be little indication of a benefit or positive transfer from one training period to another
• Possibly accelerated retraining rates in previously highly trained athletes after a long lay-off, this may be due to genetic predisposition