Facts about "Detraining"- Meta-analysis

Are you a Fitness Enthusiast?, Then you may familiar with the term "Detraining". Sometimes you may have a question, 'What happens next if i 'Quit' my training?'. Here we are coming up with a relevant information for the question. Like how your body adapts to the training and changes occurs such as change in body composition, changes in physiological, Hematological & Metabolic activities, Reversing of all these training adaptations can occur if you quit your training. Let's see deeper into this topic,

What is Detraining (AKA, Reversibility Principle of Training): It is a process, in which your training adaptations will start decline, It occurs when person quits his or her training program. Partial or complete loss of training adaptations as a result of a training reduction or cessation. It occurs due to lack of compliance with an exercise program, Injury, Illness (or) a planned periodization transition phase.

(Note: All Physiological variables don't adapt at the same rate, So all physiological variables don't reverse at same rate, After only a week or two weeks of detraining, measurable reduction in physiological function occurs, Total loss of training improvements occurring within several months) 

Let's see the detraining effects of both endurance training & Resistance training as well.

What happens to the aerobic capacity when endurance training ceases? 

Primarily Maximal volume oxygen consumption starts declining (Reduction in VO2max). Why?, Because of the reduction in cardiac output(Q) & arteriovenous oxygen difference (a-VO2 diff) overtime with detraining.

Research Findings #1: 

                                     "Effect of Detraining on Endurance Training"

                                Research conducted for 10 trained individuals for 84 days of detraining. The scientists has observed changes on day 12, day 21, day 56 & day 84. 

On day 12 of detraining they've observed reduction in VO2max(-8%), Stroke Volume, Heart Rate & Arteriovenous Oxygen Difference). Here maximal volume of oxygen consumption reduces because of decrease in stroke volume. And stroke volume reduces due to decreased plasma volume. Clinically, Restoration of Plasma Volume can improve through infusion, In results it increases the maximal oxygen consumption to the pre-detraining level  

On day 21&84 of detraining they've noticed further reduction in VO2max, Stroke Volume, Arteriovenous Oxygen Difference. In addition to that, there is a decrease in muscle mitochondrial but the capillary density remains same. Following is the graphical representation of the research findings

Research Findings #2

  

                       "Changes in cardiorepiratory & Bioenergetics variables in detraining from endurance training"

Research conducted on 5 trained individual. The subjects were asked to take bed rest for 20days followed by 12 weeks of rigorous endurance training (5d per week). The experts have identified the considerable changes occurs only after the second week of detraining and it shows the subjects lose approximately 1% of aerobic capacity and capillary numbers within the trained muscles decreased 14% to 25% over detraining period. Following graphical representation shows the research findings

Question arises from the findings, 

"what happens, If my stored glycogen decreases in detraining?"

Low Muscle Glycogen can impair the magnitude of the strength training adaptations. In other words for the first week of detraining you may experience like you have lost lost muscle but actually that is not right, your stored muscle glycogen(mmol.g. wet per muscle) level reduces. Reduction of muscle strength and hypertrophy occurs within several months. 

Research Findings #3:

                        "Effects of Training, Detraining & Retraining on Resistance Training"

Another study has conducted in 20 subjects (Untrained Individuals), The subjects were trained for 20 weeks. In which, they have gained 60% dynamic muscle strength, hypertrophy in all three muscle fibers (Type-I, Type-IIa, Type-IIx). Followed  by 30 weeks of detraining and the scientists has observed reduction in 31% in dynamic strength. Afterwards 6 weeks of retraining has given to the subjects and experts found rapid regaining of muscle strength and complete restoration of muscle fiber size back. Rapid muscular adaptations occurs as a result of reinstatement of strenght training in previously trained individuals."This is the reason why athletes begin a reconditioning program several months before the start of competitive season. This speedy improvement in muscle strength during retraining explains how athletes can often return to competitive form quickly". Refer the following graphical representation

What changes occurs, If i quit my strength training?

Compared to endurance training, rate of detraining is lower in resistance training. Only after few weeks the training adaptations starts declining. Refer above graphical representation for detailed interpretation.

Basically, decreases in trained muscle cross sectional area, Muscle glycogen content, muscle fiber size can occurs. 

In the bottom line:

• Before answer to your clients or friends know about their training protocol, Understand their physiological adaptations because everyone has unique physiology all the above mentioned information are based on the research findings not intended to follow the same procedure. There are many facets in the detraining including poor nutrition in the detraining period.
• In order to avoid detraining, you can maintain moderate intensity of exercises can slow down the rate of deconditioning.
• Findings suggested to do, One total body strength training session per week is enough to maintain the muscle strength for 12 weeks of period. 
• Detraining rate is higher in endurance training when compared to the resistance training.