A few weeks ago, I went into surgery because of an incarcerated umbilical hernia, which I noted one year ago. It had slowly been increasing in size, and could be uncomfortable, but it was treated medically until last month. Then it began causing intra-abdominal issues that were serious enough that it needed to be treated surgically. The surgical procedure went well with no major medical complications.
But it produced some non-medical complications. I had to give up my first 2019 A race, IRONMAN 70.3 Monterrey in May. That had a great psychological impact, not only because of the race, but the potential loss of the 2019 season's goals.
The surgery was in the pre-competition phase of my preparation, where I was training to reach race speed and fitness and perfect strategies after having developed enough muscular aerobic endurance and VO2max.
Post-surgery instructions included 5 weeks without any exercise - no swim, bike, run or strength training. After that period follows three weeks of only walking before returning to low intensity aerobic exercise.
According to scientific studies detrained or deconditioning occurs when you train below your exercise threshold or stop exercising completely.
Two weeks after ceasing training, it is possible to lose up to 7-14% of VO2max and after 4-12 weeks it is possible to lose up to 50% or more of VO2max.
Muscular force also suffers losses after detraining. The decrease in muscle force is due to the neural and muscular adaptations caused by the inactivity.
How fast the loss occurs depends not only on the age, fitness level, and how long the athlete has been exercising, but also on what type of exercise the athlete was doing and at what level.
What does this mean for my situation? I will lose a significant amount of VO2max after the 8 week period that includes passive rest and very low aerobic activity. Because of this loss, I must reschedule my season, and select other objectives and goals in accordance with my new physical status.
When returning to exercise following detraining or deconditioning, it is important to resume exercise with low to medium intensity aerobic exercise. It will begin a new preparation phase that will last 6-8 weeks for me. When resuming strength training, it's important to begin focusing on stability, flexibility, and balance then on muscular endurance and force.
Never resume exercise trying to perform high intensity anaerobic workouts.
Follow your certified coach's guidance to resume training, it is the safest way to resume exercise after a period of detraining.