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Deconditioning: The Reversibility of Training
July 14, 2020

March 28, 2020. This was the last time I was at the gym just prior to its closure due to the covid pandemic lockdown in Edmonton. That is 15 weeks or 3.5 months ago. However, mentally and physically, it seems so much longer. As a physiotherapist, I am aware of the effects of deconditioning if I had stopped strength training completely. During this time, I was also training to run a half marathon and I could not afford to stop strength training. Fortunately, I have some access to weights, a TRX, plyometric boxes and resistance bands at my Clinic. At home, I loaded a backpack full of anything I could find that was heavy and did a lot of body weight exercises, single leg squats and heel raises. However, like many of us, I missed the heavy loads and the variety of exercises that only a gym could provide.

Deconditioning is the loss of training adaptations that occurs when one stops exercising. This applies to strength training and cardiovascular exercise. The extent of this loss is dependent on many factors and is not the same for everyone. People who have a longer exercise history, who have a higher initial strength and fitness level and who are younger will experience less of a decline.

So, what physiological changes can you expect if you had stopped strength training altogether this past 3 months?

kettlebellsIn a study of older males aged 80+ years old, these participants started an 8 week resistance training program. This was followed by a cessation of the said program for 6 weeks. At the end of 8 weeks of training, muscle strength improved by 44%. At the end of the 6 weeks of stoppage, they only lost 25% of their gains (Kalapotharakos et al, 2010).

What is the take home message from this study? Be encouraged! The cessation of training for a short period of time does not result in a complete loss of your strength gains.  Once we lose strength from detraining, how long does it take to gain it back?

A recent study by Blocquiaux et al (2020) took older males and started them on a 12 week whole body resistance program. Then they stopped for 12 weeks (just like us!) and then re-started them back again on the same training program for 12 weeks. So: training-detraining-training. What were the results?

Training: A 22% increase in knee extension strength at 8 weeks and 36% at 12 weeks.

Detraining: A 14% reduction in strength (again, not all is lost; participants were still 22% stronger compared to when they started the study)

Training: 24% increase from when they stopped. So, these participants were stronger at the end of the second 12 week period of training than they were after the first. It would have taken them only 8 weeks to regain what they had lost in 12 weeks.

Let’s take this further. What if someone detrains for a whole year? In a study by Correa et al in 2016, participants this time were female. In the first 12 weeks of resistance training, their gains were 75%. After a year of deconditioning, they lost nearly all of their gains, understandably so. But after 12 weeks of retraining, they gained 40% of their strength back, and on average, most were only 15% short of prior to stopping.

Take home message? Regardless of how long you have stopped exercising, the key is to return to it again and the time it takes to regain your original fitness levels is much shorter than the period of deconditioning.  This is very encouraging.

In summary, what can we learn from all of these studies?

  1. When it comes to strength and cardiovascular endurance, you either “use it or lose it.” Deconditioning can occur very quickly especially during periods of bed rest or immobilization.
  2. Older people (80+ years old) can make incredible gains in muscle strength with resistance training. It is never too late to start and this is vital to combat the losses resulting from sarcopenia.
  3. All is not lost. Stopping exercise for an equivalent period compared to the period of training does not mean that you will lose all of your gains. In some situations, the loss can only be half. Of course, this will depend on many factors as mentioned earlier.
  4. You can regain your original strength levels in a shorter time period compared to the duration of cessation.

Reducing your loads is vital if you have not lifted for 3 months.

The caveat in all of these studies is that the participants were all healthy with no pre-existing injuries or medical conditions. If you are struggling with an injury or if you were strength training to rehab a pre-existing injury, then the time lines for these gains and losses can vary greatly and will most likely not follow a prescribed time line. It is best to take a more conservative approach in these cases: allow for a minimum of a 1:1 ratio for retraining. So, if you had an injury prior to the covid lockdown, then it’s best to allow 3.5 to 4 months at a minimum to return to pre-lockdown levels.  Also, be sensitive to your emotional and mental health as well as burnout, prolonged negative stress levels, fatigue, anxiety, and depression for example will surely have an impact on your physical health as well.

A return to the gym is an exciting time for many of us. Understandably, some of us will still abstain from attending public gyms. Regardless, the key is to return to some form of strength and cardiovascular training as soon as possible. And if you start today (mid July), be assured that your body will thank you and will mostly likely reward you with gains back to pre-lockdown levels by mid September.

If you do choose to attend a gym, be careful. Enjoy and give yourself at least 3 months to regain your pre-lockdown strength but take more time if you need it.

Submitted by Albert Chan and adapted from an original article written by Claire Minshull, used with permission.


Kalapotharakos et al. Effects of resistance training and detraining on muscle strength and functional performance of older adults aged 80 to 88 years. (2010). Aging Clin Exp Res,22(2): 134-140.

Blocquiaux et al. The effect of resistance training, detraining and retraining on muscle strength and power myofiber size, satellite cells and myonuclei in older men. Exp Gerontol. May;133:110860. doi: 10.1016/j.exger.2020.110860. Epub 2020 Feb 1.PMID: 32017951

Correa et al. Effects of strength training, detraining and retraining in muscle strength, hypertrophy and functional tasks in older female adults (2016). Clin Physiol Funct Imaging. 36: 306–310

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