I’ve always been a basketball boy, though I haven’t played competitively for a few years. When I’m home for the summer it’s hard to resist the playground temptation so I lace up my kicks and cycle for some hoops. My younger life was characterised by a single obsession: jumping higher. Well, you don’t care about this intro but it’s the natural setting for this post.
So, back to the playground after an entire year of little or no jumping, expecting the worse and ready to consider my 23 old body for retirement. Not really, time a few sessions and my jumping is back to all time standards and rising, if I add some specific training.
The tale might be explained with a phenomenon that seems to occur within muscles, or rather a quality that was named ‘Muscle memory’. Pretty intuitive as it sounds, the locomotors of your body probably remember they were trained in the past and they are able to quickly recover that status, so your original ability is back in the game.
How we store this information?
Most believed this was the central nervous system learning particular movement patterns which are retained somewhere in the brain and kept latent until you need them again and this is easily noticed in specific movements like shooting/kicking a ball or riding a bike. This might also affect the skill of generating force, accounting for muscle memory and the rapid recovery of strength after long periods of detraining.
Is this telling the whole story?
Probably not. It was found that muscle strength and hypertrophy (enlargement) after a resistance training program is preserved for long detraining periods, meaning that even long after stopping a training program, your muscles may be stronger than if you never trained at all. Local happenings within the muscle may determine muscle memory, changes in the muscle cell that reflect a long lasting training effect.
In the gym a muscle is overloaded and this stimulates an adaptation that should result in increased strength and size. The mechanisms regulating the translation between the mechanical input (moving the weight) and its effect are not completely understood. One theory preaches that for enlargement to occur there is a need of increasing the number of myonuclei in the muscle cell (google ‘satellite cells’ to learn more).
Bruusgaard et al found that the number of myonuclei increased after an overload (representing training) and was probably leading to muscle growth. The interesting bit is that when trained animals were denervated, a process that leads to the loss of muscle mass-atrophy, the number of myonuclei did not decrease. The muscles were atrophied, shrinked and weak but their nuclei count was maintained as right after the overload, with more nuclei than a healthy-non atrophic muscle that had never been trained.
Does the storage of a high number of nuclei in the muscle represent muscle memory?
It is indeed possible and when in need the previously-trained muscle may grow quickly back to how it was before the period of detraining, skipping the step of increasing the number of myonuclei, as these exist already. This is a sort of shortcut that accelerates re-training and strength recovery.
A final doubt on sports ethics arises: If the muscles of athletes with a history of doping ‘remember’ some of the effects of the enhancing drug, even after a long period of disqualification, this might result in cheating even when the athlete is presently clean. Should these competitors be banned for life? Only future research can tell.