PT on the Net Research

Post Virus and Weak Muscles


My client came down with a virus about two weeks ago. He just resumed weight training this week, and he noticed that his pulling muscles are as strong as ever (he can row and chin and lat pull as much as he did before the virus), but his pushing strength has really been affected by the virus. He can't bench or dip as much as he could before the virus. I've never heard of viruses affecting one muscle group more than another. I thought viruses have a systemic effect. Have you guys ever heard of a similar situation? Any ideas on how to better explain this strength discrepancy to my client would be appreciated.


In all my years of working in hospitals and rehabilitation centers, I have never heard of one particular virus affecting one group of muscles and not others. Of course, there are certain diseases that do, but in this situation, I can’t pinpoint anything to it. In most cases such as this, I personally feel it is more a psychological experience than anything else.

When we become sick, there are a lot of things physiologically, physically, nutritionally, etc. that can affect us during as well as after we recover. Certain things you need to look into are: Did your client lie in bed for two weeks or was he sitting on a couch? Did he work? What did he drink and/or eat (or NOT drink and/or eat?)? The answers to these questions will play a big part in answering some of your questions.

We have muscles in our body that are phasic:

  1. Fast twitch
  2. Prone to inhibition
  3. Mostly used for movement
  4. Have early susceptibility to fatigue
  5. React to faulty loading by weakening

We also have muscles that are tonic:

  1. Slow twitch
  2. Prone to hyperactivity
  3. Mostly postural muscles
  4. Have high endurance threshold
  5. React to faulty loading by shortening

So, when your client was sick with this “virus,” if you look at the above, most of his phasic musculature became short and tight, and his tonic musculature became lengthened. This creates a flexion/extension imbalance throughout the entire body. Thus, when working out, most people will use their global movement muscles for everything, negating the important use of the tonic postural system. This could be giving your client the psychological experience that he is stronger.

Another area to think about is that most Americans do have a flexion/extension balance in the body, secondary to working more and moving less. So we see most Americans hunched over at their desks all day, and when they get up, they look the same. There are more people with Upper Cross Syndromes walking around with short thoracic flexors and short cervical extensors and elongated long thoracic extensors and deep cervical flexors.

In the case of your client, maybe taking time off during his sick state allowed his overly shortened muscles to relax, giving him more ROM and more use of his extensor muscles, thus providing him with the experience that he is stronger when, in reality, he just has increased ROM. This is just a thought that might make sense.

One more idea is this: most people over train and think more is better. Maybe taking time off gave his body the rest it needed to recover so he is actually at his potential. Maybe he is working out too much, which is creating pattern overload and lack of recovery and is pulling him away from his potential?

Good luck!