Can muscle tightness affect lung capacity?

It might. If your muscles are tight, or painful, there will be limitation to expansion (inspiration) or expiration, making the lung capacity measurement less reliable.

Related Questions

What does 70% lung capacity mean? Can it be caused by tight muscles?

Usually seen as a- -result of PFT's & it means after all the tests are done, it means you have 70% lung function compared 2 what is expected 4 Ur age, weight & height. Causes can be smoking, second hand smoke or some other cause such as asthma. Read more...