effects of static and dynamic stress
As we are nearly always moving, muscles are in almost constant use. Harmful lifting practices can mean bruising or tearing of muscle tissue, or discomfort due to static posture which you have just experienced!
As an example consider which muscles ache after a day working in the garden. Usually the back muscles because they have undergone ‘static’ work whilst the arms have been working dynamically. Sprains are the largest group of handling injuries .but back injuries are far more serious and painful.