The tight upper trapezius muscle structure is due to posture. If you look around most individuals have some degree of tightness in their upper trapezius due to gravity acting on our shoulders whenever we are standing, sitting, etc. Most people lose awareness of their slopping shoulders which should be, in a normal length-tension relationship, at about a 90 degree angle (squared shoulders). Although there are exercises (such as trapezius shrugs) and programs such as Muscle Activation Techniques, which may help, the true “cause” lies within your posture and becoming aware of it. So in other words, even if you attempt to alleviate the tight upper trapezius muscle structure it is not going to be worthwhile if your clients are in a poor posture with slopping shoulders all day while at work or home. What most people tend to forget is that client success extends further then the fitness club. Therefore to alleviate the shoulder tension, a successful program should be incorporated to encapsulate their health throughout the day. Feel free to ask me any other questions or I may suggest looking into the National Posture Institute which focuses on the entire spectrum of musculoskeletal health as well as physiological. www.npionline.org
Try to look it the other way… why are the upper traps so tense. Some other muscle (portion) is not doing their job. To keep function and stability, the motor programs are establish overloading the traps. Look for muscles with the same function as the traps and try to test them. Look at Muscular Activation Techniques from Greg Rosckopf.