The results showed that the repetitive work to fatigue diminished the shoulder proprioception; the working time as well as the retention of subjective fatigue were partly related to the extent of changed proprioception. The findings indicate that, the longer one works to reach subjective fatigue, the longer the sensation is retained, and the greater the impairment of the position sense acuity.
The second part of the thesis explores the effects of muscle stretching on sensory mechanisms and nociception. Results showed that there was no effect of acute muscle stretching on the proprioception. A new method for testing muscle stretchability proved valid and reliable. A two-week stretching regimen increased the tolerance to stretch torque, but the range of motion remained unchanged. Finally, the experimental animal study showed that muscle stretching partly acted on the same dorsal horn neurons that responded to chemical stimulus of muscle nociceptors, and that the stretching could counteract the cell reaction induced by the chemical stimulus. This suggests that physiological static muscle stretch has the ability to counteract the response of the nociceptive dorsal horn neurons.