Skeletal muscle is the dominant organ in locomotion and energy metabolism so that maintaining skeletal muscle function is a prerequisite for our health and independent living throughout the life. A loss or decrease in skeletal muscle function leads to increased morbidity and mortality through the development of secondary diseases such as metabolic syndrome, type 2 diabetes, obesity, cardiovascular and respiratory disease. Identifying mechanisms which influence the processes regulating skeletal muscle function is a key priority. The recent discovery of microRNAs (miRNAs) provides a new knowledge controlling skeletal muscle function. miRNAs suppress gene expression through either in inhibition of protein translation or in degradation of the mRNA transcripts through a process similar to RNA interference (RNAi). This review provides the current understanding in skeletal muscle miRNA biology and focuses on their role and regulation under physiological conditions with exercise.
The purpose of this study was to clarify the relationship between the low back pain of college students and psychological factors by using a questionnaire for low back pains and five psychological tests. The tests consisted of the Hopkins Symptom Checklist (HSCL), State-Trait Anxiety Inventory (STAI), Purpose in Life (PIL) test, Hassles Scale for students and Type A test. The subjects were 337 college students (126 male, 211 female) ranging in age from 19 to 22 (mean ± SD: 20.2 ± 1.3) years. Seventy-four subjects whose lower back pain was thought to be caused by organic factors were excluded. The 263 subjects (102 males, 161 females, mean ± SD: 20.1 ± 1.1 years) were divided into three groups (NP: subjects with no pain, PND: subjects with pain but no difficulties in daily life, PD: subjects with pain and difficulties in daily life) by degrees of low back pain. The PD subjects showed a more negative attitude than those in the PND and/or NP groups for four tests, i.e., Hassles Scale and the psychosomatic component of the HSCL and State-Trait Anxiety Inventory tests. It was suggested that low back pain was related to psychological factors such as stress and anxiety.