Effects of electromagnetic waves from cell phone on the hip abduction strength / 体力科学

No consensus exists regarding the effects of electromagnetic waves from cell phones on the human body, and no studies have investigated effects on the locomotor system. To elucidate the effects on muscle strength during cell phone use, the present study investigated changes in hip abduction strength, visual analog scale (VAS) scores, surface electromyogram (EMG), and Root Mean Square (RMS) value. Hip abduction strength did not differ from the NORMAL when the cell phone was powered off, but significantly decreased when it was powered on. Moreover, no differences were observed in RMS and VAS during muscle exertion between states in which the cell phone was powered on or off. Even if there had been a placebo effect or effects of pressure on the temporal bone, the finding that some form of environmental change associated with reproducing the state in which one talks on a cell phone affects the human body is unable to be dismissed. The findings in this case were attributed to reduced function of the central nervous system rather than peripheral muscles or the peripheral nervous system. However, the cause of these findings cannot be identified from the present study. In view of the facts that “muscle strength decreases under conditions in which electromagnetic waves, however small, are emitted from cell phones” and “there are no changes in ease of exerting strength in the subjects themselves”, it was considered necessary both to investigate the causes of these findings and to implement measures in response to these facts.

EVALUATION OF ELASTIC PROPERTIES OF ACHILLES TENDON AS A FACTOR OF APOPHYSITIS IN ELEMENTARY SCHOOL SOCCER CLUB MEMBERS / 体力科学

It is well known that extreme repetitive stress on the apophysis without considering the physical characteristics of children induces a growth disorder of the growing skeleton. However, only a few studies have evaluated the indexes of the muscle-tendon complex as a risk factor of apophysitis. The purpose of this study was to investigate the relationship between the elastic properties of the Achilles tendon, physical characteristics, muscle tightness (MT) and general joint laxity score (GLP), and tenderness from typical apophysitis (calcaneal tubercle, tibial tuberosity and iliac spine) in kindergarten and elementary school students. Body and lower leg size, and MT of the calf muscle increased ; while GLP decreased significantly with age. The Elastic index of the Achilles tendon and its standard deviations were greater among 5^th and 6^th graders than among 3^rd and 4^th graders. Point tenderness was more frequent in older age groups (4^th-6^th graders) than in younger age groups (kindergartren-3^rd graders) and was greatest in 4^th graders. When subjects were categorized into groups with and without point tenderness, no significant differences were found between GLP, muscle tightness of gastrocnemius, quadriceps and iliopsoas. However subjects who showed point tenderness had a higher Elastic index (p=0.07). Considering the pathomechanics of apophysitis, repetitive traction of the apophysis by a stiffer muscle-tendon unit lead to injury of the apophysis and growth plate. Tendon properties appear to be more sensitive to the pathomechanics of apophysitis.