This study investigated the effect of treadmill running speed on bone mechanical strength in ovariectomized mice. Fifty female ICR mice were either ovariectomized (OVX, n = 40), or sham-operated (SHAM, n = 10), and the OVX groups were further randomly divided into OVX control, groups A, B, and C. Groups A, B, and C ran for 25 min/day and 5 day/week for 10 weeks at speeds of 8, 16, and 24 m/min, respectively. The bone mechanical strength of femur and tibia in OVX group was significantly less than that in SHAM group. Though the reduction of the bone mechanical strength of femur and tibia in OVX group was more than 20%, treadmill running inhibited those of femur and tibia, which were less than 15% and 10%, respectively. Compared with groups B and C, the bone mechanical strength of tibia in OVX group significantly decreased. This study demonstrated the effect of treadmill running on the bone mechanical strength, suggesting that more than the even running speed might be needed to prevent the decrease in the bone mechanical strength effectively.

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The efficacy of therapeutic ultrasound (US) was assessed for residual symptoms in patients who had received the operation on lumbar herniated nucleus and lumbar spinal canal stenosis. Subjects were 44 patients with residual symptoms such as pain or numbness in their lower extremities after lumbar discectomy and medial facetectomy during the period from September to December 2003. Mean age of the participants was 39.8 ± 18.3 years. Subjects were randomly allocated to a US group (n = 22) and a placebo group (n = 22). Treatment time was 5 minutes (frequency 0.8 MHz, on-off ratio 1:4, intensity of 1.0 W/cm²) once a day during hospitalization. The therapeutic ultrasound was applied to the skin of lumbosacral region. Placebo group received shame ultrasound (only the timer on the machine activated). The resolution of residual symptoms was assessed by visual analogue scales (VAS) and pain drawing. There were no statistically significant differences between the groups in age, length of stay, VAS, and total body area score of baseline. VAS and pain drawing in the US group improved significantly compared with placebo group at discharge, 2 weeks, and 18 months after discharge (p < 0.05). It was confirmed that US is a very useful conservative therapy for the patients with postoperative residual symptoms due to decompression posterior lumbar spine.

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This study investigated age-related changes in muscle architectural characteristics and contributing factors influencing strength of elderly persons in the human quadriceps muscles. The subjects consisted of 31 elderly women aged 81.7 ± 6.4 years, and 21 young women aged 22.6 ± 2.5 years. Muscle thickness and muscle-fiber pennation angles were measured in the vastus lateralis using B-mode ultrasonography. The location used for imaging on the right vastus lateralis muscle was a point midway between the lateral condyle of the femur and the greater trochanter. Quadriceps strength was measured using isometric maximal voluntary contraction (MVC) of the knee extension. Cross-sectional area (CSA) was estimated from muscle thickness and thigh circumference measurements. Muscle-specific force was calculated from MVC to CSA ratios (MVC/CSA). The muscle thickness and MVC of quadriceps was a significantly greater in young women than in elderly women. Decrease with aging was relatively greater for muscle strength than for muscle size. In elderly subjects, there was a significant correlation between age and quadriceps strength, but not muscle thickness or CSA. Young women had significantly greater muscle-specific force than elderly women. Furthermore, coefficients of variation of muscle-specific force tended to be greater in the elderly than in the young. These findings suggest that the decrease in muscle strength with aging may also be influenced by neural activation ability as well as by muscle size, and that a large variability in this neural factor is found in the elderly.

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The purpose of this study was to determine the effect of wide multiple wave electrical stimulation versus low frequency electrical stimulation on cutaneous blood mass, as well as to determine the utility of wide multiple wave electrical stimulation in peripheral circulatory disturbances. Participants included 28 healthy men. They were randomly assigned to one of the three groups; wide multiple wave electrical stimulation, low frequency electrical stimulation or control. The lateral head of the gastrocnemius was stimulated. Cutaneous blood mass was measured on the Achilles tendon during the baseline period and every 5 minutes during the stimulation and follow-up. Wide multiple wave electrical stimulation significantly increased blood mass from 5 to 20 minutes of stimulation compared to the control (p<0.05). Low frequency electrical stimulation significantly increased blood mass from 5 to 15 minutes of stimulation compared to the control (p<0.05). Wide multiple wave electrical stimulation with the random access frequency system prevented accommodation of circulation to electrical stimulation. Therefore, wide multiple wave electrical stimulation stabilized blood mass for long periods of time, thus it may improve peripheral circulation.

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