Effect of repetitive peripheral magnetic stimulation of the common fibular nerve on the soleus muscle Hoffmann reflex.

[Purpose] This study aimed to investigate the effects of repetitive peripheral magnetic stimulation of the common fibular nerve on the modification of neural circuit function as measured through the soleus muscle Hoffmann reflex. [Participants and Methods] Twenty-four healthy adult males were randomly and equally divided into the magnetic stimulation (experimental) and control groups. The Hoffmann reflex of the soleus muscle was analyzed before and after 10 min of repetitive peripheral magnetic stimulation for the experimental group and before and after 10 min of rest for the control group. The averages of the values for the maximum amplitude and latency of the Hoffman reflex across twenty repetitions were recorded and compared. [Results] The Hoffmann reflex amplitude decreased following stimulation in the experimental group, and significant variations were observed between the experimental and control groups. [Conclusion] The change in the Hoffmann reflex amplitude may have been caused by the magnetic stimulation to I-a sensory fibers on the common fibular nerve, suggesting that magnetic stimulation induces reciprocal inhibition of motor neurons through synapses in the spinal cord.

Investigation of absolute intra-rater and inter-rater reliabilities during the muscle hardness estimation.

[Purpose] This study aimed to investigate the absolute intra-rater and inter-rater reliabilities during the measurement of muscle hardness, which is used to evaluate physical therapy. Moreover, we examined the effects of using different equipment types and their positioning on the intra-rater and inter-rater reliabilities. [Participants and Methods] Participants of this study comprised 12 healthy adult male individuals. Two experts and two beginners measured the muscle hardness of the lumbar erector spinae and rectus femoris using three types of hardness meters at two positions, including when the muscle was relaxed and stretched. [Results] Intra-rater fixed bias was observed during some measurements by both experts and beginners. Inter-rater fixed bias was observed during measurements by some experts and not the beginners. [Conclusion] In this study, the measurement of muscle hardness demonstrated a need to reconsider the measurement position and acclimation time. These examinations require the consideration of relative and absolute reliabilities.

Fundamental research on surface electromyography analysis using discrete wavelet transform-an analysis of the central nervous system factors affecting muscle strength.

[Purpose] We aimed to investigate the central nervous system factors that affect muscle strength based on the differences in load and time using the discrete wavelet transform, which is capable of a time-frequency-potential analysis. [Participants and Methods] Surface electromyography (EMG) of the right upper bicep muscle in 16 healthy adult males were measured at 10% MVC (maximum voluntary isometric contraction), 30%, 50%, 70%, and 80% to 100% MVC. We used a discrete wavelet transform for the electromyographic analysis and calculated the median instantaneous frequency spectrum (MDF) and frequency band component content rate (FCR) at 1-ms intervals as well as their spectrum integrated values (I-EMG). [Results] MDF and FCR tended to be high throughout the measurements. Specifically, the high-frequency band component content rate was high at the time of low muscle strength; fast-twitch muscle fibers may be involved during these muscle contractions. We found significant changes in the I-EMG as the muscle strength increased from 10% MVC to 100% MVC. [Conclusion] Analyzing the surface electromyograph using discrete wavelet transform enabled us to assess the central nervous system factors that increase in the EMG amplitude integrated values and change in the median instantaneous frequency spectrum and in the frequency band component content rate.

Effects of therapeutic ultrasound on range of motion and stretch pain.

[Purpose] This study aimed to clarify the effects of therapeutic ultrasound on range of motion and stretch pain and the relationships between the effects. [Subjects] The subjects were 15 healthy males. [Methods] Subjects performed all three interventions: (1) ultrasound (US group), (2) without powered ultrasound (placebo group), and (3) rest (control group). Ultrasound was applied at 3 MHz with an intensity of 1.0 W/cm(2) and a 100% duty cycle for 10 minutes. The evaluation indices were active and passive range of motion (ROM), stretch pain (visual analog scale; VAS), and skin surface temperature (SST). The experimental protocol lasted a total of 40 minutes; this was comprised of 10 minutes before the intervention, 10 minutes during the intervention (US, placebo, and control), and 20 minutes after the intervention. [Results] ROM and SST were significantly higher in the US group than in the placebo and control groups for the 20 minutes after ultrasound, though there was no change in stretch pain. [Conclusion] The effects of ultrasound on ROM and SST were maintained for 20 minutes after the intervention. The SST increased with ultrasound and decreased afterwards. Additionally, the SST tended to return to baseline levels within 20 minutes after ultrasound exposure. Therefore, these effects were caused by a combination of thermal and mechanical effects of the ultrasound.

Effects of therapeutic ultrasound on intramuscular blood circulation and oxygen dynamics.

PURPOSE: This study aimed to clarify the effects of therapeutic ultrasound on intramuscular local blood circulation (and oxygen dynamics) using near-infrared spectroscopy (NIRS). PARTICIPANTS: The participants were 11 healthy males. METHODS: All participants performed all three trials; (1) the ultrasound (US group), (2) without powered ultrasound (placebo group), and (3) rest (control group). Ultrasound was applied at 3 MHz, 1.0 W/cm(2), and 100% duty cycle for 10 minutes. Evaluation index were oxygenated, deoxygenated, and total hemoglobin (Hb) concentrations in the intramuscular and skin surface temperature (SST). The experimental protocol was a total of 40 minutes, that is, 10 minutes before trial (rest), 10 minutes during the trial (ultrasound, placebo, and control), and 20 minutes after trial (rest). The NIRS and SST data collected before and after the trial were divided into 5 minutes intervals for further analysis. RESULTS: Oxygenated and total hemoglobin levels were significantly higher in the US group than in the placebo and control groups for the 20 minutes after ultrasound (p < 0.01). The SST was significantly higher in the US group than in the control for 15 minutes after ultrasound (p < 0.05), while it was significantly lower in the placebo group than in the US and control groups for 20 minutes after the trials (p < 0.01). CONCLUSION: The effects of ultrasound were maintained for 20 minutes after the trial on intramuscular blood circulation and oxygen dynamics. These effects were caused by a combination of thermal and mechanical effects of the ultrasound.

[Effectiveness of a community health service program using exercise intervention for elderly people with osteoarthritis of the knees: a randomized controlled trial].

OBJECTIVE: The objective of this study was to evaluate the effectiveness of an exercise program conducted as part of community health services to improve pain and physical function in elderly people with osteoarthritis of the knee (knee OA). METHODS; The subjects were 88 (12 males aged 77.8 +/- 5.4 years and 76 females aged 73.2 +/- 5.3 years) community-dwelling independent elderly people with knee OA who participated voluntarily in exercise classes sponsored by Musashino city of Tokyo. They were allocated randomly to the intervention group (n = 44) and the control group (n = 44). For the intervention group, exercise classes of 90 min duration were held 8 times over 3 months. The exercise program comprised flexibility exercises (stretching of knee and ankle joints), resistance exercises (strengthening of quadriceps, extension and flexion of the knee joint with an elastic band), and movement exercises (turning over, getting up, standing up). The subjects were instructed to perform these exercises at home every day. Knee pain scores (Western Ontario and McMaster Universities OA Index; WOMAC), peak torque of joint during knee flexion and extension, range of motion (ROM) of the knee joint, and functional fitness (standing and walking ability) were evaluated before and after the intervention period. RESULTS: Significant inter-group differences were observed for peak torque during knee flexion and standing and walking ability of females. Assessment of interactions between time and group by repeated measure ANOVA adjusted for age and sex revealed significance differences for the WOMAC score (P = 0.031), the peak torque during knee extension (P = 0.016) and knee flexion (P = 0.000), ROM (P = 0.037), standing ability (P = 0.000)and walking ability (P = 0.000). The effect of the intervention was 0.44 for WOMAC score, 0.23 for peak torque during knee extension, 0.64 for knee flexion, 0.32 for ROM, 0.81 for standing ability, and 1.13 for walking ability. CONCLUSIONS: These results suggested that the exercise program for elderly people with knee OA improved knee pain and physical function.

Effect of dentures wearing on motor reaction time and balance function in elderly people.

OBJECTIVE: To investigate the influence of dentures wearing on the parameters of physical fitness, particularly on agility and balance function in elderly people. DESIGN: A case control study. SETTING: Motohachiohjimachi, Hachiohji, Tokyo, Japan. METHODS: Motor reaction time was measured in the presence and absence of dentures in the subjects who were 1) in a sitting position and lifted the lower limbs as fast as possible in response to a stimulus (Sitting Group) and those who were 2) in a standing position and jumped upright as fast as possible in response to a light stimulus (Jumping Group). The effects of dentures wearing on balance function were investigated by comparing the measured values of static and dynamic body sway. RESULTS AND CONCLUSIONS: Light-reaction time was not significantly influenced by dentures wearing in Sitting Group performing a light body movement that required little muscular force. In a relatively heavy body movement that required agility (i.e., jumping from the standing position), the reactivity changed depending on the muscular force; which might result in the difference of the reactivity due to dentures wearing (i.e., t-test showed a significant difference in the light-reaction time under clenching posture between with and without wearing dentures (p < 0.01)). No significant difference was observed in body sway under clenching posture between with and without wearing dentures.Therefore, we assumed that reaction speed varied depending upon dentures wearing.