Acute effect of static stretching on passive and active properties of the gastrocnemius muscle–tendon unit: an investigation based on different repetition durations and numbers / 体力科学

<p>Many previous studies have reported that static stretching (SS) may decrease muscle stiffness and compromise muscles’ ability to produce maximal strength. However, the effects of SS at different repetition durations and numbers within a constant total time remain unclear. Therefore, the purpose of this study was to examine whether SS for a constant total time (2 min) with different repetition durations and numbers (e.g., 60 s × 2 times, 30 s × 4 times, and 10 s × 12 times) produces different changes in muscle stiffness and strength. Fifteen healthy males (mean age: 23.3 ± 1.0 years) participated in this study. Muscle stiffness was measured during passive ankle dorsiflexion using dynamometer and ultrasonography. In addition, muscle strength of the plantar flexors was measured using a dynamometer at 0° of plantarflexion with the hip and knee joints fully extended. Muscle stiffness and strength were measured before and immediately after SS. Each experimental protocol was conducted in random order with at least a 1-week interval but no longer than a 2-week interval between testing sessions. The results showed that there were no significant interaction effects on muscle stiffness and strength. However, in all experimental protocols, muscle stiffness and strength immediately decreased after SS. In conclusion, SS for a constant total of 2 min decreases muscle stiffness and strength regardless of repetition durations and numbers of each individual SS.</p>

Changes in the Dose of Benzodiazepines and Falls in Elderly Inpatients in an Acute-care Hospital / 薬剤疫学

Objective:It is well known that the use of benzodiazepines is associated with falling in elderly people, but there have been few researches focused on changes in the dose of benzodiazepines and falls. If the association between changes in the dose of benzodiazepines and falling becomes clear, we may take an action to prevent falling.In this study, we investigated the association between changes in the dose of benzodiazepines and falling among elderly inpatients in an acute-care hospital.<br>Design:Falling generally results from an interaction of multiple and diverse risk factors and situations, and medication history of each subject must be considered in this study. We conducted a case-crossover study in which a case was used as his/her own control at different time periods. Therefore covariates that were not time-dependent were automatically adjusted in this study.<br>Methods:Subjects were patients who had falling at one hospital between April 1, 2008 and November 30, 2009. Data were collected from incident report forms and medical records. Odds ratio for changes in the dose of benzodiazepines were calculated using conditional logistic regression analyses.<br>Results:A total of 422 falling by elderly people were eligible for this study. The odds ratio for increased amounts of benzodiazepines was 2.02(95% Confidence Interval(CI):1.15, 3.56). On the other hand, the odds ratio for decreased amounts of benzodiazepines was 1.11(95%CI:0.63,1.97).<br>Conclusion:There was an association between increased amounts of benzodiazepines and falling. Hence, it is considered meaningful to pay attention to falling when amounts of benzodiazepines are increased to prevent falling in hospitals.

CHANGE IN MUSCLE THICKNESS OF THE REGIONS OF TRANSVERSUS ABDOMINIS BY ULTRASOUND IMAGING / 体力科学

This study investigated the changes in muscle thickness of transversus abdominis (TrA) during trunk muscle training. The subjects comprised 30 young men (average age 20.1 SD1.6 years) without low back pain. The muscle thickness of the upper region of TrA, middle region of TrA and lower region of TrA were measured by B-mode ultrasound. Muscle thickness were measured at rest and during the following 5 exercises; abdominal drawing, curl up, trunk ipsilateral rotation, trunk contralateral rotation and both straight leg raise in supine. There were no significant differences in the muscle thickness of the upper region of TrA between resting condition and all exercises. Muscle thickness during drawing, curl up and ipsilateral rotation were significantly greater than that at rest in middle region of TrA, and the rate of change in muscle thickness was the largest for drawing. Muscle thickness during drawing, curl up and ipsilateral rotation were significantly greater than that at rest in the lower region of TrA, and the rate of change in muscle thickness was the largest for ipsilateral rotation. These results suggested that the changes in muscle thickness of TrA during trunk muscle training showed different patterns depending on the region of TrA.

PHYSICAL FUNCTION SCREENING OF INSTITUTIONALIZED ELDERLY WOMEN TO PREDICT THEIR RISK OF FALLING / 体力科学

This study examined the relationship between multiple physical function and falls among institutionalized elderly women, and screening methods designed to effectively identify elderly with a high risk of falling. The subjects comprised 44 elderly women aged 82±6 years residing in a nursing home. Multiple physical assessments were tested using the following measures; muscle strength(quadriceps strength and grip strength), balance test(functional reach and one-legged stance test), flexibility test(sit and reach test), agility test(stepping test), and physical performance test(TUG and chair stand test). Based on the experience of fall-related accidents within the past two years, we categorized the subjects into two groups (non-fall group and fall group). Of these measures, quadriceps strength, grip strength, functional reach, stepping test in a standing position, and chair stand test were significant factors discriminating whether the subject had a history of falls. Logistic regression analysis demonstrated that quadriceps strength, functional reach, stepping test in a standing position, and chair stand test were important predictors of falls in an institutionalized elderly population. The results of this study suggest that 0.84 Nm/kg for quadriceps strength, 26 cm for functional reach, 17 steps for stepping test, and 14 sec for chair stand test, were useful indicators for screening institutionalized elderly for risk of falling. Particularly, the stepping test was most effective in screening the elderly to assess their fall risk.

Sufficient quantity of leg exercise for prevention of disuse atrophy of the quadriceps femoris murcle / 体力科学

A study was conducted to determine the minimum quantity of leg exercise required to prevent disuse atrophy of the quadriceps femoris muscle during bed rest. The subjects were 10 normal young university students with a mean age of 21.1 years. First, analysis of rectified filtered electromyography (RFEMG) was performed on the rectus femoris and vastus medialis during walking with cadences of 100 steps/min and 150 steps/min. Then, the effects of straight leg raising (SLR), patella setting (PS), knee extension-flexion in a supine position (KEF) and knee extension in a sitting position (KE) were analysed for each muscle using the same method. Based on the value of RFEMG for each muscle during walking, the repetition number for each exercise was calculated. For the rectus femoris, the repetition number for each exercise corresponding to 10000 steps with a cadence of 100 steps/min was 289 for SLR, 466 for PS, 1255 for LEF and 1663 for KE. For the vastus medialis, the corresponding numbers were 1223, 381, 6367 and 2170, respectively. When the cadence increased to 150 steps/min, the repetition number of each exercise for each muscle also increased. These results indicate that high repetition exercise is recommendable to prevent disuse atrophy of the quadriceps femoris muscle. Therefore, the activity of patients should be increased to stimulate weakened muscles such as the quadriceps femoris during hospitalization.