The purpose of this study was to investigate whether there is a difference in the influence of peripheral nerve injury and spinal cord injury on muscle elasticity in contractures of the soleus muscle of rats. Twenty-four female 8-week-old Wistar rats were divided into four groups. One group was used as a control and animals in the three experimental groups were immobilized to cause contractures. Animals in one of the experimental groups also received a spinal cord lesion and in another a peripheral nerve lesion. After four weeks, sacrificed soleus muscles were stretched to the tearing point to measure contractures. Muscle tension necessary to reach the tearing point of the lengthened soleus muscles was 5.1 ± 0.4 N in the control, 3.5 ± 0.6 N for the immobilized, 2.5 ± 0.5 N for the spinal cord lesion, and 1.6 ± 0.8 N for peripheral nerve lesion groups. These results were significantly different at the 0.05 level for all groups. Peripheral nerve injury with immobilization in a shortened position caused the severest contracture, indicating that spinal cord injury and peripheral nerve injury may have different effects on muscle contractures.
Coughing is a defensive reflex action of the airway that removes foreign objects and mucus. Here, meta-analysis was performed to review the results of previous studies regarding the effects of coughing exercise and expiratory muscle training (EMT), and to examine the effectiveness of EMT in enhancing cough functions. A systematic literature search was performed using the EBMR, CINAHL, PEDro, MEDLINE, and Ichushi Web (NPO Japan Medical Abstracts Society) databases. Based on a methodological framework, a critical review was performed and summary effect sizes were calculated by applying the random effects model. Both the forced expiration technique (FET) and coughing alone significantly increased mucus clearance. EMT significantly increased expiratory muscle strength, suggesting that it is possible to improve cough effectiveness by EMT. Further studies with larger and more diverse sample groups are necessary to determine the effects of enhancing expiratory muscle strength on cough effectiveness.
We examined the correlation between jump distance and the maximum flexion angle of the knee joint during jumping to evaluate whether healthy men adjust to jump distance by changing the angle of the knee joint. Fourteen subjects jumped 3 times with their eyes closed to each of what they thought was 25%, 50%, and 75% of their maximum jump distance, a total of 9 jumps for both the vertical and standing broad jump. We measured the knee joint flexion angle at the time of the motion and examined the correlation between jump distance and knee joint flexion angle. The results show a relationship between jump distance and knee joint flexion angle for both the vertical and standing broad jump. We determined that jump distance is controlled by knee joint flexion angle in healthy men. Thus, a factor of jump control was clarified in this study.
While many studies have investigated muscle activity in amputated legs while walking, in physical therapy and other fields, few studies have examined muscle activity in the healthy legs of amputees. Furthermore, to the best of our knowledge, no previous investigations have examined the motor learning processes in leg amputees or efficient exercise programs for walking with a leg prosthesis. Our previous study clarified the function of the non-amputated legs of amputees while walking with a prosthetic leg by measuring muscle activity patterns using surface electromyography and ground reaction force plates. In the present study, healthy volunteers were asked to wear a pseudo-prosthetic leg and participate in either a basic or applied exercise program using clearly different exercises. Differences in muscle activity patterns between the programs were then analyzed. After 2 weeks of exercises, the exercise program allowing legs without a pseudo-prosthesis to function more like the non-amputated legs of amputees who were skilled at walking with their prosthesis was ascertained. Muscle activity patterns of volunteers on the applied exercise program tended to more closely resemble those of amputees.
This study aimed to determine the activities of the trunk muscles and the hip extensors during forced expiration maneuvers at different flow intensities in different standing postures. Thirteen male subjects participated in this study. Surface electromyographic signals from the external oblique (EO), rectus abdominis (RA), internal oblique (IO), iliocostalis (IC), longissimus (LO), multifidus (MF), gluteus maximus (GM), and biceps femoris (BF) were recorded in three postures: trunk upright, flexed at 30 degrees and extended at 15 degrees. Three forced expiration flows of slight, moderate, and maximal intensities were randomly measured. The percentages of peak expiratory flow (%PEF) and the mean electromyographic discharge (%MED) at maximal voluntary contraction in each muscle during expiration were calculated. Various conditions and muscles were compared at peak flow in each trial in terms of %MED. The results show that the correlation between the mean %PEF (%PEFmean) and %MED was significant (p<0.05) in all the muscles except BF, GM, and RA in the extended standing posture. %MED at slight and moderate flow intensities was significantly greater in the flexed standing posture than in the upright and extended standing postures in the trunk extensors, although there was no difference in the trunk flexors. In the trunk flexors, %MED of IO was greater than that of EO and RA at slight flow intensity in each posture. In the trunk extensors, %MED of LO and MF were greater than that of IC at slight and moderate flow intensities in the flexed standing posture. The results indicate that the relationship between trunk muscle activity and forced expiratory flow has high specificity in different standing postures and flow intensities.
Hepatocyte growth factor (HGF) has been suggested as a mitogen for skeletal muscle satellite cells and participates in skeletal muscle hypertrophy. The present study assessed HGF levels in mouse soleus and plantaris muscles during 14 days of tail suspension and 3 days of reloading using the enzyme-linked immunosorbent assay. Immunohistochemical analyses were used to determine the locations of HGF, its receptor (c-Met) and proliferating cell nuclear antigen. In normal mice, HGF contents were 4.4 ± 0.5 ng/g tissue in the soleus muscle and 5.9 ± 1.2 ng/g tissue in the plantaris muscle, significantly higher than in the soleus muscle. HGF level in the soleus muscle was increased 314% from normal by reloading. HGF and c-Met were expressed in small cells contiguous to muscle fibers. Cells in similar positions displayed reactivity for PCNA, suggesting that these represent activated satellite cells. Thus, production of HGF protein appears to stimulated in satellite cells during recovery from disuse atrophy.
The skills of various kinds of motion must be maintained so that activities of daily living (ADL) can be performed fluently. An important objective of Occupational Therapy is to improve a patient's ability to perform ADL. However, there are very few studies that have tried to scientifically analyze skill contributing to the quality of ADL. Therefore, we focused on the motion in wringing out of Towel, which is done frequently in ADL, and analyzed the factors that contribute to this motion. We hypothesized that the factors that contribute to this motion include the subject's age, gender, grip strength and motion pattern. These factors were analyzed. The results show that the female elderly group, although weak in hand grip strength, was able to squeeze the maximum amount of water from the towel. We speculate that this group of elderly females were most efficient at wringing the towel because this was a common household chore for them and because of this, their level of skill was the highest among all the groups.
The purpose of this study was to clarify the postural control of the initiation of lateral step and step-up motions in healthy young adults (24.3 ± 1.8 years: mean ± SD). The tasks involved the lateral step (step lengths, 10 cm and 20 cm) and lateral step-up motions (10-cm high stool; step lengths, 10 cm and 20 cm). The variables for analysis included motion duration (weight-shift phase and swing phase), shifts of the center of pressure (CoP) and the center of gravity (CoG), displacement and inclination of the shoulder and the pelvis, and root mean square electromyographic amplitude of the erector spinae, gluteus medius (GM) and adductor longus (AL) bilaterally. The CoP shift toward the stepping side was larger in the step-up task than in the step task, and it was smaller when both tasks were performed in the long lengths. The CoG shift toward the supporting side and the displacements of the shoulder and pelvis were larger in the step-up task than in the step task. However, the magnitude of GM activity of the supporting leg was larger in the step task than in the step-up task, and increased when both tasks were performed in the long lengths. In the stepping leg, the magnitude of AL activity was larger in the step-up task than in the step task, and decreased when both tasks were performed in the long lengths. These results suggest that GM activity of the supporting leg and AL activity of the stepping leg control the shift of CoG in the frontal plane. Our results indicate that the increase in GM activity does not depend on the height of stepping but on the length of stepping in lateral step and step-up motions.
The focus of this research was to investigate the efects of acute blunt trauma, on the ultrastructural and protein content of skeletal muscles. A simple device for producing a humane and reproducible experimental model of blunt trauma to rat muscle was used. Ultrastructural events in the traumatized muscle were observed over 14 days. From 0 to 2 days after trauma there was a marked loss of muscle protein content, associated with an acute inflammatory response. From day 3 to 14 days, the muscle underwent regeneration with a rapid proliferation of sarcolemmal nuclei, activation of satellite cells, and the restoration of sarcomeres. By three days post trauma, muscle protein content decreased (35-47%) compared to muscle of control rats (p>0.05).
The effect of prior exercise conditioning, on the collagenous and non-collagenous protein contents of skeletal muscle of the lower limb during recovery from acute blunt trauma were investigated. One hundred and twelve, Sprague-Dawley rats were trained following a common eight week endurance training program, producing a significant (p<0.05) increase in citrate synthase activity of the skeletal muscle1). The training protocol was implemented to duplicate the reaction to injury and to follow-up recovery on muscle which had been pre-conditioned by exercise. Rats of the same weight were then randomly assigned to one of five experimental groups following the eight weeks of training. Muscle trauma was produced utilizing a humane and reproducible experimental device. After the different treatments for ten days, results indicated that animals in the exercise trauma, produced more collagen in traumatized lower limb muscles than rats in the exercise no trauma (ENT), exercise trauma, untreated (ET), and exercise trauma groups (p<0.05). The amount of non-collagenous contractile protein was significantly lower (p<0.05) in the ENT group compared to the ET. The results suggest that the exercise has a protective effect on muscle and on the production of collagen in traumatized skeletal muscle. Finally, prior experience conditioning protected against injury and improved muscle recovery.
The purpose of this study was to examine the influence of muscle mass/power of the lower-extremities, including asymmetry in knee extension force, on gait ability of Japanese community-dwelling elderly women. The study population comprised 30 women aged 65-89 years. The parameters examined were activities of daily living, physical performance, functional capacity, isometric muscle forces of knee extension and flexion measured by a dynamometer, and muscle mass measured by bioelectrical impedance analysis. Asymmetry in knee extension force was calculated from rate of difference between the right and the left knee extension forces. One leg balance with eyes open, 6-minute walking distance (6MD) and knee extension force decreased, while 10-m obstacle walking time and asymmetry in knee extension force increased with age. Gait ability including 6MD and 10-m obstacle walking time correlated with asymmetry in knee extension force, which also exhibited correlations with one leg balance with eyes open and knee extension force. The results of the present study indicate that on increase in asymmetry in knee extension force as well as a decrease in lower-extremity muscle force might accelerate the loss of gait ability, while the improvement of asymmetry in knee extension force might be beneficial to self-supporting life in elderly individuals.
The effect of age and gender on muscle fiber conduction velocity (MFCV) was examined. Subjects were 216 healthy persons (369 limbs), of which 102 were males (180 limbs) and 114 were females (189 limbs). The method of evoked potential was used for measuring MFCV. The muscles measured were the vastus medialis of the right and / or left limbs. The measurement was taken in a sitting position with the hip and knee joints flexed at 90°. On the effect of aging, a significant correlation between MFCV and age was observed in males (r=0.63, p<0.01) and in females (r=0.52, p<0.01). There was a tendency of delay in MFCV due to aging. On the gender difference, male MFCV showed a faster rate, compared with that of females in the age group from 20's to 40's. However, no gender difference was observed in the age group of more than 50 years. Based on these results, age and gender differences must therefore be considered when determining standard values of MFCV.
In rural areas of developing countries, ankle foot orthoses that can be manufactured at low cost are required. Also, systems that can be set up with readily available, low-cost materials which can easily measure their effectiveness are also required. In this paper, I report on, a low cost motion analysis system that can easily measure the effectiveness of orthoses was developed in China. In this system, a home digital video camera was used for video recording for analysis, aluminum foil for a foot switch, and freeware for analysis software. Gait analysis was performed on a healthy person and a hemiplegic patient using this system. Then a comparison was performed between the results of this simple system and those of a 3D motion analysis system. Knee joint angles obtained by both systems were essentialy the same.
Exercise is recognized as one of the optimal managements for chronic low back pain. Among the numerous therapeutic exercises, the approaches of traditional strengthening exercise and segmental stabilization exercise are considerably different. The purpose of this study was to compare the effectiveness of the two different exercise approaches, on chronic low back pain through evaluating previous randomized control trial (RCT) studies. Pain, functional ability and physical improvement were analyzed to evaluate the recovery from chronic low back pain. While both exercises demonstrated positive effects on pain relief, functional ability and physical improvement, the evidence level of the strengthening exercise studies was not strong enough because of some methodological flaws. On the other hand, the methodological superiority of the segmental stabilization exercise studies provided high quality evidence. Another positive aspect of the segmental stabilization exercise studies was the significant long-term effect on low back pain and its low recurrence rate. Considering the overall evidence level, the segmental stabilization exercise seems to be more effective than the traditional strengthening exercise on chronic low back pain. However, the number of studies related to the segmental stabilization exercise is currently limited, therefore more direct comparative RCT studies including many other exercise approaches are necessary to confirm the effectiveness of the segmental stabilization exercise.