The Components of Lumbar Motor Control Are Not Inter-related.

OBJECTIVES: To verify the relationship between the indicators of components of lumbar motor control and determine the factors related to the indicators to each of these components. METHODS: Twenty-five healthy university students were included in the study. The lumbar spine and hip kinematic parameters of posterior/anterior pelvic tilt (mobility and smoothness), ball catching (reactivity), and forward/backward rocking (adaptive stability) were measured as indicators of lumbar motor control. Lumbar proprioception, trunk muscle strength, and lower trunk muscle thickness were also measured. Kinematic parameters of the lumbar spine and hip were measured using a small accelerometer. The data verified the relevance of indicators of lumbar motor control and the relationship with relevant factors. RESULTS: No significant correlations were found for most lumbar motor control indicators. Lumbar proprioception and rectus abdominis muscle thickness were identified as relevant indicators of lumbar motor control. CONCLUSIONS: Each component of lumbar motor control is independent and must be evaluated for the component whose function is required. Additionally, some components of lumbar motor control are associated with lumbar proprioception and rectus abdominis muscle thickness; thus, evaluation of these components is necessary when evaluating lumbar motor control.

Effects of Aging on Collagen in the Skeletal Muscle of Mice.

Aging affects several tissues in the body, including skeletal muscle. Multiple types of collagens are localized in the skeletal muscle and contribute to the maintenance of normal muscle structure and function. Since the effects of aging on muscle fibers vary by muscle fiber type, it is expected that the effects of aging on intramuscular collagen might be influenced by muscle fiber type. In this study, we examined the effect of aging on collagen levels in the soleus (slow-twitch muscle) and gastrocnemius (fast-twitch muscle) muscles of 3-, 10-, 24-, and 28-month-old male C57BL/6J mice using molecular and morphological analysis. It was found that aging increased collagen I, III, and VI gene expression and immunoreactivity in both slow- and fast-twitch muscles and collagen IV expression in slow-twitch muscles. However, collagen IV gene expression and immunoreactivity in fast-twitch muscle were unaffected by aging. In contrast, the expression of the collagen synthesis marker heat shock protein 47 in both slow- and fast-twitch muscles decreased with aging, while the expression of collagen degradation markers increased with aging. Overall, these results suggest that collagen gene expression and immunoreactivity are influenced by muscle fiber type and collagen type and that the balance between collagen synthesis and degradation tends to tilt toward degradation with aging.

Effects of Obesity in Old Age on the Basement Membrane of Skeletal Muscle in Mice.

Obesity and aging are known to affect the skeletal muscles. Obesity in old age may result in a poor basement membrane (BM) construction response, which serves to protect the skeletal muscle, thus making the skeletal muscle more vulnerable. In this study, older and young male C57BL/6J mice were divided into two groups, each fed a high-fat or regular diet for eight weeks. A high-fat diet decreased the relative gastrocnemius muscle weight in both age groups, and obesity and aging individually result in a decline in muscle function. Immunoreactivity of collagen IV, the main component of BM, BM width, and BM-synthetic factor expression in young mice on a high-fat diet were higher than that in young mice on a regular diet, whereas such changes were minimal in obese older mice. Furthermore, the number of central nuclei fibers in obese older mice was higher than in old mice fed a regular diet and young mice fed a high-fat diet. These results suggest that obesity at a young age promotes skeletal muscle BM formation in response to weight gain. In contrast, this response is less pronounced in old age, suggesting that obesity in old age may lead to muscle fragility.

Effects of stretching on the basement membrane structure in the soleus muscle of Wistar rats.

The basement membrane (BM), mainly composed of collagen IV, plays an important role in the maintenance, protection, and recovery of muscle fibers. Collagen IV expression is maintained by the balance between synthetic and degradative factors, which changes depending on the level of muscle activity. For example, exercise increases collagen IV synthesis, whereas inactivity decreases collagen IV synthesis. However, the effects of stretching on the BM structure remain unclear. Therefore, to investigate the effects of stretching on the BM of the skeletal muscle, we continuously applied stretching to the rat soleus muscle and examined the altered expression of BM-related factors and structure using quantitative polymerase chain reaction (qPCR), western blotting, zymography, immunohistochemistry, and electron microscopy. The results show that stretching increased the matrix metalloproteinase 14 (MMP14) expression and MMP2 activity, and decreased the collagen IV expression and width of the lamina densa in the soleus muscle. These results suggest that stretching promotes BM degradation in the rat soleus muscle. The findings of this study indicate a new influence of stretching on skeletal muscles, and may contribute to the new use of stretching in rehabilitation and sports fields.

Division of loading time in reloading the disused atrophic soleus muscle induces proximal muscle injury.

[Purpose] This study aimed to compare the effects of loading time division in reloading atrophied muscles in different muscle long-axis regions. [Materials and Methods] We divided 8-week-old male Wistar rats into control (CON), 14-day hindlimb suspension (HS), 7-day hindlimb suspension followed by 60-min reloading for 7 consecutive days (WO), and 7-day hindlimb suspension followed by 60-min reloading on two separate occasions for 7 days (WT) groups. After the experimental period, muscle fibre cross-sectional area and necrotic fibre/central nuclei fibre ratio were measured in the soleus muscle's proximal, middle, and distal regions. [Results] The necrotic fibre/central nuclei fibre ratio was higher in the WT group than in the other groups in the proximal region. Proximal muscle fibre cross-sectional area was higher in the CON group than in the other groups. In the middle region, only HS group had muscle fibre cross-sectional area lower than the CON group. Similarly, muscle fibre cross-sectional area of the HS group was lower than the CON and WT groups in the distal region. [Conclusion] When reloading atrophied muscles, dividing the loading time can inhibit atrophy in the distal region but induce muscle injury in the proximal region.

Reliability of lower leg muscle thickness measurement along the long axis of the muscle using ultrasound imaging, in a sitting position.

[Purpose] To verify the reliability and validity of lower leg muscle thickness (MT) assessment along the muscle's long axis using ultrasound imaging (USI) in a sitting position. [Participants and Methods] Twenty healthy adult female participants (aged, 20.3 ± 0.9 years) were included in the study. Intra- and inter-examiner reliability of the proximal, middle, and distal MT of the tibialis anterior (TA) and medial head of the gastrocnemius (GM) were verified using USI in a sitting position. Additionally, the relationship between MT measurement using USI and muscle cross-sectional area (MCSA) measurement using magnetic resonance imaging (MRI), as well as the ankle joint's maximum muscle strength, were examined. [Results] The reliability of TA and GM MT measurement using USI was high for all regions. The relationship between MCSA measurement using MRI and MT measurement using USI showed a significant correlation in all the regions for both muscles. The relationship between ankle muscle strength and USI of MT was not significantly correlated in any region for both muscles. [Conclusion] Measurement of MT using USI is reliable and valid for MCSA, but must be combined with assessments of other factors for muscle strength.

Immediate effects of elongation training using an elastic band on the hip abductor muscles.

[Purpose] This study investigated the effects of elongation training on the hip abductor muscles in comparison with the effects of general hip abductor training. [Participants and Methods] This study included 39 healthy male university students. The participants were divided into elongation training and general-weighted hip abduction training groups. An elastic band was used for elongation training, and hip abduction exercises were performed with instructions to extend the foot as far as possible to stretch the band. Measurements were taken before and after training, and the surface electromyographic data of the gluteus medius and the tensor fasciae latae were measured during isometric contraction of the hip abductor muscles. The surface electromyogram data were used to calculate integral values and median power frequencies to compare the effects of training. [Results] In comparison with general hip abductor training, elongation training yielded a larger change in the ratio of muscle integral values (gluteus medius/tensor fasciae latae). [Conclusion] Elongation training of the hip abductor muscles was more useful than general training in increasing the activity of the gluteus medius while suppressing the activity of the tensor fasciae latae.

Relationships among lumbar hip motion angle, perceptual awareness, and low back pain in young adults.

[Purpose] We aimed to examine the relationships among low back pain, lumbar-hip motion angle, and lumbar perceptual awareness in young adults to improve the treatment of low back pain. [Participants and Methods] Data were collected from 36 university students with low back pain. The items included for evaluation were the low back pain intensity (Numeric Rating Scale), disability due to low back pain (Oswestry Low Back Pain Disability Index), lumbar spine and hip motion angles in test movements, and perceptual awareness (Fremantle Back Awareness Questionnaire). The test movements employed included trunk forward bending, trunk back bending, and prone hip extension. The motion angles of the lumbar spine and hip joints were measured using a wearable sensor. [Results] The Numeric Rating Scale was not correlated with the lumbar hip motion angle and perceptual awareness. The Oswestry Low Back Pain Disability Index was correlated with lumbar hip motion angles, at the beginning of trunk forward bending and at maximum trunk backward bending, and with perceptual awareness. [Conclusion] There are relationships among disabilities due to low back pain, lumbar hip motion angles, and perceptual awareness in each test movement; however, they vary depending on the type and angle of the test movement conducted.

Relationship between iliopsoas muscle thickness and hip angle during squats in different pelvic positions.

[Purpose] This study aimed to investigate the relationships among the changes in iliopsoas muscle thickness, hip angle, and lower limb joint moment during squatting in different pelvic positions to help in performing hip-dominant squatting exercises. [Participants and Methods] The participants were seven healthy adult males. The measurement task consisted of squatting with 60 degrees of knee flexion in three positions: the anterior, neutral, and posterior pelvic tilt positions. The iliopsoas muscle thickness was measured in the center of the inguinal region using ultrasonography. A three-dimensional motion analysis system was used to measure the joint angles and joint moments. [Results] There were no significant differences in pelvic angles between the pelvic positions. The hip angle differences were significantly higher in the anterior and neutral pelvic tilt positions compared to those in the posterior tilt position. Only the anterior pelvic tilt position had a significantly positive correlation with iliopsoas muscle thickness and hip angle differences. [Conclusion] Squatting in the neutral or posterior pelvic tilt position was not associated with hip angle and iliopsoas muscle thickness changes, whereas squatting in an anterior pelvic tilt position was associated with changes in the iliopsoas muscle thickness and hip flexion angle. Our findings suggest that activation of the iliopsoas muscle might be necessary to promote hip-dominant squatting.

Relationship between low back pain and lumbar and hip joint movement in desk workers.

[Purpose] The study aimed to determine the relationship between low back pain and lumbar and hip movement in desk workers with chronic non-specific low back pain, in order to obtain basic data regarding measures for preventing low back pain in desk workers. [Participants and Methods] The study included 10 desk workers (all female, age: 47.1 ± 6.0 years). The following measurements were recorded: numerical rating scale score for pain assessment at the time of maximum forward and backward bending of the trunk while standing, and the amount of movement of the trunk and the lumbar and hip joint. The ratio of the lumbar and hip joint movements during maximum forward and backward bending of the trunk was calculated. [Results] For maximum forward and backward bending of the trunk, a positive correlation between the numerical rating scale score and the ratio of movement for the lumbar and a negative correlation with that of the hip joint were noted. [Conclusion] Moving the hip joint while suppressing excessive lumbar movement is one of the measures for preventing low back pain in desk workers.

Does elongation training effectively improve motor function?-a single-case design verification study.

[Purpose] The aim of this study was to investigate whether elongation training (ELT) was effective in improving motor function in a single case. [Participant and Methods] A 90-year-old male with Parkinson's syndrome participated in this study. This study used the A-B-A type of single case design. In the 'A' period, normal lower limb exercises (extension and abduction of the hip joint) were performed. The same exercise from the 'A' period was performed using an elongation band in the 'B' period for ELT. The implementation period included 2 weeks of the 'A' period, 2 weeks of the 'B' period, and then 2 weeks of the 'A' period again. Motor function was evaluated using the one-leg standing time on each side, and the Timed Up and Go Test (TUG). [Results] In the 'A' period, there was no change in the one-leg standing time on each side and the TUG. However, in the 'B' period, the one-leg standing time on each side increased, and the TUG values decreased. When returning to the 'A' period, the one-leg standing time on each side decreased, and the TUG increased. [Conclusion] It can be suggested that ELT safely improves motor function at home, even in older people.

Morphological changes in the long axis of the lower leg muscles during isometric contraction in the sitting position.

[Purpose] To compare the changes in the muscle cross-sectional area (MCSA) along the long axis of the lower leg muscles at rest and during ankle plantar flexors isometric contraction and to obtain basic information regarding the movement of lower leg muscles during ankle plantar flexors contraction. [Participants and Methods] Sixteen healthy young female participants (20.9 ± 1.2 years) were asked to sit with their ankles in a neutral ankle position. Images were obtained at rest and during isometric contraction of the ankle plantar flexors using gravity magnetic resonance imaging. The MCSAs of the triceps surae and tibialis anterior were measured. [Results] The middle region of the soleus muscle had a lower MCSA on contraction than at rest. In addition, the medial head of the gastrocnemius had a lower MCSA on contraction than at rest in the distal quarter. Moreover, the tibialis anterior had a lower MCSA at rest than on contraction in the middle region. [Conclusion] The area to be used as an indicator and the movement to be induced differ depending on the muscle during isometric contraction of the triceps surae.

Morphological changes of lower leg muscles according to ankle joint position during sitting evaluated by gravity mri in young females.

[Purpose] This study aimed to clarify whether the morphological changes of the lower leg muscle occur equally in the longitudinal direction of the muscle according to changes in ankle joint position during sitting. [Participants and Methods] The participants were 15 healthy young females whose dominant lower legs were analyzed. The participants sat with the lower leg vertical to the floor with a neutral, dorsiflexed, or plantarflexed ankle position. Images were obtained from the fibular head from 290 mm distal using gravity magnetic resonance imaging. The muscle cross-sectional areas of the soleus, medial and lateral heads of the gastrocnemius, and anterior tibialis were measured. [Results] The muscle cross-sectional area of the soleus at the 1/4 proximal muscle belly in the plantarflexed position was greater than those in the other positions. The 1/4 distal part in the plantarflexed position was smaller than those in the other positions. The muscle cross-sectional area of the gastrocnemius at the 1/4 distal part in the plantarflexed position was smaller than that in the dorsiflexed position. In contrast, the muscle cross-sectional area of the tibialis anterior at the 1/4 proximal part in the dorsiflexed position was greater than those in the other positions, while that at the 1/4 distal part in the dorsiflexed position was smaller than that in the plantarflexed position. [Conclusion] In the sitting position, the morphological changes of the lower leg muscle according to changes in ankle joint position are not uniform in the longitudinal muscle direction.

Change in muscle thickness during exercise to stabilize the hip joint against a load in the ventral direction of the femoral head.

[Purpose] This study aimed to measure the thickness of the muscles located on the ventral side of the hip joint and to identify the muscles involved in exercise against the load that results in femoral head translation in the ventral direction, which can be used as an index of exercise performance for the prevention and improvement of hip joint disease caused by femoral head translation. [Participants and Methods] The participants were 10 healthy young males. During the measurement task, we asked them to hold a 10 kgf load in the ventral direction to the femoral head in the supine position. We measured the thickness of the gluteus minimus, gluteus medius, tensor fascia latae, and iliopsoas both at rest and during exercise using ultrasonography. [Results] We compared muscle thicknesses at rest and during exercise and found that only the gluteus minimus had significantly lower values during exercise. We also compared the rate of change in muscle thickness and found that the gluteus minimus exhibited significantly higher values than those of the gluteus medius and tensor fasciae latae. [Conclusion] Our study indicates that the gluteus minimus is more involved than the gluteus medius, tensor fasciae latae, and iliopsoas in the exercise for the ventral displacement of the femoral head.

Effects of static interventions on disuse atrophy of the rat soleus muscle at different sites along its longitudinal axis.

[Purpose] The purpose of our study was to verify the inhibitory effects of static intervention (heat load and muscle stretching) on disuse-related adaptation changes in the soleus muscle and to compare these effects across different sites along its longitudinal axis. [Subjects] Forty 8-week-old male Wistar rats. [Methods] The effects of heat load and/or muscle stretching in the rat soleus during hindlimb suspension were evaluated by measuring the cross-sectional area of the muscle fibers, succinate dehydrogenase activity, and number of capillaries in the proximal, middle, and distal regions. [Results] With no intervention the proximal region showed the highest reduction in the cross-sectional area, whereas the distal region showed the highest reduction in succinate dehydrogenase activity and the number of capillaries due to hindlimb suspension. These differences between the proximal and distal regions decreased with both interventions, and the effects were most pronounced with a combination of heat load and muscle stretching. [Conclusion] Differences in the muscle structure between the proximal and distal regions increased due to hindlimb suspension, and this heterogeneity associated with muscle disuse was inhibited by static intervention including heat load and muscle stretching. Furthermore, the combination of heat load and muscle stretching most reduced the heterogeneity.

Effects of 6 weeks of whole-body vibration training on ankle motor control: a randomized controlled trial.

BACKGROUND: Interventions on ankle motor control are important to prevent recurrent ankle sprains. Training using whole-body vibration may easily and effectively improve ankle motor control, but the effects have not been investigated. Therefore, this study aimed to clarify the effects of 6 weeks of training with whole-body vibration on ankle motor control in a dynamic movement task among healthy participants. METHODS: Twenty healthy university students (6 males and 14 females) were randomly allocated to whole-body vibration training and control groups, with 10 participants in each group. The training was performed twice a week for 6 weeks in both groups. Primary outcome was mean ankle angular jerk cost in the star excursion balance test. Secondary outcomes were maximum ankle motion angle and maximum reach distance in the star excursion balance test, ankle proprioception, and range of ankle dorsiflexion motion in the loaded position. RESULTS: There was a significant group × period (pre- and postintervention) interaction for mean ankle angular jerk cost in the direction of ankle abduction/adduction during posterolateral reaching, which was significantly lower at postintervention than that at preintervention in the whole-body vibration group In the whole-body vibration group, the maximum ankle dorsiflexion motion angle during anterior and posterolateral reaching was significantly higher at postintervention than that at preintervention. CONCLUSIONS: Training with whole-body vibration improves ankle motor control in dynamic movement tasks, although the direction of reach and plane of motion are limited. Additionally, training with whole-body vibration is also effective in increasing the ankle dorsiflexion angle during dynamic movement tasks.

Effectiveness of Rehabilitation for Osteoarthritis of the Knee: A Scoping Review of Network Meta-Analyses.

BACKGROUND:  Although an increasing number of network meta-analyses have been conducted on the effectiveness of conservative therapy for knee osteoarthritis, these may have been poorly planned and executed.We aimed to review the qualities of a comprehensive set of network meta-analyses on rehabilitation therapies for knee osteoarthritis and provide an overview of the effectiveness of each therapy. METHODS: The eligibility criteria were as follows: (i) conservative rehabilitation was the primary treatment in the intervention group, (ii) included patients were diagnosed with knee osteoarthritis, and (iii) patient groups were aged ≤75 years, and rehabilitation interventions comprised exercise, orthotic, or physical therapies or patient education. Two independent reviewers screened the titles and abstracts of the identified records and selected the eligible reviews; their full texts were further assessed for eligibility. Then, a checklist derived from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension statement for the reporting of systematic reviews incorporating network meta-analyses of healthcare Interventions was used to validate the completeness of the reporting of each network meta-analysis. Furthermore, the statistical and outcome data regarding the quality of life, knee joint function and pain, adverse events, and physical functions were extracted using a customized spreadsheet. RESULTS: Overall, 2701 titles and abstracts were screened, and eight network meta-analyses were ultimately selected. Nearly all reviews adequately addressed the PRISMA extension checklist, and the completeness of reporting was adequate; therefore, all expected information could be extracted. However, the methodology used to confirm the transitivity assumption was insufficient in many reviews. The following interventions were effective in reducing pain and improving physical function: (i) strengthening, flexibility, aerobic, and mind-body exercises, (ii) pulsed ultrasound, (iii) focused and radial extracorporeal shockwave therapy, and (iv) continuous ultrasound. The following interventions were effective in improving the quality of life: (i) strengthening, (ii) mixed, and (iii) mind-body exercises. CONCLUSIONS: Our results suggested that exercise therapies, including muscle-strengthening, aerobic, flexibility, and mind-body exercises, are likely to be effective for pain relief and functional improvement in knee osteoarthritis. This may be the first review to provide a comprehensive perspective for considering priorities for future rehabilitation interventions for knee osteoarthritis.

Effects of axial extension on pelvic floor displacement and abdominal muscle activity during a pelvic floor muscle task.

BACKGROUND: The effects of axial extension on pelvic floor displacement and abdominal muscle activity during pelvic floor muscle (PFM) exercises are not well known. OBJECTIVE: To clarify the effect of sitting axial extension on pelvic floor displacement and abdominal muscle activity during a PFM task. METHODS: Pelvic floor displacement, abdominal muscle activity, and subjective kinesthesia of the PFM were compared between the resting and axial-extended sitting positions during a pelvic floor task in 34 healthy young men. RESULTS: No significant difference in pelvic floor displacement was observed between the resting and axial extension sitting position. Subjective kinesthesia was significantly easier to perform in axial extension than in resting sitting position during pelvic floor depression. Abdominal oblique muscle activity was higher in axial extension than in resting sitting position during pelvic floor depression. The changes in axial extension were significantly greater in the internal oblique muscles during elevation and in the internal and external oblique muscles during depression than in the lower rectus abdominis muscles. CONCLUSION: Axial extension in the sitting position does not change pelvic floor displacement during the PFM task. However, axial extension may be effective in facilitating subjective kinesthesia of PFM and in increasing oblique abdominal muscle activity.

Relationship between ankle-joint angle during dynamic balance task and ankle-joint proprioception in chronic ankle-instability individuals.

BACKGROUND: Chronic ankle instability (CAI) is a major condition in athletes. It is known that both ankle joint proprioception and joint motion control are important for the improvement of CAI, but the relationship between the two has not been clarified. The purpose of this study was to compare ankle-joint angle in dynamic balance tasks and ankle-joint proprioception in healthy and CAI individuals and to verify the relationship between ankle-joint angle in dynamic balance tasks and ankle-joint proprioception in individuals with CAI. METHODS: The participants were 27 females (age 20.3±0.9 years, healthy group: 15, CAI group: 12). The star excursion balance test (SEBT) was used for the dynamic balance task, and the ankle joint angles were measured with a small accelerometer during the movement. The error of the active joint repositioning test (AJRT) was measured to test the proprioception. RESULTS: There was no significant difference in the error in AJRT between the groups, but the joint angle in SEBT was significantly lower in the CAI group than in the healthy group for ankle dorsiflexion only. The error in AJRT of ankle inversion was correlated with the ankle inversion/eversion angle of the SEBT, and the error in AJRT of ankle plantar flexion was correlated with the ankle-dorsiflexion angle of the SEBT. CONCLUSIONS: CAI individuals showed no difference in ankle-joint proprioception compared to healthy individuals, but their ankle-joint-dorsiflexion angle in the dynamic balance task was smaller. Ankle-joint proprioception in CAI individuals was related to the ankle-joint angle in the dynamic balance task.

Relationship between pelvic floor muscle function and changes in lumbar spine and hip motion due to pelvic floor muscle contraction.

BACKGROUND: Pelvic floor muscles (PFM) are important for lumbar stability. However, the relationship between lumbar and hip motion angle changes (MAC) caused by PFM contraction and each PFM's function remains unclear. OBJECTIVE: To clarify the lumbar spine and hip motion changes produced by PFM contraction and the relationship between MAC and PFM function. METHODS: In 21 healthy females, motion angle was measured for prone hip extension movement using natural movement (NM), PFM contracting movement (PM), and reducing lumbar movement (RM) methods. The PFM functional indices were bladder base elevation distance, continuous bladder base elevation time, and pelvic floor location. RESULTS: The PM showed no significant difference in lumbar motion angle but had significantly smaller hip motion than the NM (NM; 26.1 ± 8.3, PM; 29.2 ± 11.0). MAC was significantly greater in RM (lumbar spine; 4.4 ± 3.2, hip; 5.9 ± 8.7) than in PM (lumbar spine; 0.4 ± 4.4, hip; 3.1 ± 5.1) for both the lumbar spine and hip. Lumbar spine and hip MAC of PM was significantly correlated with pelvic floor location (lumbar spine; r=-0.44, hip; r= 0.54). CONCLUSION: PFM contraction does not attenuate lumbar spine motion but reduces hip motion. MAC due to PFM contraction during lumbar movement tasks is related to the PFM functional index.