Development of Connective Tissue Area Increases by Initial Impact With High-Intensity Exercise After Reloading in Rat Soleus Muscle.

OBJECTIVE: The aim of the study is to clarify whether high-intensity exercise in atrophied skeletal muscle after reloading (1) increases the injury and promotes the development of the muscle connective tissue area in the soleus muscle and (2) delays muscle strength recovery. DESIGN: Rats had their hindlimbs suspended for 14 days followed by hindlimb reloading and squat exercise of 30% or 70%-one-repetition maximum exercise until 14 days of reloading. The influences of reloading and exercise in muscles were examined by histological and immunofluorescence analyses based on the exercise load. RESULTS: Seventy percent-one-repetition maximum exercise increased the extramyofiber area more than the control group and the central nuclear fiber number than the other groups after 7 days of reloading. Seventy percent-one-repetition maximum exercise resulted in a larger muscle connective tissue area than the control and reload groups after 14 days of reloading. Myogenin and M2-type macrophages after 7 days of reloading increased by reloading but were not increased by the exercise load. CONCLUSIONS: Seventy percent-one-repetition maximum exercise to atrophied muscle increased injury early in postreloading and increased the muscle connective tissue area after 14 days of reloading, but evidence that it delays muscle strength recovery was lacking. Therefore, muscle connective tissue area induced by high-intensity exercise after reloading seems to be associated with initial exercise damage but not with repetition over 14 days.

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.

Association of life-space with light-intensity and moderate to vigorous-intensity physical activity in older adults using daycare rehabilitation facilities.

BACKGROUND: The use of assistive devices and the presence of caregivers in the living space of older people using daycare rehabilitation facilities may increase their physical activity. However, the exact relationship between these factors and physical activity has not been well established. OBJECTIVE: We aimed to examine whether assistive devices and caregivers were life-space factors associated with light-intensity physical activity (LPA) and moderate to vigorous-intensity physical activity (MVPA) among daycare rehabilitation facility users. METHODS: Forty-seven daycare rehabilitation facility users were recruited (mean age: 76.5 ± 8.6 years; men: 16; women: 31). LPA and MVPA were measured using accelerometers and averaged over 7 days. Life-space assessment (LSA) and the Geriatric Depression Scale score were assessed. The LSA includes composite life-space, maximal life-space (LS-M), life-space using equipment (LS-E), and independent life-space. Grip strength and maximum gait speed were measured two times, and the best results were used. RESULTS: Multiple regression analysis showed that LPA was significantly associated with sex (ß = 0.773), grip strength (ß = 0.434), and LS-M (ß = 0.325), whereas MVPA was significantly associated with age (ß = -0.421) and LS-E (ß = 0.455). CONCLUSION: A close association was found between LS-M and LS-E and the intensity of physical activity in older people who used daycare rehabilitation facilities.

Effects of long-term treatment with dietary theobromine on rat skeletal muscles.

BACKGROUND: Plastic changes of skeletal muscles, such as hypertrophy and atrophy, are dependent on physiological activities and regulated by a variety of signaling pathways, including cyclic adenosine monophosphate (cAMP) pathway. The cAMP inducing agents, such as the ß2-adrenergic agonist clenbuterol, are known to induce muscle hypertrophy, and has been reported to induce slow-to-fast transitions in rat soleus muscle. Theobromine, one of the active components of cacao, functions as an inhibitor of phosphodiesterase and increases cAMP. This study hypothesized that theobromine, like clenbuterol, can induce muscle hypertrophy and influence contractile properties. METHODS AND RESULTS: Male Wistar rats were fed a normal diet or a diet containing 0.05% theobromine for 20 weeks. Using biochemical, anatomical, and physiological techniques, effects of dietary theobromine on skeletal muscles (soleus, extensor digitorum longus, plantaris, and gastrocnemius) were examined. There were no significant differences in body weight, serum levels of proteins and lipids, muscle weights, dry/wet ratio of muscle weights, mitochondrial oxidation enzyme activity of muscles, isometric contractile properties of muscles, and muscle fatigue between control and theobromine-fed rats. Quantitative analysis of mRNA, however, revealed upregulation of myosin heavy chain 2x and myogenic differentiation 1, as previously reported in clenbuterol-treated muscles. CONCLUSION: The long-term theobromine (0.05%) diet in rats had no effect in inducing muscle hypertrophy and in changing contractile properties, although it had some similar effects of clenbuterol on muscle gene expression.

Blood lipid profile changes in type 2 diabetic rats after tail suspension and reloading.

PURPOSE: The effects of the tail suspension and reloading on the protein and lipid metabolism in muscle and blood in type 2 diabetes mellitus (T2DM) are unclear. This study evaluated the hypothesis that skeletal muscle catabolism is greater in T2DM than in non-diabetes mellitus (non-DM) rats and that the activity-dependent changes in the intramuscular lipid accumulation and blood lipid profile are poorer in T2DM than in non-DM rats. METHODS: T2DM and non-DM rats were suspended for two weeks followed by reloading for two weeks. The muscle and blood were then examined. RESULTS: In contrast to our hypothesis, there was no marked difference between the T2DM and non-DM groups in terms of the skeletal muscle catabolism and activity-dependent changes in intramuscular lipid accumulation. However, the blood lipid profile increased in the T2DM group compared to the non-DM group. One interesting finding in this study was the decrease in non-high-density lipoprotein (non-HDL) cholesterol levels after one week of reloading followed by a significant increase in the non-HDL cholesterol levels after two weeks of reloading in the T2DM group. CONCLUSION: These results suggest that a dramatic increase in activity after a period of inactivity may rapidly improve the blood lipid profile in T2DM rats.

Effect of the Abdominal Draw-In Maneuver and Bracing on Abdominal Muscle Thickness and the Associated Subjective Difficulty in Healthy Individuals.

We evaluated the trunk abdominal muscle thickness while performing different exercises to identify the most effective training and to investigate the subjective difficulty associated with exercising. Twenty-eight men (mean age: 21.6 ± 0.9 years) without orthopedic diseases were enrolled. Ultrasonic imaging was used to measure the thickness of the transversus abdominis (TA), internal oblique, and external oblique muscles while at rest and while performing the abdominal draw-in maneuver and abdominal bracing. Measurements were made in the supine and sitting positions, and the subjective difficulty in performing each exercise was examined using a 5-level evaluation scale. The TA and internal oblique muscle thicknesses were significantly greater during the abdominal draw-in maneuver (ADIM) than during bracing or resting, in the supine and sitting positions. The subjective difficulty of abdominal bracing (AB) was graded significantly higher than that of ADIM. Additionally, a correlation between subjective difficulty and muscle thickness was found for the TA and IO. Our results may contribute to the choice of more effective exercises for spinal stability.

Relationship between transversus abdominis muscle thickness and urinary incontinence in females at 2 months postpartum.

[Purpose] Urinary incontinence is a frequent postpartum complication. Thus, this study aimed to examine the associations of transversus abdominis muscle thicknesses at rest and during an abdominal drawing-in maneuver with urinary incontinence in females at 2 months postpartum. [Participants and Methods] The participants included 18 females at 2 months postpartum with or without urinary incontinence, and 10 nulliparous females as controls. Transversus abdominis thickness was measured at rest and during the abdominal drawing-in maneuver using diagnostic ultrasonography. The Japanese version of the International Consultation on Incontinence Questionnaire-Short Form was used to evaluate urinary incontinence. [Results] Females at 2 months postpartum were divided into groups with and without urinary incontinence according to questionnaire scores. The muscle thickness during the abdominal drawing-in maneuver contraction was significantly lower in those with urinary incontinence than in those without urinary incontinence and controls. [Conclusion] The results showed significantly reduced transversus abdominis thickness during contraction, which suggested reduced transversus abdominis strength in females with postpartum urinary incontinence. Thus, promoting synergistic contraction of the inner unit, including the transversus abdominis, in exercise therapy may be more effective for postpartum urinary incontinence.

Effect of hindlimb unloading and reloading on the soleus and plantaris muscles in diabetic rats.

[Purpose] This study aimed to induce disuse muscle atrophy in Goto-Kakizaki rats, a type 2 diabetes model, to investigate the effects of reloading on the soleus and plantaris muscles. [Materials and Methods] Wistar and Goto-Kakizaki (GK) rats were divided into 6 groups: Wistar Control (WC), GK Control (GC), Wistar Tail suspension (WS), GK Tail suspension (GS), and Wistar Reload (WR), GK Reload (GR). [Results] Investigation of myofiber cross-sectional area in Goto-Kakizaki rat soleus muscles indicated that the GS group showed significantly lower values than the GC and GR groups. No significant differences were observed between the GC and GR groups. However, investigation of plantaris muscles in Goto-Kakizaki rats indicated that the GS and GR groups showed a significant decrease compared to the GC group. No significant differences were found between the GS and GR groups. [Conclusion] Investigation of muscle weight/body weight ratios and myofiber cross-sectional area in tail suspension groups confirmed the induction of muscular atrophy. The differences in the degree of atrophy and recovery in terms of myofiber cross-sectional area observed in Goto-Kakizaki rat plantaris muscles may be influenced by the myofiber type and diabetes.

Changes in thickness of the transversus abdominis during the abdominal drawing-in manoeuvre and expiratory muscle training in elderly people.

[Purpose] It has been reported that exercises focusing upon the transversus abdominis (TrA) ameliorate low back pain (LBP). We investigated whether expiratory muscle training (EMT) can promote activity of the TrA to the same degree as the abdominal drawing-in manoeuvre (ADIM) in elderly individuals. [Subjects and Methods] Twenty-one elderly subjects (9 males, 12 females; mean age, 84.9 ± 6.6 years) without LBP symptoms were included. Using ultrasound imaging we measured changes in thickness of the lateral abdominal muscles, TrA, internal oblique muscle (IO), and external oblique muscle (EO) during ADIM and EMT. The load in EMT was set to 15% of maximal expiratory pressure. [Results] TrA showed a significant increase in muscle thickness during ADIM and EMT compared with at rest. A significant increase in muscle thickness was noted for EMT in comparison with ADIM. No significant differences were found for IO and EO. [Conclusion] In elderly people, EMT may be an effective alternative to ADIM for promoting activity of the TrA and can be used as an exercise to maintain TrA function.

Transformative learning experience for physical therapy students through a community health promotion project for mothers of hearing-challenged children.

[Purpose] The purpose of this project was to expose physical therapy students to transformative learning through a community health promotion project for mothers of hearing-challenged children. [Subjects and Methods] The participants were three mothers with their respective hearing-challenged child and twenty physical therapy students. The project consisted of seven sessions supervised throughout by a physical therapy instructor. The students participated in seven sessions, while the mothers were required to attend only two sessions of a health checkup and exercise program. [Results] Through the interaction between the mothers and students, the former felt physically and mentally refreshed, and the latter experienced transformative learning. The mother's physical status showed that all parameters for health variables were within normal range. However, it was found that mothers had little time for their personal mental or physical well-being because their focus was on planning and executing daily assignments for development of the child's verbal skills. [Conclusion] This project contributed to the students' learning experience and provided them with tools for possible future interest and involvement in community activity. The exercise session appeared to stimulate in the mothers an awareness and importance of their own personal and mental well-being.

The Effect of the Abdominal Drawing-in Manoeuvre during Forward Steps.

[Purpose] A decrease in hip extension has been reported to be a factor in short step width and slow walking speed. Hip motion is related to pelvic and spinal motion, and transversus abdominis (TrA) activation is important for stabilising the pelvis and spine. The abdominal drawing-in manoeuvre (ADIM) can be performed to activate the TrA. The purpose of this study was to examine the influence of the ADIM on forward steps as a gait exercise. [Subjects] The subjects were 20 healthy men (mean age, 20.8 ± 2.4 years). [Methods] Thicknesses of the lateral abdominal muscles during forward step posture with and without ADIM were measured using ultrasound, and kinematics of the hip and pelvis were examined using a three-dimensional motion capture system. [Results] Thicknesses of the TrA and internal oblique increased during forward steps with ADIM. In addition, hip extension increased and pelvic rotation and oblique angles decreased during forward step with ADIM. [Conclusion] We believe that ADIM activates the so-called corset muscles, which consequently stabilise the pelvis and spine and increase hip extension. Our results suggest that an ADIM could increase hip extension during gait exercise.