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.

[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.

[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.

[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.

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.