Purpose: The aim of this study was to investigate whether low-intensity and slow-movement shoulder external rotation exercise cause stress on the infraspinatus muscle, as measured by acute changes in cross-sectional area (CSA).

Methods: Ten healthy male volunteers (mean: 25.6 ± 3.7 years) participated in this study. Using B-mode ultrasound, CSA of the infraspinatus was measured before and after shoulder external rotation exercise under three conditions in a random order (0.5 kg/5 s, 0.5 kg/1 s, and 2.5 kg/1 s). In addition, during each exercise, infraspinatus and posterior deltoid muscle activities were measured using surface electromyography (EMG).

Results: There was a greater increase in CSA of the infraspinatus at 0.5 kg/5 s than at the other exercise conditions. There were no differences in the averaged EMG values of the infraspinatus among the three conditions; however, the integrated EMG values of the infraspinatus at 0.5 kg/5 s were greater than the values at 0.5 kg/1 s and 2.5 kg/1 s.

Conclusion: These results suggest that compared to the stress caused by higher intensity and speed, low-intensity and slow-movement external rotation exercise cause greater stress on the infraspinatus.

Purpose: We aimed to clarify the mechanisms involved in moving from a kneeling position to a forward step movement.

Methods: We investigated the forward step movement from a kneeling position in 11 normal subjects. The series of movements were divided into four phases using center of pressure (COP) movement: phase I involved COP movement to the front of the stepping leg; phase II involved COP movement to the back of the supporting leg; phase III involved a left backward-left forward COP mobile phase; and phase IV involved a left forward-right forward COP mobile phase.

Results: Prior to COP movement, we found that the left adductor longus muscle and right gluteus medius muscle showed activity. For phase I, the center of gravity (COG) was observed at the back of the supporting leg. For phase II, the right back movement of COG continued. For phase III, the left forward movement of COG occurred. For phase IV, the right forward movement of COG occurred.

Conclusions: In the forward step movement from kneeling, we propose that it starts from COP movement to the front of the stepping leg and COG movement to the back of the supporting leg. The supporting side adductor longus muscles and stepping side gluteus medius muscles stat activity before COP movement, which is essential to the forward step movement from kneeling.

Purpose: This study examined the throwing factors influencing shoulder distraction, anterior force and superior force on the shoulder.

Methods: The throwing motions of 81 baseball pitchers were recorded with high-speed video cameras, and a multiple regression analysis was used.

Results: Six parameters accounted for 59% of the variance in shoulder distraction force, and the magnitude was increased by the shoulder horizontal adduction at ball release, trunk rotation at foot plant, shoulder horizontal adduction torque at foot plant, shoulder external rotation torque at maximum shoulder external rotation, shoulder adduction torque at ball release and trunk rotation at ball release. The adjusted multiple R² in shoulder anterior force was 0.46. This force was affected by shoulder horizontal abduction and shoulder horizontal abduction torque at foot plant. Seven parameters explained 55% of the shoulder superior force. This force was related to the shoulder external rotation torque at maximum shoulder external rotation, shoulder abduction torque at ball release, shoulder adduction at foot plant, shoulder internal rotation at foot plant, shoulder adduction torque at maximum shoulder external rotation, shoulder horizontal abduction torque at foot plant and trunk rotation at foot plant.

Conclusions: These data provide a scientific basis for reducing distraction, anterior force and superior force on the shoulder. Additionally, rehabilitation programs can focus on the forces that cause throwing-related pain.

Purpose: To evaluate the clinical characteristics of nocturnal pain accompanying shoulder periarthritis, the positional relationships of scapulohumeral joint and shoulder joint movements were compared among a non-nocturnal pain group, a nocturnal inflammation group, and a nocturnal contracture group.

Patients: The subjects were 100 patients (100 shoulders) with shoulder periarthritis. Based on frontal shoulder joint X-ray films of the subjects, the AHI, HHD, AHI/HHD ratio, and GHA were measured. To assess the range of shoulder join movement, flexion, lateral rotation, and internal rotation were measured and compared.

Results: No significant differences of AHI, HHD, and shoulder joint flexion were observed between the three groups. Compared to non-nocturnal pain group, the nocturnal contracture group showed a reduced range of lateral and internal rotation, while GHA was increased. Compared to the non-nocturnal pain group, the nocturnal inflammation group showed a decrease of AHI/HHD, while GHA was increased. The nocturnal contracture group showed an increase of GHA compared to the nocturnal inflammation group.

Conclusion: In the nocturnal inflammation and nocturnal contracture groups, the scapula was in a position of downward rotation. When nocturnal pain was due to inflammation, the range of shoulder joint rotation was relatively well maintained. However, the range of shoulder joint rotation was restricted when contracture was responsible for pain.

Purpose: Spontaneous movements of infants aged 2 to 5 months have been referred to as fidgety movements (FM). Assessments of FM based on either visual observation or computer-based analysis have been performed to predict future neurological impairments. In this study, we evaluated how the differences in FM are related to differences in characteristics of spontaneous movements of the limbs.

Methods: Seventy-seven very low birth weight infants were included in this study. We used video recordings of the spontaneous movements of participants in the supine position, at 49 to 60 weeks postmenstrual age. First, we classified the participants into three groups (normal FM, absent FM, and abnormal FM) by the visual gestalt perception according to Prechtl’s method. Second, we examined the following seven indices from two-dimensional trajectories of all limbs: (1) average velocity, (2) number of movement units, (3) kurtosis of acceleration, (4) jerk index, (5) average curvature, (6) lateral mobility index, and (7) correlation between limb velocities. We compared each index between normal FM groups and absent FM group.

Results: The average curvature in the absent FM group was significantly lower than that in the normal FM group. Furthermore, 24 out of 33 cases in the absent and abnormal FM group showed later developmental disability (developmental delay, autism spectrum disorder, and cerebral palsy).

Conclusion: Our results suggest that higher average curvature of the lower limbs represents the presence of FM. The present study may guide efforts in quantification of characteristics of FM and detecting earlier signs of developmental disability.

Purpose: To investigate the effects of two stretching methods on the elongation of different portions of the biceps femoris (BF).

Methods: Fifteen healthy men volunteered for this study. The shear elastic moduli of the proximal, middle, and distal portions of the BF were measured using ultrasonic shear-wave elastographic imaging at rest (supine position with 90° knee flexion and 90° hip flexion) and at two stretching positions (knee extension with 90° hip flexion [KE] and hip flexion with full knee extension [SLR]).

Results: A post-hoc test indicated that the shear elastic moduli of all portions were higher in both the KE and SLR positions than at rest. However, there were no significant differences between the KE and SLR for all portions. In addition, split-plot analysis of variance showed no significant interaction effect in the rate changes of the shear elastic modulus (three portions × two stretching positions).

Conclusion: Our results suggest that both the KE and SLR stretching positions could effectively elongate all portions of the BF and that there is no significant difference in the elongation of different portions between both the stretching methods.

Objectives: In this study, we aimed to measure the index of postural stability (IPS) and modified IPS (MIPS), both of which reflect dynamic balance capability, by using force plates. We also aimed to evaluate the repeatability of MIPS and the rubber IPS Romberg ratio (MIPS/IPS), and the effectiveness of MIPS.

Methods: The IPS, MIPS, and score in the balance capability test (one-foot standing with eyes closed [COFS]) were assessed for 80 healthy young subjects. The repeatability values of MIPS and MIPS/IPS were evaluated, considering systematic bias and random error. A histogram was generated for the effectiveness of MIPS, which was compared with that of the COFS score by using the Shapiro-Wilk test.

Results: Fixed bias was found in both the MIPS and MIPS/IPS. The intraclass correlation coefficient (1.1) was used as a measure of repeatability. The repeatability values of MIPS and MIPS/IPS were 0.723 and 0.616, respectively. The effectiveness of MIPS showed p values of 0.859. This result suggests that MIPS significantly follows a perfect normal distribution.

Discussion: MIPS can be considered a clinically applicable evaluation index. Furthermore, it can be an effective measure of balance capability of subjects in a wide age range.

Purpose: To analyze the effects of respiratory training on respiratory function, swallowing function, QOL of the community-dwelling frail elderly.

Method: Thirty one community-dwelling frail elderly using rehabilitation services underwent 12 rehabilitation sessions that included respiratory training. Outcome measures were evaluated the 12 rehabilitation sessions, prior to training, immediately after the sessions, and at 1 and 6 months after the sessions. Primary outcome measures included respiratory function, swallowing function, and QOL.

Results: Swallowing function, QOL, respiratory function, 6-min walk distance, and thorax flexibility significantly improved during respiratory rehabilitation (between the pre-training evaluation and post-training evaluation). Swallowing function, QOL, respiratory function, and physical function were significantly reduced during the follow-up period (between the post-training evaluation and 6-month follow-up evaluation).

Conclusions: Our results suggest that typical program rehabilitation without respiratory training is not sufficient for the frail elderly to maintain their QOL. Furthermore, respiratory training can help improve QOL as well as swallowing and respiratory function in the frail elderly.