[Purpose] The purpose of this study was to examine the center of pressure (COP) trajectory and response time when young adults initiate gait and step over an obstacle while simultaneously performing a secondary Stroop task. [Subjects] Twenty healthy young adults (ten males and ten females) participated in the study. [Methods] The subjects first completed a Stroop task while standing (baseline) and then initiated gait and stepped over an obstacle at a self-paced speed with and without a secondary Stroop task. The response times to the secondary task and the COP trajectory were measured. [Results] The Stroop task response time in the stepping condition was the longest, followed by the times for initiating gait and standing conditions (p<0.01). There were main effects for both the Stroop task and stepping conditions for the mediolateral (M-L) displacement of the COP and the length of the COP path for both feet (p<0.01, respectively). However, there were no significant differences among the tasks for the anteroposterior (A-P) displacement of the COP for both feet. [Conclusion] This study suggests that divided attention degrades the obstacle avoidance abilities of healthy young adults and the apparently greater demand of postural control may prove as difficult for populations that are at risk of falling.

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[Purpose] The purpose of this study was to verify a method of spectral analysis of stride-to-stride variability, and to apply this method to the analysis of the gait pattern of patients with Parkinson's disease. [Subjects] Ten healthy young individuals, ten community-dwelling elderly individuals and nine individuals with Parkinson's disease were recruited. [Methods] To quantitatively evaluate stride-to-stride variability, we used fast Fourier transform, calculated the power spectrum, and separated it into three frequency ranges. We plotted a double-log graph for the power spectrum and calculated the slope of the line using least-squares regression. For each of the participants we measured 10-meter walking speed, stride-to-stride variability, and disease severity (only Parkinson's disease). [Results] Each of three ranges of the power spectrum was four times larger for Parkinson's disease patients than for the healthy groups (p < 0.05). The severity of Parkinson's disease correlated significantly with the very low frequency range (0.01-0.05 Hz) of the power spectrum (r = 0.767, p = 0.0159) and the scaling factor β of the power spectrum (r = 0.850, p = 0.0037). [Conclusion] This method of spectral analysis of stride-to-stride variability may be useful for gait analysis of patients with Parkinson's.

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[Purpose] The purpose of this study was to assess the effects of home-based knee stretching exercises on knee range of motion (ROM) and gait speed in patients with knee osteoarthritis awaiting total knee arthroplasty. [Subjects] Thirty-six patients with severe knee osteoarthritis were randomly allocated to stretching (n=17) and control (n=19) groups. [Method] The subjects in the stretching group were instructed to perform home-based knee stretching exercises once a day for about 80 days, whereas the subjects in the control group were told to maintain their current level of physical activity. Outcomes assessed percentage changes in the total range of knee ROM in the supine position (S-ROM), pain, gait speed and knee ROM during gait (G-ROM). [Results] The stretching group showed significantly greater improvement in S-ROM, gait speed and G-ROM than the control group (control vs stretching; S-ROM, 0.4 ± 8.6% vs 9.5 ± 16.2%; gait speed, 1.6 ± 11.4% vs 11.6 ± 10.7%; G-ROM, 0.6 ± 15.2% vs 14.2 ± 14.6%; p<0.05 for all). Pain was significantly decreased in the stretching group compared to the control group (median values: -15.6% and 6.5%, p<0.01).

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[Purpose] There are no recent studies investigating the incidence of jumper's knee and knee contusions in volleyball players. A lack of understanding of knee contusions suffered by players (liberos) receiving the ball has lead doctors to diagnose jumper's knee. There have been no studies distinguishing between jumper's knee and knee contusions, which present similar symptoms. The purpose of this study was to investigate and correlate the two conditions of jumper's knee and knee contusions. [Subjects and Methods] Thirty-one female volleyball players were assessed for their maximum jumping power, body weight, whether they performed broad (slide) spikes, and whether they often hit their knees and so on. [Results] Jumper's knee was found in either or both knees of 12 (57%) of 21 spikers. For knee contusions, symptoms were found in 5 of the 10 liberos and setters, who were confirmed to actually hit their knees by observing videotapes of their practice. [Conclusion] Symptoms resembling jumper's knee were discovered in 4 of 6 liberos. It was difficult to distinguish between jumper's knee and knee contusions in terms of their symptoms, except through observation of the players' actual performance. It is important to discriminate between the two conditions clinically for treatment (including physical therapy) and prevention.

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[Purpose] The purpose of this study was to investigate the center of pressure (COP) trajectory during stair descent in young and healthy elderly adults. [Subjects] Fifteen community-dwelling healthy elderly adults (mean age, 73.1 ± 4.3 years) and 15 healthy young adults (mean age, 23.6 ± 2.4 years) volunteered to participate in this study. [Methods] Subjects stood in a predetermined position on the top of a staircase. Participants were then instructed to descend the staircase with three steps at a self-paced speed and continue for several strides after striking the force platform on the floor. Participants were required to place only one foot on each step (foot-over-foot) at a time. Performance was assessed by recording changes in the displacement of COP in the anteroposterior (A-P) and mediolateral (M-L) directions as well as recording the average velocity of COP by the use of two force platforms. [Results] The A-P and M-L displacements of COP as well as the average velocity of COP of the elderly were significantly lower than those of the young adults for both the right and the left feet (p<0.01). [Conclusion] The COP shift and velocity during stair descent might be appropriate parameters for identifying risk factors associated with stair-based accidents or falling.

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[Purpose] The purpose of this study was to investigate the function of respiratory muscles during breathing exercises by ultrasonography, and to determine if marked recruitment of respiratory muscles could be distinguished by this technique. [Methods] Thirteen healthy male subjects were asked to perform two breathing exercises in random order: diaphragmatic breathing (DB), and pursed-lip breathing (PLB). Changes in diaphragm thickness (ΔTdi) and lateral abdominal muscle thickness (ΔTlab) were measured by B mode ultrasonography. Tidal volume (TV) and respiratory rate (RR) were measured by spirometry. [Results] Compared to quiet breathing (QB), TV and ΔTdi significantly increased, whereas RR significantly decreased during the two breathing exercises. ΔTlab also significantly increased during DB, but not significantly during PLB, when compared to QB. ΔTlab during QB and DB was significantly correlated with TV. No significant difference was found, however, between the two breathing exercises in terms of TV, RR, ΔTdi, and ΔTlab. [Conclusion] Although changes in TV, RR, and ΔTdi during the two breathing exercises were comparable, the change in ΔTlab was different. Ultrasonography of respiratory muscles is a simple technique that may prove useful in the assessment of the pattern of respiratory muscle recruitment.

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[Purpose] The present study examined satellite cell and hepatocyte growth factor (HGF) responses to exercise intensity in the rat soleus muscle. [Methods] HGF levels assessed during postnatal growth of the gastrocnemius muscle. Depression of HGF levels occurred up to postnatal week 4, so 4-week-old rats were used the exercise training experiment. Rats walked or ran at speeds of 16 or 24 m/min, at -16% grade, 30 min/trial. Soleus muscles were removed after 72 h. Animals were injected with the thymidine analogue 5-bromo-2'-deoxyuridine (BrdU) 1 h before sampling. The right soleus muscle was used for immunofluorescence, and the left soleus muscle was used to measure HGF protein levels. [Result] HGF levels were unchanged, although numbers of BrdU-positive nuclei increased 2.4-fold in rats with exercise training. [Conclusion] The relationship between activation of satellite cells and HGF production after exercise training remains unclear. However, this study indicates the exercise intensity necessary to activate satellite cells. In the future, this result may facilitate the creation of exercise training intensity as an index of satellite cell activity for muscle strength training.

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[Purpose] Lower back pain is a characteristic of Kendo practitioners which is often encountered clinically. The present study was undertaken to analyze the features of the spinal alignment in Kendo practitioners and their relation to lower back pain. [Subjects and Methods] Of the 32 Kendo practitioners who consulted our hospital with a complaint of lower back pain and received physical therapy during the two years and three months from January 2005 to April 2007, On X-ray, the degree of eight kendo practitioners' spinal curvature was measured by Cobb's method. Inclination and rotation were measured at each intervertebral level of the lumbar spine. The angle of inclination at each intervertebral space (L1/2, L2/3, L3/4 and L4/5) was measured. In one of the kendo practitioners, the motion of stepping forward to make a frontal thrust was analyzed three-dimensionally. [Results] During the forward-stepping motion, the thoracic spine showed right convex curvature and the lumbar spine showed left convex curvature, with Cobb's angle being 12.4 ± 2.5 degrees for the thoracic spine and 13.7 ± 1.7 degrees for the lumbar spine. [Conclusions] These results suggest that shear stress at the left intervertebral joint at the L3/4 and L4/5 levels and stress of the facet joint capsule are involved in lower back pain.

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[Purpose] The purpose of this study was to explain the difference in characteristics of exercise limitation factors of patients with chronic obstructive pulmonary disease (COPD) and sequelea of pulmonary tuberculosis (PTB-s) . [Subjects] The subjects were 29 patients with COPD (28 males, 1 female; 70.6 8.0 years) and 8 patients with PTB-s (5 males, 3 females; 69.5 ± 9.5 years). [Method] We conducted the cardiopulmonary exercise test. This test was conducted using a respiratory metabolism measuring device with a electronically braked cycle ergometer and simultaneous breath-by-breath analysis of expired gas. Main outcome measures were oxygen uptake (peak VO₂), minute ventilation (peak VE), oxygen equivalent (peak VE/VO₂), carbon dioxide equivalent, (peak VE/VCO₂), and oxygen pulse (peak O₂ pulse) at peak exercise. [Results] There were no significant differences between peak VO₂ and peak VE/VO₂ and peak VE/VCO₂. The Peak O₂ pulse, an index of circulatory ability, was 6.6 ± 1.8 ml/beats/min in COPD and 4.5 ± 1.4 ml/beats/min in PTB-s (p<0.01), showing that the reaction of the circulatory system to exercise was poor in both groups. [Conclusions] We suggest that the difference in characteristics of exercise limitation factors of patients with COPD and PTB-S are circulatory ability. Studies of the synergistic effects of pharmacotherapy and kinesitherapy on the circulatory system may enable the establishment of a rehabilitation program based on disease-specific characteristics of PTB-s.

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[Purpose] We aimed to evaluate the muscle blood perfusion by the uptake of the radioisotope thallium-201 (²⁰¹Tl) in 5 hindlimb muscles, the soleus (Sol), plantaris (Pla), gastrocnemius (Gas), extensor digitorum longus (EDL), and tibialis anterior (TA). [Subjects] The subjects were 36 male Wistar rats. [Methods] ²⁰¹Tl uptake rates were calculated by spectrometry and visualized by autoradiography (ARG) in hindlimb unloading (U) and reloading (R) rats. [Results] The Sol ²⁰¹Tl uptake rates were significantly lower in U groups (p<0.01) than in the control group. Meanwhile the reloading day-4 group had higher values in Sol than the control (p<0.01). In U groups, the EDL and TA uptake rates were higher than in the other 3 muscles (Sol, Pla, and Gas). [Conclusion] We concluded that during 21 days of hindlimb unloading and subsequent recovery by reloading, blood capillary perfusion assessed by ²⁰¹Tl in hindlimb muscles changes in rats. The results confirm the utility of ²⁰¹Tl in quantitative and qualitative evaluation of skeletal muscle activity and blood perfusion, which has applications in rehabilitation and sports science.

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[Purpose] The purpose of this research was to investigate the impact of vertebral column alignment on respiratory function in elderly female subjects. [Subjects] The subjects were 23 female community-dwelling elderly (age: 76.8 ± 5.1 years old, BMI: 23.6 ± 2.3). [Methods] The thoracic kyphosis angle was determined by adding the angles of the superior and inferior vertebral bodies from the 1st to the 12th thoracic vertebrae, and the lumbar lordosis angle was determined by adding the angles of the superior and inferior vertebral bodies from the 1st to the 5th lumbar vertebrae. For evaluation of respiratory function, flow volume was measured with determination of forced vital capacity (FVC), % forced vital capacity (%FVC), one second forced expiratory volume (FEV_1.0), and one second forced expiratory volume rate (FEV_1.0%). [Results] No significant correlation was found with any respiratory parameter for the thoracic kyphosis angle, but the lumbar lordosis angle showed a significant correlation with FVC , %FVC , and FEV_1.0. [Conclusion] For impacts of vertebral column aligment on respiratory function the lumbar lordosis angle may be more important than the thoracic kyphosis angle.

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[Purpose] The purpose of this study was to investigate whether there is an effect of ROM exercise on rats with denervation and joint contracture. [Methods] Fifteen female 8-week old Wistar rats were used. For seven out of the fifteen rats, the left hind limbs were used as control limbs (group 1), and the right hind limbs (group 2) were fixed continuously with white tape in full plantar flexion for one week. The remaining eight rats received bilateral sciatic neurectomies. The left hind limbs (group 3) were fixed continuously with white tape in full plantar flexion for one week. The right hind limbs (group 4) were fixed in full plantar flexion with white tape that was removed daily from the second through the seventh experimental days. After the tape was removed the foot was held in dorsiflexion by a spring balancer for 30 minutes. After the ROM exercise session was completed, the white tape was reapplied, again with the ankle fixed in full plantar flexion. [Results] Before the experiment, there were no significant differences among the groups. After the experiment: compared to group 1, ROM in group 2 and group 3 was significantly increased; compared to group 2, ROM in group 3 and group 4 was significantly decreased; and compared to group 3, ROM in group 4 was significantly decreased. [Conclusion] ROM exercise was effective for preventing ROM limitation. These results suggest that ROM exercise is effective for preventing joint limitation in rats with denervation and joint contracture.

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[Purpose] This study investigated the relation between motor imagery and hamstring strain in rugby players. [Subjects] The participants of this study comprised 21 university rugby players (42 legs). [Methods] The motor imagery capacity of the subjects was evaluated using mental rotation and various motor exercises. The subjects were followed up 6 months after the measurements were taken, and the hamstring strain occurring in the intermittent period was investigated. [Results] Seven legs of 6 players (7/42, 16.7%) showed symptoms of hamstring strain within 6 months. In addition, all these subjects had medial hamstring injury that had occurred in a non-contact fashion. A significant difference was observed in the reaction time between the strain and non-strain groups for identifying photographs of the plantar view of the foot at an orientation of -90°. Furthermore, a cutoff value of 2.48 sec for this reaction time could predict hamstring strain by discriminant analysis. [Conclusion] Capacity of motor imagery influences the development of hamstring strain.

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[Purpose] The purpose of this study was to investigate how young and older adults modulate the center of pressure (COP) trajectory and stance time during obstacle negotiation. [Subjects] Fifteen healthy young adults and fifteen healthy older adults participated in the study. [Methods] The subjects stepped over an obstacle (18 cm in height, 10 cm in breadth and 140 cm in width) and a curb (18 cm in height, 140 cm in breadth and 140 cm in width) at a self-paced speed from a position of quiet stance. Performance was assessed by recording changes in the displacement of COP in the anteroposterior (A-P) and mediolateral (M-L) directions, and by measuring the average velocity of the COP and stance time using a force platform. [Results] The A-P and M-L displacement of COP and the average velocity of COP of the older adults were significantly less than those of the young adults (p<0.01). The stance time of the the older adults was significantly greater than that of the young adults (p<0.01). However, the COP variables between the stepping tasks were not significantly different. [Conclusion] The COP shift and velocity and stance time during obstacle negotiation might be appropriate parameters for evaluating the dynamic balance and motor control strategies of older adults.

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[Purpose] The purpose of this research was to clarify the effects of indirect treatment of proprioceptive neuromuscular facilitation (PNF). [Subjects] The subjects were thirty healthy male volunteers. Their mean age was 21.1 ± 1.1 years. [Methods] This study examined the extension force of the contralateral lower limb when manual isometric resistance exercise was performed by an upper limb at the start, middle, and final positions of PNF and shoulder flexion. A hand-held dynamometer measured the extension force of the contralateral lower limb. [Results] The extension force of the contralateral lower limb increased when an isometric resistance exercise was performed by an upper limb at the final position of the flexion-abduction-external rotation pattern of PNF. [Discussion] The extension force of the contralateral lower limb increased more with PNF movement than in shoulder flexion of an upper limb. The result suggests that isometric resistance exercise by an upper limb at the final position of PNF emphasized the "continue movement" and the systemic balance reaction occurred toward the side of the contralateral lower limb. This finding, therefore, could be applied to the treatment of patients having difficulty with moving their own lower limbs.

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[Purpose] The purpose of this study was to clarify the intrinsic factors influencing the deep squatting posture and to investigate the utility of ankle joint dorsiflexion measurement using this posture. [Subjects] The study subjects were 71 healthy male individuals. [Methods] The subjects were asked to squatted with their heels down and then were divided into 2 groups: possible squatting and impossible squatting. The anthropometric characteristics of the subjects were assessed, and the flexibility and movement range of the lower extremities were tested. To identify the intrinsic factors influencing the deep squatting posture, a dediscriminant analysis was performed by a stepwise procedure. The sensitivity, specificity, and cutoff values for the factors were evaluated by receiver operating characteristic curve analysis. [Results] Of the 71 participants, 55 were assigned to the possible squatting group and the remaining to the impossible squatting group. Analysis revealed that body weight and ankle dorsiflexion flexibility were significantly associated with ability to assume the deep squatting posture. In particular, ankle dorsiflexion flexibility was strongly associated with the ability to assume this posture. [Conclusion] The impossible squatting group showed reduced ankle dorsiflexion. Thus, the deep squatting posture is useful for easy and objective method for measuring ankle joint dorsiflexion flexibility.

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[Purpose] We prospectively investigated the effects of arthroplasty surgery on body weight and the effects of obesity on functional outcomes and complications in patients with total knee arthroplasty (TKA). [Subjects] One hundred eighty-six TKA patients were divided into two groups [non-obese = body mass index (BMI) < 30 kg/m² (n=70), and obese = BMI ≥ 30 kg/m² (n=116)] according to preoperative BMI values. [Methods] Patients were evaluated preoperatively and at 12 months postoperatively with regard to BMI, knee function score, pain, range of knee flexion, and complications. There were no significant postoperative differences between the groups in pain, knee function score, range of knee flexion, and complications.[Results] A statistically significant postoperative improvement was found in all parameters (p<0.05) except for BMI. In the non-obese group, BMI was unchanged whereas in the obese group there was an increase in BMI after surgery. [Conclusion] The results of this study indicate that patients do not lose weight after arthroplasty surgery. However, arthroplasty surgery offers significant improvements in knee flexion degree, knee function scores, physical function and relief of pain for patients regardless of weight. Increased mobility and decreased pain will not automatically lead to weight reduction. Therefore obesity must be addressed as an independent disease.

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[Purpose] We investigated which functional reach test was more highly correlated with center of pressure excursion, a one-arm reach or a two-arm reach, and explored the relationship between reach distance and trunk rotation in the case of one-arm reach. [Subjects] The subjects were 25 healthy young adults (14 males, 11 females; average age 21.2 years, range 19-30 years). [Methods] Three-dimensional coordinate data (of both acromions and the right index finger) and the movement of the center of pressure were recorded. [Results] In a comparison of measurements of one-arm reach and a two-arm reach, the correlation between the reach distance and the center of pressure excursion was significantly higher for the one-arm reach. In one-arm reach, there was no noticeable correlation between the reach distance and trunk rotation. With multiple regression analysis, trunk rotation was not a significant factor affecting reach distance. When using the heel as a reference, the correlation between reach distance and center of pressure excursion was the strongest. [Conclusion] To evaluate dynamic balance, the one-arm reach is more suitable for young adults. It is useful to measure the reach distance from a fixed point (e.g. heel), or to develop an adjustment technique that can reproduce the starting position.

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