Yukihide Nishimura

Age-related sex differences in erector spinae muscle endurance using surface electromyographic power spectral analysis in healthy humans.

BACKGROUND CONTEXT Previous studies reported that the erector spinae muscle is more resistant to fatigue in healthy adult women than in men. However, no study has reported changes in back muscle fatigue with aging in healthy men and women. PURPOSE The aim of this study was to evaluate age-related changes in muscle fatigue of erector spinae muscle in men and women. STUDY DESIGN/SETTING This cross-sectional study was conducted in a laboratory. PATIENT SAMPLE Fifty-three healthy subjects (11 elderly men, 11 elderly women, 17 young men, and 14 young women) without low back pain history. OUTCOME MEASURES The median frequency (MF) and mean power frequency (MPF) during trunk holding test were derived from the raw electromyographic (EMG) signal using Fast Fourier Transform spectrum analysis program. The rates of changes in MF and MPF were calculated. METHODS Subjects performed the unsupported trunk holding test until exhaustion. The results of power spectral analysis of the EMG activity of the left erector spinae muscle were compared in both age groups and sexes. RESULTS The endurance time in young men was significantly shorter than in young women. The slopes of MF and MPF in young men were significantly higher than in young women. There were no significant differences in MF and MPF slopes of elderly men and elderly women. Furthermore, the MF and MPF slopes were significantly lower in elderly men than young men but similar in the two women groups. CONCLUSIONS Age-related changes in the slopes of MF and MPF of erector spinae muscle occur in healthy men but not in healthy women.

Aerobic Exercise Combined With Noninvasive Positive Pressure Ventilation Increases Serum Brain-Derived Neurotrophic Factor in Healthy Males

Brain‐derived neurotrophic factor (BDNF) has been implicated in enhancing neuronal health. Exercise and noninvasive positive‐pressure ventilation (NPPV) are known to independently alter BDNF levels in patients with depression, dementia, type 2 diabetes, chronic obstructive pulmonary disease, and obstructive sleep apnea syndrome. However, the combined effects of exercise and NPPV on serum BDNF in normal subjects are unknown.

Fatigue-related differences in erector spinae between prepubertal children and young adults using surface electromyographic power spectral analysis

BACKGROUND The erector spinae is more resistant to fatigue in adult women than men. However, no study has reported the sex differences in back muscle fatigue in children. OBJECTIVE The aim of this study was to evaluate the fatigability of erector spinae in prepubertal children and adults, in both males and females. METHODS Fourteen prepubertal boys, 13 prepubertal girls, 14 adult men, and 13 adult women performed the Sørensen back isometric endurance test until exhaustion. The results of electromyographic (EMG) power spectral analysis of erector spinae were compared between both age groups and sexes. RESULTS The slopes of EMG power spectral median and mean power frequency were significantly higher in males than in females, in both age groups. Furthermore, the slopes were significantly lower in prepubertal children than in adults, in both males and females. CONCLUSIONS Our results showed major differences in the fatigue threshold of the erector spinae between boys and girls and children and adults. The muscle fatigued faster in prepubertal boys and adult men than in prepubertal girls and adult women. In both sexes, a lower slope of EMG power spectrum parameters of the erector spinae was noted during endurance test in prepubertal children compared to adults.

Comparison of the effects of flexion and extension of the thumb and fingers on the position and cross-sectional area of the median nerve.

Objective To assess the separate effects of thumb and finger extension/flexion on median nerve position and cross-sectional area. Methods Ultrasonography was used to assess median nerve transverse position and cross-sectional area within the carpal tunnel at rest and its movement during volitional flexion of the individual digits of the hand. Both wrists of 165 normal subjects (11 men, 4 women, mean age, 28.6, range, 22 to 38) were studied. Results Thumb flexion resulted in transverse movement of the median nerve in radial direction (1.2±0.6 mm), whereas flexion of the fingers produced transverse movement in ulnar direction, which was most pronounced during flexion of the index and middle fingers (3.2±0.9 and 3.1±1.0 mm, respectively). Lesser but still statistically significant movements were noted with flexion of the ring finger (2.0±0.8 mm) and little finger (1.2±0.5 mm). Flexion of the thumb or individual fingers did not change median nerve cross-sectional area (8.5±1.1 mm2). Conclusions Volitional flexion of the thumb and individual fingers, particularly the index and middle fingers, produced significant transverse movement of the median nerve within the carpal tunnel but did not alter the cross-sectional area of the nerve. The importance of these findings on the understanding of the pathogenesis of the carpal tunnel syndrome and its treatment remains to be investigated.

Effects of physiatrist and registered therapist operating acute rehabilitation (PROr) in patients with stroke

Objective Clinical evidence suggests that early mobilization of patients with acute stroke improves activity of daily living (ADL). The purpose of this study was to compare the utility of the physiatrist and registered therapist operating acute rehabilitation (PROr) applied early or late after acute stroke. Subjects and methods This study was prospective cohort study, assessment design. Patients with acute stroke (n = 227) admitted between June 2014 and April 2015 were divided into three groups based on the time of start of PROr: within 24 hours (VEM, n = 47), 24–48 hours (EM, n = 77), and more than 48 hours (OM, n = 103) from stroke onset. All groups were assessed for the number of deaths during hospitalization, and changes in the Glasgow Coma Scale (GCS), National Institute of Health Stroke Scale (NIHSS), and Functional Independence Measure (FIM) at hospital discharge. Interventions All patients were assessed by physiatrists, who evaluated the specific needs for rehabilitation, and then referred them to registered physical therapists and occupational therapists to provide early mobilization (longer than one hour per day per patient). Results The number of deaths encountered during the PROr period was 13 (out of 227, 5.7%), including 2 (4.3%) in the VEM group. GCS improved significantly during the hospital stay in all three groups, but the improvement on discharge was significantly better in the VEM group compared with the EM and OM groups. FIM improved significantly in the three groups, and the gains in total FIM and motor subscale were significantly greater in the VEM than the other groups. Conclusions PROr seems safe and beneficial rehabilitation to improve ADL in patients with acute stroke.

Cardiovascular Responses to Static Muscle Contraction in Patients with Brachial Plexus Injury Treated with Intercostal Nerve Transfer

Pressor response is carried in afferent fibers of somatic nerves to increase blood pressure (BP) and heart rate (HR) during static exercise in humans. However, there is no information that peripheral responses restore muscle contraction with nerve transfer operation. In this study, we aimed to assess isometric exercise-induced pressor responses in patients with brachial plexus injury (BPI) after intercostal nerve transfer (ICNT) to restore elbow flexor muscles. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR during 2-min sustained isometric muscle contraction of elbow flexors at 20% and 35% of maximal voluntary contraction (MVC) on the unaffected side and the ICNT side, were measured in seven subjects with BPI treated with ICNT. SBP, DBP, and HR during 2-min sustained isometric muscle contraction of elbow flexors at 20% of MVC on the unaffected side were similar to those recorded before and after the exercise. However, the same variables increased significantly (p<0.001) during a similar type of exercise at 35% MVC on the unaffected side. On the ICNT side, no significant differences were noted in elbow flexors at 20% and 35% MVC. Isometric static exercise at 35% of MVC did not induce pressor and HR changes on the ICNT side. The difference in the responses between the two sides could have been caused by incomplete recovery of afferent nerve function following nerve repair, despite the restoration of efferent nerve function. Alternatively, the HR and BP responses to static contraction may depend upon the active muscle mass.

Changes in oxidized LDL during a half marathon in athletes with spinal cord injuries

Introduction:We reported previously that exercise significantly increases plasma adrenaline and oxidized low-density lipoprotein (oxLDL) in healthy subjects but not in persons with spinal cord injury (SCI). Since oxLDL and adrenaline levels are associated with oxidant/antioxidant balance, and exercise training elicits production of reactive oxygen species, we elucidated the effects of exercise on adrenaline, oxidant/antioxidant balance and oxLDL in individuals with SCI.Case Presentation:Eight subjects with cervical spinal cord injury (CSCI) and nine subjects with lower lesion of SCI (lower SCI (LSCI)) participated in a wheelchair half marathon race, and blood samples were collected before (pre), immediately after (post) and 1 h after the race (post 1 h). The blood samples were used to determine adrenaline, derivatives of reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP), both as markers for oxidant/antioxidant balance.Discussion:Pre-serum oxLDL levels were 147.2±8.1 and 97.0±10.4 U l−1 (mean±s.e.m.) in LCSI and CSCI subjects, respectively, and remained stable throughout the study. Adrenaline levels were higher in LSCI athletes than in CSCI athletes, especially post half marathon. Serum d-ROMs level did not change between pre and post in both groups. The mean BAP was significantly higher in LSCI than in CSCI subjects (2574±94.6 vs 2118±94.6 μmol l−1) at post, whereas the oxidative stress index (d-ROMs/BAP) was similar in the two groups throughout the study. In conclusion, exercise did not increase the d-ROMs or d-ROMs/BAP ratio in CSCI and LSCI subjects. The lack of increase in the plasma oxLDL level in SCI subjects was not due to the lack of response of adrenaline to exercise.

Properties of Paraspinal Muscles in Japanese High School Baseball Players With Terminal-Stage Lumbar Spondylolysis

Lumbar spondylolysis is a defect in the pars interarticularis that is common in young athletes; the stress distribution at the pars interarticularis is the highest in extension and rotation movements. The paraspinal muscles play an important role in stabilization of the lumbar spine; however, no study has assessed the properties of paraspinal muscles in athletes with lumbar spondylolysis.

Noninvasive positive pressure ventilation enhances the effects of aerobic training on cardiopulmonary function

Purpose The purpose of this study was to determine the effect of aerobic training under noninvasive positive pressure ventilation (NPPV) on maximal oxygen uptake (V˙O2max). Methods Ten healthy young male volunteers participated in the study. Before the training, stroke volume (SV) and cardiac output (CO) were measured in all subjects under 0, 4, 8, and 12 cmH2O NPPV at rest. Then, the subjects exercised on a cycle ergometer at 60% of pre-training V˙O2max for 30 min daily for 5 consecutive days with/without NPPV. The 5-day exercise protocol was repeated after a three-week washout period without/with NPPV. The primary endpoint was changes in V˙O2max. The secondary endpoints were changes in SV, CO, maximum heart rate (HRmax), maximum respiratory rate (RRmax), maximum expiratory minute volume (VEmax) and the percent change in plasma volume (PV). Results NPPV at 12 cmH2O significantly reduced SV and CO at rest. V˙O2max significantly increased after 5 days training with and without NPPV, but the magnitude of increase in V˙O2max after training under 12 cmH2O NPPV was significantly higher than after training without NPPV. VEmax significantly increased after training under NPPV, but not after training without NPPV. HRmax and RRmax did not change during training irrespective of NPPV. The percent change in PV was similar between training with and without NPPV. The 5-day training program with NPPV resulted in greater improvement in V˙O2max than without NPPV. Conclusions Aerobic training under NPPV has add-on effects on V˙O2max and exercise-related health benefits in healthy young men.

Physiological basis and practice of rehabilitation medicine in the management of individuals with spinal cord injury

Rehabilitation medicine has made dramatic and successful progress in recent years, and neurologists and physiatrists have faced greater challenges in coordinating the clinical management of patients with spinal cord injuries (SCI). To ensure the best clinical outcome in SCI, physiatrist need to comprehend the dysfunctions of various body systems and the physiological aspects of the central nervous, musculoskeletal and autonomic nervous system, as well as the social support system. Furthermore, the rehabilitation team, including physiatrists, nurses, physical therapists, social workers and peer supporters, should provide surgical treatment, clinical management, drug therapy and optimal assistance for SCI. We believe that the first important task in the management of SCI patients is precise diagnosis of the site of the spinal cord lesion. This should be followed as soon as possible by spinal surgery to stabilize the vertebral column. The day after surgery, the patient should be handled by the rehabilitation team. Orthostatic loads should be applied, and exercise of the remaining muscles should begin in order to ensure early mobilization and satisfactory repair. Our group has carried out extensive research into the pathophysiology of the cardiovascular, respiratory, endocrine and autonomic nervous systems and exercise responses in SCI, and reported the benefits and improvements of early mobilization and exercise, and the safety of physical medicine and rehabilitation. The rehabilitation team should follow these individuals closely to provide long‐term clinical care, and deal with social issues arising during the chronic phase. Participation in sports activities (para‐sports) could work well to improve the physical condition of these individuals.