Acute changes in neuromuscular excitability after exhaustive whole body vibration exercise as compared to exhaustion by squatting exercise

The effects of hard squatting exercise with (VbX+) and without (VbX-) vibration on neuromuscular function were tested in 19 healthy young volunteers. Before and after the exercise, three different tests were performed: maximum serial jumping for 30 s, electromyography during isometric knee extension at 70% of the maximum voluntary torque, and the quantitative analysis of the patellar tendon reflex. Between VbX+ and VbX- values, there was no difference found under baseline conditions. Time to exhaustion was significantly shorter in VbX+ than in VbX- (349 +/- 338 s versus 515 +/- 338 s), but blood lactate (5.49 +/- 2.73 mmol l-1 versus 5.00 +/- 2.26 mmol l-1) and subjectively perceived exertion (rate of perceived exertion values 18.1 +/- 1.2 versus 18.6 +/- 1.6) at the termination of exercise indicate comparable levels of fatigue. After the exercise, comparable effects were observed on jump height, ground contact time, and isometric torque. The vastus lateralis mean frequency during isometric torque, however, was higher after VbX+ than after VbX-. Likewise, the tendon reflex amplitude was significantly greater after VbX+ than after VbX- (4.34 +/- 3.63 Nm versus 1.68 +/- 1.32 Nm). It is followed that in exercise unto comparable degrees of exhaustion and muscular fatigue, superimposed 26 Hz vibration appears to elicit an alteration in neuromuscular recruitment patterns, which apparently enhance neuromuscular excitability. Possibly, this effect may be exploited for the design of future training regimes.     

Physical,mental, and social predictors of functional outcome in unilateral lower-limb amputees

OBJECTIVE: To study the value of physical, mental, and social characteristics as predictors of functional outcome of elderly amputees. DESIGN: Prospective, inception cohort study; comparisons with reference populations. SETTING: Main hospitals, rehabilitation centers, nursing homes, patients' own residence settings in 1 of the 3 northern provinces in the Netherlands. PARTICIPANTS: Forty-six patients older than 60 years, with unilateral transtibial or transfemoral amputation or knee disarticulation because of vascular disease. INTERVENTIONS: Measurement of physical, mental, and social predictors 2 and 6 weeks postamputation. MAIN OUTCOME MEASURES: The Sickness Impact Profile (SIP-68), Groningen Activity Restriction Scale (GARS), Timed up and go (TUG) test, and prosthetic use. RESULTS: A total of 15% of amputees died within the first year after amputation. Seventy percent lived independently at home 1 year postamputation. The functional level of the patients was low, as shown by high scores on the SIP-68 (mean, 23.6), GARS (mean, 41.2), and TUG test (mean, 23.9s). Functionally effective prosthetic use, as measured with the classification of Narang and Pohjolainen, was reached by 49%. For the SIP-68 scores, age, comorbidity, 1-leg balance, and the 15-word test predicted functional outcome in 69% of amputees. For the GARS score, age, 1-leg balance, and the 15-word test predicted functional outcome in 64%. For the TUG test, age and 1-leg balance predicted functional outcome in 42% of amputees. After correction for age, the only significant predictor for prosthetic use was 1-leg balance. CONCLUSIONS: Elderly patients with a leg amputation had a low functional level 1-year postamputation. An important part of functional outcome could be predicted 2 weeks after amputation by age at amputation, 1-leg balance on the unaffected limb, and cognitive impairment. Severe comorbidity probably also played a role. The results may be used in the general policy concerning leg amputees.     

Response to high-intensity eccentric muscle contractions in persons with myopathic disease

Although the response to intense eccentric muscle contractions is well described in normal subjects, concern exists about possible untoward effects in persons with myopathic diseases. We investigated 14 subjects with slowly progressive muscular dystrophies including myotonic muscular dystrophy (n = 9), facioscapulohumeral dystrophy (n = 2), limb-girdle syndrome (n = 2), and Becker muscular dystrophy (n = 1). Control subjects consisted of 18 able-bodied persons. Subjects performed two sets of eight maximal-effort eccentric repetitions of the elbow flexors, with measurement of maximal concentric strength, serum creatine kinase, resting and flexed arm angle, arm circumference, and soreness at days 0, 3, and 7. Although the myopathic group had less initial strength, both groups demonstrated a similar response to the protocol over 7 days. Both groups had a significant rise in serum creatine kinase, which was still elevated at 7 days (P < 0.05). The control group demonstrated a slightly greater injury response in terms of soreness, resting and flexed arm angles, and arm swelling. Both groups of subjects appeared to respond similarly to an acute bout of eccentric contractions. However, the potential long-term effects of this type of exercise in persons with myopathic diseases remains unknown.     

The role of perfectionism and excessive commitment to exercise in explaining dietary restraint: replication and extension

The etiological complexity of the eating disorders has incited researchers to examine how personality characteristics and other variables operate jointly in the development of deviant eating patterns. OBJECTIVE: This study investigated the independent, interactive, and indirect prediction of dietary restraint by perfectionism and excessive commitment to exercise. METHOD: Multiple regression analyses designed to test moderating and mediating models were conducted on a sample of female university students (n = 269). RESULTS: Several dimensions of perfectionism, as well as excessive commitment to exercise, significantly and independently predicted dietary restraint in these women. There was no evidence for an interaction effect. Mediation analyses suggested that for selected dimensions of perfectionism, the direct relationship between perfectionism and dietary restraint is partially explained by excessive commitment to exercise. DISCUSSION: Interventions aimed at challenging perfectionistic standards in the context of dieting need to address not only one's self-standards, but one's perceptions of standards held by others. The mediating role of excessive exercise commitment pinpoints this variable as an alternative intervention target in the prevention of excessive dieting.     

Isolated diastolic heart failure as a cause of breathlessness in the community: the Arbroath study

The aim of this study was to examine the prevalence of exercise limitation due to diastolic heart failure among patients felt to have cardiac breathlessness by their general medical practitioner but not referred to hospital. We found that 18% of patients had a simple investigated profile compatible with isolated diastolic dysfunction as a cause of their symptoms. Symptoms appeared to pre-date major cardiac events (infarction; stroke; arrhythmia) that dominated the subsequent clinical course. The patients in this group have adverse cardiovascular risk profiles. Obesity was a common co-morbidity which may impair detailed 2-D echocardiographic assessment.     

Differential regulation by exercise of BDNF and NT-3 in rat spinal cord and skeletal muscle

We have investigated the impact of neuromuscular activity on the expression of neurotrophins in the lumbar spinal cord region and innervating skeletal muscle of adult rats. Rats were exercised on a treadmill for 1 day or 5 consecutive days and euthanized at 0, 2 or 6 h after the last bout of exercise. By Day 1, there was no clear evidence of an increase in brain-derived neurotrophic factor (BDNF) mRNA in the spinal cord or the soleus muscle. By Day 5, there was a significant increase in BDNF mRNA in the spinal cord at 2 h post-training, and the soleus muscle showed a robust increase between 0 and 6 h post-training. Immunoassays showed significant increases in BDNF protein in the soleus muscle by training Day 5. Immunohistochemical analyses showed elevated BDNF levels in motoneuron cell bodies and axons in the ventral horn. Neurotrophin-3 (NT-3) mRNA was measured to determine whether selected neurotrophins respond with a selective pattern of induction to neuromuscular activity. In the spinal cord, there was a progressive post-training decrease in NT-3 mRNA following a single bout of training, while there was a significant increase in NT-3 mRNA at 2 h post-training by Day 5. The soleus muscle showed a progressive increase in NT-3 mRNA by Days 1 and 5 following training. These results show that neuromuscular activity has specific effects on the BDNF and NT-3 systems, and that repetitive exercise affects the magnitude and stability of these responses.     

腰丛-坐骨神经联合阻滞在老年人下肢手术中的应用及对围手术期应激反应的影响

目的:探讨腰丛-坐骨神经联合阻滞和硬膜外麻醉在老年人下肢手术中的应用,比较两者临床麻醉起效和恢复时间、术后镇痛效果、血液动力学的变化及围术期应激反应的影响。方法:48例拟行单侧下肢手术的老年病人,随机分为腰丛-坐骨神经联合阻滞(NER)和硬膜外麻醉(EPI)。记录麻醉前,手术开始后15、30、45、60min,术后1h的收缩压(SBP)、舒张压(DBP)和心率(HR),以及感觉、运动神经阻滞起效及恢复时间、镇痛维持时间、效果及术前、术中、术毕的血浆皮质醇、血糖及胰岛素水平。结果:手术开始后15min,EPI组病人DBP降低明显,随后30、45、60min及术后1hEPI组病人的SBP、DBP均明显低于NER组;NER组感觉、运动神经阻滞起效时间均小于EPI组,恢复时间明显长于EPI组;两组血浆皮质醇、血糖、胰岛素均较术前明显升高,EPI组升高幅度小于NER组。结论:神经刺激器定位下行腰丛-坐骨神经联合阻滞,麻醉效果佳,且有效抑制应激反应。     

Effects of voluntary exercise and L-arginine on thrombogenesis and microcirculation in stroke-prone spontaneously hypertensive rats

1. The preventive effects of exercise and L-arginine intake on hypertension and thrombosis in stroke-prone spontaneously hypertensive rats (SHRSP) were studied. 2. Stroke-prone spontaneously hypertensive rats were divided into three groups: (i) the control, sedentary group; (ii) the exercise group, which was allowed to run voluntarily on running wheels; and (iii) the L-arginine intake group, which was given 2.25% L-arginine solution for 8 weeks from 4 to 12 weeks of age. In the control group, one rat died from stroke and symptoms of stroke were observed in the remaining animals. Similar symptoms were recorded in one rat of the exercise group, but not in the L-arginine group. 3. Blood pressure increased in the control group and this increase was suppressed significantly in the exercise and L-arginine groups. Thrombotic potential in cerebral vessels was the lowest at 4 weeks in all groups and was increased significantly at 12 weeks in the control group, but not in the exercise and L-arginine groups. Plasma concentrations of NO2/NO3 were lower in all animals at 12 weeks compared with those at 4 weeks. This reduction was significantly less marked in the L-arginine group. Cerebral arterioles in control rats at 12 weeks of age were significantly smaller in diameter than those at 4 weeks and these changes were less pronounced in the exercise and L-arginine groups. 4. The results provide clear evidence for the beneficial effects of L-arginine intake and voluntary exercise in mechanisms related to hypertension, thrombosis and stroke.