雾化施液CMP工艺及材料去除机制研究

介绍通过雾化供液方式进行化学机械抛光(CMP)的工作原理以及试验装置设计,通过雾化供液抛光工艺试验考察该方法的抛光效果,分析其材料去除机制。结果表明,雾化施液CMP方法的抛光浆料利用率高,在达到去除率为257.5 nm/min,表面粗糙度小于3.8 nm的抛光效果时,雾化抛光液消耗量仅为350 mL。雾化抛光材料去除机制是表面材料分子级氧化磨损去除,即通过抛光液中氧化剂的化学作用使表面原子氧化并弱化其结合键能,通过磨粒的机械作用将能量传递给表面分子,使表面分子的能量大于其结合键能而被去除。

一种CMP试验装置的研制

通过机械加工使硬脆材料达到亚微米级的平面度,纳米级的粗糙度是非常困难的,而广泛应用于IC加工领域的化学机械抛光(CMP)则能够实现工件的高精度加工要求。为此,设计了一台高精度的CMP试验装置,该装置用触摸屏完成人机对话,PLC作为整个测控系统的核心控制部分,通过接口完成数字、模拟信号的采集和对执行机构的控制,结构上具有结构简洁、控制方便的特点。在该装置上加工的直径100mm的不锈钢工件,平面度和粗糙度均达到或超过了设计要求。

Research on a processing model of CMP 6H-SiC(0001) single crystal wafer

Firstly, this paper presents an orthogonal test of six factors and five levels, called the chemical mechanical polishing （CMP） process parameters experiment, for determining the best process parameters and ranking the influencing factors from primary to secondary. The three most important factors are the polishing pressure, the polishing liquid concentration and the relative velocity ratio of polishing disk to polishing carrier. Then, based on this analysis, the three factors and three levels of the quadratic orthogonal regression test are put forward. A math- ematical model impacting the surface roughness has also been set up. Finally, this work has achieved a polished wafer, whose material removal rate （MRR） is in the range of 70-90 nm/h and the surface roughness （Ra） is between 0.3 nm and 0.5 nm.

Early electrical field stimulation prevents the loss of spinal cord anterior horn motoneurons and muscle atrophy following spinal cord injury

Our previous study revealed that early application of electrical field stimulation（EFS） with the anode at the lesion and the cathode distal to the lesion reduced injury potential, inhibited secondary injury and was neuroprotective in the dorsal corticospinal tract after spinal cord injury（SCI）. The objective of this study was to further evaluate the effect of EFS on protection of anterior horn motoneurons and their target musculature after SCI and its mechanism. Rats were randomized into three equal groups. The EFS group received EFS for 30 minutes immediately after injury at T_（10）. SCI group rats were only subjected to SCI and sham group rats were only subjected to laminectomy. Luxol fast blue staining demonstrated that spinal cord tissue in the injury center was better protected; cross-sectional area and perimeter of injured tissue were significantly smaller in the EFS group than in the SCI group. Immunofluorescence and transmission electron microscopy showed that the number of spinal cord anterior horn motoneurons was greater and the number of abnormal neurons reduced in the EFS group compared with the SCI group. Wet weight and cross-sectional area of vastus lateralis muscles were smaller in the SCI group to in the sham group. However, EFS improved muscle atrophy and behavioral examination showed that EFS significantly increased the angle in the inclined plane test and Tarlov＇s motor grading score. The above results confirm that early EFS can effectively impede spinal cord anterior horn motoneuron loss, promote motor function recovery and reduce muscle atrophy in rats after SCI.

Isokinetic trunk flexion-extension protocol to assess trunk muscle strength and endurance:Reliability,learning effect,and sex differences

Purpose:The purpose of this study was to examine the reliability and the learning effect of an isokinetic trunk flexion-extension protocol designed to simultaneously assess trunk muscle strength and endurance.In addition,the effect of the participants’sex on the reliability data was examined.Methods:Fifty-seven healthy and physically active young men(n=28)and women(n=29)performed the isokinetic protocol 5 times,separated by a week between each of the first 4 sessions and by a month between the last 2 sessions.The protocol consisted of performing 4 trials of 15 maximum flexion-extension concentric exertions at 120°/s(range of trunk motion=50°).The absolute and relative peak torque and total work were calculated to assess trunk flexion and extension strength.In addition,endurance ratio,modified endurance ratio,fatigue final ratio,recovery ratio,and modified recovery ratio variables were used for the assessment of trunk muscle endurance in both directions.Results:Regarding the absolute reliability,no relevant changes were found between paired-comparison sessions for most strength and endurance variables,except for total work and relative total work variables in the flexion movement in both sexes.In addition,the typical error of the isokinetic variables was lower than 10%in both males and females,and minimum detectable changes ranged from 7%to 20%,with a tendency to be higher in females and in endurance variables.The strength variables showed high-to-excellent intraclass correlation coefficients(ICCs;>0.74);however,for the endurance variables only the endurance ratio and the modified endurance ratio obtained moderate-to-high ICC values(0.57<ICC<0.82).In addition,the analysis of the variance reported no significant differences between consecutive pairs of sessions for most variables in both sexes.Conclusion:Overall,these findings provide clinicians,trainers,and researchers with a 10-min single-session protocol to perform a reliable muscle strength and endurance evaluation of trunk flexor and extensor muscles,all within the same protocol.

Direct muscle neurotization after end-to-end and end-to-side neurorrhaphy An experimental study in the rat forelimb model

The need for the continuous research of new tools for improving motor function recovery after nerve injury is justified by the still often unsatisfactory clinical outcome in these patients. It has been previously shown that the combined use of two reconstructive techniques, namely end-to-side neurorrhaphy and direct muscle neurotization in the rat hindlimb model, can lead to good results in terms of skeletal muscle reinnervation. Here we show that, in the rat forelimb model, the combined use of direct muscle neurotization with either end-to-end or end-to-side neurorrhaphy to reinnervate the denervated flexor digitorum muscles, leads to muscle atrophy prevention over a long postoperative time lapse （10 months）. By contrast, very little motor recovery （in case of end-to-end neurorrhaphy） and almost no motor recovery （in case of end-to-side neurorrhaphy） were observed in the grasping activity controlled by flexor digitorum muscles. It can thus be concluded that, at least in the rat, direct muscle neurotization after both end-to-end and end-to-side neurorrhaphy represents a good strategy for preventing denervation-related muscle atrophy but not for regaining the lost motor function.

Dyspnea and respiratory muscle strength in end-stage liver disease

AIM:To investigate the prevalence of chronic dyspnea and its relationship to respiratory muscle function in end-stage liver disease.METHODS:Sixty-eight consecutive,ambulatory,Caucasian patients with end-stage liver disease,candidates for liver transplantation,were referred for preoperative respiratory function assessment.Forty of these(29 men) were included in this preliminary study after applying strict inclusion and exclusion criteria.Seventeen of 40 patients(42%) had ascites,but none of them was cachectic.Fifteen of 40 patients(38%)had a history of hepatic encephalopathy,though none of them was symptomatic at study time.All patients with a known history and/or presence of co-morbidities were excluded.Chronic dyspnea was rated according to the modified medical research council(mMRC) 6-point scale.Liver disease severity was assessed according to the Model for end-stage liver disease(MELD).Routine lung function tests,maximum static expiratory(Pemax) and inspiratory(Pimax) mouth pressures were measured.Respiratory muscle strength(RMS) was calculated from Pimax and Pemax values.In addition,arterial blood gases and pattern of breathing(VE:minute ventilation;VT:tidal volume;VT/TI:mean inspiratory flow;TI:duration of inspiration) were measured.RESULTS:Thirty-five(88%) of 40 patients aged(mean ± SD) 52 ± 10 years reported various degrees of chronic dyspnea(mMRC),ranging from 0 to 4,with a mean value of 2.0 ± 1.2.MELD score was 14 ± 6.Pemax,percent of predicted(%pred) was 105 ± 35,Pimax,%pred was 90 ± 29,and RMS,%pred was 97 ± 30.These pressures were below the normal limits in 12(30%),15(38%),and 14(35%) patients,respectively.Furthermore,comparing the subgroups of ascites to non-ascites patients,all respiratory muscle indices measured were found significantly decreased in ascites patients.Patients with ascites also had a significantly worse MELD score compared to non-ascites ones(P = 0.006).Significant correlations were found between chronic dyspnea and respiratory muscle function indices in all patients.Specifically,mMRC score was significantly correlated with Pemax,Pimax,and RMS(r =-0.53,P < 0.001;r =-0.42,P < 0.01;r =-0.51,P < 0.001,respectively).These correlations were substantially closer in the non-ascites subgroup(r =-0.82,P < 0.0001;r =-0.61,P < 0.01;r =-0.79,P < 0.0001,respectively) compared to all patients.Similar results were found for the relationship between mMRC vs MELD score,and MELD score vs respiratory muscle strength indices.In all patients the sole predictor of mMRC score was RMS(r =-0.51,P < 0.001).In the subgroup of patients without ascites this relationship becomes closer(r =-0.79,P < 0.001),whilst this relationship breaks down in the subgroup of patients with ascites.The disappearance of such a correlation may be due to the fact that ascites acts as a "confounding" factor.PaCO2(4.4 ± 0.5 kPa) was increased,whereas pH(7.49 ± 0.04) was decreased in 26(65%) and 34(85%) patients,respectively.PaO2(12.3 ± 0.04 kPa) was within normal limits.VE(11.5 ± 3.5 L/min),VT(0.735 ± 0.287 L),and VT/TI(0.449±0.129 L/s) were increased signifying hyperventilation in both subgroups of patients.VT/TI was significantly higher in patients with ascites than without ascites.Significant correlations,albeit weak,were found for PaCO2 with VE and VT/TI(r =-0.44,P < 0.01;r =-0.41,P < 0.01,respectively).CONCLUSION:The prevalence of chronic dyspnea is 88% in end-stage liver disease.The mMRC score closely correlates with respiratory muscle strength.

Design and test of pneumatic artificial muscle driven variable trailing-edge camber wing

A variable camber wing driven by pneumatic artificial muscles is developed in this paper. Firstly, the experimental setup to measure the static output force of pneumatic artificial muscle is designed and the relationship between the static output force and the air pressure is investigated. Experimental results show that the static output force of pneumatic artificial muscle decreases nonlinearly with the increase of contraction ratio. Secondly, the model of variable camber wing driven by pneumatic artificial muscles is manufactured to validate the variable camber concept. Finally, wind tunnel tests are conducted in the low speed wind tunnel. It is found that the wing camber increases with the increase of air pressure. When the air pressure of PAMs is 0.4 MPa and 0.5 MPa, the tip displacement of the trailing-edge is 3 mm and 5 mm, respectively. The lift of aerofoil with flexible trailing-edge increases by 87% at AOA of 5°.

Efficacy of Slow Reversal Hold and Isometrics in Improving Muscle Strength, Increasing Range of Motion, and Reducing Pain in Patients with Osteoarthritis of Knee

Osteoarthritis of knee is a common problem in the elderly population worldwide. Physical therapy has been shown to be useful in decreasing pain and increasing mobility in this population. The aim of this study was to study the effectiveness of slow reversal hold and isometric exercise techniques in reducing pain, increasing muscle strength, and increasing range of motion for knee flexion in patients with osteoarthritis of knee. The other aim of this study was to compare the relative effectiveness of these two interventions. 60 subjects participated in this study and were randomly assigned either to the slow reversal hold group (n = 30) or, to the isometrics exercise group (n = 30). All subjects performed their respective exercises for 3 weeks. Pain scores using the visual analog scale, muscle strength using manual muscle testing of quadriceps and hamstrings, and range of motion (ROM) for knee flexion using a goniometer were recorded both pre-treatment and post-treatment for both left and right knees. Both the interventions showed a significant decrease in pain scores, an increase in muscle strength, as well as an increase in the ROM. However, ROM was significantly increased in the slow reversal hold group as compared to the isometrics group in both knees. It was concluded that both exercise techniques could be useful in patients with osteoarthritis of knee for decreasing pain and increasing muscle strength. Slow reversal hold technique might be a better technique than isometrics for increasing ROM for knee flexion.

Modeling of Pneumatic Muscle with Shape Memory Alloy and Braided Sleeve

Pneumatic muscle （PM） of flexible actuators used in bionic robot is an active area of recent research. A novel PM with shape memory alloy （SMA） braided sleeve is proposed in this paper, and SMA is used to improve PM working characteristics. Based on the principle of virtual work, output force model of PM and relationship with braided wire inner-stress are established, and analysis of PM deformation has shown that braided wire length is the key factor of output force characteristic. Based on the crystal structure transitions, the relationship of temperature with wire shrinkage is derived. Then, the synthetic dynamics of novel PM is established. A physical prototype of PM with SMA braided sleeve is developed, and test platform that is built for the experiment. Experiment and simulation test of static isometric-length, static isobaric-pressure, and dynamic characteristics are done. The experimental results are compared with the simulation of theoretical model. Moreover, based on experiment, model of output force was improved by adding a correction factor to deal with the elastic force of rubber tube. The results analysis demonstrates that the established models are correct, and SMA wires can reinforce PM and make PM working characteristics adjustable. PM proposed in this paper has greater output force and is beneficial to achieve more accurate control that is useful for manipulating fragile things.

NEAR-INFRARED MONITORING OF THE LUMBAR ERECTOR SPINAE MUSCLE IN HEALTHY MEN AND WOMEN DURING STATIC AND DYNAMIC ENDURANCE WORK

Understanding muscle hemodynamics using near-infrared spectroscopy is increasingly evident in the recent spinal disorders-related literature.However,none of these human studies addressed the issue of physiological limits for the lumbar muscle within the same participants during various exercise modes.The purpose of this study is to evaluate physiological limits for the lumbar muscle during dynamic and static endurance tests.On three separate days,22 healthy men and women performed three endurance protocols(static prone trunk extension,arm cranking,and pushing
pulling)until volitional exhaustion.For each protocol,minimum and maximum oxygenation and blood volume responses from the right lumbar erector spinae were obtained using a continuous dual wavelength near-infrared spectroscopy(Micro-Runman,NIM Inc.,PA,USA).Statistical analysis showed that greatest reduction in oxygenation(minimum)were obtained during dynamic exercises:pushing
pulling(2.1 times)and arm cranking(2.03 times)versus static test (P<0:05).Physiological change(calculated as the difference between maximum during recovery and minimum at the point of volitional exhaustion)during static test was lower[(66-75%for oxygenation)and(34-46%for blood volume)]than dynamic exercises (P<0:05).Contrary to the theory that sufficient occlusion of bloodflow to the lumbar muscle is possible with static trunk extension,it was concluded that a dynamic protocol until volitional exhaustion might be a good alternative in establishing near-infrared spectroscopy-derived physiological limits to the lumbar muscle.Further research is essential to identify an optimal calibration procedure for establishing true hypoxic values for the human lumbar muscle.

Randomized trial estimating effects of hypnosis versus progressive muscle relaxation on medical students’test anxiety and attentional bias

BACKGROUND Test anxiety is prevalent among medical students and leads to impaired academic performance.Test-related attentional bias has been identified as an important maintaining factor in test-anxious individuals.AIM To evaluate whether hypnosis and progressive muscle relaxation(PMR)could modify medical college students’test anxiety and attentional bias.METHODS A total of 598 medical students were screened.The participants were divided into higher and lower test anxiety groups according to their scores on the test anxiety scale(TAS).Ninety medical college students with high TAS score were randomly assigned to a hypnosis or PMR group.Another 45 students with low TAS score were included,forming a baseline control group.The intervention was conducted weekly for 6 wk,and each session lasted approximately 30 min.The total intervention time and the number of intervention sessions for the hypnosis and PMR groups were equal.Data were collected at the pretest,posttest,and 2-mo follow-up.RESULTS Hypnosis group participants had a significantly lower TAS score at posttest(t=-21.827,P<0.001)and at follow-up(t=-14.824,P<0.001),compared to that at pretest.PMR group participants also had a significantly lower TAS score at posttest(t=-10.777,P<0.001)and at follow-up(t=-7.444,P<0.001),compared to that at pretest.At the posttest level,the hypnosis group had a significantly lower TAS score than the PMR group(t=-3.664,P<0.001).At the follow-up level,the hypnosis group also had a significantly lower TAS score than the PMR group(t=-2.943,P=0.004).Clinically significant improvement was found in both the hypnosis and PMR groups(hypnosis=64.0%;PMR=62.22%).Hypnosis was more effective than PMR in reducing test anxiety among medical college students.Hypnosis could modify attentional bias toward threatening stimuli,but PMR could not.CONCLUSION These results suggest that attentional bias plays an important role in test anxiety treatment.

The Effect of Active Knee Extension in Sitting on Lumbopelvic Curvature in Individuals with Clinically Tight Hamstring Muscles: A Cross-Sectional Reliability Study

Relative flexibility between the hamstring and lumbar extensor muscles, which can be evaluated using lumbopelvic curvature during active knee extension in sitting, can sometimes be assessed in physical therapy. However, reliability for its quantitative measure has not been established yet and its establishment was the aim of the current study. Twenty-seven individuals with clinically tight hamstring muscles were recruited. On two separate sessions, the lumbopelvic curvature was evaluated in sitting when the right knee was moved from 90&deg flexion to 10&deg flexion on 15 occasions using a flexible ruler by two examiners on Day 1 and one on Day 2. Lines drawn tangential to the lumbopelvic curvature were traced at T12 and S2 vertebral levels and the angle between the two vertical lines was calculated. Using Day 1 data, the minimum number of repetitions and inter-examiner reliability were assessed. Inter-session reliability was also examined. As a result, there was no statistical difference (P?> 0.05) in the mean absolute difference between the mean value of N-1 and N repetitions (6 ≤ N ≤ 15) in the lumbopelvic curvature angle, indicating that five was considered the minimum number of repetitions. Intraclass correlation coefficient (ICC)(1, 5)?for the inter-session reliability and ICC(2, 5)?for the inter-examiner reliability was 0.97 and 0.93, respectively, indicating excellent reliability. The measure for the lumbopelvic curvature during active knee extension in sitting, which was established in the current study, will be a foundation for further research regarding the relative flexibility of the lumbar and adjunct regions.

Nerve function restoration following targeted muscle reinnervation after varying delayed periods

Targeted muscle reinnervation has been proposed for reconstruction of neuromuscular function in amputees.However,it is unknown whether performing delayed targeted muscle reinnervation after nerve injury will affect restoration of function.In this rat nerve injury study,the median and musculocutaneous nerves of the forelimb were transected.The proximal median nerve stump was sutured to the distal musculocutaneous nerve stump immediately and 2 and 4 weeks after surgery to reinnervate the biceps brachii.After targeted muscle reinnervation,intramuscular myoelectric signals from the biceps brachii were recorded.Signal amplitude gradually increased with time.Biceps brachii myoelectric signals and muscle fiber morphology and grooming behavior did not significantly differ among rats subjected to delayed target muscle innervation for different periods.Targeted muscle reinnervation delayed for 4 weeks can acquire the same nerve function restoration effect as that of immediate reinnervation.

Field-based Simplified Approach of Evaluating Knee Extensor Muscle Strength and Size in Male University Freshmen

The purpose of this study was to examine the relationship between field-based simplified approaches and knee extensor muscle strength/size in young men. Knee extensor muscle thickness （MT） of 104 healthy university freshmen was measured at the anterior half of thigh length; maximal voluntary isometric contraction （MVIC） was measured when subjects performed knee extension. Field-based simplified approaches [sit-to-stand, standing long jump （SLJ）, handgrip and upper-leg-50% （thigh） girth] were also measured. MVIC was correlated with SLJ （r = 0.361, P 〈 0.001）, handgrip （r = 0.523, P 〈 0.001） and thigh girth （r = 0.401, P 〈 0.001）, but not with the sit-to-stand test （r = 0.126, P 〉 0.05）. MT was correlated with handgrip （r = 0.317, P 〈 0.001） and thigh girth （r = 0.632, P 〈 0.001）, but not with SLJ （r = 0.038, P 〉 0.05） or the sit-to-stand test （r = 0.145, P 〉 0.05）. A stepwise multiple-regression analysis was applied to the predictor thigh girth to predict knee extensor MT （R2 = 0.399）. To predict knee extensor MVIC, the predictor handgrip, thigh girth and SLJ were applied （R2 = 0.381）. In conclusion, knee extensor muscle strength/size could be evaluated by the field-based simplified approaches, in particular by the thigh girth measurement, which may be major determinant to maintain activities of daily living for healthy young men. However, the 4 field-based simplified approaches appear to be still not of high impact.

Measurement Reliability for Evaluating Lumbopelvic Curvature during Active Knee Extension in Sitting Using a Flexible Ruler in Individuals with Clinically Tight Hamstring Muscles: A Secondary Analysis

In a previous study, we established reliability of a method for determining the angle of lumbopelvic sagittal alignment during active knee extension in sitting (AKEiS) using a flexible ruler and image analysis software (2-point-Method). In addition to this method, a flexible ruler can also be used to measure lumbopelvic sagittal alignment without image analysis software. This study primarily aimed to investigate the minimum number of repetitions, inter-session reliability and inter-examiner reliability of two alternative methods of measurement in a secondary analysis of our previous study. A flexible ruler was used to measure lumbopelvic curvature during AKEiS when the knee reached 10° flexion from 27 individuals with clinically tight hamstring muscles and subsequently analyzed. Lumbopelvic sagittal alignment was evaluated for the region between T12 and S2 using the maximum depth to the curvature (Max-Method) or depth to the curvature at the middle point between T12 and S2 vertebral levels (Mid-Method). It was determined that four repetitions for the Max-Method and 11 repetitions for the Mid-Method were required for the minimum number of repetitions, respectively. Inter-session reliability and inter-examiner reliability were assessed using Intraclass Correlation Coefficients and were 0.91 and 0.91 for the Max-Method and 0.90 and 0.91 for the Mid-Method, respectively. The current study suggests that the Mid-Method would not be recommended for use in the clinical setting as 11 repetitions of data sampling is required. The 2-point-Method or Max-Method may be promising but the ideal measurement method will be identified when the validity of these methods has been established.

Test-retest strength reliability of the Electronic Push/Pull Dynamometer (EPPD) in the measurement of the quadriceps and hamstring muscles on a new chair

Background: Test-retest strength reliability of the Electronic Push/Pull Dynamometer (EPPD) in the measurement of the extensor and flexor muscles on a new constructed chair. The objective of the study was to assess reliability of Electronic Push/Pull Dynamometer in the measurement of the knee flexion and extension at 90° and 60° on a new constructed chair. The aims of the author: To assess reliability of Electronic Push/Pull Dynamometer in the measurement of the knee flexion and extension at 90° and 60° on a new constructed chair. Design: A test-retest reliability study. Subjects: One hundred healthy students male and female (mean age, 21y). Methods: Maximum isometric strength of the quadriceps and hamstring muscle groups was measured using the EPPD were recorded at 60° and 90° for 3 trials on 2 occasions. Reliability was assessed with the Intraclass correlation coefficient (ICC), mean and standard deviation (SD) of measurements, and smallest real differences were calculated for the maximum and for the mean and work of the 3 repetitions. Results: Mean strength ranged from 50.44 kg for knee flexion to 55.76 kg for knee extension 50.44 kg to 61.98 kg at 90° hip flexion. Test-retest reliability Intraclass correlation coefficients (ICCs) ranged from 0.85 to 0.99. ICCs for test-retest reliability ranged from 0.780 to 0.998. Conclusions: The results of the reliability study indicate that the EPPD in reliable dynamometer to use in determining lower limb muscle force production. It can be used to measure disease progression and to evaluate changes in knee extension and flexion strength at the individual patient level.

膝骨关节炎患者膝关节屈伸肌群不同角速度等速肌力测试研究

目的观察膝骨关节炎患者膝关节屈伸肌群不同角速度等速肌力变化。方法选取2021年1月至2022年12月本院康复科符合纳入标准的患者及健康女性各40名分为观察组与对照组,分别在60°/s、180°/s角速度下进行膝关节屈伸肌群等速肌力测试,对比两组受试者峰力矩(PT)、总做功(TW)、腘绳肌/股四头肌(H/Q)等速测试指标。结果观察组膝关节屈伸肌群60°/s等速肌力测试PT、TW、H/Q值比180°/s高(P<0.05)。对照组膝关节屈伸肌群60°/s等速肌力测试PT、TW值比180°/s高(P<0.05)。两组膝关节屈伸肌群分别在两种角速度下PT、TW、H/Q比较,差异均有统计学意义(P<0.05)。结论可以采用60°/s角速度的等速指标评估膝骨关节炎患者屈伸肌群的肌力,建立膝骨关节炎的等速评估方案。

近红外光谱技术监控不同水平运动员递增负荷肌群肌氧变化特征

为了分析不同水平赛艇运动员在递增负荷测试中三个关键环节不同肌肉SMO_(2)变化特征,找出不同水平运动员SMO_(2)变化与常用指标变化的关系,提高递增负荷测试在赛艇训练监控中的针对性和实效性。通过实验将45名男子赛艇运动员,依据赛艇测功仪2000 m成绩分为A、B、C三个组。三组分别完成递增负荷测试,全程记录左右侧肱二头肌、竖脊肌和股内侧肌肌氧变化,同时记录心率、血乳酸等指标。实验数据使用Shapiro-Wilk法检验数据的正态性,相同运动员不同肌肉SMO_(2)变化测试结果对比使用非参数检验分析。不同水平运动员递增负荷测试结果的对比使用双尾独立T检验。相同运动员不同部位SMO_(2)与其他指标之间变化相关关系采用Pearson相关分析。结果表明:A、B、C三组不同部位ΔSMO_(2)在每级负荷中均与ΔHR有相关关系。A组股内侧肌ΔSMO_(2)与ΔHR全程高度相关(r=0.74-0.82,P<0.01),肱二头肌ΔSMO_(2)与ΔHR全程高度相关(r=0.32-0.88,P<0.01),竖脊肌ΔSMO_(2)与ΔHR全程高度相关(r=0.49-0.81,P<0.01);BLA变化幅度为-4.36 mmol/L时,对应B组ΔSMO_(2)变化幅度为-18.64%,C组ΔSMO_(2)变化幅度为-9.31%。可见不同水平运动员在赛艇递增负荷测试中均呈现出随着负荷增加SMO_(2)逐级下降的趋势。但是,不同水平运动员三个关键环节主要肌肉SMO_(2)变化特征呈现出一定程度的差异;赛艇递增负荷测试时,水平高的运动员综合ΔSMO_(2)变化率、ΔHR变化率和ΔBLA变化率相对较小;运动员SMO_(2)“拐点”与“乳酸阈拐点”相一致。相同BLA下,水平高的运动员SMO_(2)变化幅度较大,水平低的运动员SMO_(2)变化幅度较小。SMO_(2)变化只代表局部氧化代谢和运动能力,无法反应整体运动表现。

水平减速能力研究进展

水平减速能力是人体在水平方向运动过程中快速改变速度和方向的基础,对运动表现具有重要影响。对国内外相关研究进行系统梳理,归纳总结水平减速能力的测试评估、影响因素和训练策略的研究现状发现:(1)水平减速能力的测试方法主要有最大水平减速能力测试、特定距离内水平减速能力测试和变向能力测试;直接测评指标主要有减速度、制动距离和制动时间,衍生性指标包括制动力、制动冲量、制动功率、减速指数和减速赤字等;(2)水平减速能力影响因素主要包括下肢肌肉力量、肌力不对称和制动技术;(3)水平减速能力的训练策略可运用下肢离心力量训练结合向心快速力量训练提高制动力的产生与运用能力和动态姿势控制能力;采用超等长收缩训练结合离心落地控制能力训练,有效提升制动过程中的拉长-缩短周期运动能力;选择单侧和双侧力量训练,改善肢体间离心制动的不对称性;运用专门性水平减速训练,并结合抗阻训练,针对性地提高运动员面对不同外部刺激时的预测和响应能力,改善制动技术动作,显著优化制动力分配和调控能力。