The effects of fast bowling fatigue and adhesive taping on shoulder joint position sense in amateur cricket players in Victoria,Australia

The impact that muscle fatigue and taping have on proprioception in an applied sporting context remains unclear. The purpose of this study was to investigate disturbances in position sense at the shoulder joint, and asses the effectiveness of adhesive tape in preventing injury and improving performance, after a bout of cricket fast bowling. Among amateur cricket players (N = 14), shoulder position sense, maximum voluntary contraction (MVC) force and bowling accuracy was assessed before and immediately after a fatiguing exercise bout of fast bowling. Participants were tested with the shoulder taped and untapped. Shoulder extension MVC force dropped immediately and 30 min after the exercise (P < 0.05 and P < 0.05, respectively). Position sense errors increased immediately after exercise (P < 0.05), shifting in the direction of shoulder extension for all measurements. Taping had no effect on position errors before exercise, but did significantly reduce position errors after exercise at mid-range shoulder flexion angles (45° and 60°; P < 0.05 and P < 0.05, respectively). Taping had no significant effect on bowling accuracy. These findings may be explained by a body map shift towards a gravity neutral position. Added cutaneous input from the tape is proposed to contribute more to shoulder position sense when muscles are fatigued.     

局部肌肉疲劳对踝关节本体感觉的影响

目的:通过分析局部肌肉疲劳前、后踝关节在矢状面内运动的位置觉、肌肉力觉的变化,探讨局部肌肉疲劳对踝关节本体感觉的影响,为踝关节损伤防治和康复训练提供基础理论和实验依据。方法:选取14名无踝关节疾患的受试者为实验对象,踝关节位置觉采用对踝关节跖屈5°的被动定位、被动复位能力进行测试,肌肉力觉采用受试者踝关节对跖屈肌群25%最大等长峰值力矩值的复制能力进行测试;疲劳测试采用60最大等速向心运动模式;对于局部肌肉疲劳前、后踝关节本体感觉的对比,采用重复测量方差分析进行。结果:踝关节的位置觉(VEJPS和AEJPS)和肌肉力觉(RVEFS和RAEFS)在局部肌肉疲劳前、后的差异均有统计学意义(P<0.05)。结论:1)最大等速向心运动至局部肌肉疲劳后,踝关节的位置觉均较疲劳前下降;2)最大等速向心运动至局部肌肉疲劳后,踝关节的肌肉力觉均较疲劳前下降;3)踝关节最大等速向心运动至局部肌肉疲劳后,受试者的中枢控制策略发生改变。     

肌肉能量技术结合肌内效贴治疗肩周炎的临床疗效分析

目的:探究肌肉能量技术结合肌内效贴扎治疗肩周炎是否优于常规康复治疗手段。方法:收集金秋医院康复科门诊进行治疗的40名肩周炎患者,排除其他干扰因素后,将其随机分为实验组和对照组,每组20人,实验组在常规治疗肩周炎基础上采取肌肉能量技术和肌内效贴扎结合治疗,对照组进行常规治疗。结果:8周治疗后,两组患者主动关节活动度(AROM)、视觉类比评分(VAPS)等相关评分均明显优于治疗前(P<0.05),且实验组各项评分更优于对照组(P<0.05)。结论:在常规康复治疗的基础上应用肌肉能量技术与肌内效贴扎相结合的治疗措施能更有效地改善肩周炎患者的功能障碍,减轻患者痛苦,加快患者康复进程。     

不同身体姿势与运动节奏对男子游泳选手腹直肌训练效果影响的肌电特征分析

对15名男子游泳选手腹直肌在仰卧起坐练习下肌电特征进行分析。研究结果表明:(1)无论是向心收缩过程,还是离心收缩过程,斜靠仰卧起坐姿势时,锻炼效果最好;(2)在仰卧起坐动作练习时,采用斜靠仰卧起坐动作且使用加速起(快起),减速落(慢落)的运动节奏,对腹直肌训练效果较好;(3)提出了练习仰卧起坐动作的动作要领。     

Effect of fatigue on reaction time,response time,performance time,and kick impact in taekwondo roundhouse kick

Reaction time and response time are considered important abilities and can potentially affect combat performance. This study investigated the effect of a specific fatigue protocol on reaction time, response time, performance time, and kick impact. Seven male athletes reported to the laboratory on two different days. During day one, athletes performed a specific progressive taekwondo test, and on day two, a protocol for determining reaction time, response time, performance time, and kick impact before and after a time to exhaustion test at an intensity level corresponding to the maximal kick frequency obtained during the specific progressive taekwondo test. Muscle activation from rectus femoris and kick impact of the preferred limb were assessed. No differences were observed for response time and performance time. However, kick impact decreased (43 ± 27 to 13 ± 10 g, p < 0.01) while reaction time increased (145 ± 51 to 223 ± 133 ms, p < 0.05). Moderate correlation was observed between kick impact and response time (r = 0.565; p < 0.01), and kick impact and performance time (r = 0.494; p < 0.05). Results indicate that coaches and athletes may use taekwondo training programmes on coordination-based exercises leading to improve response time and to reduce fatigue effects in order to improve technique effectiveness and enhance the possibilities of scoring in a competitive situation.     

Effect of Kinesio Taping and balance exercises on postural control in amateur soccer players: A randomised control trial

ABSTRACT

The objective of this study was to determine the effect of Kinesio Taping (KT), alone or together with balance exercises (BE), on parameters related to postural control, such as dynamic balance, static balance and flexibility. Forty-four male amateur soccer players (mean age 24.45 (4.79) years) were randomly allocated to 3 groups: KT+BE that received KT and BE (n = 16); KT_p+BE, in which the KT was used as a placebo (n = 15) and KT alone (n = 13). The intervention period lasted 4 weeks. Star Excursion Balance Test (SEBT), Unipedal Stance Test (UST) and the Toe Touch Test (TTT) were assessed at baseline (pre), two weeks after beginning the treatment (mid) and after the intervention (post). We observed a significant improvement on the SEBT (mid and post-treatment) and the UST (post-treatment), but not on the TTT in either KT+BE or KT_p+BE groups post treatment. No differences were found either in KT group at any time point or between groups in any variable studied. In conclusion, KT functional correction technique does not improve static and dynamic balance when applied alone, whereas BE alone or combined with KT significantly improves these variables. None of these techniques has any effect on flexibility.

Abbreviation: KT: Kinesiotaping; BE: Balance exercises; KTp: Placebo Kinesiotaping; UST: Unipedal Stance Test; SEBT: Star Excursion Balance Test; TTT: Toe Touch Test     

Effect of gender on trunk and pelvis control during lateral movements with perturbed landing

In lateral reactive movements, core stability may influence knee and hip joint kinematics and kinetics. Insufficient core stabilisation is discussed as a major risk factor for anterior cruciate ligament (ACL) injuries. Due to the higher probability of ACL injuries in women, this study concentrates on how gender influences trunk, pelvis and leg kinematics during lateral reactive jumps (LRJs). Perturbations were investigated in 12 men and 12 women performing LRJs under three different landing conditions: a movable landing platform was programmed to slide, resist or counteract upon landing. Potential group effects on three-dimensional trunk, pelvic, hip and knee kinematics were analysed for initial contact (IC) and the time of peak pelvic medial tilt (PPT). Regardless of landing conditions, the joint excursions in the entire lower limb joints were gender-specific. Women exhibited higher trunk left axial rotation at PPT (women: 4.0 ± 7.5°, men: ?3.1 ± 8.2°; p = 0.011) and higher hip external rotation at both IC and PPT (p < 0.01). But women demonstrated higher knee abduction compared to men. Men demonstrated more medial pelvic tilt at IC and especially PPT (men: –5.8 ± 4.9°, women: 0.3 ± 6.3°; p = 0.015). Strategies for maintaining trunk, pelvis and lower limb alignment during lateral reactive movements were gender-specific; the trunk and hip rotations displayed by the women were associated with the higher knee abduction amplitudes and therefore might reflect a movement strategy which is associated with higher injury risk. However, training interventions are needed to fully understand how gender-specific core stability strategies are related to performance and knee injury.     

The effect of low back pain on trunk muscle size/function and hip strength in elite football (soccer) players

ABSTRACT

Low back pain (LBP) is a common problem in football (soccer) players. The effect of LBP on the trunk and hip muscles in this group is unknown. The relationship between LBP and trunk muscle size and function in football players across the preseason was examined. A secondary aim was to assess hip muscle strength. Twenty-five elite soccer players participated in the study, with assessments conducted on 23 players at both the start and end of the preseason. LBP was assessed with questionnaires and ultrasound imaging was used to assess size and function of trunk muscles at the start and end of preseason. Dynamometry was used to assess hip muscle strength at the start of the preseason. At the start of the preseason, 28% of players reported the presence of LBP and this was associated with reduced size of the multifidus, increased contraction of the transversus abdominis and multifidus muscles. LBP decreased across the preseason, and size of the multifidus muscle improved over the preseason. Ability to contract the abdominal and multifidus muscles did not alter across the preseason. Asymmetry in hip adductor and abductor muscle strength was found between players with and without LBP. Identifying modifiable factors in players with LBP may allow development of more targeted preseason rehabilitation programmes.     

对高校体育改革若干问题的思考

目前在高校体育改革与发展中,存在着许多亟待解决的理论与实践的热点问题.着重从体育在高校教育目标中的地位,当前人们体育思想观念转变发展的趋势和高校体育学科的建设这三个问题,并结合当前的一些新思想、新观念进行简单的分析与探讨,希望这些问题在改革的进程中能引起同仁们充分的重视.     

静力拉伸对跆拳道运动员最大肌力及肌电的影响

静力拉伸作为提高运动员柔韧性素质的主要手段之一，可以有效提高运动员柔韧素质，但有研究指出大强度、长时间静力拉伸会影响运动员的爆发力水平。对静力拉伸与无静力拉伸的情况进行实验对比分析，以30名近期腿部无大损伤的山东大学男性跆拳道专选学生为被试对象，对其分别施加蹬车和蹬车，拉伸两套不同方案的训练，然后对最大肌力、力量-时间曲线的主要指标，以及参与工作部位的肌电图进行对比分析，分析拉伸对运动员以上指标的影响，研究结果显示适量的拉伸练习不会显著地影响上述指标，从而提出适宜拉伸训练的负荷强度、时机，为科学训练提供依据。     

体育在新世纪经济和社会发展中的地位与作用

依据未来知识经济社会的特点和要求,从体育是影响生产力的一个不可忽视的因素、体育是教育的重要组成部分、身体素质是国民素质的组成部分等方面阐述体育在新世纪经济和社会发展中的地位;从体育为政治、经济和满足人的发展和需要服务等6个方面阐述体育在新世纪经济和社会发展中的作用。     

Effect of bag holding on the center of foot pressure and the lower leg muscle activities

Abstract

This study examined the influence of holding a bag with one hand on the center of foot pressure (COP) and the electromyographic responses in lower leg muscles. Thirteen healthy male adults participated in this study to keep an upright posture while holding a load with the dominant hand with four bag weight conditions (0%, 15%, 30%, and 45% of maximal voluntary contraction (MVC) of the jerk strength). Integrated Electromyography (iEMG) and mean power frequency (MPF) of EMG were calculated to estimate the degree of muscle activity and fatigue in the tibialis anterior and soleus that are involved in ankle joint control. Body sway was evaluated by the mean position of left-right (X) and front-back (Y) axis sway and the following 4 body sway factors; unit time sway factor (F1), front-back sway factor (F2), left-right sway factor (F3), high frequency band power spectrum factor (F4). When holding a bag at 45% MVC or more of the jerk strength with a single hand for one minute, muscle activity in the lower leg on the side of the bag increased markedly, and muscle fatigue was induced in the antigravity muscles of both legs. As a result, anteroposterior sway increased to a short, quick sway.     

Reproducibility of measurement techniques used for creatine kinase,interleukin-6 and high-sensitivity C-reactive protein determination over a 48 h period in males and females

To examine the reproducibility of three measurement techniques used to determine creatine kinase, interleukin-6 and high-sensitivity C-reactive protein, 50 participants had blood samples taken on two occasions. Fingertip plasma samples were analysed using the Reflotron for CK determination. Venous blood samples collected into serum separator tubes were used for IL-6 and hs-CRP analyses. IL-6 was measured using an enzyme linked immune assay development kit. The hs-CRP was measured by an in-house ELISA method. Dependent t-tests showed no systematic bias between samples. The interdian CV was 20.0% for CK, 15.3% for IL-6 and 44.2% for hs-CRP. The intraclass correlation coefficient was 0.90 for CK, 0.98 for IL-6 and 0.70 for hs-CRP. The 95% limits of agreement were ?69.7 to 63.5 IU/L for CK, ?1.48 to 1.80 pg/ml for IL-6 and ?1.10 to 0.91 µg/L for hs-CRP. The results demonstrate low absolute reproducibility, which may obscure a true experimental effect.     

Effects of an 8-weeks erythropoietin treatment on mitochondrial and whole body fat oxidation capacity during exercise in healthy males

The present investigation was performed to elucidate if the non-erythropoietic ergogenic effect of a recombinant erythropoietin treatment results in an impact on skeletal muscle mitochondrial and whole body fatty acid oxidation capacity during exercise, myoglobin concentration and angiogenesis. Recombinant erythropoietin was administered by subcutaneous injections (5000 IU) in six healthy male volunteers (aged 21 ± 2 years; fat mass 18.5 ± 2.3%) over 8 weeks. The participants performed two graded cycle ergometer exercise tests before and after the intervention where VO_2max and maximal fat oxidation were measured. Biopsies of the vastus lateralis muscle were obtained before and after the intervention. Recombinant erythropoietin treatment increased mitochondrial O₂ flux during ADP stimulated state 3 respiration in the presence of complex I and II substrates (malate, glutamate, pyruvate, succinate) with additional electron input from β-oxidation (octanoylcarnitine) (from 60 ± 13 to 87 ± 24 pmol · s^?1 · mg^?1 P < 0.01). β-hydroxy-acyl-CoA-dehydrogenase activity was higher after treatment (P < 0.05), whereas citrate synthase activity also tended to increase (P = 0.06). Total myoglobin increased by 16.5% (P < 0.05). Capillaries per muscle area tended to increase (P = 0.07), whereas capillaries per fibre as well as the total expression of vascular endothelial growth factor remained unchanged. Whole body maximal fat oxidation was not increased after treatment. Eight weeks of recombinant erythropoietin treatment increases mitochondrial fatty acid oxidation capacity and myoglobin concentration without any effect on whole body maximal fat oxidation.     

离心运动对大鼠骨骼肌结蛋白分布和表达的影响--对骨骼肌损伤机制的研究

方法：48只7周龄雌性SD大鼠进行一次性下坡跑至力竭，取比目鱼肌进行desmin免疫组化染色，然后光镜观察切片，并用图像分析仪对免疫染色切片进行定量分析。结果：1)离心运动后肌纤维局部desmin染色不同程度、不同范围地出现了变淡、模糊、甚至缺失，出现desmin阴性纤维；2)与对照组相比，力竭运动后即刻desmin平均光密度显著降低，在力竭后1天降到最低点，随后desmin平均光密度开始逐渐上升，到第7天，desmin阳性区域的平均光密度均显著高于对照组C。desmin阳性面积百分比和积分光密度结果变化趋势一致，离心运动组desmin阳性面积百分比低于对照组，desmin阳性面积百分最低点出现在运动后第1天。结论：1)desmin细胞骨架破坏是离心运动诱导损伤的形态学标志；2)Desmin免疫组化染色可以作为评估骨骼肌早期损伤的工具。     

运动竞赛中"瓦伦达心态"现象的成因及其控制路径

从研究瓦伦达心态出发,阐述了瓦伦达心态的理论内涵,并把其引入运动竞赛之中,分析在各种运动竞赛中运动员出现的瓦伦达心态现象,进一步找出运动员在竞赛中出现"瓦伦达心态"现象的成因:即内在因素和外在因素.并有针对性地提出一些控制这种现象出现的路径,试图为运动员参加运动竞赛提供一些理论参考.     

排球教学中时空知觉,运动知觉的训练

随着排球运动的发展,人们都重视运用时空知觉,运动知觉的训练来提高排球技术水平。本人在总结教学实践和文献搜集的基础上,对时空知觉,运动知觉作些分析,以供同行参考。     

Effect of time-of-day-specific strength training on maximum strength and EMG activity of the leg extensors in men

Abstract

In this study, we examined the effects of time-of-day-specific strength training on maximum strength and electromyography (EMG) of the knee extensors in men. After a 10-week preparatory training period (training times 17:00–19:00 h), 27 participants were randomized into a morning (07:00–09:00 h, n = 14) and an evening group (17:00–19.00 h, n = 13). Both groups then underwent 10 weeks of time-of-day-specific training. A matched control group (n = 7) completed all testing but did not train. Unilateral isometric knee extension peak torque (MVC) and one-repetition maximum half-squat were assessed before and after the preparatory training and after the time-of-day-specific training at times that were not training-specific (between 09:00 and 16:00 h). During training-specific hours, peak torque and EMG during MVC and submaximum isometric contraction at 40% MVC were assessed before and after the time-of-day-specific training. The main finding was that a significant diurnal difference (P < 0.01) in peak torque between the 07:00 and 17:00 h tests decreased after time-of-day-specific training in the morning group but not in the evening or control groups. However, the extent of this time-of-day-specific adaptation varied between individuals. Electromyography during MVC did not show any time-of-day-specific adaptation, suggesting that peripheral rather than neural adaptations are the main source of temporal specificity in strength training.     

The Effect of the Rate of Muscle Contraction on the Force-Time Curve Parameters of Male and Female Subjects

Purpose: Suprapostural task performance (manual tracking) and postural control (sway and frequency) were examined as a function of attentional focus, age, and tracking difficulty. Given the performance benefits often found under external focus conditions, it was hypothesized that external focus instructions would promote superior tracking and reduced postural sway for both age groups, most notably as a function of tracking difficulty. Method: Postural sway, frequency of postural adjustments, and tracking accuracy under two levels of task difficulty were assessed for younger (M _age = 20.98 years) and older (M _age = 70.80 years) participants while they manually tracked a pursuit-rotor target. Participants received instructions to focus on either their actions (internal focus) or the effect of their actions (external focus). Results: Analyses revealed a beneficial effect of an external focus on suprapostural performance on the less-difficult (0.5 Hz) tracking task, and this performance was associated with a modest improvement in medial-lateral postural sway. Conclusion: The findings offer limited support for external focus-of-attention benefits under a mildly challenging tracking task. While older adults tend to adopt a conservative postural control strategy regardless of tracking task difficulty, external focus instructions on a suprapostural task promoted a modest, beneficial shift in postural control.     

运动因子在心血管功能中的调控作用及相关机制研究进展

心血管疾病(cardiovascular disease,CVD)是包括动脉粥样硬化、心力衰竭、心脏缺血后再灌注损伤和心肌梗死等血管和心脏的复杂病症。血管内皮细胞、平滑肌细胞和心肌细胞生理功能障碍是诱发CVD的关键因素。研究表明,运动能够对心脏和动脉的形态、功能起到积极的调控作用,可作为CVD非药物疗法的重要手段之一。运动可通过调控多种运动因子的表达水平,如肌肉分泌的Fstl1、Irisin和MSTN,脂肪分泌的Omentin、Apelin、CTRP3和CTRP9,肝脏分泌的FGF21、ANGPTL3和ANGPTL4等,进而调控血管内皮细胞、平滑肌细胞和心肌细胞的分化、增殖和凋亡,从而发挥其防治CVD作用。本文试图梳理肌肉、脂肪和肝脏分泌的运动因子与调控心脏和动脉功能之间的相关信号通路及其机制,为运动干预防治CVD提供新的思路。