Correlation network analysis shows divergent effects of a long-term,high-fat diet and exercise on early stage osteoarthritis phenotypes in mice

Background:Obesity increases knee osteoarthritis(OA) risk through metabolic,inflammatory,and biomechanical factors,but how these systemic and local mediators interact to drive OA pathology is not well understood.We tested the effect of voluntary running exercise after chronic diet-induced obesity on knee OA-related cartilage and bone pathology in mice.We then used a correlation-based network analysis to identify systemic and local factors associated with early-stage knee OA phenotypes among the different diet and exercise groups.Methods:Male C57 BL/6 J mice were fed a defined control(10% kcal fat) or high fat(HF)(60% kcal fat) diet from 6 to 37 weeks of age.At 25 weeks,one-half of the mice from each diet group were housed in cages with running wheels for the remainder of the study.Histology,micro computed tomography,and magnetic resonance imaging were used to evaluate changes in joint tissue structure and OA pathology.These local variables were then compared to systemic metabolic(body mass,body fat,and glucose tolerance),inflammatory(serum adipokines and inflammatory mediators),and functional(mechanical tactile sensitivity and grip strength) outcomes using a correlation-based network analysis.Diet and exercise effects were evaluated by two-way analysis of variance.Results:An HF diet increased the infrapatellar fat pad size and posterior joint osteophytes,and wheel running primarily altered the subchondral cortical and trabecular bone.Neither HF diet nor exercise altered average knee cartilage OA scores compared to control groups.However,the coefficient of variation was≥25% for many outcomes,and some mice in both diet groups developed moderate OA(>33% maximum score).This supported using correlation-based network analyses to identify systemic and local factors associated with early-stage knee OA phenotypes.In wheel-running cohorts,an HF diet reduced the network size compared to the control diet group despite similar running distances,suggesting that diet-induced obesity dampens the effects of exercise on systemic and local OA-related factors.Each of the 4 diet and activity groups showed mostly unique networks of local and systemic factors correlated with early-stage knee OA.Conclusion:Despite minimal group-level effects of chronic diet-induced obesity and voluntary wheel running on knee OA pathology under the current test durations,diet and exercise substantially altered the relationships among systemic and local variables associated with early-stage knee OA.These results suggest that distinct pre-OA phenotypes may exist prior to the development of disease.     

有氧运动对肥胖大鼠脂肪组织perilipin A基因表达的影响

目的:研究8周有氧运动对肥胖大鼠腹内脂肪组织perilipin A基因表达的影响。方法:健康雄性SD大鼠60只(60～95g),随机抽取10只作为普通膳食对照组(C),喂养标准普通饲料。其余50只喂养高脂膳食,7周后建立肥胖大鼠模型16只,再随机分为2组:肥胖非运动组(Ob,n=8)和肥胖运动组(Ob-E,n=8)。8周后测定大鼠体重、血脂、腹内脂肪组织perilipin A mRNA表达。结果:肥胖不运动组(Ob组)大鼠体重、腹内脂肪总量、脂体比、血清TG、腹内脂肪组织perilipin A mRNA表达显著高于对照C组;肥胖运动组(Ob-E组)大鼠腹内脂肪总量、脂体比、血清TG、腹内脂肪组织perilipin A mRNA表达相比Ob组显著降低。结论:8周有氧跑台运动明显降低了高脂饮食肥胖大鼠的腹部脂肪含量,改善了血脂水平及明显降低腹内脂肪组织perilipin A mRNA表达。     

运动减肥对肥胖儿童少年红细胞膜磷脂酰丝氨酸外翻及ATPase酶活性的影响

目的:探讨肥胖儿童少年红细胞膜PS外翻水平和ATP酶活性及运动减肥干预对其的影响.方法:对64名肥胖儿童少年(按体脂百分比分为轻、中和重度肥胖组共3组)进行4周有氧运动减肥,采用流式细胞术测定红细胞膜PS外翻,干预前后进行血脂、PS外翻及Na K+ - ATPase和Ca2+ Mg2+- ATPase酶活性的测定.结果:运动干预前轻度肥胖组PS外翻与其他2组肥胖者之间存在显著性差异(P≤0.05),HDL仅在轻度组和重度组之间存在显著性差异;运动干预后Na+ K+ -ATPase活性显著增加(P≤0.05),CE2+ Mg2+- ATPase活性虽有增加,但未呈显著性水平;运动干预后PS外翻虽然有所下降,但无显著性差异.结论:脂代谢紊乱的初期,膜PS外翻可能比血脂指标更能体现肥胖的发展.有氧运动减肥能显著增加红细胞膜Na+ K+ - ATPase活性,改善红细胞膜PS外翻水平,但后者对运动干预的效应滞后于血脂变化.     

不同保守疗法治疗运动员膝关节内侧副韧带损伤的疗效对比分析

目的:对比不同保守疗法治疗运动员膝关节内侧副韧带(MCL)损伤的临床疗效。方法:2018年6月至2022年12月期间膝关节MCL损伤的运动员共72例,随机分为电针+推拿组(对照组)、电针+推拿+康复训练组(实验组),每组36人,进行为期4周的治疗。采用疼痛视觉模拟评分(VAS).Lysholm膝关节功能评分,对不同组的运动员治疗前后的疼痛、膝关节功能进行评定,并进行临床疗效评估。结果:对照组和实验组治疗后的有效率分别为76%和94%,VAS评分均显著降低(P<0.45),Lysholm评分均显著增加(P<0.05);治疗后,实验组的VAS评分.Lysholm评分均优于对照组,且差异显著(P<0.05)。结论:电针结合推拿和康复训练治疗运动员膝关节MCL损伤的疗效要优于电针结合推拿治疗方法,能够明显改善患者膝关节周围疼痛及膝关节整体功能。     

等动训练促进运动员膝关节术后肌肉力量恢复的研究

为探讨等动训练对促进运动员膝关节术后肌肉力量恢复的应用价值，采用了美国产CYBEX770等动力系统对3名膝关节术后运动员进行膝关节肌肉4周力量恢复训练。结果表明，等动训练后运动员膝关节肌肉力量明显提高，提示等动训练对促进运动员膝关节术后肌肉力量恢复具有良好的效果。     

Biomechanical risk factors and mechanisms of knee injury in golfers

Knee injuries in golf comprise approximately 8% of all injuries, and are considered to result from overuse, technical faults or a combination of those factors. This review examines factors involved in injury, including the structure of the knee joint, kinematics and kinetics of the golf swing, forces sustained by knee joint structures and the potential for joint injury as well as injury prevention strategies. The golf swing generates forces and torques which tend to cause internal or external rotation of the tibia on the femur, and these are resisted by the knee ligaments and menisci. Research has shown that both maximum muscle forces and the forces sustained during a golf swing are less than that required to cause damage to the ligaments. However, the complex motion of the golf swing, involving both substantial forces and ranges of rotational movement, demands good technique if the player is to avoid injuring their knee joint. Most knee injury in golf is likely related to joint laxity, previous injuries or arthritis, and such damage may be exacerbated by problems in technique or overuse. In addition to appropriate coaching, strategies to remedy discomfort include specific exercise programmes, external bracing, orthotics and equipment choices.     

高住低训中EPO变化规律的研究

血清EPO(erythropoietin，促红细胞生成素)与红细胞的生成有密切关系。为确切了解EPO在高住低训中的变化规律，将14名大学生分为高住低训组和低住低训组，每组7人。高住低训组每天低压低氧(2500m模拟高度)暴露12小时；低住低训组在实验期间不进行低氧暴露。两组每天在常压常氧环境下进行一次3000m跑训练。实验为期4周。结果表明，促红细胞生成素在间断性低氧暴露初期就有升高变化，1天后出现高峰，这一高EPO水平一直维持到低压氧暴露结束。另外，对第2次低氧暴露完当天出低压氧仓即刻与常氧暴露10h后所测EPO结果的比较表明，常氧暴露后EPO呈下降趋势，说明间断性低氧暴露对EPO生成存在着慢性积累的过程。低住低训组的EPO水平一直比较平稳，说明常氧环境对EPO的分泌无明显影响。     

等动测力及康复训练系统在运动员膝关节损伤后力量训练中的应用

研究利用等动测力及康复系统对膝关节损伤的女运动员进行等速向心训练。经过约8周的训练,患膝屈伸肌群的峰值力矩在不同测试速度下均有显著提高,但伸肌峰值力矩提高较屈肌快。此次研究表明等速向心训练对膝关节损伤后的肌肉功能恢复有一定的促进作用。     

Stressors,social support,and effects upon performance in golf

Abstract

In this study, we investigated the effect of eccentric exercise on position sense and reaction angle of the elbow and knee flexors. Twelve males underwent two eccentric exercise sessions involving a randomized crossover design. In the first session participants used their elbow flexors and in the other session their knee flexors. Muscle damage indices, position sense, and joint reaction angle to release of the elbow and knee flexors were measured before, immediately after, and up to 7 days after exercise. Exercise induced greater muscle damage in the elbow flexors than knee flexors. Exercise disturbed position sense of the elbow and knee joint. For both limbs, the participants adopted a more extended position than the reference angle. The elbow and knee joint reaction angles to release increased after exercise for both the elbow and knee flexors. The disturbances in position sense and reaction angle after exercise were greater in the elbow flexors than knee flexors. The elbow flexors remained more accurate and faster than the knee flexors at all time points. These results may be explained by the higher density of muscle spindles and the lower innervation ratio of the elbow flexors compared with the knee flexors, as well as the fact that the arms are more accustomed than the legs to perform fast and accurate movements.     

膝关节损伤对排球运动员急停纵跳的影响

目的:对辽宁省排球队女运动员下肢急停纵跳落地时的力矩和最大关节角度进行研究,以期对有膝关节损伤的排球运动员进行科学训练提供参考。方法:以14名辽宁省排球队女运动员为研究对象,将运动员分为两组,其中无伤组8人,损伤组6人,采用三维测力平台和红外光电运动捕捉系统,记录受试者在完成急停纵跳动作落地时的髋关节、膝关节、踝关节的力矩以及最大关节角度数据。结果:在急停纵跳落地时,损伤膝关节的旋转、收展力矩大于无伤组,屈伸力矩小于无伤组,损伤组的髋关节的屈伸、收展、旋转力矩均大于无伤组;损伤组的踝关节旋转力矩小于无伤组,收展力矩和屈伸力矩大于无伤组。损伤组的踝关节在屈伸、收展和旋转时的最大关节角度大于无伤组;损伤组的膝关节在屈伸和收展时的最大关节角度大于无伤组,旋转时小于无伤组;损伤的髋关节屈伸和收展时的最大关节角度大于无伤组,髋关节旋转时的最大关节角度左侧小于无伤组,右侧大于无伤组。结论:膝关节损伤的运动员完成急停纵跳动作落地时,通过代偿性改变增大髋关节力矩、增加膝关节旋转和收展力矩,增大踝关节收展和屈伸力矩,增加膝关节和髋关节在屈伸和收展时活动角度,增加膝关节屈伸和收展时活动角度来完成动作。     

Effects of Exercise and Milk Consumption on Blood Serum Cholesterol in Rats

Abstract

This study investigated the effects of exercise on blood cholesterol and correlated those effects with estimates of body fat through experiments with 45 albino weanling rats (15 litter mate trios). The rats were confined to individual cages in a temperature-controlled room and fed a stock diet until they were 11 weeks old. At this time the trios were divided. Group A was continued on a stock diet and exercised for an hour in the morning and an hour in the afternoon by forced swimming. Group B was subjected to the same exercise but a portion of the stock diet was replaced with powdered whole milk, so that 30 percent of the caloric intake was derived from the whole milk supplement. Group C was fed the stock diet but activity was restricted. After 15 weeks blood samples were taken, the animals sacrificed, and the heart and adrenals weighed. The specific gravity of the carcass was also determined. Exercise resulted in a statistically significant decrease in total and free blood serum cholesterol concentration. These animals were also leaner and had larger hearts and adrenal glands. Serum cholesterol was negatively related to carcass specific gravity. The milk supplement had no significant effect on any of these measures. Several possible explanations for the effects of exercise on blood cholesterol are discussed.     

排球运动员膝关节损伤机理与预防措施研究

排球运动是一项时限性极其苛刻的运动，运动员瞬间的身体位置调整和频繁的爆发性用力起跳，很容易导致膝关节损伤。本文对排球运动员膝关节损伤的机理、症状及相应的急救方法进行讨论，并针对性地提出预防措施，旨在供运动员和教练员实践中参考。     

Trends in Selected Kinematic and Myoelectric Variables Associated with Learning a Novel Motor Task

Abstract

Cinematographic and electromyographic methods were used to coordinate the collection of kinematic and myoelectric data on 41 male subjects. The novel motor task consisted of propelling a four-wheeled carriage along a level aluminum track to a criterion velocity by a knee extension movement. Mean performance scores demonstrated that a significant amount of learning took place over 21 trials. The finding of learning over practice provided a basis by which changes in the kinematic and myoelectric variables were analyzed. Statistical analysis consisted of a One-Sample Hotelling's T² Test and Trend Analysis using a Multiple Regression Program. Data were collected on trials 1, 2, 6, 15, and 21. Results revealed that: (1) both knee joint and ankle joint angular velocities at release followed the same trend as performance scores; (2) two myotemporal variables had no significant trends on the four muscles under investigation; and (3) two knee flexors had linear trends and two knee extensors had cubic trends on the variable maximum integrated electromyographic (Iemg) amplitude. It was concluded that: (1) trends of joint angular velocities over practice more closely resembled the performance score trends than did myoelectric activity; (2) when myotemporal changes are not evident over practice, changes in maximum Iemg amplitude of muscles are responsible for increasing performance proficiency; and (3) if performance demands an increase in joint angular velocity, agonistic as well as antagonistic myoelectric activity will increase in muscles which act at the joint.     

专项运动员半月板损伤的生理学及生物力学分析与预防对策

方法：采用问卷调查法、数理统计法和文献资料法,对陕西省优秀男子运动员膝关节半月板运动损伤情况进行研究。结果：在接触性运动项目中,关月板损伤率较大,且与训练年限有正相关。其损伤的原因主要是准备活动不充分、膝关节力量不足、训练方法不当、身体疲劳及长期局部劳损等。结论：根据半月板损伤的机制与病因,结合生物力和运动解剖学知识,提出科学的预防措施,为康复治疗和运动训练提供理论参考。     

运动疗法对膝骨性关节炎患者关节滑液中高敏C反应蛋白的影响

目的：观察运动疗法对膝骨性关节炎（KOA）患者关节滑液中细胞因子高敏C反应蛋白（hs-CRP）的影响,探讨其治疗骨性关节炎的作用机制。方法：80例KOA患者随机分为治疗组和对照组,各组40例,对照组患者口服双氯芬酸钠治疗,治疗组在对照组治疗基础上同时进行运动疗法治疗,治疗4周。分别于治疗前后检测两组患者膝关节滑液中hs-CRP和MMP-9的含量。结果：治疗后,两组患者膝关节滑液中hs-CRP和MMP-9水平均较治疗前显著下降（P〈0.01）,治疗组患者膝关节滑液中hs-CRP和MMP-3含量均明显低于对照组,差异有统计学意义（P〈0.01）。结论：运动疗法能够减少KOA患者关节滑液中hs-CRP和MMP-9的产生,抑制炎症因子对关节软骨的破坏。     

Quasi-stiffness of the knee joint in flexion and extension during the golf swing

Biomechanical understanding of the knee joint during a golf swing is essential to improve performance and prevent injury. In this study, we quantified the flexion/extension angle and moment as the primary knee movement, and evaluated quasi-stiffness represented by moment–angle coupling in the knee joint. Eighteen skilled and 23 unskilled golfers participated in this study. Six infrared cameras and two force platforms were used to record a swing motion. The anatomical angle and moment were calculated from kinematic and kinetic models, and quasi-stiffness of the knee joint was determined as an instantaneous slope of moment–angle curves. The lead knee of the skilled group had decreased resistance duration compared with the unskilled group (P < 0.05), and the resistance duration of the lead knee was lower than that of the trail knee in the skilled group (P < 0.01). The lead knee of the skilled golfers had greater flexible excursion duration than the trail knee of the skilled golfers, and of both the lead and trail knees of the unskilled golfers. These results provide critical information for preventing knee injuries during a golf swing and developing rehabilitation strategies following surgery.     

运用仿真计算对跳远踏跳姿势的优化

运用多刚体模型及现代计算机仿真技术,探讨人体在不同姿势下踏板所引起的跳远远度的变化特征,以寻找最佳的起跳着板姿势。结果表明:着板时小腿的姿态角、膝关节角不同组合可以使人体获得相同的远度,故仅凭着板角的大小来衡量着板技术的优劣显然是不合理的;跳远踏跳着板时刻、人体各环节姿态角对跳远距离的影响作用大小并不一致,其重要性排序依次为踏跳腿小腿的姿态角最重要,其次是踏跳腿的膝角,而躯干斜角、大腿夹角及摆动腿的膝角对跳远距离的影响相对较小;运动员在跳远踏跳着板时刻,一定存在一个最佳的踏跳腿膝关节角和小腿与地面的夹角,以这种方式上板,可获得最大的跳远距离。     

The effects of eccentric exercise-induced muscle damage on running kinematics at different speeds

Abstract

This study investigated the effects of knee localised muscle damage on running kinematics at varying speeds. Nineteen young women (23.2 ± 2.8 years; 164 ± 8 cm; 53.6 ± 5.4 kg), performed a maximal eccentric muscle damage protocol (5 × 15) of the knee extensors and flexors of both legs at 60 rad · s^-1. Lower body kinematics was assessed during level running on a treadmill at three speeds pre- and 48 h after. Evaluated muscle damage indices included isometric torque, muscle soreness and serum creatine kinase activity. The results revealed that all indices changed significantly after exercise, indicating muscle injury. Step length decreased and stride frequency significantly increased 48 h post-exercise only at the fastest running speed (3 m · s^-1). Support time and knee flexion at toe-off increased only at the preferred transition speed and 2.5 m · s^-1. Knee flexion at foot contact, pelvic tilt and obliquity significantly increased, whereas hip extension during stance-phase, knee flexion during swing-phase, as well as knee and ankle joints range of motion significantly decreased 48 h post-exercise at all speeds. In conclusion, the effects of eccentric exercise of both knee extensors and flexors on particular tempo-spatial parameters and knee kinematics of running are speed-dependent. However, several pelvic and lower joint kinematics present similar behaviour at the three running speeds examined. These findings provide new insights into how running kinematics at different speeds are adapted to compensate for the impaired function of the knee musculature following muscle damage.     

散打鞭腿动作技术的二环节链模型的运动学分析

鞭腿动作是散打腿法技术的核心,将散打鞭腿动作简化为一个二环节运动链模型,对散打鞭腿动作的髋、膝关节和大腿、小腿环节在三维平面内进行位置矢量的确定,以此确定在鞭腿动作中,各关节和环节的运动学参数,然后确定目标函数(末端速度V),建立了人体鞭腿动作的三维运动学方程,将鞭腿动作各环节要领数学化描述,结论认为:(1)鞭腿动作中大腿的角速度由腰部角速度和髋关节角速度决定,小腿的角速度由大腿和膝关节的角速度决定,三者密切配合共同决定着鞭腿末端的速度;(2)在T1阶,大小腿下潜完曲度不易超过450,在进攻腿离地瞬间,小腿环节的角速度大于大腿环节的角速度时最有利于膝关节速度的增加,进攻退离地时膝关节的角速度主要由小腿蹬地时的地面反作用力决定;(3)在T2阶段,大小腿充分折叠有利于膝关节角速度的加大;(4)人体的鞭腿环节链模型中,鞭打原理遵从动量由近端环节向远端环节传递的原理,通过髋关节及时有效的制动可使膝关节动量增加,通过膝关节的制动可使动量传递到末端,引起末端加速。(5)在散打鞭腿环节链模型中只有多环节和关节依次协调配合才能使末端发挥最佳击打效果。     

Knee joint forces during downhill walking with hiking poles

The aim of this study was to determine external and internal loads on the knee joint during downhill walking with and without hiking poles. Kinematic, kinetic and electromyographic data were collected from eight males during downhill walking on a ramp declined at 25 degrees. Planar knee joint moments and forces were calculated using a quasi-static knee model. The results were analysed for an entire pole-cycle as well as differentiated between single and double support phases and between each step of a pole-cycle. Significant differences between downhill walking with and without hiking poles were observed for peak and average magnitudes of ground reaction force, knee joint moment, and tibiofemoral compressive and shear forces (12-25%). Similar reductions were found in patellofemoral compressive force, the quadriceps tendon force and the activity of the vastus lateralis; however, because of a high variability, these differences were not significant. The reductions seen during downhill walking with hiking poles compared with unsupported downhill walking were caused primarily by the forces applied to the hiking poles and by a change in posture to a more forward leaning position of the upper body, with the effect of reducing the knee moment arm.