强化循环训练对大鼠骨骼肌有氧能力影响的研究

目的比较跑步训练、游泳训练和强化循环训练对发展骨骼肌有氧能力的作用。方法25只雄性Wistar大鼠分为对照组1、对照组2、跑步组、游泳组和强化循环训练组（n=5），运用组织形态计量学的方法观察各组大鼠比目鱼肌有氧代谢能力的变化。结果3种耐力性训练都能有效地提高大鼠骨骼肌的有氧代谢能力。其中，强化循环训练较单纯游泳与跑步训练能更好地促进骨骼肌的塑形改建及提高骨骼肌的功能。结论强化循环训练能缩短骨骼肌塑形的过程，并且有利于发展骨骼肌的有氧代谢能力。     

循环训练模式对兔跟腱末端区组织形态学的影响

目的 观察循环训练对兔跟腱末端区组织形态学的影响,探讨循环训练对训练性末端病的预防作用.方法 72只日本大耳白兔随机分为正常对照组、跑步训练组、跳跃训练组、循环训练组(n=18),各组于第2、3、4、6、8、10周时随机处死3只动物,取双侧后足跟腱末端区组织,光镜下观察病理形态学变化,进行病理学评分及统计学分析.结果 光镜观察显示,跳跃训练模式下末端区组织腱纤维部分和纤维软骨部分受损严重;跑步训练模式下末端区组织腱纤维部分受损严重,纤维软骨部分受损较轻;与跳跃训练组及跑步训练组比较,循环训练模式下末端区组织损伤明显减轻.跳跃训练组第2、3、4、6、8、10周时跟腱末端区组织病理学评分分别为1.17±0.12、2.19±0.15、3.23±0.20、4.66±0.16、4.71±0.18、4.63±0.13,而跑步训练组分别为1.16±0.13、1.15±0.14、2.18±0.12、2.99±0.15、3.98±0.16、4.01±0.12,跳跃训练组病理学评分升高早于跑步训练组,且从第3周起其分值即明显高于跑步训练组(P＜0.05),两组评分差异主要源于潮线的变化.循环训练组第2、3、4、6、8、10周时跟腱末端区组织病理学评分分别为1.13±0.14、1.16±0.17、1.15±0.13、2.18±0.13、2.17±0.12、2.92±0.11,早期阶段病理学评分与正常对照组比较无明显差异,在训练晚期(6周以后)评分升高,但其分值低于跳跃训练组及跑步训练组(P＜0.05),且评分改变主要源于腱周组织和潮线的病理学变化.结论 循环训练可以为跟腱末端区组织塑形改建提供充分的修复时间,降低末端区组织受损程度.应用循环训练法不仅可有效预防末端病的发生,还可促进末端区组织的塑形改建,增强其抗损伤能力.     

强化训练对狗关节软骨的组织学影响

目的研究强化训练下狗膝关节软骨的组织学变化,以了解不同运动训练模式对膝关节软骨早期塑形改建的影响。方法20只实验用狗随机分为一般训练组（训练组,n=8）、强化训练组（强化组,n=8）和对照组（n=4）,训练组与强化组分别以不同的训练方式进行训练。训练10周后所有实验动物均被施行安乐死,膝关节软骨行组织学检查。结果训练组和强化组训练10周时膝关节软骨有明显损伤及修复迹象,强化组关节软骨塑形改建情况优于训练组,但代表损伤程度的Mankin评分两组无明显差别。结论长时间大强度运动易产生软骨运动性损伤,修复过程也随之发生;强化训练较一般训练能更好地促进关节软骨的塑形改建。     

骨应力性塑形改建的研究及其对新兵基础训练的指导意义

分组模拟训练的２８８只兔股骨标本病理观察及扭断试验结果表明,较大强度和时限训练的主导作用是加速骨塑形改建,增强抗骨折能力。分３组经３种方法训练的１８０只大鼠的胚骨上段病理切片及电镜观察表明,强化循环训练组的改建完成率（４１．７％）高于其它两组（２６．１％,２１．９％）,而应力性骨折发生率（１１．５％）则低于其它两组（２２．９％,１８．８％）。对１１２９名新兵１２周基础训练的前瞻性流行病学调查证实,下肢长管状骨经历约９周的应力性塑形改建期,训练的第２、７周出现的应力性骨折高发的双峰现象可随训练强度与时限的加大或减少,而提前或延迟出现。在训练中采用“强化循环训练法”将加速骨的塑形改建及降低应力性骨折发生率。     

振动训练对大鼠跟腱粘弹性的影响

目的:探讨振动训练对大鼠跟腱粘弹性的影响。方法:3月龄健康雄性SD大鼠30只被随机分成对照组和训练组,每组15只。训练组大鼠进行纵向振动训练,每天2次,每次15 min,每次训练后休息5 min,振动频率为25 Hz,振幅为3 mm,每周训练5天,共8周。取大鼠下肢跟腱,使用AGIS-MS型电子万能试验机,对大鼠跟腱进行滞后、应力松弛、蠕变实验。结果:与对照组相比,振动训练组大鼠跟腱的归一化滞后环面积显著减小(P<0.05),循环拉伸10次后跟腱的力学性能趋于稳定;振动训练组大鼠跟腱的归一化应力松弛显著加快(P<0.01),归一化蠕变显著增加(P<0.01)。结论:振动训练导致大鼠跟腱的粘弹特性发生改变,这些改变使得跟腱在运动过程中的能量损耗减少,提高了能量利用率,有利于跟腱的自我保护,降低跟腱损伤的发生率。     

不同训练模式对跟腱组织结构影响的实验研究及其对军事训练的指导意义

目的观察跟腱在不同训练模式下生物力学性能的改变,探讨跟腱末端病的发生发展规律及其在外力作用下塑形改建的特点,并据此对军事训练提出相应的预防措施。方法在特制的兔跑跳装置中,采用不同负荷和时间的训练模式对成年兔进行训练,切取跟腱及其末端区,进行组织学、超微结构观察和生物力学检测。结果跟腱在训练周期的第4周存在结构薄弱期,而且训练负荷对跟腱生物力学性能的影响比时间更明显。结论过度负荷是跟腱损伤及其末端病发生的主要原因,强调循环训练法对预防军事训练损伤有积极意义。     

长期跑台运动对大鼠跟腱胶原和胰岛素生长因子表达的影响

目的:探讨长期跑台运动对大鼠跟腱胶原含量、胶原I、胶原III及胰岛素生长因子(IGF-I)表达的影响。方法:20只SD雄性大鼠随机分为对照组和运动组。对照组不运动。运动组进行12周跑台运动,速度为20m/min,坡度为10%,每天40min。采用ELISA法测定I型胶原的前胶原氨基末端肽(PINP)I、II型胶原的前胶原氨基末端肽(PIIINP)和IGF-I含量;采用实时荧光定量PCR法测定前胶原Iα1 mRNA、前胶原IIIα1 mRNA和IGF-I mRNA表达水平。结果:与对照组相比,运动组血清IGF-I含量、跟腱PINP和IGF-I含量及前胶原Iα1mRNA和IGF-I mRNA表达显著升高(P<0.01)。结论:长期跑台运动可以通过提高跟腱胶原I合成量来适应负荷I,GF-I在跟腱对运动的适应中可能有一定作用。     

骨应力性塑形改建的研究及其对新兵基础训练的指导意义

分组模拟训练的２８８只兔股骨标本病理观察及扭断试验结果表明，较大强度和时限训练的主导作用是加速骨塑形改建，增强抗骨折能力。分３组经３种方法训练的１８０只大鼠的股骨上段病理切片及电镜观察表明，强化循环训练组的改建完成率高于其它两组，而应力性骨折发生率则低于其它两组。对１１２９名新兵１２周基础训练的前瞻性流行病学调查证实，下肢长管状骨经历约９周的应力性塑形改建期，训练的第２，７周出现的应力性骨折高发的     

大鼠低顺应性膀胱组织中Ⅰ型、Ⅲ型胶原蛋白基因的表达

目的　检测低顺应性膀胱组织中Ⅰ型、Ⅲ型胶原蛋白基因的表达。方法　用RT PCR的方法检测大鼠梗阻性低顺应性膀胱组织中Ⅰ型、Ⅲ型胶原蛋白基因表达的改变。结果　与正常对照组相比 ,低顺应性膀胱组逼尿肌层中Ⅲ型胶原蛋白基因的表达明显上调 ,Ⅰ型胶原蛋白基因的表达上调。结论　膀胱组织肌层内Ⅰ型、Ⅲ型胶原蛋白基因表达上调与梗阻后低顺应性膀胱的形成存在一定的关系。     

长期不同负荷运动训练对大鼠血浆血管活性肽含量及自由基代谢的影响

目的:探讨不同负荷运动训练对大鼠心血管系统内分泌功能及自由基代谢的影响。方法:将30只SD大鼠随机分为对照组、90min训练组和180min训练组。测定8周不同负荷游泳训练后大鼠血浆内皮素(ET)、肾上腺髓质素(ADM)、丙二醛(MDA)含量及血清超氧化物歧化酶(SOD)活性。结果:180min训练组与90min训练组相比ADM含量显著下降(P<0·05);180min训练组ET较对照组显著上升了17·70%(P<0·05)。90min训练组MDA含量与对照组相比显著下降(P<0·05),180min训练组MDA含量显著高于对照组和90min训练组(均P<0·05);各组SOD活性无显著性差异。结果表明,中等负荷运动训练后机体清除自由基能力增强,ET、ADM适度分泌;大负荷的运动训练降低机体清除自由基的能力,血管活性肽分泌失衡。     

Androgenic-anabolic steroids associated with mechanical loading inhibit matrix metallopeptidase activity and affect the remodeling of the achilles tendon in rats

BACKGROUND: The indiscriminate use of anabolic-androgenic steroids has been shown to induce pathologic changes in the Achilles tendon in several situations. PURPOSE: To study tendon remodeling in rats treated with anabolic-androgenic steroids combined with an exercise program. STUDY DESIGN: Controlled laboratory study. METHODS: Wistar rats were grouped as follows: sedentary (group I), injected with anabolic-androgenic steroids only (group II), trained only (group III), and trained and injected with anabolic-androgenic steroids (group IV). The trained groups performed jumps in water: 4 series of 10 jumps each, with an overload of 50% to 70% of the animal's body weight and a 30-second rest interval between series, for 6 weeks. Anabolic-androgenic steroids (5 mg/kg) were injected subcutaneously. Activity of matrix metallopeptidases, a marker for tendon remodeling, was analyzed in tissue extracts by zymography on gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis. RESULTS: Morphological analyses of tendons showed that in group II, the most external layer that covers the tendon was thicker with aggregation of the collagen fibers, suggesting an increase in collagen synthesis. In group IV, an inflammatory infiltrate and fibrosis in tendons as well as a pronounced increase of the serum corticosterone level were observed. This training protocol upregulated matrix metallopeptidase activity, whereas anabolic-androgenic steroid treatment strongly inhibited this activity. The appearance of lytic bands with molecular masses of approximately 62 and 58 kDa suggests the activation of matrix metallopeptidase-2. CONCLUSION: Anabolic-androgenic steroid treatment can impair tissue remodeling in the tendons of animals undergoing physical exercise by down-regulating matrix metallopeptidase activity, thus increasing the potential for tendon injury. CLINICAL RELEVANCE: Since the AAS abuse is so widespread, a better comprehension of the pathological effects induced by these drugs may be helpful for the development of new forms of therapy of AAS-induced lesions.     

Effect of ultrasound therapy on the repair of Achilles tendon injuries in rats

The purpose was to determine the effects of selected regimens of ultrasound therapy on the rates of repair of injured Achilles tendons of rats. Specific dependent variables examined were tendon breaking strength and rate of collagen formation. A puncture technique was used to induce injuries to both Achilles tendons of rats. Continuous ultrasound was administered to the left tendon for 4 min per treatment session at an intensity of 1.5 W.cm-2. Rats were sacrificed 2, 5, 9, 15, and 21 d following injury for measurement of tendon breaking strength and 3 and 5 d postinjury for analysis of collagen synthesis. Breaking strength was defined as the minimum force required to completely rupture the tendon. Collagen synthesis was indicated by the conversion of labeled proline to hydroxyproline. The breaking strengths of the treated tendons were significantly greater than strengths of the untreated tendons 5, 9, 15, and 21 d postinjury. Collagen synthesis was increased in the treated tendons compared with the untreated tendons 5 d postinjury. The results indicate that ultrasound treatment increases the rate of repair of injured Achilles tendons of rats. The results are also consistent with an association between increased collagen synthesis and greater breaking strength during tendon repair.     

Eccentric rehabilitation exercise increases peritendinous type I collagen synthesis in humans with Achilles tendinosis

It has been shown that 12 weeks of eccentric heavy resistance training can reduce pain in runners suffering from chronic Achilles tendinosis, but the mechanism behind the effectiveness of this treatment is unknown. The present study investigates the local effect of an eccentric training regime on elite soccer players suffering from chronic Achilles tendinosis on the turnover of the peritendinous connective tissue. Twelve elite male soccer players, of whom six suffered from unilateral tendinosis and six were healthy controls, participated in this study. All participants performed 12 weeks of heavy-resistance eccentric training apart from their regular training and soccer activity. Before and after the training period the tissue concentration of indicators of collagen turnover was measured by the use of the microdialysis technique. After training, collagen synthesis was increased in the initially injured tendon (n=6; carboxyterminal propeptide of type I collagen (PICP): pre 3.9+/-2.5 microg/L to post 19.7+/-5.4 microg/L, P<0.05). The collagen synthesis was unchanged in healthy tendons in response to training (n=6; PICP: pre 8.3+/-5.2 microg/L to post 11.5+/-5.0 microg/L, P>0.05). Collagen degradation, measured as carboxyterminal telopeptide region of type I collagen (ICTP), was not affected by training neither in the injured nor in the healthy tendons. The clinical effect of the 12 weeks of eccentric training was determined by using a standardized loading procedure of the Achilles tendons showing a decrease in pain in all the chronic injured tendons (VAS before 44+/-9, after 13+/-9; P<0.05), and all subjects were back playing soccer following the eccentric training regime. The present study demonstrates that chronically injured Achilles tendons respond to 12 weeks of eccentric training by increasing collagen synthesis rate. In contrast, the collagen metabolism in healthy control tendons seems not to be affected by eccentric training. These findings could indicate a relation between collagen metabolism and recovery from injury in human tendons.     

Blood flow of the Achilles tendon during military training

The purpose of this study was to evaluate the vascular response of the Achilles tendon as indicated by power Doppler activity during a military training program of 6 weeks. 49 male military recruits (98 tendons) volunteered for this study. Before and during the military training program, the Achilles tendons were screened with gray-scale ultrasonography and power Doppler US. Reactive tendinopathies of the Achilles tendons were registered by means of a clinical examination, VAS-scores and VISA-A scores. The US examination, the clinical examination, VAS-scores and VISA-A scores showed that 13/98 tendons developed a reactive tendinopathy. 3 of these 13 symptomatic tendons showed intratendinous Doppler activity. In these tendons, pain was always present before the vascular response of the Achilles tendon. Both pain and hypervascularisation remained visible till the end of the basic military training. In 5 asymptomatic tendons with no structural changes of the tendon, a vascular response was seen during one single measurement. It can be hypothesized that there is no relationship between the vascular response of the Achilles tendon and the pain in a reactive tendinopathy. In a reactive tendinopathy, other pain mechanisms must be investigated in future research.     

Chronic Achilles tendon pain treated with eccentric calf-muscle training

Injuries involving the Achilles tendon and manifested as chronic tendon pain are common, especially among recreational athletes. In a pilot study on a small group of patients with chronic painful mid-portion Achilles tendinosis, eccentric calf-muscle training was shown to give good clinical results. The aim of this prospective study was to investigate if the previously achieved good clinical results could be reproduced in a larger group of patients, and also to investigate the effects of eccentric calf-muscle training in patients with chronic insertional Achilles tendon pain. Seventy-eight consecutive patients, having chronic painful Achilles tendinosis at the mid-portion (2–6 cm level) in a total of 101 tendons (55 unilateral and 23 bilateral), and thirty consecutive patients with chronic insertional Achilles tendon pain in 31 tendons (29 unilateral and one bilateral) were treated with eccentric calf-muscle training for 12 weeks. Most patients were recreational athletes. Evaluation of the amount of tendon pain during activity was recorded on a visual analogue scale (VAS), before and after treatment. In 90 of the 101 Achilles tendons (89%) with chronic painful mid-portion Achilles tendinosis, treatment was satisfactory and the patients were back on their pre-injury activity level after the 12-week training regimen. In these patients, the amount of pain during activity, registered on the VAS-scale (mean±SD), decreased significantly from 66.8±19.4 to 10.2±13.7. On the contrary, in only ten of the tendons (32%) with chronic insertional Achilles tendon pain was treatment satisfactory, with a significant decrease on the VAS-scale (mean±SD), from 68.3±7.0 to 13.3±13.2. Our conclusion is that treatment with eccentric calf-muscle training produced good clinical results in patients with chronic painful mid-portion Achilles tendinosis, but not in patients with chronic insertional Achilles tendon pain.     

Tenocytes from ruptured and tendinopathic achilles tendons produce greater quantities of type III collagen than tenocytes from normal achilles tendons. An in vitro model of human tendon healing

Type I collagen is the main collagen in tendons; type III collagen is present in small amounts. Ruptured Achilles tendons contain a significantly greater proportion of type Ill collagen, which predisposes them to rupture. We used an in vitro model to determine whether tenocytes from Achilles tendons that were ruptured (N = 22), nonruptured (N = 7), tendinopathic (N = 12), and fetal (N = 8) show different behavior. Samples of Achilles tendon were digested with collagenase and the released tenocytes were collected. Primary tenocyte cultures were established and subsequently cultured onto glass coverslips. Once a confluent monolayer was obtained, the cell populations were "wounded" by scraping a pipette tip along the surface. The cultures were further incubated for either 1, 4, 8, 12, 16, or 24 hours, and production of types I and II collagen was assessed by immunostaining. In cultures from ruptured and tendinopathic tendons, there was increased production of type Ill collagen. Athletic participation places excess stress on the Achilles tendon, which could potentially lead to areas of microtrauma within the tendon. These areas may heal by the production of type III collagen, which is an abnormal healing response. Accumulation of such episodes of microtrauma could resuit in a critical point where the resistance of the tissue to tensile forces is compromised and tendon rupture occurs.     

Achilles tendon adaptation during strength training in young adults

PURPOSE: Tendons are specialized musculoskeletal structures responsible for transferring forces between muscles and bones. To maintain joint mechanics and structural integrity, tendons must adapt to changes in mechanical loading, but little is known about the interaction between muscle and tendon adaptations in vivo. We tested the hypothesis that tendons adapt to changes in muscle strength to maintain strains within a preferred operating range. METHODS: The right lower leg of 10 male subjects, age 24.9 +/- 3.4 yr (mean +/- SD), mass 78.1 +/- 9.7 kg, and height 176.5 +/- 7.2 cm, were tested before and during weeks 1, 2, 4, 6, and 8 of an 8-wk ankle plantar flexion strength training program. Subjects performed isometric plantar flexion efforts slowly ramping up from rest to a maximum effort. Plantar flexion force, Achilles tendon deformation, and cross-sectional area were measured. Triceps surae muscle force (assumed equal to Achilles tendon force), normalized force, and Achilles tendon stress and strain were calculated. Achilles tendon strains during maximum plantar flexion efforts (epsilon(max)) were compared between weeks to test the hypothesis. Repeated-measures ANOVA was used to test for significant changes during the 8 wk, with alpha = 0.05 used as the criterion for significance. RESULTS: There were no significant differences in the group's mean percent or absolute change in epsilon(max) (P = 0.607 and 0.351, respectively) despite a 21.4% average increase in muscle strength during the 8 wk. CONCLUSIONS: This is the first study that quantifies Achilles tendon strain throughout a strength training program. Findings indicate that the Achilles tendon adapts quickly to muscle strength training and experiences relatively little change in peak strain despite large increases in muscle strength.     

Effect of eccentric training on the plantar flexor muscle-tendon tissue properties

PURPOSE: It has been shown that eccentric training can be effective in the rehabilitation of patients with Achilles tendonopathy. The mechanism behind these results is not clear. However, there is evidence that tendons are able to respond to repeated forces by altering their structure and composition, and, thus, their mechanical properties change. In this regard, the objective of the present study was to investigate whether eccentric training affects the mechanical properties of the plantar flexor's muscle-tendon tissue properties. METHODS: Seventy-four healthy subjects were randomized into two groups: an eccentric training group and a control group. The eccentric training group performed a 6-wk eccentric training program for the calf muscles. Before and after this period, all subjects were evaluated for dorsiflexion range of motion using universal goniometry, passive resistive torque of the plantar flexors, and stiffness of the Achilles tendon. Passive resistive torque was measured during ankle dorsiflexion on an isokinetic dynamometer. Stiffness of the Achilles tendon was assessed using a dynamometer, in combination with ultrasonography. RESULTS: The results of the study reveal that the dorsiflexion range of motion was significantly increased only in the eccentric training group. The eccentric heel drop program also resulted in a significant decrease of the passive resistive torque of the plantar flexors (from 16.423 +/- 0.827 to 12.651 +/- 0.617 N.m). The stiffness of the Achilles tendon did not change significantly as a result of training. CONCLUSION: These findings provide evidence that an eccentric training program results in changes to some of the mechanical properties of the plantar flexor muscles. These changes were thought to be associated with modifications to structure rather than to stretch tolerance.     

Effects on neovascularisation behind the good results with eccentric training in chronic mid-portion Achilles tendinosis?

The background to the good clinical results reported using painful eccentric calf-muscle training as treatment for chronic painful mid-portion Achilles tendinosis is not known. Recently, using ultrasound and colour Doppler technique, we showed that painful tendinosis was associated with a local neovascularisation. Furthermore, in a pilot study, destroying these neovessels by sclerosing therapy cured the pain in most patients. Dynamic ultrasound and colour Doppler examination has shown that the flow in the neovessels stops during dorsiflexion in the ankle joint. Therefore, it was of interest to study the occurrence of neovascularisation before and after eccentric training. Forty-one tendons in 30 patients (22 men and 8 women, mean age 48 years) with chronic painful mid-portion Achilles tendinosis were examined with ultrasonography and colour Doppler, before and after 12 weeks of eccentric calf-muscle training. Before treatment, there was a local neovascularisation in the area with tendon changes (hypo-echoic areas, irregular fibre structure) in all tendons. At follow-up after treatment (mean 28 months), there was a good clinical result (no tendon pain during activity) in 36/41 tendons, and a poor result in 5/41 tendons. In 34/36 tendons with a good clinical result of treatment there was a more normal tendon structure, and in 32/36 tendons there was no remaining neovascularisation. In 5/5 tendons with a poor clinical result there was a remaining neovascularisation in the tendon, and in 2/5 tendons there were remaining structural abnormalities. In conclusion, in patients with chronic painful mid-portion Achilles tendinosis, a good clinical result after eccentric training seems to be associated with a more normal tendon structure and no remaining neovascularisation. Action on the area with neovessels during the eccentric training regimen might possibly be responsible for the good clinical results.