作者希望感谢大家对这项研究中的所有主题表示感谢。资助来源捷克科学基金会 GACR 16-13750S、PRIMUS/17/MED/5 和叔叔032项目的研究补助金。

该议定书遵循了查尔斯大学人类研究伦理学委员会的指导方针, 体育体育系, 并已被批准作为研究的一部分。
1. 通过以下步骤熟悉所有受试者的等速测试
<ol><li>确保在过去的6月内, 受试者在下肢没有任何最近的肌肉骨骼损伤或疼痛。如果一个主题报告最近的膝盖疼痛, 或在测试期间膝盖疼痛, 排除的主题。</li>
	<li>由于偏心等速测试可能是对许多人的一种新的刺激, 使主题与协议在一个有效的等速测功机19,20 (步骤1.3 到 1.7.6, 下面) 至少两次, 然后参加官方测试。指导受试者在测试前不进行任何低体阻力训练或其他剧烈运动, 72 小时。</li>
	<li>
首先, 通过一般的热身来引导主题。
	<ol>
<li>指示受试者慢跑5-10 分钟或周期为5-10 分钟的测力计与阻力 1.5-2 瓦特/千克的身体质量与节奏在 60-90 rpm 之间。</li>
		<li>骑自行车后, 指示受试者在瑞士球上执行两组8-10 身体重量的刺和8-10 腿筋卷曲, 每条腿与1分钟的休息之间的集合。</li>
		<li>接下来, 引导主题通过动态伸展下肢, 包括四头肌和腿筋21。</li>
	</ol>
</li>
	<li>将该主题显示为等速力矩角曲线的一个例子, 并说明在测试期间将提供实时视觉反馈。</li>
	<li>解释, 这个主题应该 "尽可能快地踢出", 为同心膝关节伸展和 "尽可能快地拉回" 为同心膝关节屈曲。还解释说, 这台机器在偏心动作时会自行移动, 但在偏心膝部伸展时, 受试者应尽量 "用力推" (四头肌偏心作用) 和 "尽可能用力拉"。(腿筋的偏心动作)。</li>
	<li>允许主题询问任何问题, 并确保他们了解在测试过程中会发生什么。明确指出, 如果在测试过程中遇到任何疼痛或不适, 使主题希望在任何时候终止测试, 则该主题应立即通知研究员, 测试可以安全地中止。</li>
	<li>
启动表1中列出的预置协议, 并通过该协议不断引导主题。
	<ol>
<li>使用棕22的建议, 将主题定位在测功器上, 该位置具有100°的臀部角度。调整测功机的设置, 以确保主体的臀部一直向后和与椅子接触, 而测功机的转轴轴与受试者膝部的旋转轴线是一致的。</li>
		<li>在使用测功机上的垫片和皮带时, 指示受试者在固定肩部、骨盆和大腿时要保持深呼吸。将测功机的杠杆臂固定在胫骨远端, 垫放在内侧踝尖部2.5 厘米以上, 但不支持非运动下肢。</li>
		<li>在调整皮带、测功机设置或两种必要的同时, 允许主体被动地、积极地进行运动的完全伸展和屈曲范围。</li>
		<li>确保主题可以看到一个屏幕, 显示扭矩角度曲线, 并提供一个口头倒计时开始测试。在所有测试工作中, 指示受试者持有位于座椅一侧的拉手。</li>
		<li>通过使用诸如 "去"、"用力推"、"拉"、"拉"、"拉"、等等短语来开始测试并口头鼓励主题。在休息时间间隔内, 为主题提供有关即将完成任务的简短说明。</li>
		<li>完成该协议后, 允许主体从测功机椅上取出, 并调整测功机以测试另一肢。</li>
		<li>在重新定位和调整机器后, 再次执行重力校正测量, 并开始对未测试的下肢进行测试。</li>
	</ol>
</li>
	<li>
打开显示角扭矩曲线的测试结果, 并检查该主体是否达到了整个运动所选的收缩速度。
	<ol>
<li>要确定所需的速度是否已完成, 请确保角度-扭矩曲线似乎没有中断 (图 1)。</li>
		<li>如果曲线看起来中断 (图 2), 则可能是该主题没有足够快地推动或拉动杠杆臂, 以使测功器能够注册扭矩。如果该主题无法达到所需的角速度和寄存器扭矩, 继续与其他熟悉或排除该主题从研究和检查关节膝盖病变的可能性23。</li>
	</ol>
</li>
</ol>2. 两次熟悉访问后的等速强度测量
<ol><li>根据表 1设置测功机的软件来执行测试, 并完成步骤1.3 至1.7.6 中所述的协议。</li>
	<li>在协议结束后, 允许主题离开椅子, 开始分析数据。</li>
</ol>3. 腿筋对股四头肌功能比率计算
<ol><li>在每一个给定的速度和类型的肌肉行动中, 使用所有三试验的最佳峰值扭矩值。将峰值扭矩数据和结果比率插入到数据组织软件中, 可以以图形方式描述诸如 Microsoft Excel 这样的数据。</li>
	<li>通过在 60°·s-1的四头肌同心峰值扭矩除以 60°·s-1上的腿筋偏心峰值扭矩, 计算 H/QFUNC60比率。</li>
	<li>通过在 180°·s-1的四头肌同心峰值扭矩除以 180°·s-1上的腿筋偏心峰值扭矩, 计算 H/QFUNC180比率。</li>
	<li>通过在 240°·s-1的四头肌同心峰值扭矩除以 240°·s-1上的腿筋偏心峰值扭矩, 计算 H/QFUNC240比率。</li>
	<li>
创建类似于表2的表后, 将 H/Q 函数的比率与不同的速度以及左右四肢进行比较.
	<ol>
<li>将实测峰值与同一年龄和性别的类似运动组的规范性数据进行比较。</li>
		<li>通过比较左右四肢在每一个测试的速度来确定双边失衡是否存在。</li>
		<li>确定同一个速度的同侧 H/Qconv比率是否高于或低于 0.624。如果值低于 0.6, 则与股四头肌相比, 同侧肌腱无力;设计一个特定的腿筋加强干预 (4 节)。</li>
		<li>确定同侧的 H/Q 函数比率是否随速度的增加而增加, 并达到所需的值 1.012, 18, 最好是 180°·s-1的速度。如果总部的功能不随速度的增加而增加, 则实施腿筋训练以解决腿筋的相互作用 (4 节).</li>
	</ol>
</li>
</ol>4. 偏心肌筋强度训练实例
<ol><li>
请咨询训练有素的专业25, 如认证的强度和调理专家, 以选择各种运动, 目标的腿筋横跨各种肌肉长度, 速度和运动模式。
	<ol>
<li>请咨询练习专家, 以了解在着陆和跳跃过程中改善神经肌肉控制的练习, 以及减少腿部肌腱损伤风险的练习。</li>
		<li>在专业人士的指导下, 使用北欧卷曲 (俄罗斯卷曲) 运动, 可以加强腿部筋和降低伤害的风险26,27, 因为这项工作的重点是偏心筋肌腱加强。</li>
		<li>在专业指导下, 在瑞士球上使用单边膝 flexions 加强筋, 并可能减少双边强度赤字28,29。</li>
		<li>在专业人士的指导下, 使用单边或双边罗马尼亚 deadlifts, 良好的晨操, 或两者都加强臀部伸展功能的腿筋28,30,31。</li>
		<li>在专业的指导下, 使用复杂的练习来加强腿筋和四头肌在 "三重伸展" 练习中, 臀部, 膝盖和脚踝同时弯曲和伸展, 如蹲, deadlift 和刺。</li>
		<li>在专业人士的指导下, 使用运动, 如跳跃或其他重复跳跃训练本体在下肢。</li>
	</ol>
</li>
	<li>在专业指导下, 逐步增加体重练习中的集合和重复次数, 如北欧卷曲和瑞士球32上的单边腿筋卷曲, 同时也逐渐增加外部阻力和减少复杂练习中的重复次数 (例如, 请参见表 3)。</li>
</ol>

报告没有利益冲突。

上述议定书的第一个关键步骤是运动员的熟悉, 特别是对偏心测试。对象可能需要熟悉三次, 以确保可靠的数据, 在这种等速测试。此外, 如果测试会话相隔两个月以上, 则重新熟悉主题可能是一个好主意。第二个关键步骤是在测功机上正确设置运动员, 确保膝轴与测功机轴线保持一致;同样重要的是要注意的是, 更强的个人可能会推或拉如此用力的杠杆臂, 座椅垫变得沮丧或膝关节可能会略微向前或向后移动。这些可能性应该被考虑在安置运动员和在测试期间。另一个关键点是运动员能够在所有测试的速度条件下产生最大的扭矩, 并在不断增加的速度上减少负载范围的数据。最大可达到的扭矩高度依赖于收缩速度, 这意味着在高速协议 (240°·s-1) 中, 检查运动员是否能在整个运动范围 (ROM) 中产生扭矩对杠杆臂.).沿着这些线, 应减少负载范围数据, 通过消除第一个和最后一个10°的运动22的测量范围, 以避免在可能发生在 ROM 开始和结束的扭矩输出信号的人为峰值。
完成一个成功的测试后, 正确地解释数据也很重要。如果 H/Qconv值 (例如, 在 m∙s-1) 低于 0.6, 则与四头肌相比, 同侧肌腱的弱点存在。然而, 单单评估这一比例是不够的, 以预测可能的腘绳肌劳损或前交叉韧带损伤33,34。更重要的是要评估 H/Q 函数比是否随测试的速度一起增加.未充分建立在不同测试速度之间的最小建议的 H/Q 函数增量.但是, 我们建议最佳的 H/Q 函数从0.6 以上的 240°·s-1到0.8 以上, 到 0.113,18的速度之间增加。对 h/q 函数也应与特定的运动员组进行评估, 在 60°∙s -1测试的未受伤的精英短跑运动员被报告为 h/q 函数 0. 83 0.17 和受伤的短跑运动员 0.73 @ 0.1235。腿间的比较可能也是有价值的信息。例如, 双侧强度差大于 15% (以相同速度测量) 被认为是增加运动员膝伤的风险36和20% 以上的差异表明运动员易受伤害37。另一方面, 不到10% 的双边赤字不被认为是一个严重的失衡, 被解释为运动员在受伤后的不平衡或运动员在伤病后进行修复的目标2。
虽然所提出的协议可以在许多运动人群中使用, 但有可能调整速度和收缩模式, 以测试未经训练的或极具训练的科目。如果有必要进行最大强度测试, 也可以在测功机上执行等距测试, 并可与动态测试38结合使用。如果运动员训练有素或参与高速运动, 接近 300°·s-1 39或更多的速度可能是适当的。无论使用的速度如何, 所提出的方法仅限于等速收缩和单关节运动, 这两种动作都不是在运动过程中发生的。然而, 在实验室设置中, 等速测量可能为评估膝关节屈伸和屈伸22的同心和偏心强度提供了最有效和可靠的数据。评估肌肉净力的另一种方法是计算它从无功功率40;但是, 这种方法无法隔离特定肌肉群产生的力或扭矩。
如果教练或从业人员正在寻找额外的数据来为不同的肌肉群创建全球力量测量, 则可以对下体的肌肉执行额外的测试35,41,42 ,43,44,45。在一起, h-/Q 函数比与髋关节 adductors、劫持器和屈伸的强度测量相结合, 可以提供大量的数据, 可以用来监测抵抗训练计划的有效性. 该方法的未来应用可能与其他孤立强度措施相结合, 具体目的比较膝关节角度的规范13, 并与多关节运动 (如腿部按 46) 相结合.或蹲47。

膝关节屈肌与伸肌腱的关系已被确定为评估一个人的下肢损伤风险的一个重要参数1。具体来说, 当与 quadricep 强度2相比, 当同侧或双侧肌筋强度失衡时, 腿部肌腱损伤的几率增加。因此, 许多体育科学家和从业者测试膝盖屈和伸肌的力量, 以确定是否有可能导致腿部肌腱损伤的运动员。但是, 使用各种测试方法, 不允许在方法 (例如、不同的收缩速度、不同的肌肉动作和现场测试与实验室测试) 之间进行直接比较3,4,5,6,7,8,9. 虽然不同的测试方法提供了不同的关于强度水平的有价值的信息, 但是大腿肌肉等速强度测试的方法学方法应该统一起来, 以便在个人之间进行比较,人口和时间。
尽管对同侧膝屈伸和屈伸之间的失衡的评估常常被描述为使用传统的同心肌腱与同心四头肌比率 (H/QCONV)10,11,膝关节屈伸和屈伸的共同激活是已知的发生在所有的运动和发生通过反对收缩模式。解释, 膝关节屈伸主要参与跳跃和跑步过程中的推进, 而膝盖屈伸主要是稳定的膝盖在着陆和运行通过减速下肢和抵消快速和有力的同心屈伸的收缩。由于大多数运动运动需要同时同心膝关节伸展和偏心膝关节屈曲, 两者之间的相对强度比较是适当的。因此, 相对于同心膝伸肌强度的偏心膝屈强度是常见的测试, 被称为 "功能比" (H/Q 函数)12。
与0.43 到 0.90 12之间的 h/qCONV比率相比, h-/q 函数比率可以从0.4 到 1.413不等, 这表明不同协议中的数据不应相互比较。虽然最大同心扭矩减少, 同心速度增加14,15,16, 偏心扭矩大于同心扭矩, 因为速度增加16,17。因此, 当测试收缩速度增加 1318时, H/Q 函数比可以接近值1.0。由于大多数运动运动发生在高速度, 膝伸和屈肌强度测试可能更符合生态学上的更高速度。因此, 这种强度测试协议应包括逐步提高的速度逐步推进。
如果等速测试显示偏心筋和同心 quadricep 强度存在较大差异, 则应通过训练缩小差异。为此, 减少膝伸肌的强度绝不应补偿弱膝屈伸, 以牺牲更有利的 H/Q 功能比率, 特别是在体育环境中.另一种选择是渐进和密集地增加膝关节屈肌强度, 使腿筋变得更强, 特别是与四头肌腱, 以更高的速度。因此, 如果等速测试揭示了某种程度的腘绳肌无力, 训练干预可能是必要的, 以增加腿部肌肉的力量, 特别是在偏心运动的动作。与所有训练干预一样, 应进行随访测试, 以确定偏心聚焦的腘绳肌强度训练计划的有效性, 并可能需要进一步调整。本文的目的是描述如何测试等速功能偏心肌筋强度, 揭示潜在的腘绳肌无力, 并建议如何解决功能性腘绳无力。

<table><tbody><tr><td>HumacNorm</td><td>CSMI, Stoughton, MA, USA</td><td>021-54412236 (model 502140)</td><td>Standard Dynamometr</td></tr><tr><td>SoftwareHumac 2015</td><td>Computer Sports Medicine Inc. Stoughton, MA, USA</td><td>Version155</td><td>Software for dynamometr</td></tr></tbody></table>

muscle imbalances: testing and training functional eccentric hamstring strength in athletic populations

在身体活动期间发生的许多肌腱损伤发生在肌肉延长时, 在偏心的腿筋肌肉动作。与这些偏心的腿筋的行动相反的是同心四头肌的行动, 其中较大和可能更强的四头肌伸直膝。因此, 为了在运动中稳定下肢, 腿筋必须与四头肌强烈的膝关节矫直力矩进行偏心的对抗。因此, 相对于同心 quadricep 强度表示的偏心肌筋强度通常称为 "功能比", 因为大多数运动运动都需要同时同心膝关节伸展和偏心膝关节屈曲。为了提高腿筋的强度、韧性和功能性, 有必要对不同偏心速度下的腘绳筋进行测试和训练。这项工作的主要目的是提供测量和解释偏心腿筋强度的指导。提供了用等速功测量函数比的方法, 并比较了样本数据。此外, 我们简要描述如何解决腿部肌肉的力量不足或单边力量的差异, 使用专门侧重于增加偏心肌筋强度的演习。

下面的例子显示了年轻的优秀足球运动员 (15.4 岁0.5 岁, 身体质量 62.7, 8.2 公斤, 身高 175, 9.1, 训练经验超过8年) 的差异, 执行偏心腿筋训练 (EHT, n = 18) 和没有 EHT (n = 15) 12 周 (图 3)。执行 EHT 的小组每周两次包括这项练习, 而没有 EHT 的小组则进行了核心训练和一般的下肢计划。两个小组参加了他们的节目四月。
在训练计划之前, 两组都没有增加他们的 H/Q 函数, 因为测试的速度增加了 ( 图 3)。经过12周的培训, EHT 播放器在每次测试的速度上都有显著提高的 H/Q 函数.此外, EHT 组在速度 60°·s-1、 180°·s-1和 240°·s-1之间显示了增加的 H/q 函数, 而核心训练组 (没有 EHT) 显示了 h/q 函数仅在速度 60°·s-1之间增加和 240°·s-1。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57508/57508fig1.jpg"> 图 1: 适当膝屈伸和伸扭矩在10-90°膝关节屈曲范围内的运动.(A) 用于膝关节伸展的扭矩/角度强度曲线 (B) 膝关节屈曲的扭矩/角度强度曲线。<a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57508/57508fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57508/57508fig2.jpg"> 图 2:。膝关节屈伸和伸肌扭矩在10-90°膝关节屈曲范围内被打断.(A) 用于膝关节伸展的扭矩/角度强度曲线 (B) 膝关节屈曲的扭矩/角度强度曲线。<a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57508/57508fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57508/57508fig3.jpg"> 图 3: H/Q 函数具有和不需要特定的腿筋训练的代表性结果.H: 腿筋, Q: 四头肌, EHT: 偏心腿筋训练, 前: 测试在具体训练之前, 岗位: 测试在12星期以后具体训练。数据显示为平均标准偏差。误差线表示标准偏差。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td>测试阶段</td>
			<td>任务</td>
			<td>休息</td>
		</tr>
<tr>
<td>预测试</td>
			<td>重力矫正, 设置膝盖屈曲到 90°, 设置范围的运动从90°到 10° (其中的 0° = 完全延伸)</td>
			<td></td>
		</tr>
<tr>
<td>在 60°·s-1中试用
</td>
			<td>同心膝伸展/屈曲1重复</td>
			<td>十五年代</td>
		</tr>
<tr>
<td>在 60°·s-1中进行测试
</td>
			<td>同心膝伸展/屈曲3重复</td>
			<td>六十年代</td>
		</tr>
<tr>
<td>在 60°·s-1中试用
</td>
			<td>偏心膝关节伸展/屈曲1重复</td>
			<td>十五年代</td>
		</tr>
<tr>
<td>在 60°·s-1中进行测试
</td>
			<td>偏心膝关节伸展/屈曲3重复</td>
			<td>六十年代</td>
		</tr>
<tr>
<td>在 180°·s-1中试用
</td>
			<td>同心膝伸展/屈曲1重复</td>
			<td>十五年代</td>
		</tr>
<tr>
<td>在 180°·s-1中进行测试
</td>
			<td>同心膝伸展/屈曲3重复</td>
			<td>六十年代</td>
		</tr>
<tr>
<td>在 180°·s-1中试用
</td>
			<td>偏心膝关节伸展/屈曲1重复</td>
			<td>十五年代</td>
		</tr>
<tr>
<td>在 180°·s-1中进行测试
</td>
			<td>偏心膝关节伸展/屈曲3重复</td>
			<td>六十年代</td>
		</tr>
<tr>
<td>在 240°·s-1中试用
</td>
			<td>同心膝伸展/屈曲1重复</td>
			<td>十五年代</td>
		</tr>
<tr>
<td>在 240°·s-1中进行测试
</td>
			<td>同心膝伸展/屈曲3重复</td>
			<td>六十年代</td>
		</tr>
<tr>
<td>在 240°·s-1中试用
</td>
			<td>偏心膝关节伸展/屈曲1重复</td>
			<td>十五年代</td>
		</tr>
<tr>
<td>在 240°·s-1中进行测试
</td>
			<td>偏心膝关节伸展/屈曲3重复</td>
			<td>六十年代</td>
		</tr>
</tbody></table>表 1: 等速测试协议。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td>右下下肢</td>
			<td>腿筋峰值扭矩 (N∙m)</td>
			<td>四头肌峰值扭矩 (N∙m)</td>
			<td>常规的 H/Q</td>
			<td>H/Q 功能</td>
		</tr>
<tr>
<td>60°·s-1同心</td>
			<td>117</td>
			<td>243</td>
			<td>0.48</td>
			<td rowspan="2">0。7</td>
		</tr>
<tr>
<td>60°·s-1偏心</td>
			<td>171</td>
			<td>327</td>
			<td>0.52</td>
		</tr>
<tr>
<td>180°·s-1同心</td>
			<td>123</td>
			<td>168</td>
			<td>0.73</td>
			<td rowspan="2">0.95</td>
		</tr>
<tr>
<td>180°·s-1偏心</td>
			<td>159</td>
			<td>327</td>
			<td>0.59</td>
		</tr>
<tr>
<td>240°·s-1同心</td>
			<td>98</td>
			<td>137</td>
			<td>0.71</td>
			<td rowspan="2">1.21</td>
		</tr>
<tr>
<td>240°·s-1偏心</td>
			<td>167</td>
			<td>297</td>
			<td>0.56</td>
		</tr>
<tr>
<td>左下肢</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
<tr>
<td>60°·s-1同心</td>
			<td>118</td>
			<td>245</td>
			<td>0.48</td>
			<td rowspan="2">0.62</td>
		</tr>
<tr>
<td>60°·s-1偏心</td>
			<td>152</td>
			<td>282</td>
			<td>0.54</td>
		</tr>
<tr>
<td>180°·s-1同心</td>
			<td>113</td>
			<td>151</td>
			<td>0.75</td>
			<td rowspan="2">0.99</td>
		</tr>
<tr>
<td>180°·s-1偏心</td>
			<td>149</td>
			<td>286</td>
			<td>0.52</td>
		</tr>
<tr>
<td>240°·s-1同心</td>
			<td>114</td>
			<td>134</td>
			<td>0.85</td>
			<td rowspan="2">1.14</td>
		</tr>
<tr>
<td>240°·s-1偏心</td>
			<td>153</td>
			<td>298</td>
			<td>0.51</td>
		</tr>
</tbody></table>表 2: 具有测试结果值的组织表.H: 腿筋, Q: 四头肌。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td>周</td>
			<td>每周会话</td>
			<td>集</td>
			<td>重复</td>
		</tr>
<tr>
<td>1</td>
			<td>1</td>
			<td>1</td>
			<td>5</td>
		</tr>
<tr>
<td>2</td>
			<td>2</td>
			<td>2</td>
			<td>6</td>
		</tr>
<tr>
<td>3</td>
			<td>2</td>
			<td>3</td>
			<td>6-8</td>
		</tr>
<tr>
<td>4</td>
			<td>2</td>
			<td>3</td>
			<td>8-10</td>
		</tr>
<tr>
<td>5</td>
			<td>3</td>
			<td>3</td>
			<td>8-10</td>
		</tr>
<tr>
<td>6-12</td>
			<td>3</td>
			<td>3</td>
			<td>12108</td>
		</tr>
</tbody></table>表 3: 北欧卷曲运动量的进展根据 Mjølsnes32.

Watch this Scientific Journal Video about Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations at JoVE.com

Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations

肌肉失衡: 运动人群功能性偏心肌筋强度的检测与训练

腿筋是一组肌肉, 有时是问题的运动员, 导致软组织损伤的下肢。为了防止这种伤害, 对腿筋的功能训练需要强烈的偏心收缩。另外, 在不同的收缩速度下, 应根据 quadricep 功能对腘绳肌功能进行测试。

Many hamstring injuries that occur during physical activity occur while the muscles are lengthening, during eccentric hamstring muscle actions. Opposite ...

muscle-imbalances-testing-training-functional-eccentric-hamstring

Nanyang Technological University

Research

JoVE Journal

Medicine

15.3K 次观看.  Charles University. 腿筋是一组肌肉, 有时是问题的运动员, 导致软组织损伤的下肢。为了防止这种伤害, 对腿筋的功能训练需要强烈的偏心收缩。另外, 在不同的收缩速度下, 应根据 quadricep 功能对腘绳肌功能进行测试。

视频: Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations

An Inertial Measurement Unit Based Method to Estimate Hip and Knee Joint Kinematics in Team Sport Athletes on the Field

Current athlete monitoring practice in team sports is mainly based on positional data measured by global positioning or local positioning systems. The disadvantage of these measurement systems is that they do not register lower extremity kinematics, which could be a useful measure for identifying injury-risk factors. Rapid development in sensor technology may overcome the limitations of the current measurement systems. With inertial measurement units (IMUs) securely fixed to body segments, sensor fusion algorithms and a biomechanical model, joint kinematics could be estimated. The main purpose of this article is to demonstrate a sensor setup for estimating hip and knee joint kinematics of team sport athletes in the field. Five male subjects (age 22.5 &#177; 2.1 years; body mass 77.0 &#177; 3.8 kg; height 184.3 &#177; 5.2 cm; training experience 15.3 &#177; 4.8 years) performed a maximal 30-meter linear sprint. Hip and knee joint angles and angular velocities were obtained by five IMUs placed on the pelvis, both thighs and both shanks. Hip angles ranged from 195&#176; (&#177; 8&#176;) extension to 100.5&#176; (&#177; 8&#176;) flexion and knee angles ranged from 168.6&#176; (&#177; 12&#176;) minimal flexion and 62.8&#176; (&#177; 12&#176;) maximal flexion. Furthermore, hip angular velocity ranged between 802.6 &#176;&#183;s-1 (&#177; 192 &#176;&#183;s-1) and -674.9 &#176;&#183;s-1 (&#177; 130 &#176;&#183;s-1). Knee angular velocity ranged between 1155.9 &#176;&#183;s-1 (&#177; 200 &#176;&#183;s-1) and -1208.2 &#176;&#183;s-1 (&#177; 264 &#176;&#183;s-1). The sensor setup has been validated and could provide additional information with regard to athlete monitoring in the field.&#160;This may help professionals in a daily sports setting to evaluate their training programs, aiming to reduce injury and optimize performance.

Monitoring athletes is essential for improving performance and reducing injury risk in team sports. Current methods to monitor athletes do not include the lower extremities. Attaching multiple inertial measurement units to the lower extremities could improve monitoring athletes in the field.

一种基于惯性测量单元的方法，以评估场上团队运动运动员的臀部和膝盖关节运动学

Current athlete monitoring practice in team sports is mainly based on positional data measured by global positioning or local positioning systems. The ...

科研

行为学

Applications of In Vivo Functional Testing of the Rat Tibialis Anterior for Evaluating Tissue Engineered Skeletal Muscle Repair

Despite the regenerative capacity of skeletal muscle, permanent functional and/or cosmetic deficits (e.g., volumetric muscle loss (VML) resulting from traumatic injury, disease and various congenital, genetic and acquired conditions are quite common. Tissue engineering and regenerative medicine technologies have enormous potential to provide a therapeutic solution. However, utilization of biologically relevant animal models in combination with longitudinal assessments of pertinent functional measures are critical to the development of improved regenerative therapeutics for treatment of VML-like injuries. In that regard, a commercial muscle lever system can be used to measure length, tension, force and velocity parameters in skeletal muscle. We used this system, in conjunction with a high power, bi-phase stimulator, to measure in vivo force production in response to activation of the anterior crural compartment of the rat hindlimb. We have previously used this equipment to assess the functional impact of VML injury on the tibialis anterior (TA) muscle, as well as the extent of functional recovery following treatment of the injured TA muscle with our tissue engineered muscle repair (TEMR) technology. For such studies, the left foot of an anaesthetized rat is securely anchored to a footplate linked to a servomotor, and the common peroneal nerve is stimulated by two percutaneous needle electrodes to elicit muscle contraction and dorsiflexion of the foot. The peroneal nerve stimulation-induced muscle contraction is measured over a range of stimulation frequencies (1-200 Hz), to ensure an eventual plateau in force production that allows for an accurate determination of peak tetanic force. In addition to evaluation of the extent of VML injury as well as the degree of functional recovery following treatment, this methodology can be easily applied to study diverse aspects of muscle physiology and pathophysiology. Such an approach should assist with the more rational development of improved therapeutics for muscle repair and regeneration.

Applications of In Vivo Functional Testing of the Rat Tibialis Anterior for Evaluating Tissue Engineered Skeletal Muscle Repair

We describe an in vivo protocol to measure dorsiflexion of the foot following stimulation of the peroneal nerve and contraction of the anterior crural compartment of the rat hindlimb. Such measurements are an indispensable translational tool for evaluating skeletal muscle pathology and tissue engineering approaches to muscle repair and regeneration.

中的应用<em&gt;在体内</em&gt;评定组织的鼠胫骨前的功能测试工程化骨骼肌修复

Despite the regenerative capacity of skeletal muscle, permanent functional and/or cosmetic deficits (e.g., volumetric muscle loss (VML) resulting from ...

生物工程

Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test

Theoretically, the electromyographic (EMG) fatigue threshold is the exercise intensity an individual can maintain indefinitely without the need to recruit more motor units which is associated with an increase in the EMG amplitude. Although different protocols have been used to estimate the EMG fatigue threshold they require multiple visits which are impractical for a clinical setting. Here, we present a protocol for estimating the EMG fatigue threshold for cycle ergometry which requires a single visit. This protocol is simple, convenient, and completed within 15-20 min, therefore, has the potential to be translated into a tool that clinicians can use in exercise prescription.

This protocol describes the electromyographic fatigue threshold which demarcates between nonfatiguing and fatiguing exercise workloads. This information could be used to develop a more individualized training program.

确定肌电疲劳阈值以下单次访问运动试验

Theoretically, the electromyographic (EMG) fatigue threshold is the exercise intensity an individual can maintain indefinitely without the need to recruit ...

医学

Assessment of Neuromuscular Function Using Percutaneous Electrical Nerve Stimulation

Percutaneous electrical nerve stimulation is a non-invasive method commonly used to evaluate neuromuscular function from brain to muscle (supra-spinal, spinal and peripheral levels). The present protocol describes how this method can be used to stimulate the posterior tibial nerve that activates plantar flexor muscles. Percutaneous electrical nerve stimulation consists of inducing an electrical stimulus to a motor nerve to evoke a muscular response. Direct (M-wave) and/or indirect (H-reflex) electrophysiological responses can be recorded at rest using surface electromyography. Mechanical (twitch torque) responses can be quantified with a force/torque ergometer. M-wave and twitch torque reflect neuromuscular transmission and excitation-contraction coupling, whereas H-reflex provides an index of spinal excitability. EMG activity and mechanical (superimposed twitch) responses can also be recorded during maximal voluntary contractions to evaluate voluntary activation level. Percutaneous nerve stimulation provides an assessment of neuromuscular function in humans, and is highly beneficial especially for studies evaluating neuromuscular plasticity following acute (fatigue) or chronic (training/detraining) exercise.

We present a protocol to assess changes in neuromuscular function. Percutaneous electrical nerve stimulation is a non-invasive method that evokes muscular responses. Electrophysiological and mechanical properties of these responses permit the evaluation of neuromuscular function from brain to muscle (supra-spinal, spinal and peripheral levels).

神经肌肉功能的应用经皮神经电刺激评估

Percutaneous electrical nerve stimulation is a non-invasive method commonly used to evaluate neuromuscular function from brain to muscle (supra-spinal, ...

神经科学

Adapted Resistance Training Improves Strength in Eight Weeks in Individuals with Multiple Sclerosis

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis (MS). It is known that resistance strength training (RST) can improve strength in individuals with MS, however; it remains unclear the duration of RST that is needed to make strength gains and how to adapt hip strengthening exercises for individuals of varying strength using only resistance bands. This paper describes the methodology to set up and implement an adapted resistance strength training program, using resistance bands, for individuals with MS. Directions for pre- and post-strength tests to evaluate efficacy of the strength-training program are included. Safety features and detailed instructions outline the weekly program content and progression. Current evidence is presented showing that significant strength gains can be made within 8 weeks of starting a RST program. Evidence is also presented showing that resistance strength training can be successfully adapted for individuals with MS of varying strength with little equipment.

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis. Isolated muscle strengthening is a useful method to target specific weaknesses. This protocol describes a progressive resistance-training program using exercise bands to increase hip muscle strength.

改编阻力训练提高力量在八周内的个人与多发性硬化症

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis (MS). It is known that resistance strength training (RST) can ...

Induction and Assessment of Exertional Skeletal Muscle Damage in Humans

Contraction-induced muscle damage via voluntary eccentric (lengthening) contractions offers an excellent model for studying muscle adaptation and recovery in humans. Herein we discuss the design of an eccentric exercise protocol to induce damage in the quadriceps muscles, marked by changes in strength, soreness, and plasma creatine kinase levels. This method is simple, ethical, and widely applicable since it is performed in human participants and eliminates the interspecies translation of the results. Subjects perform 300 maximal eccentric contractions of the knee extensor muscles at a speed of 120&#176;/sec on an isokinetic dynamometer. The extent of the damage is measurable using relatively non-invasive isokinetic and isometric measures of strength loss, soreness, and plasma creatine kinase levels over several days following the exercise. Therefore, its application can be directed to specific populations in an attempt to identify mechanisms for muscle adaptation and regeneration.

This article describes a safe and reliable method to induce and quantify exertional skeletal muscle damage in human subjects.

诱导和人类劳力骨骼肌损伤评估

Contraction-induced muscle damage via voluntary eccentric (lengthening) contractions offers an excellent model for studying muscle adaptation and recovery ...

Improving Strength, Power, Muscle Aerobic Capacity, and Glucose Tolerance through Short-term Progressive Strength Training Among Elderly People

This protocol describes the simultaneous use of a broad span of methods to examine muscle aerobic capacity, glucose tolerance, strength, and power in elderly people performing short-term resistance training (RET). Supervised progressive resistance training for 1 h three times a week over 8 weeks was performed by RET participants (71&#177;1 years, range 65-80). Compared to a control group without training, the RET showed improvements on the measures used to indicate strength, power, glucose tolerance, and several parameters of muscle aerobic capacity. Strength training was performed in a gym with only robust fitness equipment. An isokinetic dynamometer for knee extensor strength permitted the measurement of concentric, eccentric, and static strength, which increased for the RET group (8-12% post- versus pre-test). The power (rate of force development, RFD) at the initial 0-30 ms also showed an increase for the RET group (52%). A glucose tolerance test with frequent blood glucose measurements showed improvements only for the RET group in terms of blood glucose values after 2 h (14%) and the area under the curve (21%). The blood lipid profile also improved (8%). From muscle biopsy samples prepared using histochemistry, the amount of fiber type IIa increased, and a trend towards a decrease in IIx in the RET group reflected a change to a more oxidative profile in terms of fiber composition. Western blot (to determine the protein content related to the signaling for muscle protein synthesis) showed a rise of 69% in both Akt and mTOR in the RET group; this also showed an increase in mitochondrial proteins for OXPHOS complex II and citrate synthase (both ~30%) and for complex IV (90%), in only the RET group. We demonstrate that this type of progressive resistance training offers various improvements (e.g., strength, power, aerobic capacity, glucose tolerance, and plasma lipid profile).

The effect of short-term resistance training on elderly people was investigated through the simultaneous use of several methods. Compared to a control group, many improvements were seen, including on muscle aerobic capacity, glucose tolerance, strength, power, and muscle quality (i.e., protein involved in cell signaling and muscle fiber type composition).

通过长期进步力量训练提高力量，力量，肌肉有氧能力和葡萄糖耐量

This protocol describes the simultaneous use of a broad span of methods to examine muscle aerobic capacity, glucose tolerance, strength, and power in ...

Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies

Critical to the evaluation of potential therapeutics for muscular disease are sensitive and reproducible physiological assessments of muscle function. Because many pre-clinical trials rely on mouse models for these diseases, isolated muscle function has become one of the standards for Go/NoGo decisions in moving drug candidates forward into patients. We will demonstrate the preparation of the extensor digitorum longus (EDL) and diaphragm muscles for functional testing, which are the predominant muscles utilized for these studies. The EDL muscle geometry is ideal for isolated muscle preparations, with two easily accessible tendons, and a small size that can be supported by superfusion in a bath. The diaphragm exhibits profound progressive pathology in dystrophic animals, and can serve as a platform for evaluating many potential therapies countering fibrosis, and promoting myofiber stability. Protocols for routine testing, including isometric and eccentric contractions, will be shown. Isometric force provides assessment of strength, and eccentric contractions help to evaluate sarcolemma stability, which is disrupted in many types of muscular dystrophies. Comparisons of the expected results between muscles from wildtype and dystrophic muscles will also be provided. These measures can complement morphological and biochemical measurements of tissue homeostasis, as well as whole animal assessments of muscle function.

Muscle function measurements contribute to the evaluation of potential therapeutics for muscle pathology, as well as to the determination of mechanisms underlying physiology of this tissue. We will demonstrate the preparation of the extensor digitorum longus and diaphragm muscles for functional testing. Protocols for isometric and eccentric contractions will be shown, as well as differences in results between dystrophic muscles, representing a pathological state, and wildtype muscles.

等距和骨骼肌产生偏心力评估隔离肌营养不良症的小鼠模型

Critical to the evaluation of potential  therapeutics for muscular disease are sensitive and reproducible physiological  assessments of muscle function. ...

生物学

Lower Limb Biomechanical Analysis of Healthy Participants

Biomechanical analysis techniques are useful in the study of human movement. The aim of this study was to introduce a technique for the lower limb biomechanical assessment in healthy participants using commercially available systems. Separate protocols were introduced for the gait analysis and muscle strength testing systems. To ensure maximum accuracy for gait assessment, attention should be given to the marker placements and self-paced treadmill acclimatization time. Similarly, participant positioning, a practice trial, and verbal encouragement are three critical stages in muscle strength testing. The current evidence suggests that the methodology outlined in this article may be effective for the assessment of lower limb biomechanics.

This article introduces a comprehensive experimental methodology on two of the latest technologies available to measure the lower limb biomechanics of individuals.

健康参与者的下肢生物力学分析

Biomechanical analysis techniques are useful in the study of human movement. The aim of this study was to introduce a technique for the lower limb ...

In vivo Measurement of Knee Extensor Muscle Function in Mice

Skeletal muscle plasticity in response to countless conditions and stimuli mediates concurrent functional adaptation, both negative and positive. In the clinic and the research laboratory, maximal muscular strength is widely measured longitudinally in humans, with knee extensor musculature the most reported functional outcome. Pathology of the knee extensor muscle complex is well documented in aging, orthopedic injury, disease, and disuse; knee extensor strength is closely related to functional capacity and injury risk, underscoring the importance of reliable measurement of knee extensor strength. Repeatable, in vivo assessment of knee extensor strength in pre-clinical rodent studies offers valuable functional endpoints for studies exploring osteoarthritis or knee injury. We report an in vivo and non-invasive protocol to repeatedly measure isometric peak tetanic torque of the knee extensors in mice across time. We demonstrate consistency using this novel method to measure knee extensor strength with repeated assessment in multiple mice producing similar results.

Quantification of knee extensor maximal strength is imperative to understand functional adaptations to aging, disease, injury, and rehabilitation. We present a novel method to repeatedly measure in vivo knee extension isometric peak tetanic torque.

小鼠膝盖外展肌肉功能的体内测量

Skeletal muscle plasticity in response to countless conditions and stimuli mediates concurrent functional adaptation, both negative and positive. In the ...