不稳定表面可改善股四头肌与腘绳肌的共同收缩，用于前交叉韧带损伤预防策略。
Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies.
作者信息
Shultz Rebecca, Silder Amy, Malone Maria, Braun Hillary Jane, Dragoo Jason Logan
机构信息
Human Performance Lab, Sports Medicine Center, Department of Orthopaedic Surgery, Stanford University, Palo Alto, California ; Division of Sports Medicine, Department of Orthopaedic Surgery, Stanford University, Palo Alto, California.
Human Performance Lab, Sports Medicine Center, Department of Orthopaedic Surgery, Stanford University, Palo Alto, California ; Department of BioEngineering, Stanford University, Palo Alto, California.
出版信息
Sports Health. 2015 Mar;7(2):166-71. doi: 10.1177/1941738114565088.
BACKGROUND
Increasing quadriceps:hamstring muscular co-contraction at the knee may reduce the risk of anterior cruciate ligament (ACL) injury. The purpose of this investigation was to examine muscle activation in the quadriceps and hamstrings and peak kinematics of the knee, hip, and trunk when performing a single-leg drop (SLD) on to a Bosu ball (unstable surface) compared with on to the floor (stable surface).
HYPOTHESES
(1) The SLD on an unstable surface would lower the quadriceps to hamstrings electromyographic (EMG) activation ratio (Q:H EMG activation ratio) compared with being performed on the floor. (2) Lower Q:H EMG activation ratio would be caused by a relative increase in hamstring activation, with no significant change in quadriceps activation.
STUDY DESIGN
Controlled laboratory study.
METHODS
Thirty-nine Division I National Collegiate Athletic Association (NCAA) female athletes performed 3 SLDs per leg onto a Bosu ball and onto the floor. Muscle activity of the vastus lateralis and lateral hamstrings were used to estimate peak quadriceps and hamstring activation, along with the Q:H EMG activation ratio. Kinematic measures at the knee, hip, and trunk were also estimated. Differences between landings were assessed using a 2-level analysis of variance (limb and surface).
RESULTS
The maximum Q:H EMG activation ratio was significantly reduced when athletes performed an SLD onto the Bosu ball (20%, P < 0.001) compared with the floor. Peak hamstring activity was higher when athletes landed on a Bosu ball (18% higher, P = 0.029) compared with when they landed on the floor.
CONCLUSION
Compared with landing on the floor (a stable surface), landing on a Bosu ball (unstable surface) changed the athlete's co-contraction at the knee and increased hamstring activity. However, landing on a Bosu ball also decreased the athlete's knee flexion, which was an undesired effect.
CLINICAL RELEVANCE
These findings highlight the potential utility of unstable surfaces as a training tool to reduce the risk of ACL injury in female athletes.
背景
增加膝关节处股四头肌与腘绳肌的共同收缩可能会降低前交叉韧带（ACL）损伤的风险。本研究的目的是比较在Bosu球（不稳定表面）上与在地面（稳定表面）上进行单腿下落（SLD）时，股四头肌和腘绳肌的肌肉激活情况以及膝关节、髋关节和躯干的峰值运动学参数。
假设
（1）与在地面上进行SLD相比，在不稳定表面上进行SLD会降低股四头肌与腘绳肌的肌电图（EMG）激活率（Q:H EMG激活率）。（2）较低的Q:H EMG激活率是由腘绳肌激活的相对增加引起的，股四头肌激活无显著变化。
研究设计
对照实验室研究。
方法
39名美国大学体育总会（NCAA）一级联盟的女运动员每条腿在Bosu球上和地面上各进行3次SLD。使用股外侧肌和外侧腘绳肌的肌肉活动来估计股四头肌和腘绳肌的峰值激活以及Q:H EMG激活率。还估计了膝关节、髋关节和躯干的运动学参数。使用两级方差分析（肢体和表面）评估着陆之间的差异。
结果
与在地面上相比，运动员在Bosu球上进行SLD时，最大Q:H EMG激活率显著降低（20%，P < 0.001）。运动员在Bosu球上着陆时，腘绳肌的峰值活动高于在地面上着陆时（高18%，P = 0.029）。
结论
与在地面（稳定表面）着陆相比，在Bosu球（不稳定表面）着陆改变了运动员膝关节处的共同收缩，并增加了腘绳肌的活动。然而，在Bosu球上着陆也降低了运动员的膝关节屈曲度，这是一个不良影响。
临床意义
这些发现凸显了不稳定表面作为一种训练工具在降低女运动员ACL损伤风险方面的潜在效用。
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