US Army-Baylor University Doctoral Program in Physical Therapy, Fort Sam Houston, TX.
J Orthop Sports Phys Ther. 2013 Oct;43(10):685-92. doi: 10.2519/jospt.2013.4542. Epub 2013 Sep 9.
Observational.
To compare lower extremity negative joint work and vertical ground reaction force loading rates in rearfoot-striking (RS) and Chi runners.
Alternative running styles such as Chi running have become a popular alternative to RS running. Proponents assert that this running style reduces knee joint loading and ground reaction force loading rates.
Twenty-two RS and 12 Chi runners ran for 5 minutes at a self-selected speed on an instrumented treadmill. A 3-D motion analysis system was used to obtain kinematic data. Average vertical ground reaction force loading rate and negative work of the ankle dorsiflexors, ankle plantar flexors, and knee extensors were computed during the stance phase. Groups were compared using a 1-way analysis of covariance for each variable, with running speed and age as covariates.
On average, RS runners demonstrated greater knee extensor negative work (RS, -0.332 J/body height × body weight [BH·BW]; Chi, -0.144 J/BH·BW; P<.001), whereas Chi runners demonstrated more ankle plantar flexor negative work (Chi, -0.467 J/BH·BW; RS, -0.315 J/BH·BW; P<.001). RS runners demonstrated greater average vertical ground reaction force loading rates than Chi runners (RS, 68.6 BW/s; Chi, 43.1 BW/s; P<.001).
Chi running may reduce vertical loading rates and knee extensor work, but may increase work of the ankle plantar flexors.
观察性研究。
比较后足着地（RS）和 Chi 跑者的下肢负关节功和垂直地面反作用力加载率。
替代跑步方式，如 Chi 跑，已成为 RS 跑步的一种流行替代方式。支持者声称，这种跑步方式可以减少膝关节的负荷和地面反作用力的加载率。
22 名 RS 和 12 名 Chi 跑者在仪器化跑步机上以自选速度跑 5 分钟。使用三维运动分析系统获取运动学数据。在站立阶段计算踝关节背屈肌、踝关节跖屈肌和膝关节伸肌的平均垂直地面反作用力加载率和负功。使用协方差的单因素分析比较每个变量的组间差异，跑步速度和年龄作为协变量。
平均而言，RS 跑者的膝关节伸肌负功更大（RS，-0.332 J/身高×体重 [BH·BW]；Chi，-0.144 J/BH·BW；P<.001），而 Chi 跑者的踝关节跖屈肌负功更大（Chi，-0.467 J/BH·BW；RS，-0.315 J/BH·BW；P<.001）。RS 跑者的平均垂直地面反作用力加载率大于 Chi 跑者（RS，68.6 BW/s；Chi，43.1 BW/s；P<.001）。
Chi 跑可能会降低垂直加载率和膝关节伸肌的功，但可能会增加踝关节跖屈肌的功。
