Lidstone Daniel E, van Werkhoven Herman, Needle Alan R, Rice Paige E, McBride Jeffrey M
Appalachian State University, Department of Health & Exercise Science, Neuromuscular & Biomechanics Laboratory, Boone, NC, USA.
Appalachian State University, Department of Health & Exercise Science, Neuromuscular & Biomechanics Laboratory, Boone, NC, USA.
J Electromyogr Kinesiol. 2018 Feb;38:175-181. doi: 10.1016/j.jelekin.2017.12.006. Epub 2017 Dec 23.
The purpose of this investigation was to compare fascicle and tendon length of the gastrocnemius at the end of the eccentric phase during a hop utilizing a single countermovement (sCM) versus multiple countermovement (mCM1, mCM2, mCM3) strategy. Seventeen healthy males performed nine hopping trials of sCM and nine trials of mCM. Ankle and knee joint angle and lower leg length from videography and muscle ultrasound were used to calculate muscle-tendon unit (MTU), fascicle and tendon length. Sacral marker data was used to determine hopping height. Force- and displacement-time curves were utilized to calculate work. Muscle activity of the lateral and medial gastrocnemius was also measured. Fascicle length was significantly shorter (mCM3: 6.2 ± 1.5 cm, sCM: 7.3 ± 2.0 cm) and tendon length was significantly longer (mCM3: 36.5 ± 3.6 cm, sCM: 35.5 ± 3.8 cm) at the end of the eccentric phase in mCM3 in comparison to sCM. Maximal hopping height (mCM: 14.6 ± 3.1 cm, sCM: 13.1 ± 2.5 cm), eccentric phase gastrocnemius muscle activity (mCM medial gastrocnemius: 0.10 ± 0.03 mV, mCM lateral gastrocnemius: 0.08 ± 0.04 mV, sCM medial gastrocnemius: 0.07 ± 0.03 mV, sCM lateral gastrocnemius: 0.05 ± 0.04 mV), and both eccentric (mCM3: 46.6 ± 19.4 J, sCM: 38.5 ± 15.9 J) and concentric work (mCM3: 87.6 ± 26.5 J, sCM: 80.9 ± 27.6 J) were significantly higher for mCM3 compared to sCM. The results indicate that a multiple countermovement hop strategy results in shorter fascicle length and longer tendon length at the end of the eccentric phase. In addition, greater eccentric phase muscle activity during the third countermovement (mCM3) in comparison to a single countermovement hop (sCM) was observed. A multiple countermovement strategy appears to result in higher hopping height and greater work done in both the eccentric and concentric phase indicating possible contribution of stored-elastic energy from the tendon.
本研究的目的是比较在单反向动作(sCM)与多反向动作(mCM1、mCM2、mCM3)策略的单腿跳离心阶段结束时腓肠肌的肌束长度和肌腱长度。17名健康男性进行了9次sCM单腿跳试验和9次mCM单腿跳试验。利用摄像和肌肉超声测量的踝关节和膝关节角度以及小腿长度来计算肌肉-肌腱单元(MTU)、肌束长度和肌腱长度。使用骶骨标记数据确定单腿跳高度。利用力和位移-时间曲线计算功。还测量了腓肠肌外侧和内侧的肌肉活动。与sCM相比,mCM3离心阶段结束时肌束长度显著缩短(mCM3:6.2±1.5厘米,sCM:7.3±2.0厘米),肌腱长度显著延长(mCM3:36.5±3.6厘米,sCM:35.5±3.8厘米)。最大单腿跳高度(mCM:14.6±3.1厘米,sCM:13.1±2.5厘米)、离心阶段腓肠肌肌肉活动(mCM内侧腓肠肌:0.10±0.03毫伏,mCM外侧腓肠肌:0.08±0.04毫伏,sCM内侧腓肠肌:0.07±0.03毫伏,sCM外侧腓肠肌:0.05±0.04毫伏)以及离心功(mCM3:46.6±19.4焦,sCM:38.5±15.9焦)和向心功(mCM3:87.6±26.5焦,sCM:80.9±27.6焦),mCM3均显著高于sCM。结果表明,多反向动作单腿跳策略在离心阶段结束时导致肌束长度缩短和肌腱长度延长。此外,观察到与单反向动作单腿跳(sCM)相比,第三次反向动作(mCM3)期间离心阶段肌肉活动更大。多反向动作策略似乎导致更高的单腿跳高度以及在离心和向心阶段完成更多的功,这表明肌腱储存的弹性能可能起到了作用。