Kay Anthony D, Dods Steven, Blazevich Anthony J
Sport, Exercise and Life Sciences, The University of Northampton, Boughton Green Road, Northampton, NN2 7AL, UK.
Centre for Exercise and Sport Science Research (CESSR), School of Exercise and Health Sciences, Edith Cowan University, Joondalup, Australia.
Eur J Appl Physiol. 2016 Mar;116(3):611-21. doi: 10.1007/s00421-015-3320-8. Epub 2016 Jan 4.
Contract-relax (CR) stretching increases range of motion (ROM) substantively, however its use in athletic environments is limited as the contractions performed in a highly stretched position require partner assistance, are often painful, and may induce muscle damage. Therefore, the acute effects of performing the contractions 'off stretch' in the anatomical position [stretch-return-contract (SRC)] were compared with traditional CR stretching in 14 healthy human volunteers.
Passive ankle joint moment and dorsiflexion ROM were recorded on an isokinetic dynamometer with electromyographic monitoring of the triceps surae, whilst simultaneous real-time motion analysis and ultrasound imaging recorded gastrocnemius medialis muscle and Achilles tendon elongation. The subjects then performed CR or SRC stretches (4 × 10-s stretches and 5-s contractions) randomly on separate days before reassessment.
Significant increases in dorsiflexion ROM (4.1°-4.0°; P < 0.01) and peak passive moment (10.9-15.1%; P < 0.05) and decreases in the slope of the passive moment curve (19.1-13.3%; P < 0.05), muscle stiffness (21.7-21.3%; P < 0.01) and tendon stiffness (20.4-15.7%; P < 0.01) were observed in CR and SRC, respectively. No between-condition differences were found in any measure (P > 0.05).
Similar mechanical and neurological changes were observed between conditions, indicating that identical mechanisms underpin the ROM improvements. These data have important practical implications for the use of this stretching mode in athletic environments as performing the contractions 'off stretch' eliminates the pain response, reduces the risk of inducing muscle damage, and removes the need for partner assistance. Thus, it represents an equally effective, simpler, and yet potentially safer, stretching paradigm.
收缩-放松（CR）拉伸可显著增加关节活动范围（ROM），然而其在运动环境中的应用受到限制，因为在高度拉伸位置进行的收缩需要同伴协助，通常会很疼，而且可能会导致肌肉损伤。因此，在14名健康志愿者中，比较了在解剖位置进行“非拉伸状态下”收缩[拉伸-恢复-收缩（SRC）]与传统CR拉伸的急性效应。
在等速测力计上记录被动踝关节力矩和背屈ROM，同时对腓肠肌进行肌电图监测，而同步实时运动分析和超声成像记录腓肠肌内侧头和跟腱的伸长情况。然后，受试者在重新评估前的不同日子里随机进行CR或SRC拉伸（4次×10秒拉伸和5秒收缩）。
CR组和SRC组分别观察到背屈ROM显著增加（4.1°-4.0°；P<0.01）、被动力矩峰值增加（10.9%-15.1%；P<0.05），以及被动力矩曲线斜率降低（19.1%-13.3%；P<0.05）、肌肉僵硬度降低（21.7%-21.3%；P<0.01）和肌腱僵硬度降低（20.4%-15.7%；P<0.01）。各测量指标在不同条件之间均未发现差异（P>0.05）。
两种条件下观察到了相似的机械和神经学变化，表明相同的机制支撑了ROM的改善。这些数据对于在运动环境中使用这种拉伸方式具有重要的实际意义，因为在“非拉伸状态下”进行收缩可消除疼痛反应，降低诱发肌肉损伤的风险，且无需同伴协助。因此，它代表了一种同样有效、更简单且可能更安全的拉伸模式。
