Osternig L R, Robertson R, Troxel R, Hansen P
Department of Physical Education, University of Oregon, Eugene 97403-1273.
Am J Phys Med. 1987 Oct;66(5):298-307.
Proprioceptive neuromuscular facilitation (PNF) techniques are often used to induce muscle relaxation and increase joint range of motion (ROM). However, the relationship between muscle activation and ROM with PNF is not well understood. The purpose of this study was to investigate the effect of three common PNF stretching techniques on hamstring muscle activation and knee extension. Three PNF techniques: stretch-relax (SR), contract-relax (CR) and agonist contract-relax (ACR) were applied to ten male and female subjects aged 23-36 years who were stabilized to isolate knee extension measurements. Knee joint position and EMG activity from quadriceps and hamstring muscles were computer processed throughout technique application. The results revealed mean hamstring EMG activity increased 8-43% within a given trial of ACR and CR respectively, and did not diminish across trials. SR produced a 11% decrease in mean hamstring EMG activity. ACR produced 3-6% greater knee extension values than CR and SR respectively, in spite of 71-155% greater hamstring EMG activity during ACR. The data suggest that CR and ACR do not evoke sufficient relaxation in muscles opposing knee extension to overcome tension facilitation generated by stretch. Thus, increases in ROM are achieved while the hamstrings are under considerable tension. Such tension increases muscle vulnerability to soreness and strain if stretching continues. The degree of knee extension produced via SR, although 3-6% less than CR and ACR, was achieved during simultaneous reduction in hamstring activity and may be the safer stretching technique.
本体感觉神经肌肉促进法（PNF）技术常用于诱导肌肉放松并增加关节活动范围（ROM）。然而，人们对PNF中肌肉激活与ROM之间的关系尚未完全了解。本研究的目的是调查三种常见的PNF拉伸技术对腘绳肌激活和膝关节伸展的影响。对10名年龄在23至36岁的男性和女性受试者应用了三种PNF技术：伸展-放松（SR）、收缩-放松（CR）和主动肌收缩-放松（ACR），受试者保持稳定以分离膝关节伸展测量。在整个技术应用过程中，对膝关节位置以及股四头肌和腘绳肌的肌电图活动进行计算机处理。结果显示，在ACR和CR的给定试验中，腘绳肌平均肌电图活动分别增加了8%至43%，且在各试验中均未减弱。SR使腘绳肌平均肌电图活动降低了11%。尽管在ACR期间腘绳肌肌电图活动比CR和SR分别高出71%至155%，但ACR产生的膝关节伸展值分别比CR和SR大3%至6%。数据表明，CR和ACR未能在对抗膝关节伸展的肌肉中引起足够的放松，以克服拉伸产生的张力促进作用。因此，在腘绳肌处于相当大张力的情况下实现了ROM的增加。如果继续拉伸，这种张力会增加肌肉酸痛和拉伤的易感性。通过SR产生的膝关节伸展程度虽然比CR和ACR少3%至6%，但却是在腘绳肌活动同时降低的情况下实现的，可能是更安全的拉伸技术。
