Unbound MEDLINE

Muscle activation during proprioceptive neuromuscular facilitation (PNF) stretching techniques.

Abstract

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.

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    • Authors

    Osternig LR, Robertson R, Troxel R, Hansen P

    Institution

    Department of Physical Education, University of Oregon, Eugene 97403-1273.

    Source

    American journal of physical medicine 66:5 1987 Oct pg 298-307

    MeSH

    Adult
    Electromyography
    Exercise Therapy
    Female
    Humans
    Knee Joint
    Male
    Muscle Contraction
    Muscles
    Physical Exertion
    Proprioception

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    3434629