The study aims to determine if proprioceptive neuro­muscular facilitation (P.N.F.) of neck extensor muscles effects the measure of the basic straight leg raise (S.L.R). Hence, these effects will be compared with the effects on the S.L.R. due to P.N.F. of hamstring muscles.

The clinical trial proposes to examine approximately 90 subjects between the ages of 18-35 in a double-blind study. A pre-test measure of the S.L.R. will be recorded using a goniometre to measure angle of inclination of the leg and a force transducer to standardise the measurement by investigator X. The patients will then be randomly allocated to one of three groups to be treated by investigator Y. Group 1 will be treated with P.N.F. of the neck extensor muscles. Group 2 will be treated with P.N.F. of the hamstring muscles and group 3, a control group, will have neither procedure. Investigator X will then perform and record a post-test measure of the S.L.R.

P.N.F. is a commonly used therapeutic technique used to stretch muscles such as hamstrings. As hamstring length and tension are factors which will influence S.L.R., P.N.F. of this muscle should cause an increase in the measure of S.L.R. It is hypothesised in this study that P.N.F. of neck extensor muscles will also have an effect on S.L.R. even though these muscles are not local to the hip joint and low back. There are several possible mechanisms for this relationship. P.N.F. resets neuromuscular spindle cells in the upper cervical area which may cause a decrease in tension of the dura which attaches to the axis. As a result, there may be less tension where the dura attaches to the nerve roots in the low back and nerve root stretch becomes· less of a limiting factor of the S.L.R. There could also be direct neurological pathways where resetting of cervical proprioceptors effects tension in lower body musculature via reticulospinal and vestibulospinal spinal tracts which are concerned with postural reflexes and adjusting body position in relation to head position.

Grant Value: $350
Chief Investigator: Dr Henry Pollard
Status: Complete

Research report:

  • May 1993
    The project demonstrated that under controlled conditions, a procedure approximating that used by many AK practitioners demonstrated a greater ability to improve hip flexion range of motion than did a PNF stretch applied directly at the hip joint.  It is hoped that this research may be expanded in the coming years to investigate both the unilateral and contralateral effects of adjustments on similar measurements.