PROLONGED EFFECTS OF MODIFIED PNF STRETCH TECHNIQUES ON HIP JOINT FLEXIBILITY

  • W. Cornelius
  • K. Graves
  • D. Hill

Abstract

PURPOSE AND METHODS The purpose of this study was to evaluate the acute and prolonged effects of three stretching techniques on hip joint flexibility. Seventy-five male and female college students volunteered to participate in this study. The participants were evenly divided among five groups, and they were tested on three different days. Active range of motion (ROM) during hip joint flexion was the dependent variable. Three measures of ROM were obtained each day; prior to the treatment (baseline) each day; immediately after the treatment (post 0) each day; and then 5 minutes after the treatment on one day (post 5). 15 minutes after the treatment on another day (post 15), and 30 minutes after the treatment on another day (post 30). Each treatment group performed a different stretching maneuver. The PIC group performed a passive stretch (P) of the hip extensors followed by an isometric contraction (1) of the extensors and a concentric contraction (c) of the hip flexors. The PC group performed a passive stretch (P) of the hip extensors followed by a concentric contraction (c) of the hip flexors. The third treatment group, the C group, performed a concentric contraction (c) of the hip flexors. There were also two control groups which performed no stretching. One was a resting control whose members sat quietly when not being tested and the other was an active control whose members walked at a moderate intensity between the measurements of active flexibility. RESULTS AND CONCLUSION The results indicated that all three stretch treatment groups (PIC, PC, and C) exhibited significant acute increases in flexibility (i.e., at post 0) compared to both the active and resting control groups. Mean improvements were 9 degrees for PIC, 5 degrees for PC, and 4 degrees for C. However, 5 minutes after treatment (at post 5), ROM remained elevated above baseline levels only in the PIC and PC groups. ROM had returned to baseline levels at post 15 and post 30 in all groups. These results indicate the PNF stretching techniques results in an acute improvement in ROM. However, the duration of the improvement is short-lived (less than 15 minutes) and dependent upon the stretching technique that is used.