Flexibility training: ballistic, static or proprioceptive neuromuscular facilitation?

The effects of stretching techniques on the flexibility of the shoulder, trunk, and hamstring muscles were compared in college men. Subjects were randomly assigned to one of 4 groups: control (n=10), ballistic (n=11), static (n=10), or proprioceptive neuromuscular facilitation (PNF) (n=12). Baseline measurements (Leighton flexometer) were obtained on 2 separate days prior to and following a 3-day per week, 6-week flexibility training program. A 4x3 (subject group x muscle group) unweighted mean factorial analysis of variance for the difference scores (post minue pre) revealed significant (p less than 0.05) main effects for the 4 subjects groups and the 3 muscle groups. Post hoc analysis showed that only the PNF group had flexibility increases (10.6 degrees) greater than the control (3.4 degrees), and that the hamstrings (9.4 degrees increase) improved more than the trunk (5.2 degree increase). Furthermore, reliability was generally higher for the post-training scores, and the variability between days was lower for the post-training scores of the shoulder and hamstrings (p less than 0.05). The significant (p less than 0.05) between-day changes in flexibility pre-training confirm the importance of establishing baseline data prior to any training study. The findings indicate that PNF may be the preferred technique for improving flexibility, and that flexibility training results in an increased consistency of flexibility scores.