The effects of two different 8-week stretching protocols on postural stability in amateur sportsmen

Purpose: The purpose of this study was to compare the long-term effects of a static versus proprioceptive neuromuscular facilitation (PNF) stretching protocols by means of spinometry and baropodometry. We hypothesized that PNF may be more effective than static stretching in supporting the static and dynamic balance. Methods: Thirty-six sport science students were divided into three groups: the first group attended a warm-up protocol on the treadmill only (warm-up group) while the other two carried out the same warm-up protocol followed by a static stretching (static group) or by a Contract Relax Antagonist Contract stretching (CRAC group). Stretching programs were performed three times per week on lower limb muscles and the postural stability of each participant was evaluated at entry (pre) and after 8 weeks of training (post). Results: The ellipse area after a warm-up-only protocol did not change; after the static stretching protocol, it was significantly increased (from 111.3 ± 35.8 to 135.0 ± 32.3, p < 0.05), while after the CRAC protocol, it significantly decreased (from 119.1 ± 23.0 to 88.2 ± 19.8, p < 0.01). CRAC group had a significant reduction in average forces (− 3.9% from pre to post, p < 0.05) and in load response (− 0.6% from pre to post, p < 0.05). Pelvic inclination was reduced from 2.22 to 1.33 mm (p < 0.01) and pelvic torsion decreased by 0.94 ± 0.22° (p < 0.05) after the CRAC protocol. Conclusions: Eight-week CRAC protocol was an excellent training for static and dynamic balance improvement and it was more effective than static stretching.