Abstract
BACKGROUND AND PURPOSE: Short Hamstring Syndrome (SHS) is described as a deficit of extensibility of this musculature. In contrast to Proprioceptive Neuromuscular Facilitation (PNF), which is widely used in these cases, the abdominal hypopressive technique (AHT) is presented as a possible method to improve flexibility. The primary aim of this trial was to assess the feasibility and acceptability of a single-session AHT program versus PNF stretching in adults with SHS, while the secondary, exploratory aim was to estimate their immediate effects on hamstring flexibility to inform the design and sample size of a future definitive trial. METHODS: A pilot randomized controlled trial of a single treatment session was designed, with a pre- and post-treatment evaluation to assess the effects of both techniques on flexibility. 19 subjects were randomized into an AHT group and a PNF stretching group. The Straight Leg Raise and Toe Touch tests assessed changes after treatment. Paired samples t-tests and independent samples t-tests were used to statistically analyze changes within and between groups, respectively. RESULTS: Significant improvements were observed in both groups on all tests pre- and post-intervention. However, no significant differences were found between the groups following the intervention. DISCUSSION: Both AHT and PNF techniques produced immediate improvements in hamstring flexibility in adults with shortened hamstring syndrome. However, these findings are exploratory, and, given the pilot nature of the trial, no conclusions can be drawn regarding the superiority of one method over the other.