Determinants of acute effects of stretching vs. foam rolling: Morphological, sensory and fluid responses

Background: A single bout of foam rolling (FR) or static stretching is effective to increase the range of motion (ROM) without impairments in performance. Recently, non-rolling methods with FR have been investigated, but the effects of these methods are still unclear. Objective: This study aimed to compare and examine the effects of different FR interventions and SS on the plantar flexor (PF) muscles. Methods: Dominant PF of 24 participants was investigated under four conditions: Control (CC), FR, FR with dynamic movement (FR-DM), and SS. Each condition was performed unilaterally for 4 sets of 30 s. Outcome variables were ankle dorsiflexion ROM, pain pressure thresholds (PPT), tissue hardness, localized bioimpedance analysis (L-BIA), and unilateral drop jump (DJ). Measures were assessed before (T0), immediately after (T1), and 10-min after (T2). Results: ROM improved for SS, FR and FR-DM from T0 to T1 while remaining elevated in T2 only for SS and FR-DM. A significant increase in PPT was observed for SS and FR (T1). L-BIA showed a significant change of the vector position in the resistance-reactance graph only for FR (T1 and T2). DJ and tissue hardness did not change for any group at any time-point. Conclusion: PF-ROM can be acutely improved by either FR, FR-DM, or SS by a modification of local pain perception without any variation in tissue morphology and performance. FR was the only intervention to acutely change fluids distribution.