The influence of stretching and educational messages on measures of neuromuscular control and the perceived importance of stretching
Pre-exercise stretching has the potential to influence the ability of the active muscular control system to dynamically stabilize affected joints during high-risk athletic maneuvers. Likewise, even though controversial research evidence exists regarding the role of stretching, many athletes continue to perform pre-exercise stretching and continue to believe it is important to engage in this practice, suggesting an underlying psychosocial interaction. Therefore, the purposes of this study were to: (1) explore the influence of pre-exercise stretching on measures of neuromuscular control of the lower extremity during landing; (2) evaluate the relationship between historical educational messages about pre-exercise stretching and current perceptions of its value; (3) evaluate the relationship between subjects’ perceptions and actual performance outcomes; (4) investigate the influence of the type of warm-up intervention on subjects’ perceptions of its value; and (5) evaluate the influence of current educational messages on perceptions of the value of pre-exercise stretching. Forty-four college-age recreationally active individuals participated in a clinical control trial design requiring one day of testing involving a warm-up followed by a vertical drop jump test before and after a stretching intervention or rest period. The stretch-intervention group participated in a 16 minute stretching routine, while the control group rested for the same time period. Pre and Post-intervention measurements of electromyography (EMG), knee and hip kinematics, ground reaction force (GRF), and muscle flexibility of the dominant lower extremity were examined for both groups. The EMG, kinematic, and GRF measurements were gathered during the first landing phase of a vertical drop jump test. Upon completion of the second vertical drop jump test, subjects completed a survey instrument utilizing a standard visual analogue scale to evaluate perceptions. Inferential statistical analyses demonstrated no significant differences between the stretching and control groups in EMG, kinematic, GRF or flexibility measurements as a result of the stretching intervention. Additionally, correlation analyses found no relationship between what the subjects had been taught regarding the value of pre-exercise stretching and their perception of its value, yet a positive relationship was found between perceptions and the actual vertical drop jump measures. Finally, inferential statistical analyses revealed that written educational messages significantly altered subjects’ perceptions of the value of pre-exercise stretching. Based on these findings it was suggested that a moderate stretching routine prior to a landing task may not negatively influence the ability of the neuromuscular system to safely control joint motion during landing. Likewise, it was concluded that current educational messages can alter perceptions of the value of pre-exercise stretching and perceptions about a specific warm-up routine may influence performance outcomes, possibly as a result of a heightened state of self-efficacy.