Date of Award

2021-05-01

Degree Name

Doctor of Philosophy

Department

Interdisciplinary Health Sciences

Advisor(s)

Sandor Dorgo

Abstract

Warm-ups are essential components of all training sessions, sports, and physical activities. Warm-ups are typically composed of a variety of stretches. Two stretching modalities that are commonly performed before any physical activity are the static and dynamic stretching modalities. Historically, static stretching has been used as a preferred stretching modality during the warm-up period. However, research indicates that static stretching â?? if done prior to the training session â?? may inhibit the expression of muscular strength, muscular activation, and vertical jump height. On the contrary, dynamic stretching has been shown to improve the expression of muscular strength, muscular activation, and vertical jump performance. In addition, the effects of static stretching are modulated by the time under stretch, training history of the individual, and pre-warm-up activities. More recently, static stretching of the antagonist muscles has been shown to improve muscular strength and power of the agonist muscles during knee extension and vertical jump. Moreover, we ought to expand on the previous results of antagonist static stretching and explore if dynamic stretching of the agonist and static stretching of the antagonist would improve muscular isokinetic strength, power, muscular activation, and vertical jump performance. The purpose of this project was to explore the effects of static and dynamic stretching under different configurations at the agonist (quadriceps and gastrocnemius) and antagonist (hamstrings and tibialis anterior) muscular complex on isokinetic strength, vertical jump height, and muscular activation (electromyography) of the lower body. A randomized repeated measures within, and between subjectâ??s design was utilized for this study. Sixteen male subjects completed this study (n=16, trained=8, untrained=8) For every testing session, subjects performed a general warm-up consisting of a 3-5-minute self-paced jog. Following this, subjects performed a total of 9 conditions in a randomized order throughout nine testing sessions: 1) Baseline, 2) Static of Agonist, 3) Static of Antagonist, 4) Static of Agonist and Antagonist, 5) Dynamic of Agonist, 6) Dynamic of Antagonist, 7) Dynamic of Agonist and Antagonist, 8) Static of Agonist and Dynamic of Antagonist, and 9) Dynamic of Agonist and Static of Antagonist. Subjects performed a series of stretches for each of these conditions in separate sessions. Thereafter, subjects performed four repetitions of isokinetic knee extensions and flexions. Finally, subjects performed five repetitions of the countermovement jump, squat jump, and drop jump. A series of individual repeated measures ANOVA and Friedman tests for non-parametric repeated measures data were utilized to determine the interaction of the stretching conditions on isokinetic peak and mean torque, and power, electromyography, and vertical jump performance. Results indicated a significant interaction on Isokinetic Peak Knee Extension and Flexion Torque, Power, and Average Torque, with pairwise comparisons favoring Dynamic stretching conditions. However, the analyses revealed no significant interactions for muscular activation. Furthermore, there was no interaction on Vertical Jump Height. However, there was a small worthwhile change favoring the dynamic of agonist and antagonist condition. Therefore, it was concluded that the Dynamic of Agonist and Antagonist improves physical performance in concordance with the previous literature. Moreover, results show that stretching dynamically the agonist and the antagonist in a static manner also improves performance, with no differences between these two stretching conditions. The Dynamic of Agonist and Static of Antagonist can be an alternative to a Dynamic stretching of Agonist and Antagonist commonly performed to improve isokinetic strength and vertical jump height. Future studies with athletes from different sports are needed to extrapolate these results in different sport populations and situations.

Language

en

Provenance

Received from ProQuest

File Size

206 p.

File Format

application/pdf

Rights Holder

Samuel Montalvo

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