Date of Award

2015

Degree Type

Thesis

Degree Name

Bachelor of Science (Sports Science) Honours

School

School of Exercise and Health Sciences

Faculty

Faculty of Health, Engineering and Science

First Advisor

Associate Professor Anthony Blazevich

Second Advisor

Dr Eric Drinkwater

Third Advisor

Professor David Behm

Abstract

Background: Research has shown that static stretching may improve muscle flexibility as well as minimise soft tissue injury. However, recent studies have recommended the removal static muscle stretching from pre-exercise routines due to its deleterious effect on physical performance. Nonetheless, research has shown a duration-dependent effect of static stretching, with total muscle stretch durations < 45 s having little influence on subsequent sporting performance. Furthermore, some evidence indicates that muscle stretching may not influence performance when a sport-specific warm-up follows the stretching component. However, this protocol has not been implemented in most studies.

Purpose: The purpose of the present study was to compare the effects of shorter (5 s) and longer (30 s) periods of static stretching to dynamic stretching on vertical jump performance in sub-elite athletes when the stretches are completed early in a complete pre-exercise routine. It was hypothesised that none of the three stretching conditions would elicit reductions in jumping performance when compared to a no-stretch condition, but that both static stretch conditions would induce greater improvements in ROM.

Design and Methods: Twenty healthy, athletic men (age = 21.1 ± 3.1 years, body mass = 73.37 ± 6.83 kg, height = 179.2 ± 70.13 cm) volunteered for this study. The participants were tested under four experimental conditions where 1) 5 s static stretching, 2) 30 s static stretching, 3) dynamic stretching, or 4) no stretching was performed after a short warm-up but before a longer, task-specific warm-up. Following all conditions, participants were tested with standard laboratory- and field-based (squat, countermovement and depth jump) and sport-specific (3 m running vertical jump) tests as well as a test of static range-of-motion (ROM) (sit-and-reach). Repeated measures multiple analyses of variance (MANOVAs) were used to compare the test performance between conditions with alpha level set at 0.05 Magnitude-based inference tests were then used to analyse the likelihood of an effect having a standardised (Cohen’s) effect size exceeding 0.20.

Results: There were no significant differences between conditions for vertical jump (p > 0.290) or sit-and-reach (p = 0.076) tests. The three stretch conditions were >85% likely to have trivial effects on the 3 m running vertical jump and countermovement jump scores when compared to the control (no stretch) condition. The dynamic stretch condition was 98% likely to elicit trivial effects on sit-and-reach score. There was a 96% likelihood that differences in countermovement jump height between the 5 s static stretch and dynamic stretch conditions were trivial.

Conclusions: Given that no significant differences were observed between stretching conditions, the current findings demonstrated no unfavourable effects of static stretching on subsequent jumping performance when included as part of a complete pre-exercise routine. Although these durations of static stretching did not tend to show improvements in ROM, other potential benefits such as injury prevention or peripheral feedback may exist. Hence, recommendations to exclude static stretching in a pre-exercise routine seem premature. However, further research is warranted to investigate the benefits of static stretching in order to recommend its inclusion.

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