Negative effect of static stretching restored when combined with a sport specific warm-up component

Abstract

There is substantial evidence that static stretching may inhibit performance in strength and power activities. However, most of this research has involved stretching routines dissimilar to those practiced by athletes. The purpose of this study was to evaluate whether the decline in performance normally associated with static stretching pervades when the static stretching is conducted prior to a sport specific warm-up. Thirteen netball players completed two experimental warm-up conditions. Day 1 warm-up involved a submaximal run followed by 15 min of static stretching and a netball specific skill warm-up. Day 2 followed the same design; however, the static stretching was replaced with a 15 min dynamic warm-up routine to allow for a direct comparison between the static stretching and dynamic warm-up effects. Participants performed a countermovement vertical jump and 20 m sprint after the first warm-up intervention (static or dynamic) and also after the netball specific skill warm-up. The static stretching condition resulted in significantly worse performance than the dynamic warm-up in vertical jump height (−4.2%, 0.40 ES) and 20 m sprint time (1.4%, 0.34 ES) (p < 0.05). However, no significant differences in either performance variable were evident when the skill-based warm-up was preceded by static stretching or a dynamic warm-up routine. This suggests that the practice of a subsequent high-intensity skill based warm-up restored the differences between the two warm-up interventions. Hence, if static stretching is to be included in the warm-up period, it is recommended that a period of high-intensity sport-specific skills based activity is included prior to the on-court/field performance.

Introduction

The purpose of the pre-competition warm-up is to prepare athletes for the demands of the competition. A well-designed warm-up can assist the athlete in mentally focusing on the upcoming task and to bring about various physiological changes to optimise performance.¹ A pre-game warm-up for team sports typically includes a period of sub maximal running, static stretching of the major muscle groups and sport specific movements incorporating various range of motion (ROM) exercises with skill-based drills executed at, or just below game intensity.²

Low to moderate intensity aerobic activity is an important element of the warm-up as it increases muscle temperature, which is directly responsible for a number of mechanisms important for short term performance, including range of movement about the joints, increased rate of nerve impulses, and an altered force–velocity relationship.³ In contrast, the static stretching component, which is routinely practiced in team sports, has little scientific basis to support a beneficial effect on sports performance. In fact, substantial evidence exists that static stretching may acutely inhibit performance in strength and power activities, with previous research reporting negative effects on maximal isometric force,4, 5 one repetition maximum strength⁶ and explosive performance as measured by a countermovement vertical jump,7, 8 drop-jumps7, 8, 9 and 20 m sprint performance.10, 11 Acute bouts of stretching have also been shown to impair balance, reaction time and movement time.¹² The lack of evidence in favour of static stretching during a warm-up has led some authors to recommend the exclusion of this component from the warm-up for strength and power activities.13, 14

Awareness of the substantial evidence suggesting acute impairment of strength and power following static stretching has led to some coaches combining and/or replacing static stretching with dynamic warm-up routines. McMillian et al.¹⁵ found that a dynamic stretching routine produced higher (2.8%, ES 0.24) scores for a five-step jump than when static stretching was utilised. Similarly, dynamic stretching produced faster (2.8%, ES 0.51) 20 m sprint performance¹⁰ and greater (11.56%, ES 2.23) leg extension power¹⁶ than static stretching. Such evidence suggests that dynamic warm-up routines have a greater beneficial effect on powerful-based performances than static stretching routines. However, an important component of the warm-up sequence that has generally been overlooked in the literature to date is the sport specific warm-up activities that are commonly included in many team sport warm-up routines. Only Young and Behm⁷ have investigated the effect of specific rehearsal of the test activity subsequent to a bout of static stretching. They examined the influence of practice jumps in combination with a 4 min submaximal run and static stretching and reported better performance for a variety of jump variables when the subjects were given opportunity to perform practice jumps. The authors suggested that rehearsal of the skill to be performed may have had an effect of “opening up” the specific neural pathways, facilitating motor unit activation, and therefore assisting to improve explosive performance.⁷ In addition to these findings, Young and Behm⁷ also reported that a run + stretch condition produced very similar mean results to their control condition, leading them to believe that perhaps the run + stretch condition might be made up of a positive influence (run) and a negative influence (stretch), which counteracted each other to produce results similar to the control condition. While their study design did not include an additional warm-up condition to examine the effect of a warm-up consisting of only two positive influences, for example the run + skill rehearsal, they hypothesised such a warm-up routine may be the most beneficial combination of activities.

Therefore, the purpose of the current research was to replicate current warm-up practice in netball to evaluate differences in speed and leg extensor power after static stretching and dynamic warm-up routines. A further objective was to determine if differences in performance remained after a period of moderate to high intensity skill rehearsal. That is, we were interested in investigating if the hypothesised negative effect of stretching would remain after a sport specific warm-up sequence.