13/01/2015
Chers amis et patients danseurs, voici un article très intéressant sur l'intérêt de l'échauffement et des étirements musculaires chez les danseurs. Vous trouverez le résumé ci-dessous.
Acute Effects of Warm-up Stretch Protocols on Balance, Vertical Jump Height, and Range of Motion in Dancers.
Abstract
The aim of this study was to examine the acute effects of static stretching (SS), dynamic stretching (DS), and a combined (static and dynamic) stretch protocol on vertical jump (VJ) height, balance, and range of motion (ROM) in dancers. A no-stretch (NS) intervention acted as the control condition. It was hypothesized that the DS and combination stretch protocols would have more positive effects on performance indicators than SS and NS, and SS would have negative effects as compared to the NS condition. Ten trained female dancers (27 ± 5 years of age) were tested on four occasions. Each session began with initial measurements of hamstring ROM on the dominant leg. The participants subsequently carried out a cardiovascular (CV) warm-up, which was followed by one of the four randomly selected stretch conditions. Immediately after the stretch intervention the participants were tested on VJ performance, hamstring ROM, and balance. The data showed that DS (p < 0.05) and the combination stretch (p < .05) produced significantly greater VJ height scores as compared to SS, and the combination stretch demonstrated signifi- cantly enhanced balance performance as compared to SS (p < 0.05). With regard to ROM, a one-way ANOVA indicated that SS and the combination stretch displayed significantly greater changes in ROM than DS (p < 0.05). From comparison of the stretch protocols used in the current study, it can be concluded that SS does not appear to be detrimental to a dancer’s performance, and DS has some benefits but not in all three key area’s tested, namely lower body power (VJ height), balance, and range of motion. However, combination stretching showed signifi- cantly enhanced balance and vertical jump height scores and significantly improved pre-stretch and post-stretch ROM values. It is therefore suggested that a combined warm-up protocol consisting of SS and DS should be promoted as an effective warm-up for dancers.
Stretching is commonly included in the warm-up procedure before participation in physical activities, such as dance, as it is purported to enhance performance and prevent injury.1 In addition to the demand for power and control, dancers are expected to display large ranges of motion. As a result of this particular requirement, it is thought that dancers are prime candidates for engaging in excessive static stretching (SS) prior to class or performance. In recent years, the use of SS has been called into question. The literature points toward a reduction in muscular performance after stretching.1-16
Currently, two theories aim to explain the reduction in efficiency caused by pre-performance SS. It has been found that SS reduces musculotendinous unit (MTU) stiffness.7,17,18 This may negatively alter the length-tension and force-velocity relationships, thus lowering the rate of force production. The second theory involves the neurological system. A number of studies show that SS reduces neural drive,9,11,18 which may lead to an inhibition of optimal muscle activation.
In contrast to SS, support for dynamic stretching (DS) prior to per- formance is growing. The acute effects of DS have been shown to enhance many aspects of sports performance, such as lower leg power,19-21 vertical jump (VJ) performance,22-24 agility,19,25 and strength.8 These findings should promote the use of a dynamic stretch routine prior to engaging in sport or dance. The mechanisms responsible for the increases in performance have not been thoroughly investigated. However, recent research has shown that DS causes an increase in elec- tromyographic (EMG) activity.8,23,26 This increase in muscle activation suggests a “postactivation potentia- tion” (PAP) effect. This phenomenon would encourage muscle contractions to be more rapid and forceful, thus enhancing the explosive aspects of athletic and dance performance. Other mechanisms relate to a change in body temperature. Dynamic stretching is aerobic in nature,27 and this characteristic allows for the suggestion that enhanced performance following DS may also be related to an increase in body temperature. This would positively affect the force-velocity and length-tension relationships,28 enhance nerve conduction velocity (NCV),29,30 and increase enzyme activity.31
The literature has begun to focus attention on investigating the effects of combined warm-up stretch protocols. Researchers have found that by combining a static stretch and dynamic stretch protocol, the harm- ful effects of SS can be reduced.21,25 In addition, high intensity sport-specific skills following SS have been shown to counteract its negative effects and show enhanced VJ height and sprint performance.32 However, the research remains inconclusive, as Chaouachi and coworkers found no perfor- mance decrements following SS and no performance benefits following a dynamic or combined stretch proto- col.33 With the aim of adding further understanding of pre-performance stretch protocols, the current study addresses the acute effects of SS, DS, and a combined stretch protocol on VJ height, balance, and hamstring ROM in dancers. These three variables are important indicators of dance performance, as they encompass the athleticism, control, and flexibility that are expected of dancers.
Affiliations: 1: University of Bedfordshire, Park Square, Luton LU1 3JU, UK; Dance UK, London, UK. niamh.morrin@beds.ac.uk 2: Trinity Laban, London, UK
