DANCE MEDICINE

sustained was a result of extrinsic or intrinsic factors. Bronner et al (5) include extrinsic factors as being the type of work, exposure or duration of workload, equipment and environmental conditions.

The type of work, exposure and duration of workload in dance can vary considerably, and is very often influenced by whether it is a rehearsal or performance period. Our prospective study was based on a year that entailed 25 weeks of rehearsal and 22 weeks of performances, totalling 150 performances throughout the season. During a rehearsal period a dancer may complete up to one hour of class, encompassing both technical and physical training, followed by up to six hours of rehearsals. During a performance period, this will be extended to include evening, and occasionally afternoon shows, performing normally eight shows over five days during a six-day working week.

Conditioning The impact of such a schedule can be counted in a number of ways. Dancers generally have poor physiological conditioning compared to other sporting populations (14) due to their high skill levels resulting in very good economy of movement whilst dancing. Simply put, dancing no longer places a physiological stress on them. Dance can be classified as high intensity intermittent exercise (15) and a pre-requisite for this type of exercise is a good aerobic foundation. Dancers have been shown to have very poor aerobic capacities compared to other similar sports people (16) and this weakness could be the underlying source of many injury problems. Laws (11) noted that the majority of dancers perceived that the cause of their injuries was fatigue/tiredness orientated. Dance is a high skill movement form and mild fatigue has a major affect on the quality of movement, resulting in poor alignment of limbs and therefore misplacement of force. When this is accompanied by low strength levels as seen in dancers (17), injury again is more prevalent (18). Longitudinal research has shown that dancers increase their aerobic capacities during the performance period with no significant adaptations occurring during the prior rehearsal period (19). This suggests that dancers enter the performance period without the aerobic capacity to cope with the cardiorespiratory demands of performing (most dancers admit it takes two weeks of performing before they feel “fit enough to really go for it”). Myths abound within the dance world and there is often a reticence to engage in supple- mental training or even an inability due to time restrictions caused by rehearsal schedules. For instance, strength training and running are often avoided as they are considered to alter the dancers’ body-shape away from the ideal.

Nutrition The nutritional impact is also significant. The nature of dance tends to bias towards high intensive intermittent exercise with explosive, anaerobic periods lasting up to six minutes within solo roles, but the basis of dance is long rehearsals periods utilising low level aerobic demands. The consequence nutritionally is two fold. Firstly the content and quantity of the fuel required, and secondly the timing of the fuel intake. Adherence to an optimal nutritional strategy is difficult because the time available to take on foods is normally close to actual performance time. This leads to the dancers decreasing the volume of food taken so as not to hinder performance, resulting in a restriction of the amount of

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energy sup- plied to their muscle systems. This may ulti- mately lead to diminished perfomance capabilities and increase the risk of injury. In addition, this may also result in the failure to provide the required post-rehearsal exercise nutrition needed to optimise recovery (20).

Dance surface The variability of surfaces that athletes are exposed to and the impact of surfaces on biomechanics, loading and injury have been topical in sports medicine. Within dance, the surfaces can vary greatly. A dancer may spend the majority of his/her time rehearsing in a studio that has well-sprung floors, but be expected to perform on a solid stage, that may also be raked (tilted to afford the audience a better overall view). Awareness of the impact of surfaces is important in the management of dancers, and attempts are always made to provide a graded exposure to all surfaces when recovering from injury.

Costume Another extrinsic factor needing consideration is costumes. Within sport, the application of additional layers is not unusual, but generally they do not differ, allowing athletes to accommo- date to their chosen sport’s requirements. Within dance, costumes can vary greatly, from show to show, as well as within shows, eliminating the dancers’ ability to grow accustomed to its presence. Costumes can be heavy and restrictive, altering the natural movement of the

Figure 1: Costume for the Beast 7