The Efficacy of Physical Fitness Training on Dance Injury: A Systematic Review.

Greater levels of physical fitness have been linked to improved dance performance and decreased injury incidence. The aim was to review the efficacy of physical fitness training on dance injury. The electronic databases CINAHL, Cochrane Library, PubMed, Web of Science, MEDLINE, China National Knowledge Infrastructure were used to search peer-reviewed published articles in English or Chinese. Studies were scored using Strength of the Evidence for a Conclusion and a risk bias checklist. 10 studies met the inclusion criteria from an initial 2450 publications. These studies offered physical fitness training for professional (n=3) and pre-professional dancers (n=7), participant sample size ranged between 5 to 62, ages from 11 to 27 years, and most participants were females. Assessment scores were classified as Fair (n=1), Limited (n=7), and Expert Opinion Only (n=2) and risk of bias scores ranged from 22.7-68.2%. After physical fitness training, 80% of studies reported significant benefits in injury rate, the time between injuries, pain intensity, pain severity, missed dance activities and injury count. This review suggests that physical fitness training could have a beneficial effect on injury incidence in dance. The evidence is limited by the current study methodologies.

Impact Attenuation and Deformation Characteristics of Dance Floors on Jump Kinematics.

Specialist dance floors have been promoted to reduce impact forces and reduce lower limb injury for dancers. 18 trained female dancers carried out 70 continuous ballet jumps on 4 different surfaces wearing an XSENS suit. Three specialist dance floors, Floor A (64% force reduction), Floor B (67% force reduction), Floor C (no data) were compared to Floor D (vinyl-covered concrete - control). Dependent variables for each analysed jump (2,3,4, and 67,68,69) were ankle, knee, hip range of movement (ROM); lower and upper leg angular velocities and pelvis vertical acceleration. No main effects were reported for dance floor, first and last jump series. Comparison of the floors against Floor D reported a main effect for the dance floors (p=0.001), first and last jump series (p=0.001). Between-subject effects noted that ankle ROM was significantly greater for trials on floor A (p=0.007) compared to floor D. ROM data significantly decreased between the first and last jump series whilst vertical pelvis accelerations increased except for floor A. Within the current study, a foam backed vinyl floor (C) provided better shock absorption than floors with higher deformation characteristics (A and B) and none of the specialist dance floors performed better than vinyl covered concrete (D).

Injury Incidence and Severity in Musical Theatre Dance Students: 5-year Prospective Study.

Dance injury research has mainly focused on ballet and modern dance with little data on musical theatre dancers. The purpose was to assess the incidence and severity of injuries in a musical theatre dance college over a 5-year period; 198 pre-professional musical theatre dancers (3 cohorts on a 3-year training course) volunteered for the study; 21 students left the course over the study period. Injury aetiology data were collected by an in-house physiotherapy team. Differences between academic year and sex were analysed using a Poisson distribution model; significant difference was set at p≤0.05. In total, 913 injuries were recorded, and more injuries occurred in academic year 1 than year 2 and 3. Overall injury incidence was 1.46 injuries per 1000 hours (95% CI 1.34, 1.56); incidence significantly decreased between year 1, 2 and 3 (p<0.05). There was no significant sex difference for incidence or severity. Most injuries were classified as overuse (71% female, 67% male). Pre-professional musical theatre dancers report a high proportion of lower limb and overuse injuries comparable to other dance genres. Unlike other studies on pre-professional dancers, injury incidence and severity decreased with academic year, even though workload increased across the course.

The Relationship between Vitamin D Levels, Injury and Muscle Function in Adolescent Dancers.

Vitamin D has been shown to benefit a diverse range of health functions including muscle function. The aim of the present study was to identify serum 25(OH)D3 levels in a sample of adolescent dancers and compare them to muscle function and injury incidence. We incorporated a cross-sectional design to study 49 pre-professional male and female dancers (17±4.44 yrs, 52.1±6.72 kg, 1.63±0.07 m) in full-time training in Bazil. Serum 25[OH]D3 was analyzed by Enzyme-linked Immunosorbent Assay; quadriceps and hamstring peak torque and muscle fatigue were measured by isokinetic dynamometer at 60 and 300° s-1. Injury type and location in the previous 6-months were determined by self-report questionnaire. Participants were categorized into 2 groups: normal or insufficient/deficient (>or<30 ng/ml 25[OH]D3). Results indicated the normal serum 25[OH]D3 group had significantly lower fatigue rates than the insufficient/deficient group (p<0.05) but not for the other muscle function parameters. Fifty-seven percent of participants reported at least 1 injury. The most common were sprains (33%) and tendinopathies (19%). Injured dancers had significantly lower peak torque at 60°/s. The link between serum 25[OH]D3 and reduced muscle fatigue resistance has not been shown before, though the underlying mechanisms aren't apparent and the link between muscular strength and injury has been previously evidenced.

Workload Intensity and Rest Periods in Professional Ballet: Connotations for Injury.

Fatigue and overwork have been cited as the main cause of injury with the dance profession. Previous research has shown a difference in workload between professional dancers of different rank, but the role of sex has not been examined. The purpose of this study was to determine workload intensity, rest, and sleep profiles of professional ballet dancers. 48 professional ballet dancers (M=25, F=23) took part in an observational design over 7-14 days using triaxial accelerometer devices. Minutes in METS at different intensities, total time asleep and rest breaks were analysed. Significant main effects for rank (p<0.001) and rank by sex (p=0.003) for total PA, working day activity, post work activity and sleep. Sleep ranged between 2.4-9.6 h per night. All participants spent more time between 1.5-3 METS outside of work. Significant amounts of exercise where carried out outside of their work day, therefore when injury is reported per 1000 h dance activity, this extra-curricular activity might need to be included. When looking at potential causes of injury in dance, a global perspective of physical activity is required that includes activity outside of work and sleep patterns, all activities that influence physiological recovery.