Hip and ankle range of motion and hip muscle strength in young female ballet dancers and controls.
OBJECTIVES: To compare the hip and ankle range of motion and hip muscle strength in 8-11 year old novice female ballet dancers and controls. METHODS: Subjects were 77 dancers and 49 controls (mean (SD) age 9.6 (0.8) and 9.6 (0.7) years respectively). Supine right active hip external rotation (ER) and internal rotation (IR) were measured using an inclinometer. A turnout protractor was used to assess standing active turnout range. The measure of ER achieved from below the hip during turnout (non-hip ER) was calculated by subtracting hip ER range from turnout range, and hip ER:IR was derived by dividing ER range by IR range. Range of right weight bearing ankle dorsiflexion was measured in a standing lunge using two methods: the distance from the foot to the wall (in centimetres) and the angle of the shank to the vertical via an inclinometer (in degrees). Right calf muscle range was measured in weight bearing using an inclinometer. A manual muscle tester was used to assess right isometric hip flexor, internal rotator, external rotator, abductor, and adductor strength. RESULTS: Dancers had less ER (p<0.05) and IR (p<0.01) range than controls but greater ER:IR (p<0.01). Although there was no difference in turnout between groups, the dancers had greater non-hip ER. Dancers had greater range of ankle dorsiflexion than controls, measured in both centimetres (p<0.01) and degrees (p<0.05), but similar calf muscle range. After controlling for body weight, controls had stronger hip muscles than dancers except for hip abductor strength which was similar. Regression analyses disclosed a moderate relation between turnout and hip ER (r = 0.40). There were no significant correlations between range of motion and training years and weekly training hours. CONCLUSIONS: Longitudinal follow up will assist in determining whether or not hip and ankle range in young dancers is genetically fixed and unable to be improved with further balletic training. (+info
Serogroup C meningococcal disease outbreak associated with discotheque attendance during carnival.
In the week following a carnival during 19-24 February 1998, an outbreak of meningococcal disease occurred in a rural German county. The available isolates belonged to phenotype C:2a:P1.2,5 and were clonally related by pulsed-field gel electrophoresis. A case-control study was done to identify risk factors for the outbreak and to define possible vaccination target groups. Five persons aged 13-16 years who fell ill during 24-27 February were included in the study. Four of 5 cases and 10 of 32 controls visited local discotheques (OR = 8.8; P = 0.06). Cases also visited discotheques more frequently than controls (chi2 for trend, P = 0.0002). Multiple discotheques during the carnival may have been predominant locations of transmission in this outbreak. Because this risk factor was limited in time, a mass community vaccination campaign was not initiated. (+info
Long-term persistence of a discotheque-associated invasive Neisseria meningitidis group C strain as proven by pulsed-field gel electrophoresis and porA gene sequencing.
A cluster of a Neisseria meningitidis serogroup C strain causing invasive disease was investigated. Five out of seven cases were associated with a particular discotheque. The strains were indistinguishable, as revealed by pulsed-field gel electrophoresis and sequencing of variable regions of the porA gene, but caused strikingly different clinical presentations during 5 months. (+info
Changes in hip and ankle range of motion and hip muscle strength in 8-11 year old novice female ballet dancers and controls: a 12 month follow up study.
OBJECTIVES: To evaluate in a 12 month longitudinal study changes in hip and ankle range of motion and hip muscle strength in young female novice ballet dancers. METHODS: Fifty three of the original 77 (69%) female dancers aged 8-11 years and 40 of the original 49 (82%) controls returned for follow up measurements one year later. Supine right active hip external (ER) and internal (IR) rotation were measured using an inclinometer. A turnout protractor was used to assess standing active turnout range. Range of right weight bearing ankle dorsiflexion and calf muscle length were measured in a standing lunge position using an inclinometer. A manual muscle tester was used to assess right hip flexor, IR, ER, abductor and adductor strength. RESULTS: The mean (SD) 12 month change in hip ER did not differ between dancers (11.7 (11.3)degrees) and controls (8.1 (17.6)degrees). Dancers gained 12.5 (13.5)degrees hip IR which was significantly greater than controls (0.5 (13.9)degrees). Greater IR change was associated with improved IR strength (r = 0.34, p<0.001). Dancers increased total turnout (12.0 (16.7)degrees) significantly more than controls (2.2 (20.0)degrees). There was no significant change in ankle dorsiflexion range in either group. Dancers and controls increased in all measures of hip muscle strength (p<0.001) and dancers achieved significantly greater gains in three out of five muscle groups (all, p<0.05). CONCLUSIONS: Total hip range of motion increased in both ballet students and controls at this young age. However, ankle dorsiflexion did not, which is probably due to this movement being blocked by bony apposition, rather than soft tissue stretch. This has implications for ballet teachers, as it has long been accepted that this movement could be improved with training. Dancers had greater increases in hip strength after 12 months compared with controls in muscles specific for ballet, suggesting that hip strength can be trained at this young age. Whether these gains are permanent requires further study. (+info
Case report. Paraphimosis due to erotic dancing.
Paraphimosis usually develops when a tight foreskin is retracted over the glans penis for a prolonged period. Many esoteric aetiologies have been implicated in the development of paraphimosis including piercing the foreskin, Plasmodium falciparum infection, application of celadine juice to the foreskin, chancroid, pessaries and the implantation of pearls. We report the first two cases of paraphimosis developing during wining, an erotic dance native to Trinidad & Tobago. (+info
Cluster of tuberculosis cases among exotic dancers and their close contacts--Kansas, 1994-2000.
During January 2001, the Wichita-Sedgwick County Department of Community Health (WSCDCH), the Kansas Department of Health and Environment (KDHE), and CDC investigated a cluster of tuberculosis (TB) cases that occurred from 1994 to 2000 among women with a history of working as dancers in adult entertainment clubs (i.e., exotic dancers) and persons who were close contacts of exotic dancers. This report describes the results of the investigation and illustrates the need for early identification of TB clusters through ongoing surveillance and resources for health departments to respond rapidly to TB outbreaks. (+info
Bone mineral density in young female Chinese dancers.
To evaluate of the effect of dancing on bone mineral density (BMD) we compared 29 Chinese girls who had been receiving regular ballet training for at least 6 years with a control group of 20 nonathletic sex- and age-matched Chinese girls. BMD was measured at the second to fourth lumbar spine and at the right femoral neck using a commercial dual-energy X-ray absorptiometer (DEXA). There were no significant differences in either measured BMD or spinal BMD after adjusting for body weight (body mass index). Adjusted BMD of the femoral neck, however, showed significant differences (P <0.05). Results revealed that the ballet dancers were significantly thinner than the control group and the negative effect of a lower bodyweight may neutralize the positive effect of ballet dancing on BMD, especially in the femoral neck. (+info
A comparison of physiological responses and rating of perceived exertion in two modes of aerobic exercise in men and women over 50 years of age.
OBJECTIVES: To compare the physiological responses and ratings of perceived exertion to aerobic dance and walking sessions completed at a self selected pace. METHODS: Six women and six men with a sample mean (SD) age of 68 (7) years completed aerobic dance and walking sessions in random order. A treadmill test was performed by each subject from which peak oxygen uptake (.VO(2)) and maximum heart rates (HRmax) were determined. During the aerobic dance and walking sessions, heart rate and .VO(2) were measured continuously throughout. Rate of perceived exertion (RPE) was measured every three minutes throughout the session. RESULTS: The sample means (SD) for %peak .VO(2) were 67 (17)% for the aerobic dance sessions and 52 (10)% for the walking sessions, and the %HRmax sample means (SD) were 74 (12)% for the aerobic dance sessions and 60(8)% for walking sessions. The sample mean (SD) RPE for the aerobic dance sessions was 11(2), and for the walking sessions it was 10(2). CONCLUSIONS: %peak .VO(2), %HRmax, and RPE were significantly higher for aerobic dance than for walking. However, both the aerobic dance and walking sessions were of adequate intensity to improve aerobic fitness in most subjects. Further investigation into the relation between RPE and %peak .VO(2) in a field setting over representative exercise time periods would be useful. (+info