Knee angular displacement analysis in amateur ballet dancers: a pilot study

Ballet gestures are highly non-anatomical and physiological, leading to compensatory behaviors. The knee joint is most affected by this behavior, leading to an increase risk of injury. Our purpose is to describe the knee angular displacement in amateur dancers, during a demi-plié exercise, with emphasis on valgus mechanisms frequency. Methods: 192 demi-pliés collected in six amateur female dancers (mean age = 15.33 ± 1.37 years), were analyzed regarding sagittal and frontal plane angular displacement, with an electrogoniometer connected to a signal acquisition unit at 1000 Hz. Results: all subjects presented valgus peaks along the trials, despite the global varus tendency of the knee frontal plane behavior. A significant positive correlation between the frequency of valgus and practice time was noted. Discussion: A variable angular frontal displacement was observed, with some trials comprehending a high incidence of valgus peaks along the ascending or descending phase of the demi-plié exercise. Conclusion: the frontal knee angle behavior is variable. It may present fast peaks of valgus or an initial trend of varus/valgus that is different from the global varus trend. The analysis of the activity should be considered in the training. The practice time may be related to the observed behavior.

Análise do comportamento angular da articulação do joelho no plano frontal em bailarinas amadoras de élite durante o demi-plié: um estudo piloto

Mestrado em Fisioterapia

Physiotherapy and Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a severe, progressive disease first described by Meryon in 1852 and later by Guillaume Duchene. It is the most common and severe form of childhood muscular dystrophy, affecting 1 in 3500 live male births. Is caused by an X—linked recessive genetic disorder resulting in a deficiency of the dystrophin protein, responsible for linking contractile proteins to the sarcolemma. Diagnosis is not always easy and the first symptoms are often related to weakness and difficulty or delay in acquiring the ability to perform simple activities. Progressive weakness leads to the use of compensatory strategies in order to maintain the ability to walk and perform other activities. Respiratory muscles are also affected and the complications resulting from its impairments are frequently the cause of early death of these patients. The advances in DMD management has increased life expectancy of these children with the need for adequate care in adulthood. DMD manifestations include muscle weakness, contractures, respiratory and cardiac complications. Some authors also refer that one-third of patients have difficulties with learning and delayed global development because the gene that encodes dystrophyn expresses various dystrophin isoforms that are found in Schwann and Purkinje celis in the brain. Body functions and structure impairments like muscle weakness, contractures and reduced range of motion lead to limitations in activities, i.e., impairments affect the performance of tasks by the individual. In a physiotherapist’s point of view analysing these limitations is mandatory because physiotherapy’s final purpose is to restore or preserve the ability to perform ADL and to improve quality of life.