Classical ballet involves the performance of complex movements that require high-level motor skills and good postural control. This study explored postural sway in passé en demi-pointe position in dancers and compared single-leg standing sway (with and without visual restriction) between dancers and non-dancers. Fourteen professional dancers and 14 sex- and age-matched volunteers who were not ballet dancers participated in the study. Participants stood on a force plate on the dominant leg in the following positions: 1. single-leg stance with eyes open (reference task) and with eyes closed and blindfolded for 35 seconds; and 2. passé en demi-pointe position with eyes open for 20 seconds (dancers only). The center of pressure signal was used to calculate the following variables: average velocity; anteroposterior and mediolateral velocity peaks; anteroposterior and mediolateral displacement ranges; average displacement; and ellipse area. Significant interaction effects (p < 0.001, η2 = 0.419) were observed between groups and postural tasks, with higher stabilometric values for the dancer group during the single-leg stance with eyes closed and blindfolded task, as evidenced by the average displacement of 241.0 cm in dancers and 147.1 cm in non-dancers (p = 0.025), and by the ellipse area of 9.5 cm2 for dancers and 4.9 cm2 for non-dancers (p = 0.001). In regard to the positions with eyes open, an increase was noted only in the average sway velocity and mediolateral velocity in passé en demi-pointe position compared with the single-leg stance with eyes open (p < 0.001). Greater postural sway might be interpreted as the result of either inadequate postural stability or exploratory behavior to maintain postural stability in more challenging tasks. It is concluded that professional ballet dancers show greater visual dependency for balance adjustment with reduced influence of the supporting base on postural sway.
CKCUES test kinematic and kinetic measures were not different among 3 conditions based on distance between hands. However, the test might not be suitable for initial or mild-level rehabilitation due to its challenging requirements.
HTLV-1-associated myelopathy is a progressive disabling disease associated with gait abnormalities. Objective To identify and quantify the main muscles affected by weakness and spasticity, their impact on gait, functional capacity and on quality of life of HTLV-1-associated myelopathy patients. Method We evaluated lower limbs muscular strength according to the Medical Research Council scale, spasticity according to the modified Ashworth scale, daily activities according to the Barthel Index and quality of life according to the Short-Form Health Survey-36 of 26 HTLV-1-associated myelopathy patients. Results The muscles most affected by weakness included the dorsal flexors and knee flexors. Spasticity predominated in the hip adductor muscles and in plantar flexors. Assistance for locomotion, minimal dependence in daily activities, limitations in functional capacity and physical aspects were the most common findings. Conclusion The impairment of gait, functional dependence and quality of life were predominantly a consequence of intense muscle weakness in HTLV-1-associated myelopathy patients.
| Dance involves integration between movement, postural balance and the multiple aspects involved with postural control. Information regarding the balance of ballet dancers is of great importance, as they are considered models of great postural control. The aim was to review studies about static and dynamic postural balance of ballet dancers, characterizing visual dependency in the postural control of these athletes to maintain balance. A review of literature was performed on PubMed, SciELO, Lilacs, and Science Direct databases considering the period between 1997 and 2013, and using the descriptors balance, postural control, force plates ballet dancers, classical ballet dancers and visual afferences. Eighteen articles were considered able to provide the quantitative and qualitative data to assess the balance among those athletes, and were thus, selected. These papers were classified by Oxford level of evidence. The reviewed literature shows full consensus regarding the effect of removing visual information over postural stability according to the experience of subjects considered highly trained dancers. Studies comparing the balance of ballet dancers to other sporting techniques confirmed that they have a specific postural balance pattern. Nevertheless, in association with visual restriction, ballet dancers show a greater center of pressure dislocation and instability compared to other sports, which suggests that they have higher visual dependence to maintain balance. Ballet dancers have better static balance compared to non-trained subjects and other types of athletes, but greater visual dependence to maintain balance.
BACKGROUND: Ballet is a high-performance activity that requires an advanced level of
technical skills. Ballet places great stress on tendons, muscles, bones, and
joints and may act directly as a trigger of injury by overuse. OBJECTIVES: 1) to describe the main types of injuries and affected areas related to classical
ballet and 2) to compare the frequency of musculoskeletal injuries among
professional and non-professional ballet dancers, considering possible gender
differences among the professional dancers. METHOD: A total of 110 questionnaires were answered by professional and non-professional
dancers. The questionnaire contained items related to the presence of injury, the
regions involved, and the mechanism of the injury. RESULTS: We observed a high frequency of musculoskeletal injuries, with ankle sprains
accounting for 69.8% of injuries in professional dancers and 42.1% in
non-professional dancers. Pirouettes were the most frequent mechanism of injury in
professional dancers, accounting for 67.9% of injuries, whereas in the
non-professional dancers, repetitive movement was the most common mechanism
(28.1%). Ankle sprains occurred in 90% of the women's injuries, and muscle sprains
occurred in 54.5% of the men's injuries. The most frequent injury location was the
ankle joint in both sexes among the professional dancers, with 67.6% in women and
40.9% in men. CONCLUSIONS: The identification of the mechanism of injury and time of practice may contribute
to better therapeutic action aimed at the proper function of the dancers' bodies
and improved performance by these athletes.
The objective of this study was to compare the electromyographic (EMG) activity of vastus medialis obliquus (VMO), vastus lateralis longus (VLL) and vastus lateralis oblíquus (VLO) during wall slide squat isometric exercises at 45° (WS 45°) and at 60° (WS 60°) of knee flexion. Fifteen healthy control women and fifteen women with patellofemoral pain syndrome (PPS) participated in this study. The EMG activity was registered during WS 45° and WS 60° performed at maximal isometric voluntary contraction (MIVC) using surface differential electrodes connected to an EMG system. The EMG signals were analyzed using the root mean square (RMS) values and were normalized by MIVC obtained at 75° of knee flexion. To compare data between groups and exercises, the ANOVAtwo-way and Duncan post hoc tests were applied (p < 0.05). The results demonstrated higher EMG activity for all muscles studied at WS 60° when compared to WS 45° in both control and PPS groups. There were not significant differences between muscles during WS 60° in the control group, although a higher activity of VLL in relation to VMO and VLO was observed during WS 45° in control group. For the PPS group, no statistical difference was observed between muscles during both exercises. Thus, strengthening programs using WS 60° could be more effective for healthy women; however, both exercises could be indicated for rehabilitation programs aimed at women with PPS. In addition, the absence of significant differences between muscles in PPS group verified in this study suggests that muscle unbalance could not be a predisposing factor for PPS in women.
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