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1.
The aim of this study was to assess changes in body morphology, anatomical alignment and prevalence of patellofemoral pain (PFP) in young female dancers along one year of pubertal growth, and to identify the risk factors related to PFP in these young dancers. Both legs of 60 dancers were evaluated during grade 7 and again after 1-year. At each of these points in time, the dancers were interviewed concerning their background, and anthropometric measurements, lower-limb physical examinations and knee ultrasound scans were performed. Morphological parameters changed significantly from baseline to follow-up. PFP was found in 53.3% of the dancers’ knees at baseline. At follow-up, 55.4% of the asymptomatic knees at baseline developed PFP, and only 9.4% of the symptomatic knees at baseline recovered. Lower BMI was identified among dancers who developed PFP during follow-up compared with dancers with no PFP, either at baseline or at follow-up. A positive grinding and positive Patellar Inhibition Test (PIT) were found to be risk factors for PFP at follow-up. A high prevalence of young dancers suffered PFP, from injuries they sustained mostly during the 1-year of dance practice. Parameters predisposing the dancers to PFP should be identified at early stages of dance class.  相似文献   

2.
ABSTRACT

Ankle injuries are highly prevalent in ballet, with strength highlighted as a primary risk factor. To profile ankle strength, fourteen female ballet dancers (age: 19.29 ± 1.59 years) completed an isokinetic testing protocol comprising concentric eversion (CONEV) and inversion (CONINV), and, eccentric inversion (ECCINV) trials at four angular velocities (30° · s?1, 60° · s?1, 90° · s?1, 120° · s?1) for both the dominant and non-dominant limb. In addition to Peak Torque (PT) and the corresponding Dynamic Control Ratios (DCRs), angle-specific derivatives of strength (AST) and Functional Range (FR) were calculated. There was no evidence of any significant bilateral strength asymmetry (p = 0.90) across all metrics, and no significant interactions with limb and contraction mode or velocity. A significant main effect for contraction mode (p = 0.001) highlighted greater ECCINV strength – which was maintained with increasing isokinetic velocity – in contrast to reductions in CONEV and CONINV strength. Specifically, dancers are ECCINV dominant at angular velocities greater than 60° · s?1, which is likely to be characteristic of most functional tasks. The lack of bilateral asymmetry may be attributed to dance training interventions that facilitate bilateral development, but ipsilateral mode and velocity-specific asymmetries have implications for injury risk and the training needs of female ballet dancers.  相似文献   

3.
Turns (pirouettes) are an important movement in ballet and may be affected by “lateral bias”. This study investigated physiological differences exhibited by experienced and novice dancers, respectively, when performing pirouette with dominant and non-dominant leg supports, respectively. Thirteen novice and 13 experienced dancers performed turns on dominant or non-dominant legs. The maximum ankle plantarflexion, knee extension and hip extension were measured during the single-leg support phase. The inclination angle of rotation axis is the angle between instantaneous rotation axis and global vertical axis in the early single-leg support phase. Both groups exhibited a greater hip extension, knee extension, and ankle plantarflexion when performing a turn on the non-dominant leg. For experienced dancers, the inclination angle of rotation axis during the pre-swing phase was generally smaller for dominant leg support than non-dominant leg. However, no significant difference was found in inclination angle of rotation axis of novice dancers. For experienced dancers, an improved performance is obtained when using the dominant leg for support. By contrast, for novice dancers, the performance is independent of choice of support leg. The significant lateral bias in experienced dancers indicates the possible influence of training. That is, repetitive rehearsal on the preferred leg strengthens the impact of side dominance in experienced dancers.  相似文献   

4.
In the present study, we tried to determine the association between joint ranges of motion, anatomical anomalies, body structure, dance discipline, and injuries in young female recreational dancers. A group of 1336 non-professional female dancers (age 8-16 years), were screened. The risk factors considered for injuries were: range of motion, body structure, anatomical anomalies, dance technique, and dance discipline. Sixty-one different types of injuries and symptoms were identified and later classified into four major categories: knee injuries, foot or ankle tendinopathy, back injuries, and non-categorized injuries. We found that 569 (42.6%) out of the 1336 screened dancers, were injured.The following factors were found to be associated with injuries (P < 0.05): (a) range of motion (e.g. dancers with hyper hip abduction are more prone to foot or ankle tendinopathies than dancers with hypo range of motion; (b) anatomical anomalies (scoliotic dancers manifested a higher rate of injuries than non-scoliotic dancers); (c) dance technique (dancers with incorrect technique of rolling-in were found to have more injuries than dancers with correct technique); (d) dance discipline (an association between time of practice en pointe and injury was observed); and (e) early age of onset of menarche decreased risk for an injury. No association between body structure and injury was found. Injuries among recreational dancers should not be overlooked, and therefore precautionary steps should be taken to reduce the risk of injury, such as screening for joint range of motion and anatomical anomalies. Certain dance positions (e.g. en pointe) should be practised only when the dancer has already acquired certain physical skills, and these practices should be time controlled.  相似文献   

5.
Whilst the measurement and quantification of vertical leg stiffness (Kvert) asymmetry is of important practical relevance to athletic performance, literature investigating bilateral asymmetry in Kvert is limited. Moreover, how the type of task used to assess Kvert may affect the expression of asymmetry has not been properly determined. Twelve healthy males performed three types of performance tasks on a dual force plate system to determine Kvert asymmetries; the tasks were (a) bilateral hopping, (b) bilateral drop jumping and (c) unilateral drop jumping. Across all the three methods, Kvert was significantly different between compliant and stiff limbs (P < 0.001) with a significant interaction effect between limb and method (P = 0.005). Differences in Kvert between compliant and stiff limbs were ?5.3% (P < 0.001), ?21.8% (P = 0.007) and ?15.1% (P < 0.001) for the bilateral hopping, bilateral drop jumping and unilateral drop jumping methods, respectively. All the three methods were able to detect significant differences between compliant and stiff limbs, and could be used as a diagnostic tool to assess Kvert asymmetry. Drop jumping tasks detected larger Kvert asymmetries than hopping, suggesting that asymmetries may be expressed to a greater extent in acyclic, maximal performance tasks.  相似文献   

6.
With the aim of determining both the acute and the chronic effects of textured insoles on the ankle discrimination and performance ability of dancers, 60 ballet dancers from the Australian Ballet School, aged 14–19 years, were divided into three groups (two intervention groups and a control group), age- and level-matched. In the first 5 weeks (weeks 1 to 5), the first intervention group (GRP1) was asked to wear textured insoles in their ballet shoes and the second intervention group (GRP2) was not given textured insoles to wear. In the next 5 weeks (weeks 6 to 10), GRP2 was asked to wear the same type of textured insoles and GRP1 did not wear the textured insoles. The control group (CTRL) did not wear textured insoles during the whole 10 weeks. All participants were tested preintervention, after 5 weeks and after 10 weeks for ankle discrimination score (AUC scores). Dance performance was assessed by 5–7 dance teachers. Pre-to-post change in AUC scores was significantly greater for the groups wearing insoles than for the controls (P = .046) and the size of pre-to-post changes did not differ between the two intervention groups (P = .834). Significant correlation was found between ankle discrimination score and performance scores, using the textured insoles (r = .412; P = .024). In conclusion, the stimulation to the proprioceptive system arising from textured insoles worn for five weeks was sufficient to improve the proprioceptive ability and performance ability of ballet dancers.  相似文献   

7.
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8.
Ballerinas use their ankle joints more extremely and sustain injuries on the ankle joint more frequently than non-dancers. Therefore, the ankle movement of dancers is important and should be studied to prevent injuries. Measuring ankle joint range of motion (ROM) using radiographs could demonstrate the contribution to motion of each joint. The aim of this study was to analyse and compare ankle joint movements and the ratio of each joint’s contribution during movement between dancers and non-dancers, using radiographic images. Dancers have lower dorsiflexion (26.7 ± 6.2°), higher plantarflexion (74.3 ± 7.1°) and higher total (101.1 ± 10.8°) ROMs than non-dancers (33.9 ± 7.0°, 57.2 ± 6.8° and 91.1 ± 9.3°, respectively) (p < 0.05). Although the ROMs were different between the two groups, the ratios of each joint movement were similar between these two groups, in all movements. Regarding total movement, the movement ratio of the talocrural joint was almost 70% and other joints accounted for almost 30% of the movement role in both dancers and non-dancers. Therefore, the differences in ROM between dancers and non-dancers were not a result of a specific joint movement but of all the relevant joints’ collaborative movement.  相似文献   

9.
BackgroundAnkle complex proprioceptive ability, needed in active human movement, may change from childhood to elderly adulthood; however, its development across all life stages has remained unexamined. The aim of the present study was to investigate the across-the-lifespan trend for proprioceptive ability of the ankle complex during active ankle inversion movement.MethodsThe right ankles of 118 healthy right-handed participants in 6 groups were assessed: children (6–8 years old), adolescents (13–15 years old), young adults (18–25 years old), middle-aged adults (35–50 years old), old adults (60–74 years old), and very old adults (75–90 years old). While the participants were standing, their ankle complex proprioception was measured using the Active Movement Extent Discrimination Apparatus.ResultsThere was no significant interaction between the effects of age group and gender on ankle proprioceptive acuity (F (5, 106) = 0.593, p = 0.705, η2p = 0.027). Simple main effects analysis showed that there was a significant main effect for age group (F (5, 106) = 22.521, p < 0.001, η2p = 0.515) but no significant main effect for gender (F (1,106) = 2.283, p = 0.134, η2p = 0.021) between the female (0.723 ± 0.092, mean ± SD) and the male (0.712 ± 0.083) participants. The age-group factor was associated with a significant linear downward trend in scores (F (1, 106) = 10.584, p = 0.002, η2p = 0.091) and a strong quadratic trend component (F (1,106) = 100.701, p < 0.001, η2p = 0.480), producing an asymmetric inverted-U function.ConclusionThe test method of the Active Movement Extent Discrimination Apparatus is sensitive to age differences in ankle complex proprioception. For proprioception of the ankle complex, young adults had significantly better scores than children, adolescents, old adults, and very old adults. The middle-aged group had levels of ankle proprioceptive acuity similar to those of the young adults. The scores for males and females were not significantly different. Examination of the range of the scores in each age group highlights the possible level that ankle complex movement proprioceptive rehabilitation can reach, especially for those 75–90 years of age.  相似文献   

10.
Abstract

The aim of this study was to compare the bone mineral density (BMD) of young dancers suspected of suffering from the female athlete triad syndrome and eumenorrhoeic/normal weight dancers with eumenorrhoeic non-exercising controls. Full-time dance students from a collegiate academy of performing arts were recruited. The female athlete triad syndrome was suspected when oligo/amenorrhoea was present together with underweight (body mass index below 18.5 kg · m?2). The non-exercising group consisted of eumenorrhoeic age-matched patients presenting to an adolescent gynaecology clinic. All participants had a full hormonal profile, pelvic ultrasound, bio-impedance estimation of body fat, together with dual energy X-ray absorptiometry (DXA) and quantitative peripheral computed tomography scans (pQCT) to determine bone mineral density. A total of 47 dancers aged 17–20 years were recruited, of whom 14 (29.7%) fell within the criteria for suspected female athlete triad syndrome. Comparing the dancers with suspected female athlete triad with 36 non-exercising controls showed no significant differences in BMD at most sites between the two groups. Comparing the normal dancers (n=33) with the same control group showed the dancers had significantly higher BMD at the hip sites (P<0.005), as well as higher core tibial volumetric BMD (P=0.04) than the controls. Young dancers with oligo/amenorrhoea and apparent under-nutrition that fitted the clinical diagnosis of female athlete triad syndrome did not have lower BMD than non-exercising eumenorrhoeic controls, while eumenorrhoeic dancers actually had higher BMD. In addition, no significant differences were seen between eumenorrhoeic dancers and those with suspected female athlete triad. The risk of osteoporosis was apparently offset by the benefits of regular intensive weight-bearing exercises in those participants with suspected female athlete triad.  相似文献   

11.
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12.
PurposeThis study aimed to (a) investigate the proportion of overweight/obesity in a cohort of young adults with patellofemoral pain (PFP) and (b) explore the association of body mass index (BMI), body fat, and lean mass with functional capacity and hip and knee strength in people with PFP.MethodsWe included a mixed-sex sample of young adults (18−35 years old) with PFP (n = 100). Measurements for BMI, percentage of body fat, and lean mass (assessed by bioelectrical impedance) were obtained. Functional capacity was assessed by the Anterior Knee Pain Scale, plank test, and single-leg hop test. Strength of the knee extensors, knee flexors, and hip abductors was evaluated isometrically using an isokinetic dynamometer. The proportion of overweight/obesity was calculated based on BMI. The association between BMI, body fat, and lean mass and functional capacity and strength was investigated using partial correlations, followed by hierarchical regression analysis, adjusted for covariates (sex, bilateral pain, and current pain level).ResultsA total of 38% of our cohort had their BMI categorized as overweight/obese. Higher BMI was associated with poor functional capacity (ΔR2 = 0.06−0.12, p ≤ 0.001) and with knee flexion strength only (ΔR2 = 0.04, p = 0.030). Higher body fat was associated with poor functional capacity (ΔR2 = 0.05−0.15, p ≤ 0.015) and reduced strength (ΔR2 = 0.15−0.23, p < 0.001). Lower lean mass was associated with poor functional capacity (ΔR2 = 0.04−0.13, p ≤ 0.032) and reduced strength (ΔR2 = 0.29− 0.31, p < 0.001).ConclusionBMI, body fat, and lean mass should be considered in the assessment and management of young people with PFP because it may be detrimental to function and strength.  相似文献   

13.
Abstract

The purpose of this study was to determine the presence of the bilateral deficit both as a function of overall and individual joint power. Most studies addressing the deficit have assessed force; however, in most sporting events maximal power is more important than maximal force production. To address this, in the current study we assessed the bilateral deficit for multi-joint movements as measured by overall lower extremity and individual joint power. We assessed power production using an isokinetic machine permitting both unilateral and bilateral leg extensions. Several significant effects and interactions between the contraction type (unilateral, bilateral, alternating unilateral), side of the body, lower extremity joint, and percentage of a 1-RM load were revealed. All interactions were between the lower extremity joints (hip, knee, ankle) and involved the contraction protocol (P=0.001), the percentage of 1-RM load (P=0.0002), and the side of the body (P=0.0003). Taken together, the results indicate that the bilateral deficit is manifested using a measure of power, but more importantly, the deficit has differential implications based on the overall resistance, and various joints involved in the movement. In conclusion, a reduction in power generation was evidenced for both simultaneous contractions of the leg extensors as well as reciprocal contractions. With reduced contributions from the knee joint during bilateral and reciprocal contractions, combined with past research demonstrating differential activation of mono-articular knee joint muscles, evidence for reduced contributions from the peripheral nervous system are suggested based on the results of this study.  相似文献   

14.
We studied differences in physical activity (PA), sedentary behaviour (SB), and the types of PA and SB between Finnish girls and boys and children from different socioeconomic backgrounds (SES). We assessed PA, SB, parental education, and household income using detailed questionnaires in a representative population sample of 486 children (238 girls, 248 boys) aged 6–8 years. Girls spent on average 1.7 h/day and boys 2.0 h/day in total PA (p?=?0.002). Altogether 66% of girls and 54% of boys had less than 2 h of total PA per day (p?=?0.012). Girls had lower levels of unsupervised PA (45 vs. 54 min/day, p?=?0.001), supervised PA (1.5 vs. 1.9 h/week, p?=?0.009), and PA during school recess (1.8 vs. 1.9 h/week, p?=?0.032) than boys. Girls had higher levels of total SB (3.8 vs. 3.4 h/day, p?=?0.015) but lower levels of screen-based SB (1.5 vs. 1.9 h/day, p?<?0.001) than boys. Lower parental education and household income were associated with lower levels of supervised PA in girls (p?=?0.011 and p?=?0.008, respectively) and in boys (p?=?0.006 and p?=?0.003, respectively). Lower parental education and household income were also related to higher levels of screen-based SB in boys (p?=?0.005 and p?<?0.001, respectively) but not in girls. Girls have lower levels of total, unsupervised, and supervised PA, PA during recess, and screen-based SB but higher levels of total SB than boys. Lower parental education and household income are associated with lower levels of supervised PA in both genders and higher levels of screen-based SB in boys.  相似文献   

15.
The influence of a 12-week-proprioceptive training on functional ankle stability was investigated in young speed skaters. Twenty-eight speed skaters were randomly divided into an intervention (n = 14) and into a control group (n = 14). A 15-min circle training was performed 5 times per week over a 12-week period. Measurements were taken prior to the training, after 6 and 12 weeks of training. Kinaesthesia was evaluated with the Isomed2000 in all movements of the ankle joint. Dynamic balance was tested with the Biodex Stability System at the stable level 8 and at the unstable level 2, measuring the overall stability index, the anterior/posterior and the medial/lateral scores. Static single-leg stance was evaluated using the Kistler force platform. Kinaesthesia of the intervention group improved significantly for plantarflexion of the right foot (P = 0.001) after 12 weeks. Dynamic balance showed significant differences in the intervention group after 12 weeks in comparison with the first measurement for each foot in the overall stability index, the anterior/posterior and the medial/lateral scores (P ≤ 0.017, respectively) at the unstable level 2. Functional ankle stability improved in terms of dynamic balance after 12 weeks of proprioceptive training. Therefore, inclusion of proprioceptive exercises in the daily training programme is recommended for young speed skaters.  相似文献   

16.
Abstract

To determine if unilateral measures of muscle architecture in the rectus femoris (RF) and vastus lateralis (VL) were related to (and predictive of) sprinting speed and unilateral (and bilateral) force (FRC) and power (POW) during a 30 s maximal sprint on the Woodway Curve 3.0TM non-motorized treadmill (TM). Twenty-eight healthy, physically active men (n = 14) and women (n = 14) (age = 22.9 ± 2.4 years; body mass = 77.1 ± 16.2 kg; height = 171.6 ± 11.2 cm; body-fa t = 19.4 ± 8.1%) completed one familiarization and one 30-s maximal sprint on the TM to obtain maximal sprinting speed, POW and FRC. Muscle thickness (MT), cross-sectional area (CSA) and echo intensity (ECHO) of the RF and VL in the dominant (DOM; determined by unilateral sprinting power) and non-dominant (ND) legs were measured via ultrasound. Pearson correlations indicated several significant (p < 0.05) relationships between sprinting performance [POW (peak, DOM and ND), FRC (peak, DOM, ND) and sprinting time] and muscle architecture. Stepwise regression indicated that POWDOM was predictive of ipsilateral RF (MT and CSA) and VL (CSA and ECHO), while POWND was predictive of ipsilateral RF (MT and CSA) and VL (CSA); sprinting power/force asymmetry was not predictive of architecture asymmetry. Sprinting time was best predicted by peak power and peak force, though muscle quality (ECHO) and the bilateral percent difference in VL (CSA) were strong architectural predictors. Muscle architecture is related to (and predictive of) TM sprinting performance, while unilateral POW is predictive of ipsilateral architecture. However, the extent to which architecture and other factors (i.e. neuromuscular control and sprinting technique) affect TM performance remains unknown.  相似文献   

17.
Change of direction speed (CODS) underpins performance in a wide range of sports but little is known about how stiffness and asymmetries affect CODS. Eighteen healthy males performed unilateral drop jumps to determine vertical, ankle, knee and hip stiffness, and a CODS test to evaluate left and right leg cutting performance during which ground reaction force data were sampled. A step-wise regression analysis was performed to ascertain the determinants of CODS time. A two-variable regression model explained 63% (R2 = 0.63; P = 0.001) of CODS performance. The model included the mean vertical stiffness and jump height asymmetry determined during the drop jump. Faster athletes (n = 9) exhibited greater vertical stiffness (F = 12.40; P = 0.001) and less asymmetry in drop jump height (F = 6.02; P = 0.026) than slower athletes (n = 9); effect sizes were both “large” in magnitude. Results suggest that overall vertical stiffness and drop jump height asymmetry are the strongest predictors of CODS in a healthy, non-athletic population.  相似文献   

18.
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19.
ABSTRACT

Previous studies have been limited to describe asymmetries during pedalling and suggest possible repercussion on performance and/or injury risks. However, few studies have presented strategies to mitigate asymmetries. The purpose of this study was to assess the effectiveness of a pedalling retraining intervention to reduce bilateral pedal force asymmetries. Twenty cyclists were assessed and 10 enrolled in a pedalling retraining method receiving visual and verbal feedback of pedal forces. The asymmetry index was computed for comparison of bilateral peak pedal forces and used during retraining (12 trials at 70% of peak power). Significantly larger asymmetry was observed for asymmetrical cyclists at the first three trials (P < 0.01 and ES = 1.39), which was reduced when post-retraining was compared to measures from symmetrical cyclists (P = 0.69 and ES = 0.18). Cyclists with larger asymmetry (>20%) in bilateral pedal forces reduce their asymmetries using sessions of pedalling retraining and achieve asymmetry indices similar to symmetrical cyclists.  相似文献   

20.
BackgroundAcute ankle injury causes damage to joint mechanoreceptors and deafferentation and contributes to proprioception deficits in patients with chronic ankle instability (CAI). We aimed to explore whether deficits of proprioception, including kinesthesia and joint position sense (JPS), exist in patients with CAI when compared with the uninjured contralateral side and healthy people. We hypothesized that proprioception deficits did exist in patients with CAI and that the deficits varied by test methodologies.MethodsThe study was a systematic review and meta-analysis. We identified studies that compared kinesthesia or JPS in patients with CAI with the uninjured contralateral side or with healthy controls. Meta-analyses were conducted for the studies with similar test procedures, and narrative syntheses were undertaken for the rest.ResultsA total of 7731 studies were identified, of which 30 were included for review. A total of 21 studies were eligible for meta-analysis. Compared with the contralateral side, patients with CAI had ankle kinesthesia deficits in inversion and plantarflexion, with a standardized mean difference (SMD) of 0.41 and 0.92, respectively, and active and passive JPS deficits in inversion (SMD = 0.92 and 0.72, respectively). Compared with healthy people, patients with CAI had ankle kinesthesia deficits in inversion and eversion (SMD = 0.64 and 0.76, respectively), and active JPS deficits in inversion and eversion (SMD = 1.00 and 4.82, respectively). Proprioception deficits in the knee and shoulder of patients with CAI were not statistically significant.ConclusionProprioception, including both kinesthesia and JPS, of the injured ankle of patients with CAI was impaired, compared with the uninjured contralateral limbs and healthy people. Proprioception varied depending on different movement directions and test methodologies. The use of more detailed measurements of proprioception and interventions for restoring the deficits are recommended in the clinical management of CAI.  相似文献   

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