Patellofemoral pain and musculoskeletal features in young pre- and post-pubertal female dancers.

The aim of this study was to examine associations between patellofemoral pain (PFP) and musculoskeletal features (such as tendon structure and bone properties) in young (pre- and post-pubertal) female dancers. A total of 49 dancers participated in this study (mean age 13.6 ± 2.9; weight 47.0 ± 13.2; height 153.7 ± 12.9 and body mass index (BMI) 19.4 ± 3.1) and were assessed for the following factors: dance background and Tanner stage through interviews; ultrasonography assessments of bone properties and patellar tendon structure through ultrasonographic tissue characterization and quantitative ultrasound, respectively; and anthropometric measurements, muscle strength, range of motion (ROM), hypermobility and PFP through physical examinations. PFP was found in 49% of the participants. Post-pubertal dancers with no-PFP were found to have greater muscle strength, greater radial and tibial properties, and better tendon structure compared to pre-pubertal dancers with PFP and compared to pre-pubertal dancers with no-PFP [F(2, 41) = 18.64, p < .001; F(2, 41) = 20.46, p < .001; F(2, 41) = 33.06, p < .001; and, F(2, 41) = 6.02, p = .007, respectively]. Logistic regression showed that tibial bone properties and range of movement (ROM) in hip external rotation were significantly associated with PFP [odds ratio (OR) = .889 and OR = 2.653, respectively; Cox & Snell R2 = .701]. The study revealed a high prevalence of PFP among young dancers, with low bone properties and hyperjoint ROM emerging as the main factors that are related to PFP. These findings should be addressed by medical teams, athletic trainers, and dance teachers regarding the need for implementing modifications to dance training programmes and injury-prevention strategies in young pre-pubertal dancers.

Is there an association between joint range of motion and muscle strength in young female dancers? And, does it depend on the effects of age and menarche?

Aiming to determine the association between joint range of motion (ROM) and muscle strength; and, the effect of age and menarche on those two factors; 132 pre-and post-menarche dancers, aged 12-14 years were assessed for joint ROM and for muscle strength at the hip, knee and ankle and foot joints. En-pointe ROM was significantly correlated with ankle plantar-flexors' (r = -.184) and with ankle dorsiflexors' muscle strength (r = -.221). Hip external rotation ROM was significantly correlated with knee extensors' strength (r = -.263). Pre-menarche dancers had higher joint ROM compared with post-menarche dancers; yet, dancers at post-menarche were stronger compared to dancers at pre-menarche. The slope coefficient was negative at the age of 12 in hip external rotation and in en-pointe (-0.80 and -0.52, respectively) and became steeper with age (age 13: -3.52 and -3.28, respectively; age 14: -6.31 and -4.42, respectively). Along maturation, dancers with high joints ROM showed reduced muscle strength. Pre-menarche dancers have higher joint ROM, yet reduced muscle strength, compared with post-menarche dancers. As the association between joint ROM and muscle strength might be involved with growth and development, young dancers should be screened along pubertal stages in order to decide the correct curricula and to prevent future injuries.

Minimizing treatment complexity of combat-related soft tissue injuries using a dedicated tension relief system and negative pressure therapy augmented by high-dose in situ antibiotic therapy and oxygen delivery: a retrospective study.

BACKGROUND: Following combat-related, extensive soft tissue injury from gunshot wounds or blasts, prolonged duration from injury to full wound closure is associated with infection, increased morbidity and mortality, failure to mobilize, poor functional outcome and increased cost. The purpose of this study was to evaluate a novel treatment enabling early primary closure of combat wounds. METHODS: This was a retrospective study of 10 soldiers and civilians with extensive combat-related soft tissue limb injuries (5 gunshot wounds, 5 blasts) treated using the TopClosure® Tension Relief System (TRS) with simultaneous administration of regulated oxygen-enriched and irrigation negative pressure-assisted wound therapy (ROINPT) via the Vcare α® device. RESULTS: Nine patients were treated during the acute phase of injury and one was treated following removal of a flap due to deep infection 20 years after injury and flap reconstruction. Two patients had upper limb injury and the rest lower limb injury. With the aid of the TRS and/or ROINPT, immediate primary closure during reconstruction was achieved in 6 patients and delayed primary closure in three. Only one patient required a skin graft to close a small area of the wound after most of the wound had been closed by delayed primary closure. Wound closure was achieved within 0-37 days (median: 12.5 days, interquartile range: 2.75-19.75) from injury. CONCLUSIONS: The TRS is a novel device for effective, early skin stretching and secure wound closure through the application of stress relaxation and mechanical creep, achieving primary closure of large defects using a simplified surgical technique and reducing the need for closure using skin grafts and flaps and the use of tissue expanders. Delivering supplemental oxygen to the wound by ROINPT reverses the reduced oxygen levels inherent in conventional negative pressure-assisted wound therapy, mitigating anaerobic contamination and reducing infection. Irrigation may accelerate the evacuation of infectious material from the wound and provide a novel method for antibiotic administration. The combination of TRS and ROINPT devices allow for early primary closure with improved functionality of combat-related limb injuries.

Generalized joint hypermobility, scoliosis, patellofemoral pain, and physical abilities in young dancers.

BACKGROUND: Many young girls with generalized joint hypermobility (GJH) choose to participate in dance because their bodies are suited for this activity. Scoliosis tends to occur often in thin girls, who also are more likely to choose dance. Both anomalies (GJH and scoliosis) may be related to reduced abilities such as diminished strength and insufficient postural balance, with increased risk for musculoskeletal conditions. The main objectives of the present study were to determine the prevalence of dancers with GJH, the prevalence of dancers with scoliosis, and the prevalence of dancers with these two anomalies; and, to determine differences in physical abilities and the presence of patellofemoral pain (PFP) between young female dancers with and without such anomalies. METHODS: One hundred thirty-two female dancers, aged 12-14 years, were assessed for anthropometric parameters, GJH, scoliosis, knee muscle strength, postural balance, proprioception ability, and PFP. RESULTS: GJH was identified in 54 dancers (40.9%) and scoliosis in 38 dancers (28.8%). Significant differences were found in the proportion of dancers with no anomalies (74 dancers, 56.1%) and dancers with both anomalies (34 dancers, 25.8%) (p < .001). Dancers with both anomalies had reduced dynamic postural balance in the anterior direction (p = .023), reduced proprioception ability (p < .001), and weaker knee extensors (p = .036) and flexors (p = .040) compared with dancers with no anomalies. Among dancers with both anomalies, 73.5% suffered bilateral PFP, 17.6% suffered unilateral PFP, and 8.8% had no PFP (p < .001). CONCLUSIONS: A high prevalence of young girls participating in dance classes had GJH, as the increased joint flexibility probably provides them with some esthetic advantages. The high prevalence of scoliosis found in these young dancers might be attributed to their relatively low body mass, their delayed maturation, and the selection process of dancers. Dancers with both GJH and scoliosis had decreased muscle strength, reduced postural balance, reduced proprioception, with higher risk of PFP. The main clinical implications are the need to reduce the risk of PFP among dancers by developing appropriate strength and stabilizing exercises combined with proprioceptive and postural balance training, to improve the correct alignment of the hyperextended and hypermobile joints, and to improve their supporting muscle strength.

Unilateral and bilateral patellofemoral pain in young female dancers: Associated factors.

Aiming to evaluate the prevalence of unilateral/bilateral patellofemoral pain (PFP) among young dancers, and to investigate whether different factors are associated with PFP in young dancers, 132 dancers aged 12-14 years were assessed for PFP. Anthropometric parameters, proprioception ability, dynamic postural balance (DPB), and muscle strength were measured. PFP was found in 64.1% of the dancers. No significant differences in the prevalence of dancers with no, unilateral, or bilateral PFP at different ages were found. Significant age effects were found for anthropometric and developmental measurements, and for intensity of training. PFP effect was found for DPB asymmetry, ankle proprioception, and leg-length %height. A higher hip abductor/adductor ratio was associated with PFP in 14-year-old dancers. Binomial logistic regression showed that increased number of hours per day (h/day) and decreased number of hours per week (h/week), low proprioception scores, greater leg length as %height, and more anterior DPB asymmetry were significant predictors of PFP. In conclusion: unilateral/bilateral PFP is common among young dancers. Body morphology, reduced ankle proprioception ability, DPB asymmetry, and increased h/day of practice are associated with PFP. Dance teachers should start monitoring the impact of training and implement injury modification/prevention strategies when their students are at a young age.

Isometric exercises and somatosensory training as intervention programmes for patellofemoral pain in young dancers.

Patellofemoral pain (PPF) is a common problem experienced by young dancers. Currently, there is no clear indication as to the optimal intervention programme for reducing the level of pain and improving functional abilities in young dancers with PFP. Our aim was to examine the efficacy of two intervention programmes compared with controls in relation to PFP symptoms (shown by pain level, Grinding test, and patellar inhibition test-PIT) and functional abilities of dancers with PFP. Ninety-eight young dancers (mean age 13.4 ± .97) with PFP were assessed for clinical parameters and functional abilities pre and post an intervention programme lasting 12 weeks. Using cluster sampling controlling for grade and school, the dancers were divided into three groups: isometric exercises (IE), somatosensory training (ST), and control (CO). Post-intervention, significantly lower pain levels upon patellar provocation testing were reported for the two treatment groups compared with controls. There was a significantly lower rate of legs recovered in the CO group compared with both intervention groups on the Grinding test, and on the PIT. Postural balance ability and proprioception abilities were significantly better post-treatment for the two treatment groups compared with controls. A significant interaction showed that hip abduction muscle strength improved more in the IE group. In conclusion, both isometric exercises and somatosensory training were effective for decreasing clinical symptoms and improving some functional abilities in young dancers with PFP. Further studies on these types of interventions could determine the most effective training protocol for prevention and treatment of PFP in young dancers.

Patellofemoral pain, body morphology and alignment in female pubertal dancers: One-year follow-up.

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.

Fall incidence and associated risk factors among people with a lower limb amputation during various stages of recovery - a systematic review.

Purpose: The objective of this study was to estimate fall incidence and describe associated risk factors among people with a lower limb amputation (LLA) during various stages of recovery: the surgical ward, in-patient rehabilitation and return to community life. Materials and methods: A systematic search of relevant English language articles was performed using PubMed and EMBASE. Out of 310 initial "hits," six retrospective cohort studies, one prospective cohort study and eleven cross-sectional studies from which fall incidence and risk factors could be extracted, were selected for critical review. Fall incidence and associated risk factors were extracted and analyzed in the context of various clinical stages of recovery after amputation. The studies were evaluated for quality using the "Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies." Results: Results showed that during all stages of recovery, people with a LLA are at increased risk of falling compared with able-bodied individuals, as well as other clinical populations. Each stage of recovery is associated with different fall risk factors. The current review is limited mainly by the paucity of studies on the topic. Conclusions: Specialised care focusing on the most relevant risk factors for each stage of recovery may enhance fall prevention during post-fall recovery. Implications for rehabilitation •  People with a lower limb amputation are at a high risk of falling in all stages of their clinical course.     •  Health professionals should be aware that people with a lower limb amputation in the first 4 years ofamputation or with four or more health-related problems are at an increased risk.   â€¢  Health professionals should also be aware that increased gait variability, excess confidence in balance andwalking abilities and less cautious stair walking, impose an elevated risk of falling and should focus theirefforts in reducing these factors.

The association between menarche, intensity of training and passive joint ROM in young pre-professional female dancers: A longitudinal follow-up study.

OBJECTIVES: To determine the association between the status of menarche (yes/no), the intensity of training and the potential to improve passive joint range of motion (ROM) over a 12-month period of dance training. DESIGN: Prospective cohort study. SETTING: Dance studio. PARTICIPANTS: Fifty-nine female dancers aged 12.8 ±â€¯0.5. MAIN OUTCOME MEASURES: The dancers were asked about their dance intensity and screened for anthropometric parameters and passive joint ROM in Grades 7 and 8. RESULTS: Along the 12 months of dance training, we found significantly increased ankle-foot en-pointe, hip abduction, and hip external rotation (ER); significantly decreased hip internal rotation (IR); and significant increased hip ER:IR ratio. In Grade 7, 26 dancers (44.1%) reached menarche (Yes menarche); in Grade 8 an additional 23 dancers (39.0%) reached menarche (No/Yes menarche); and 10 dancers (16.9%) had not reached menarche (No menarche). MANOVA (mixed models) with repeated measures to compare joint ROM between the three menarche groups (Yes; No/Yes; No), with h/week dance practice as a co-variant, showed that hip ER, ankle-foot en-pointe, and ER:IR were significantly correlated with h/week in all three menarche groups. CONCLUSIONS: Most passive joint ROM can be improved over 12 months of dancing around the age onset of menarche. H/week of dance practice is a main factor contributing to improved hip ER, ankle-foot en-pointe and ER/IR ratio.

Ultrasonography and clinical examination of knee injuries in pre- and post- menarche dancers.

This study aimed at evaluating whether the prevalence of knee injuries and morphological features are different among pre-and-post menarche dancers; Sixty-seven pre-and-post menarche dancers were screened for anthropometric parameters; knee laxity; patella femoral pain syndrome (PFPS), pathologies and anatomical structure of the knees. Both groups showed a high and similar prevalence of PFPS. The post-menarche dancers produced a significantly higher rate of Tanner stages 3-4 (p = .010), greater weight (p < .001) higher BMI (p = .003); and, higher prevalence of MCL pathology, pes planus, and scoliosis compared with pre-menarche dancers (p < .05). The pre-menarche dancers started dance practice earlier (p = .008); and, showed significantly higher prevalence of lateral laxity, patellar laxity, positive Lachman test and positive Drawer test compared with post-menarche dancers (p < .05). Interactions (menarche yes/no by PFPS no/one leg/both legs) were found for BMI (p = .044; η2 = .187), trochlear cartilage thickness (p = .020; η2 = 0.121) and tip of patella - trochlear groove distance (p = .024; η2 = .150). Pre-and-post-menarche female dancers demonstrated similar prevalence of knee injuries, with different body morphology.

Ultrasonography findings and physical examination outcomes in dancers with and without patellofemoral pain.

OBJECTIVES: To identify whether a physical examination for patello-femoral pain (PFP) is related to ultrasonography findings at the knee, and to identify possible factors related to PFP in young dancers. METHODS: Sixty-seven young female dancers (7th grade, aged 12.8 ± 0.5) from three schools with identical special dance programs were included in the study. All the dancers were interviewed for demographic details, dance background, and training intensity; were evaluated for anthropometric measurements; underwent physical examination of both knees for PFP and for knee range of motion (ROM); and, had ultrasonography assessment for pathologies and of anatomical parts of their knees. RESULTS: PFP was found in 54.5% of the 134 knees physically examined. In ultrasonography assessment, infra-articular effusion was found in 46.2% of the knees examined. H/week of dance practice was significantly higher among dancers with PFP (in both knees) compared with dancers with no PFP (p < .05). Knees with PFP had a significantly higher prevalence of intra articular effusion (p = .018) and higher prevalence of genu-recurvatum (p = .042). Knees with PFP had significantly greater growth plate width-anterior tibial tuberosity (p = .022) and a greater bony trochlear groove angle (p = .048). CONCLUSION: This study describes the relationship between physical examination for PFP and the sonographic findings, and the factors related to knee injuries. The results showed a high prevalence of PFP and intra articular knee effusion among young dancers at the age of 12-13 years; and, that the number of hours of practice and anatomical structure are related to PFP. Our results should alert physicians, physiotherapists, athletic trainers and dance teachers to the need for devising modifications of training and injury prevention strategies from a young age (<12 years old).

Lower extremity and spine characteristics in young dancers with and without patellofemoral pain.

Very little is known about patellofemoral pain syndrome (PPFS) among young dancers. Understanding the mechanism of the injury and implementing a preventative programme are important in order to minimize the risk of PFPS. The aim of the current study is to determine the extent to which factors such as lower extremity and back characteristics are common among dancers with PFPS. The study population included 271 dancers with PFPS and 271 non-injured dancers, aged 10-16 years. All dancers were screened for morphometric profile, dance discipline (h/week), anatomical anomalies (present/absent of scoliosis, genu valgus/varum, etc.), and joint range of motion (measured by goniometer at the hip, knee, ankle, foot, and spinal joints). The predicting factors for PFPS among young dancers (10-11 years old) were: hyper hip abduction (OR = 0.906) and lower back and hamstring flexibility (OR = 3.542); for adolescent dancers (12-14 years old): hyper ankle dorsiflexion (OR = 0.888), hind foot-varum (OR = 0.260), and mobility of patella (OR = 2.666); and, for pre-mature dancers (15-16 years old): scoliosis (OR = 5.209), limited ankle plantar-flexion (OR = 1.060), and limited hip internal rotation (OR = 1.063). In conclusion, extrinsic and intrinsic parameters predisposing the dancers to knee injuries should be identified by screening in early stages of dance classes.

Psychometric properties of the Hebrew version of the Oswestry Disability Index.

BACKGROUND: Low back pain (LBP) is one of the most common health complaints, with lifetime prevalence rates as high as 84%. The Oswestry Disability Index (ODI) is often the measure of choice for LBP in both research and clinical settings and, as such, has been translated into 29 languages and dialects. Currently, however, there is no validated version of Hebrew-translated ODI (ODI-H). OBJECTIVE: To examine the psychometric properties of the ODI-H. METHODS: Cross-culturally appropriate translation into Hebrew was conducted. A convenience sample of 115 participants (Case Group) with LBP and 68 without LBP (Control Group) completed the ODI-H, SF-36 Health Survey, and two Visual Analog Scales (VAS). RESULTS: Internal consistency was α = 0.94 and test-retest reliability for 18 participants repeating the ODI-H was 0.97. No floor or ceiling effects were noted for Cases, although there was a floor effect for the Control Group. Scores were significantly different for the two groups, indicating discriminant validity. Concurrent validity was reflected by significant correlations with SF-36 scores, particularly the Physical Functioning and Bodily Pain subscales (-0.83 and -0.79, respectively) and with the VAS (0.84 and 0.79). CONCLUSIONS: The ODI-H is a valid and reliable measure of low back pain-related disability for the Hebrew-speaking public.

Joint Hypermobility and Joint Range of Motion in Young Dancers.

BACKGROUND: Joint range of motion (ROM) refers to the extent of movement of the joint, recorded using standard goniometers. Joint hypermobility (JHM) is a condition in which most of the synovial joints move beyond the "normal" limits. Joint hypermobility is recognized as a feature of heritable disorders of the connective tissue and can be identified mostly by the Beighton scale. Data on the possible relationship between JHM and joint ROM are lacking in the literature. The main objective of the present study was to evaluate the relationship between JHM and joint ROM in the different lower-extremity joints in young dancers. METHODS: Joint hypermobility and ROM were assessed among 240 female dancers, aged 8 to 16 years, and 226 nondancers of similar age. RESULTS: The prevalence of JHM is significantly higher among dancers compared with the control subjects (P < 0.001). Joints' ROM is higher among dancers with JHM compared with dancers without JHM (P < 0.05). This phenomenon, however, is age dependent; as in young dancers (aged 8-10 years), this pertains only to the ankle dorsiflexion ROM. In adolescent dancers (aged 11-13 years), this relationship has been observed in most joints: ankle/foot en pointe, ankle dorsiflexion, hip external rotation, hip abduction, and hip extension. In mature dancers (aged 14-16 years), dancers with JHM had greater ROM in ankle/foot en pointe, hip abduction, and knee flexion (P < 0.05). CONCLUSIONS: (1) Joint ROM and JHM are associated one with the other; (2) the relationship between joint ROM and JHM is age dependent; and (3) JHM is common among young nonprofessional dancers compared with control subjects. The main clinical implications of the current study are to try and reduce the risk of injuries among JHM dancers by developing proprioceptive trainings to improve the correct alignment of the hyperextended joints, to increase their muscle strength for better stabilization of the hypermobile joints, and to provide them additional balancing and stabilizing exercises for their supporting muscles.

Cognitive Dysfunction: Part and Parcel of the Diabetic Foot.

OBJECTIVE: The presence of a foot ulcer increases the self-treatment burden imposed on the individual with diabetes. Additionally, this condition increases the cognitive demands needed for adherence to medical recommendations. A potential gap could exist between medical recommendations and the individual's ability to implement them. Hence, the goal of this study was to examine whether the cognitive profile of people with diabetic foot ulcers differs from that of people with diabetes without this complication. RESEARCH DESIGN AND METHODS: This was a case-control study. Ninety-nine individuals with diabetic foot ulcers (case patients) and 95 individuals with type 2 diabetes (control subjects) (age range 45-75 years), who were matched for diabetes duration and sex, underwent extensive neuropsychological evaluation using a NeuroTrax computerized battery, digit symbol, and verbal fluency tests. A global cognitive score after standardization for age and education was computed as well as scores in the following six cognitive domains: memory, executive function, reaction time, attention, psychomotor abilities, and estimated premorbid cognition. RESULTS: Individuals with diabetic foot ulcers had significantly (P < 0.001) lower cognitive scores than individuals with diabetes without this complication, in all tested cognitive domains, excluding estimated premorbid cognition. Individuals with diabetic foot ulcers demonstrated a significant difference between precognitive and current cognitive abilities, as opposed to the nonsignificant difference among control subjects. The differences persisted in multivariable analysis after adjusting for depression and smoking. CONCLUSIONS: Individuals with diabetic foot ulcers were found to possess fewer cognitive resources than individuals with diabetes without this complication. Thus, they appear to face more self-treatment challenges, while possessing significantly fewer cognitive resources.

[MEASURING ADHERENCE TO SELF-CARE GUIDELINES FOR PATIENTS WITH TYPE 2 DIABETES WITH DIABETIC ULCERS ADMITTED to THE ORTHOPEDIC REHABILITATION DEPARTMENT AT TEL HASHOMER HOSPITAL DURING 2012-2013].

INTRODUCTION: Diabetic foot is a devastating complication of diabetes and represents the major cause of lower limb amputations in the western world in the 21st century. The World Health Organization predicts a dramatic increase in the number of diabetes patients over the next decade and by the year 2025, their number is expected to increase to 300 million. AIMS: Examine whether training leads to improving performance in the built-in self-care guidelines in patients with type 2 diabetes who were hospitalized with diabetic ulcers in the Orthopedic Rehabilitation Ward in Tel Hashomer between the years 2012-2013. METHODS: The study included 68 type 2 diabetic patients with diabetic ulcer aged 30-80 years, regardless of gender, who were hospitalized following a worsening ulcer. The research tools included demographic, medical and self-care diligence questionnaires and HbA1c measurements in a sugar balance report. RESULTS: Results show significant change in eating habits, number of patient measurements performed during the week and treatment of the diabetic foot between the treatment group and the control group. In addition, support has been found to positively affect self-care response. The only variable where no benefit changes could be observed was the medicines consumption variable. DISCUSSION: Prescriptive guidance, routinely performed, results in improvement in self-care among diabetic patients. Mentoring is enabling people to understand the importance of carrying out instructions received.

Self-selected gait speed--over ground versus self-paced treadmill walking, a solution for a paradox.

BACKGROUND: The study of gait at self-selected speed is important. Traditional gait laboratories being relatively limited in space provide insufficient path length, while treadmill (TM) walking compromises natural gait by imposing speed variables. Self-paced (SP) walking can be realized on TM using feedback-controlled belt speed. We compared over ground walking vs. SP TM in two self-selected gait speed experiments: without visual flow, and while subjects were immersed in a virtual reality (VR) environment inducing natural visual flow. METHODS: Young healthy subjects walked 96 meters at self-selected comfortable speed, first over ground and then on the SP TM without (n=15), and with VR visual flow (n=11). Gait speed was compared across conditions for four 10 m long segments (7.5 - 17.5, 30.5 - 40.5, 55.5 - 65.5 and 78.5-88.5 m). RESULTS: During over ground walking mean (± SD) gait speed was equal for both experimental groups (1.50 ± 0.13 m/s). Without visual flow, gait speed over SP TM was smaller in the first and second epochs as compared to over ground (first: 1.15 ±0.18 vs. second: 1.53 ± 0.13 m/s; p<0.05), and was comparable in the third and fourth (1.45 ± 0.19 vs. 1.49 ± 0.15 m/s; p>0.3). With visual flow, gait speed became comparable to that of over ground performance already in the first epoch (1.43 ± 0.22 m/s; p>0.17). Curve fitting analyses estimated that steady state velocity in SP TM walking is reached after shorter distanced passed with visual flow (24.6 ± 14.7 m) versus without (36.5 ± 18.7 m, not statistically significant; p=0.097). Steady state velocity was estimated to be higher in the presence of visual flow (1.61 ± 0.17 m/s) versus its absence (1.42 ± 1.19 m/s; p<0.05). CONCLUSIONS: The SP TM walking is a reliable method for recording typical self-selected gait speed, provided that sufficient distance is first passed for reaching steady state. Seemingly, in the presence of VR visual flow, steady state of gait speed is reached faster. We propose that the gait research community joins forces to standardize the use of SP TMs, e.g., by unifying protocols or gathering normative data.

Balance maintenance as an acquired motor skill: Delayed gains and robust retention after a single session of training in a virtual environment.

Does the learning of a balance and stability skill exhibit time-course phases and transfer limitations characteristic of the acquisition and consolidation of voluntary movement sequences? Here we followed the performance of young adults trained in maintaining balance while standing on a moving platform synchronized with a virtual reality road travel scene. The training protocol included eight 3 min long iterations of the road scene. Center of Pressure (CoP) displacements were analyzed for each task iteration within the training session, as well as during tests at 24h, 4 weeks and 12 weeks post-training to test for consolidation phase ("offline") gains and assess retention. In addition, CoP displacements in reaction to external perturbations were assessed before and after the training session and in the 3 subsequent post-training assessments (stability tests). There were significant reductions in CoP displacements as experience accumulated within session, with performance stabilizing by the end of the session. However, CoP displacements were further reduced at 24h post-training (delayed "offline" gains) and these gains were robustly retained. There was no transfer of the practice-related gains to performance in the stability tests. The time-course of learning the balance maintenance task, as well as the limitation on generalizing the gains to untrained conditions, are in line with the results of studies of manual movement skill learning. The current results support the conjecture that a similar repertoire of basic neuronal mechanisms of plasticity may underlay skill (procedural, "how to" knowledge) acquisition and skill memory consolidation in voluntary and balance maintenance tasks.

Injuries in female dancers aged 8 to 16 years.

CONTEXT: Most studies of injured dancers have been carried out on professional adult dancers; data on young, nonprofessional injured dancers are sparse. OBJECTIVE: To identify the types of injuries sustained by recreational dancers and to examine their association with age, joint range of motion, body structure, age at menarche, presence of anatomic anomalies, and physical burden (i.e., practice hours en pointe). DESIGN: Descriptive epidemiology study. SETTING: The Israel Performing Arts Medicine Center, Tel Aviv. PATIENTS OR OTHER PARTICIPANTS: A total of 569 injured female dancers, aged 8 to 16 years. MAIN OUTCOME MEASURE(S): Dependent variables were 61 types of current injuries that were later classified into 4 major categories: knee injuries, foot and ankle tendinopathy, back injuries, and other injuries. Independent variables were age, joint range of motion, body size and shape, age at menarche, anatomic anomalies, and dance discipline (e.g., hours of practice per week en pointe). RESULTS: At least 1 previous injury had been sustained by 42.4% of the dancers. The most common injuries involved the knee (40.4%), followed by other injuries (23.4%). The relative frequency of back injuries and tendinopathy decreased with age, whereas knee injuries increased. Types of injuries were significantly associated with ankle plantar flexion, hip external rotation, hip abduction, and knee flexion. Multinomial regression analysis revealed only 3 predictive variables (with other as baseline), all for back injury: scoliosis, age, and hip external rotation. CONCLUSIONS: Joint range of motion and scoliosis may signal the potential for future injury. Young dancers (less than 10 years of age) should not be exposed to overload (especially of the back) or extensive stretching exercises.