Lateral Shuffle-Induced Fatigue Effects on Ankle Proprioception and Countermovement Jump Performance.

To determine how lateral shuffling/lateral shuffle (LS) -induced fatigue affects ankle proprioception and countermovement jump (CMJ) performance. Eighteen male college athletes performed 6 modes of a repeated LS protocol with 2 distances (2.5 and 5 m) and 3 speeds (1.6, 1.8, and 2.0 m/s). After LS, ankle inversion proprioception (AIP) was measured using the active movement extent discrimination apparatus (AMEDA). CMJ, blood lactate (BLa), heart rate (HR) and rating of perceived exertion (RPE) were measured before and after LS. The number of changes of direction (CODs) in each protocol was recorded. LS-induced fatigue was evident in BLa, HR and RPE (all p < 0.05), increasing with shorter shuffle distance and faster speed. RM-ANOVA showed a significant distance main effect on both AIP (p < 0.01) and CMJ (p < 0.05), but the speed main effect was only significant for CMJ (p ≤ 0.001), not AIP (p = 0.87). CMJ performance was correlated with BLa, HR and RPE (r values range from -0.62 to -0.32, all p ≤ 0.001). AIP was only correlated with CODs (r = -0.251, p < 0.01). These results suggested that in LS, shorter distance, regardless of speed, was associated with worse AIP, whereas subsequent CMJ performance was affected by both LS distance and speed. Hence, AIP performance was not related to physiological fatigue, but CMJ performance was. Results imply that LS affects processing proprioceptive input and producing muscular output differently, and that these two aspects of neuromuscular control are affected by physiological fatigue to varying degrees. These findings have implications for injury prevention and performance enhancement.

Use of Dual-Task Timed-Up-and-Go Tests for Predicting Falls in Physically Active, Community-Dwelling Older Adults-A Prospective Study.

This prospective study aimed to determine which specific mobility tests were the most accurate for predicting falls in physically active older adults living in the community. Seventy-nine physically active older adults who met the American College of Sports Medicine physical activity guidelines volunteered. Participants were assessed and followed up for 12 months. Mobility assessments included the 30-s sit-to-stand test, five times sit-to-stand test, single-task timed-up-and-go test (TUG), motor dual-task TUG (Mot-TUG), and cognitive dual-task TUG (Cog-TUG). Mot-TUG and Cog-TUG performances were moderately correlated with number of falls (r = .359, p < .01 and r = .372, p < .01, respectively). When Mot-TUG, Cog-TUG, or Age were included as fall predictors, discrimination scores represented by the area under the receiver operating characteristic curve (AUC) were AUC (Mot-TUG) = 0.843 (p < .01), AUC (Cog-TUG) = 0.856 (p < .01), and AUC (Age) = 0.734 (p < .05). The cutoff point for Cog-TUG was 10.98 s, with test sensitivity of 1.00 and specificity of 0.66. Fall predictors for different populations may be based on different test methods. Here, the dual-task TUG test more accurately predicted falls in older adults who met American College of Sports Medicine's physical activity guidelines.

Ankle complex proprioception and plantar cutaneous sensation in older women with different physical activity levels.

Ankle complex proprioception and plantar sole sensitivity have been separately reported to be essential sensory components in balance control among the elderly. However, their inter-relationship is still unknown. Further, although optimal proprioceptive ability has been related to regular physical exercise, the association between physical activity (PA) levels, ankle proprioceptive acuity and plantar cutaneous sensation is unclear. Therefore, this study aims to compare ankle proprioceptive acuity and plantar cutaneous sensitivity scores between groups of older women with different PA levels, and to determine any relationships between plantar sole cutaneous sensitivity, ankle proprioceptive performance and PA levels. 68 older female participants were recruited who were distributed over three PA levels: highly active, moderately active, and inactive. PA level was assessed by the International Physical Activity Questionnaire. Ankle proprioceptive acuity was tested in full weight-bearing stance using the ankle Active Movement Extent Discrimination Apparatus (AMEDA) and plantar cutaneous sensitivity was assessed with the Nylon Semmes-Weinstein monofilaments test. Results showed that ankle proprioceptive acuity scores were strongly positively related to plantar sole sensitivity scores (r = 0.80, p < 0.001; effect size: η2 = 0.715), and both scores correlated with PA level. In conclusion, plantar cutaneous sensitivity and ankle complex proprioception were strongly correlated in older females with different levels of physical activity, suggesting that the former may be an integral part of the latter. Given the previously reported contribution of AMEDA ankle proprioceptive acuity to sport performance level, the health of the plantar sole of the foot may be important as a performance determinant.

Can Therapeutic Exercises Improve Proprioception in Chronic Ankle Instability? A Systematic Review and Network Meta-analysis.

OBJECTIVE: To assess exercise therapies that aim to enhance proprioception in individuals with chronic ankle instability (CAI). DATA SOURCES: Five databases (PubMed, Embase, Cochrane Library, Web of Science, and EBSCO) were searched in October 2021. STUDY SELECTION: Randomized controlled trials involving exercise therapy conducted on individuals with CAI were included. DATA EXTRACTION: Data were extracted by 2 independent reviewers using a standardized form. Methodological quality and risk of bias were assessed with the Physiotherapy Evidence Database scale. DATA SYNTHESIS: The end trial weighted mean difference and standard deviations were analyzed, and the synthetic value for the improvement in error scores of ankle joint position sense in multiple directions was evaluated. RESULTS: Eleven trials with 333 participants were eligible for inclusion in this systematic review and were included in the network meta-analysis. Foot and ankle muscle strengthening exercise showed the highest probability of being among the best treatments (surface under the cumulative ranking [SUCRA]=74.6%). The next 2 were static balance exercise only (SUCRA=67.9%) and corrective exercise (SUCRA=56.1%). The SUCRA values of proprioceptive exercise, dynamic balance exercise only, aquatic exercise, rehabilitation exercise with brace, mixed static/dynamic balance exercise, and control were at relatively low levels and scored at 49.6%, 48.8%, 47.8%, 47.7%, 44.0%, and 13.5%, respectively. CONCLUSIONS: Foot and ankle muscle strengthening exercise may have a good effect when used to improve joint position sense in individuals with CAI. The more complex balance exercise intervention becomes, the less effective the proprioceptive outcome.

Association Between Neck Pain, Range of Motion, and Proprioception in Elite Female International Standard Dancers: A Case-Control Study.

BACKGROUND: Neck pain is common in dancers, especially female dancers, and the injury pattern varies in different genres of dance. Among dancesport performers, intensive neck left rotation is required in female International Standard dancers, but it is unknown whether neck pain is associated with neck rotation range of motion and proprioception. OBJECTIVES: To explore the associations between neck pain, cervical rotation range of motion, and proprioception in female International Standard dancers. METHODS: Twelve dancers with dance-related neck pain (age 19.9±1.9 yrs) volunteered, matched with 12 not reporting neck pain (age 22.2±2.4 yrs). A 100-mm visual analog scale (VAS) was used to record neck pain. Active rotation range of motion (AROM) of the cervical spine was measured using a tape measure. A cervical rotation reposition test that used a head-mounted laser projector on a linear scale was employed to measure the cervical spine proprioception, and the absolute error (AE) and variable error (VE) were calculated as proprioceptive acuity scores. RESULTS: Nine of 12 participants in the group with neck pain declared left side pain, with 2 reporting pain on both sides. The group with neck pain had significantly lower left rotation AROM (p<0.05). For proprioceptive acuity, mixed model ANOVA only showed that repositioning of the right side of the neck is more accurate and consistent than that of the left (both AE and VE p<0.05). Linear regression analysis indicated that left rotation AROM was significantly influenced by left neck pain (t=3.061, p=0.006, adjusted R2 = 0.267, and Durbin-Watson value = 1.776). CONCLUSIONS: Most participants in the group with neck pain showed left side pain, associated with decreased left rotation AROM. Early screening on cervical rotation mobility may be necessary to reduce future dance-related injury after the onset of neck pain. Proprioceptive acuity of the left side neck was significantly impaired compared with that of the right, indicating future proprioceptive intervention on the left side neck.

Proprioceptive accuracy after uni-joint and multi-joint patterns of arm-raising movements directed to overhead targets.

AIM: To determine the effect of arm-raising pattern on upper limb proprioceptive accuracy for movements made to overhead targets. MATERIALS AND METHODS: Sixteen healthy young adults were tested in standing with arms at the sides, made dominant arm-raising movements to an unseen overhead stop, randomly placed at one of five different overhead targets. Movements were made either as a uni-joint shoulder flexion movement in an arc, or as an unconstrained arm raising that was a series of multi-joint movements involving the shoulder, elbow, and wrist. RESULTS: Overall proprioceptive accuracy for discrimination between the five unseen overhead targets was not different after arm-raising with either a uni-joint or mult-joint pattern (F1, 15 = 0.50, p = 0.49, partial η2 = 0.03). Better performers with one pattern also tended to perform well with the other (r = 0.70, p = 0.003). Trend analysis across the 4 pairwise scores for discriminations between the target positions (171.8°-173.6°, 173.6°-175.4°, 175.4°-177.2°, and 177.2°-179.0°) showed worsening discrimination towards the more distant targets (F1, 15 = 8.44, p = 0.01, partial η2 = 0.36). However, this linear trend of falling discrimination accuracy was not different between the two movement patterns (p = 0.27). CONCLUSION: Proprioceptive accuracy did not differ between simple uni-joint and more complex multi-joint arm-raising movement patterns, and the further the extent of the overhead target movement, the worse proprioceptive discrimination sensitivity for both movement patterns. Upper limb proprioceptive accuracy was therefore movement extent dependent, but movement pattern independent.

Vibration of calf muscles has reverse effects on right and left ankle proprioception in high and low proprioceptive performer groups.

PURPOSE: Previous research has found hemispheric asymmetries in the utilization of proprioceptive information. It is undetermined, however, if there is any change in asymmetry in proprioceptive function when external stimulation, such as vibration, is presented. The present study was to investigate the immediate effects of vibration stimulation (VS) on bilateral ankle proprioception. MATERIALS AND METHODS: Forty-six recreational male basketball players were included. Proprioception was assessed by using the active movement extent discrimination apparatus (AMEDA) in standing, and vibration was provided by using a vibrating form roller on the peroneal or gastrocnemius muscles. RESULTS: When participants were divided into high score and low score groups, according to the median of the baseline proprioceptive performance, VS (irrespective of whether vibrating the peroneal or gastrocnemius muscles) significantly improved left non-dominant ankle proprioception in the low proprioceptive performer group (p = 0.019), while significantly deteriorated right dominant ankle proprioception in the high proprioceptive performer group (p = 0.011). CONCLUSIONS: The results found that external stimuli reversely affect proprioception in better and worse performing groups. This suggests that there are differences in the processing of external stimulus signals on different bilateral hemispheres and in different groups (high score vs low score groups), which may be related to hemispheric asymmetry and stochastic resonance. Therefore, it is necessary to explore more specific interventions in the future.

Stationary cycling exercise for knee osteoarthritis: A systematic review and meta-analysis.

OBJECTIVE: To evaluate effects of stationary cycling exercise on pain, function and stiffness in individuals with knee osteoarthritis. DATA SOURCES: Systematic search conducted in seven databases (PubMed, Embase, Cochrane Library, Web of Science, EBSCO, PEDro, and CNKI) from inception to September 2020. REVIEW METHODS: Included studies were randomized-controlled trials involving stationary cycling exercise conducted on individuals with knee osteoarthritis. End-trial weighted mean difference (WMD) and 95% confidence interval (CI) were analyzed, and random-effects models were used. Methodological quality and risk bias were assessed by using the Physiotherapy Evidence Database scale and Cochrane Collaboration tool, respectively. RESULTS: Eleven studies with 724 participants were found, of which the final meta-analysis was performed with eight. Compared to a control (no exercise), stationary cycling exercise resulted in reduced pain (WMD 12.86, 95% CI 6.90-18.81) and improved sport performance (WMD 8.06, 95% CI 0.92-15.20); although most of the meta-analysis results were statistically significant, improvements in stiffness (WMD 11.47, 95% CI 4.69-18.25), function (WMD 8.28, 95% CI 2.44-14.11), symptoms (WMD 4.15, 95% CI -1.87 to 10.18), daily living (WMD 6.43, 95% CI 3.19 to 9.66) and quality of life (WMD 0.99, 95% CI -4.27 to 6.25) for individuals with knee osteoarthritis were not greater than the minimal clinically important difference values for each of these outcome measures. CONCLUSIONS: Stationary cycling exercise relieves pain and improves sport function in individuals with knee osteoarthritis, but may not be as clinically effective for improving stiffness, daily activity, and quality of life.

Injury Prevention Exercises for Reduced Incidence of Injuries in Combat Soldiers.

ABSTRACT: Steinberg, N, Bar-Sela, S, Moran, U, Pantanowitz, M, Waddington, G, Adams, R, Band, SS, and Funk, S. Injury prevention exercises for reduced incidence of injuries in combat soldiers. J Strength Cond Res 35(11): 3128-3138, 2021-The aim of this study was to determine the influence of an "all-cause injury" prevention program, focused on static-to-dynamic transitions, on injury prevalence in a military commanders course. Two cohorts of male infantry commanders were recruited (intervention [INT group], n = 196 and controls [CO group], n = 169) and tracked by a physiotherapist, who recorded any injuries that occurred during the 14-week course. Soldiers were tested precourse, midcourse, and postcourse for anthropometrics, proprioception ability, and dynamic postural balance (DPB). The INT group performed injury prevention exercises for 5 minutes, 3 times a week, and the CO group continued with their routine physical fitness sessions. The prevalence of injuries reported to the physiotherapist during the course was significantly lower for the INT group compared with the CO group (14.8 and 34.3%, respectively, p < 0.001). Similarly, rates of injury in the INT group were significantly lower than in the CO group (p < 0.001; hazard = 2.53, 95% confidence interval = 1.62-3.95). Precourse proprioception ability was significantly lower in those that became injured during the commanders course, irrespective of the group. Likewise, for DPB parameters, the injured subjects in both groups had significantly lower precourse scores than the noninjured subjects. From pretesting to midtesting, the injured soldiers in the INT group improved their ability up to the level of the noninjured subjects. A reduced prevalence of injuries was found for soldiers who completed the injury prevention program. Because the subjects soldiers injured on the course had reduced somatosensory abilities at the outset, and as these abilities can be improved by static-to-dynamic exercises, identifying at-risk soldiers and providing them with appropriate strategies for improvement beforehand is indicated.

Joint position reproduction and joint position discrimination at the ankle are not related.

Purpose: Limited data in current literature can be found on the relation between the two commonly-used active proprioception assessment methods -active joint position reproduction (JPR) and active movement extent discrimination assessment (AMEDA). The current study compared the two active methods, JPR and AMEDA, to investigate their interrelationship over two studies that differed in task difficulty, using active ankle inversion movements made in weight-bearing to maximise ecological validity.Methods: 50 participants volunteered in this research, 20 of whom on a harder protocol and the other 30 on an easier protocol, were tested by both methods, JPR and AMEDA. Proprioceptive acuity was represented by absolute error (AE) and variable error (VE) for JPR and by AE and the area under the curve (AUC) for AMEDA.Results: Proprioceptive acuity scores are found to be significantly correlated within test methods but not between methods for either hard or easy tasks, where JPR AE and VE scores were not correlated with either AMEDA AE or AUC. Further, proprioceptive acuity scores were significantly higher on the easy task when tested with the AMEDA method, but not with JPR method.Conclusion: Scores obtained from the two active movement proprioception tests, movement extent discrimination and joint position reproduction, were not significantly correlated. Taken together with previous findings, these results show that for proprioception, scores from the three classical psychophysical methods for measuring sensitivity (adjustment, limits and constant stimuli) are not correlated with each other. This suggests that each proprioception measurement system assesses a different aspect of proprioception.

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.

Shoulder internal and external rotation strength and prediction of subsequent injury in water-polo players.

Water-polo players have greater isokinetic shoulder strength than age-matched controls. Due to the repetitive demands of throwing, however, water-polo players demonstrate an altered strength ratio, with greater internal rotation (IR) strength relative to external rotation (ER). The relationship between shoulder strength and risk of shoulder injury is unknown. In addition, the effect on test position for strength testing on the reliability of handheld dynamometry (HHD) in this population is not known. The aims were to determine the: (a) Inter-rater reliability of HHD testing of IR and ER strength in two positions: neutral and 90°abduction-90°ER (90-90) and (b) relationship between preseason shoulder strength and occurrence of future injury in sub-elite water-polo players. Two assessors measured shoulder IR and ER strength using HHD in 15 water-polo players across two testing days. Athletes were followed over a 6-month period, and injury was assessed and recorded by the team physiotherapist. Measurement of water-polo players' isometric IR and ER strength in the clinical setting had good to excellent inter-rater reliability; however, systematic error was observed in the neutral position but not the 90-90 position. Irrespective of testing position, the neutral and 90-90 test position showed a significant difference (P = 0.01) in absolute preseason IR and ER mean strength between prospectively injured and non-injured players. There was no significant difference in strength ratio or strength normalized for body mass index. These results suggest that preseason strength testing may help identify players at risk of in-season shoulder injury.

Throwing performance in water polo is related to in-water shoulder proprioception.

Water polo players require a high level of upper-extremity strength, flexibility and coordination to achieve a peak level of throwing performance. Increased levels of shoulder proprioceptive acuity, strength and range of motion (ROM) have been previously associated with higher sporting performance. A coach-rating scale, used to quantify an athlete's kicking proficiency in soccer; was adapted in the current study to measure each coach's subjective expert opinion regarding athletes' throwing mechanics, velocity, and accuracy. To examine this hypothesis shoulder proprioception acuity of 18 water polo players was measured both in-water and on-land using an AMEDA apparatus and correlated with coach-rated throwing performance and clinical measures of shoulder strength and ROM. There was a moderate positive correlation between the in-water and the on-land proprioception acuity (r = 0.47, p < 0.05). The in-water score showing a strong positive correlation with coach rated throwing mechanics (r = 0.68, p < 0.05) and velocity (r = 0.75, p = 0.02), suggesting that superior proprioception acuity contributed to fast, mechanically-efficient throwing. These findings support the notion that in-water proprioceptive acuity is an important determinant of the throwing performance achieved by water polo athletes and its measurement may be a valuable adjunct to current athlete screening.

Effects of Textured Balance Board Training in Adolescent Ballet Dancers With Ankle Pathology.

CONTEXT: Ankle sprains are common among adolescent ballet dancers and may be attributed to inadequate ankle proprioception. Thus, a short period of training utilizing proprioceptive activities requires evaluation. OBJECTIVE: To assess training conducted for 3 or 6 weeks on a textured-surface balance board using ankle proprioception scores for ballet dancers with and without chronic ankle instability, and with and without previous ankle sprain (PAS). DESIGN: Intervention study. SETTING: The Australian Ballet School. PARTICIPANTS: Forty-two ballet dancers, aged 14-18 years. INTERVENTIONS: Dancers randomized into 2 groups: group 1 undertook 1 minute of balance board training daily for 3 weeks; group 2 undertook the same training for 6 weeks. MAIN OUTCOME MEASURES: Preintervention, Cumberland Ankle Instability Tool questionnaire data were collected, and PAS during the last 2 years was reported. Active ankle inversion movement discrimination ability was tested immediately pre and post intervention and at 3 and 4 weeks. RESULTS: Ankle discrimination acuity scores improved over time for both groups, with a performance decline associated with the early cessation of training for group 1 (P = .04). While dancers with PAS had significantly worse scores at the first test, before balance board training began (P < .01), no significant differences in scores at any test occasion were found between dancers with and without chronic ankle instability. A significantly faster rate of improvement in ankle discrimination ability score over the 4 test occasions was found for dancers with PAS (P = .002). CONCLUSIONS: Three weeks of textured balance board training improved the ankle discrimination ability of ballet dancers regardless of their reported level of chronic ankle instability and at a faster rate for dancers with PAS. Previous ankle sprain was associated with a lower level of ankle discrimination ability; however, following 3 weeks of balance board training, previously injured dancers had significantly improved their ankle discrimination acuity scores.

Recent Ankle Injury, Sport Participation Level, and Tests of Proprioception.

OBJECTIVE: Assessing the effects of ankle injury and sport participation level on ankle proprioceptive sensitivity using a joint position reproduction (JPR) test and an inversion movement extent discrimination test. DESIGN: Cross-sectional. SETTING: Biomechanics lab. PARTICIPANTS: Forty-five student athletes ages 21-30 (mean = 24.8 y). MAIN OUTCOME MEASURES: Participants were tested for ankle inversion sensitivity using 2 devices; movement reproduction error was obtained from JPR in a non-weight-bearing (N-WB) state at 10° and 15° of inversion, and an ankle proprioceptive sensitivity score was obtained from the active movement extent discrimination apparatus (AMEDA), representing the ability to differentiate 5 inversion movement extents between 10.5° and 14.5°, with testing in both N-WB and weight-bearing (WB) states. RESULTS: For the 34 athletes with no ankle injury in the previous 12 months, the sensitivity scores achieved on the AMEDA were significantly higher (P < .01) than those for the 11 athletes with ankle injury, and the injury effect was significantly greater in WB (P = .01). In JPR testing, the 2.96° error of reproduction for athletes with no recent ankle injury was not significantly different from the 3.36° error for those with ankle injury (P = .46). Correlation of current sport participation level with JPR showed less error for higher-level performers (r = .49, P = .001) but no significant relationship to WB or N-WB AMEDA scores (both P > .61). WB AMEDA scores were significantly higher for athletes who had competed at a higher level of sport competition when <18 years old (r = -.57, P < .001). CONCLUSIONS: Previous ankle sprains affected proprioceptive scores on the WB AMEDA and N-WB AMEDA tests, indicating the sensitivity of the AMEDA movement discrimination test to the effects of ankle injury. The correlation between JPR scores and current level of sport participation suggests the sensitivity of the JPR test to current ankle use.

Translation, cultural adaption, and test-retest reliability of Chinese versions of the Edinburgh Handedness Inventory and Waterloo Footedness Questionnaire.

Quantitative assessments of handedness and footedness are often required in studies of human cognition and behaviour, yet no reliable Chinese versions of commonly used handedness and footedness questionnaires are available. Accordingly, the objective of the present study was to translate the Edinburgh Handedness Inventory (EHI) and the Waterloo Footedness Questionnaire-Revised (WFQ-R) into Mandarin Chinese and to evaluate the reliability and validity of these translated versions in healthy Chinese people. In the first stage of the study, Chinese versions of the EHI and WFQ-R were produced from a process of translation, back translation and examination, with necessary cultural adaptations. The second stage involved determining the reliability and validity of the translated EHI and WFQ-R for the Chinese population. One hundred and ten Chinese participants were tested online, and the results showed that the Cronbach's alpha coefficient of internal consistency was 0.877 for the translated EHI and 0.855 for the translated WFQ-R. Another 170 Chinese participants were tested and re-tested after a 30-day interval. The intra-class correlation coefficients showed high reliability, 0.898 for the translated EHI and 0.869 for the translated WFQ-R. This preliminary validation study found the translated versions to be reliable and valid tools for assessing handedness and footedness in this population.

The natural history of children with joint hypermobility syndrome and Ehlers-Danlos hypermobility type: a longitudinal cohort study.

Objectives: The objective of the manuscript was to describe the natural history of complaints and disability in children diagnosed with joint hypermobility syndrome (JHS)/Ehlers-Danlos-hypermobility type (EDS-HT) and to identify the constructs that underlie functional decline. Methods: One hundred and one JHS/EDS-HT children were observed over 3 years and assessed at three time points on the following: functional impairments, quality of life, connective tissue laxity, muscle function, postural control and musculoskeletal and multi-systemic complaints. Cluster analysis was performed to identify subgroups in severity. Clinical profiles were determined for these subgroups, and differences were assessed by multivariate analysis of covariance. Mixed linear regression models were used to determine the subsequent trajectories. Finally, an exploratory factor analysis was used to uncover the underlying constructs of functional impairment. Results: Three clusters of children were identified in terms of functional impairment: mild, moderately and severely affected. Functional impairment at baseline was predictive of worsening trajectories in terms of reduced walking distance and decreased quality of life (P ⩽ 0.05) over 3 years. Multiple interactions between the secondary outcomes were observed, with four underlying constructs identified. All four constructs (multi-systemic effects, pain, fatigue and loss of postural control) contributed significantly to disability (P ⩽ 0.046). Conclusion: Children diagnosed with JHS/EDS-HT who have a high incidence of multi-systemic complaints (particularly, orthostatic intolerance, urinary incontinence and diarrhoea) and poor postural control in addition to high levels of pain and fatigue at baseline are most likely to have a deteriorating trajectory of functional impairment and, accordingly, warrant clinical prioritization.

Influence of Textured Insoles on Dynamic Postural Balance of Young Dancers.

BACKGROUND: Postural balance (PB) is a significant factor in dance performance and injury prevention. We aimed to determine whether the use of textured insoles inserted into casual walking shoes of dancers improved their dynamic PB and whether dancers with previous injury manifested different dynamic PB compared with non-injured dancers. METHODS: In this crossover design study, 26 ballet dancers from the Australian Ballet School, aged 14-19 yrs, were divided into two groups matched by sex and class levels. Group 1 wore the textured insoles in their walking shoes for at least 2 hrs/day during weeks 1 to 4 of the study, and group 2 wore the textured insoles in their walking shoes during weeks 5 to 8. Reports from the school medical staff identified dancers who had previous injuries. All participants were tested pre-intervention and at 4 and 8 weeks by an accelerometer for dynamic PB (average acceleration magnitude, root mean square acceleration, range, and mean frequency) during single-leg fondu, flexing and extending of the knee. FINDINGS: Interactions (group x time) were found in dynamic PB measured in the mediolateral direction, indicating significant differences between the groups at the three testing times. Furthermore, both previously injured and noninjured dancers manifested significant time effects from pre-intervention to 8 weeks, indicating a significant improvement in their PB after using the textured insoles. CONCLUSION: Textured insoles can improve the dynamic PB of ballet dancers and can also be useful as a routine intervention. PB was improved among both dancers with previous injury and non-injured dancers.

Proprioceptive ability at the lips and jaw measured using the same psychophysical discrimination task.

In the human face, the muscles and joints that generate movement have different properties. Whereas the jaw is a conventional condyle joint, the facial musculature has neither distinct origin nor insertion points, and the muscles do not contain muscle spindle proprioceptors. This current study aims to compare the proprioceptive ability at the orofacial muscles with that of the temporomandibular joint (TMJ) in 21 neuro-typical people aged between 18 and 65 years. A novel psychophysical task was devised for use with both structures that involved a fixed 30.5 mm start separation followed by closure onto stimuli of 5, 6, 7, 8 mm diameter. The mean proprioceptive score when using the lips was 0.84 compared to 0.79 at the jaw (p < 0.001), and response error was lower by 0.1 mm. The greater accuracy in discrimination of lip movement is significant because, unlike the muscles controlling the TMJ, the orbicularis oris muscle controlling the lips inserts on to connective tissue and other muscle, and contains no muscle spindles, implying a different more effective, proprioceptive mechanism. Additionally, unlike the lack of correlation previously observed between joints in the upper and lower limbs, at the face the scores from performing the task with the two different structures were significantly correlated (r = 0.5, p = 0.018). These data extend the understanding of proprioception being correlated for the same left and right joints and correlated within the same structure (e.g. ankle dorsiflexion and inversion), to include use-dependant proprioception, with performance in different structures being correlated through extended coordinated use. At the lips and jaw, it is likely that this arises from extensive coordinated use. This informs clinical assessment and suggests a potential for coordinated post-injury training of the lips and jaw, as well as having the potential to predict premorbid function via measurement of the uninjured structure, when monitoring progress and setting clinical rehabilitation goals.

Can textured insoles improve ankle proprioception and performance in dancers?

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.