Head injury trends and helmet use in skiers and snowboarders in Western Canada, 2008-2009 to 2012-2013: an ecological study.

This research explored associations between helmet use and head injuries in snowsports by investigating reported snowsport injuries in Western Canada from 2008-2009 to 2012-2013. The key finding was that increased helmet use (from 69% to 80%) was not associated with a reduction in reported head injuries. Over the study period, the average rate of reported head injuries was 0.2/1000 skier visits, with a statistically significant variation (P < 0.001). The line of best fit showed an non-significant upward trend (P = 0.13). Lacerations were the only subcategory of head injuries that decreased significantly with helmet use. A higher proportion of people who reported a head injury were wearing a helmet than for injuries other than to the head. Skiers were more likely to report a head injury when wearing a helmet than snowboarders (P < 0.001 cf. P = 0.22). There were significant differences in characteristics of helmet and non-helmet wearers. Helmet wearers were more likely to be: young adults (P < 0.001); beginner/novices (P = 0.004); and snowboarders (P < 0.001), but helmet wearing was not associated with gender (P = 0.191). Further research is needed to explore the possible reasons for the failure of helmets to reduce head injuries, for example, increased reporting of head injuries and increased risk-taking combined with over-rating of the helmets' protection.

Cognitive motor interference for gait and balance in stroke: a systematic review and meta-analysis.

BACKGROUND AND PURPOSE: An increasing interest in the potential benefits of cognitive motor interference (CMI) for stroke has recently been observed, but the efficacy of CMI for gait and balance is controversial. A systematic review and meta-analysis of randomized controlled trials was performed to estimate the effect of CMI on gait and balance in patients with stroke. METHODS: Articles in Medline, EMBASE, the Cochrane Library, Web of Science, CINAHL, PEDro and the China Biology Medicine disc were searched from 1970 to July 2014. Only randomized controlled trials examining the effects of CMI for patients with stroke were included, and no language restrictions were applied. Main outcome measures included gait and balance function. RESULTS: A total of 15 studies composed of 395 participants met the inclusion criteria, and 13 studies of 363 participants were used as data sources for the meta-analysis. Pooling revealed that CMI was superior to the control group for gait speed [mean difference (MD) 0.19 m/s, 95% confidence interval (CI) (0.06, 0.31), P = 0.003], stride length [MD 12.53 cm, 95% CI (4.07, 20.99), P = 0.004], cadence [MD 10.44 steps/min, 95% CI (4.17, 16.71), P = 0.001], centre of pressure sway area [MD -1.05, 95% CI (-1.85, -0.26), P = 0.01] and Berg balance scale [MD 2.87, 95% CI (0.54, 5.21), P = 0.02] in the short term. CONCLUSION: Cognitive motor interference is effective for improving gait and balance function for stroke in the short term. However, only little evidence supports assumptions regarding CMI's long-term benefits.

Does Wearing Textured Insoles during Non-class Time Improve Proprioception in Professional Dancers?

This study sought to determine whether textured insoles inserted in the sports shoes of young dancers improved their inversion and eversion ankle movement discrimination. 26 ballet dancers (14 female, 12 male) from the Australian Ballet School, ages 14-19 years, were divided into 2 groups according to sex and class levels. During the first 4 weeks, the first intervention group (GRP1) was asked to wear textured insoles in their sports shoes during non-class periods, and the second intervention group (GRP2) followed standard practice. In the next 4 weeks, GRP2 was asked to wear the textured insoles and GRP1 did not wear the textured insoles. Participants were tested pre-intervention, after 4 weeks, and at 8 weeks for both inversion and eversion ankle discrimination. In both inversion and eversion testing positions, interaction was found between the 2 groups and the 3 testing times (p<0.001), with significant differences between the first testing and the second testing (p=0.038 and p=0.019, respectively), and between the third testing and the second testing (p=0.003 and p=0.029, respectively). In conclusion, the stimulation to the proprioceptive system arising from textured insoles worn for 4 weeks was sufficient to improve the ankle proprioception of ballet dancers, in both inversion and eversion movements.

Walking for fitness: is it enough to maintain both heart and bone health?

Exercising at levels of whole body accelerations exceeding 3.6g has been shown to have positive effects on cardiovascular fitness, bone density and balance. This pilot research project evaluated the whole body accelerations and cardiovascular challenge provided by selected walks in the Canberra region of Australia to determine if walks could be ranked according to potential level of impact on both cardiovascular fitness and bone health. Nine participants, who described themselves as walking at least 3km, three times per week, wore a data logging device recording heart rate, acceleration and GPS position while walking three outdoor tracks: (1) the running track of an athletics stadium; (2) on a hill climb path through bushland; and (3) on a route through suburban streets. There was a significant difference (P<0.05) for heart rate, distribution of whole body accelerations and average walking speed between track 2 and tracks 1 and 3. There was a significant difference for heart rate, distribution of whole body accelerations and average walking speed between the walks. The running track and the suburban walk provide a moderate exercise challenge, with the hill climb walk providing progressively greater vertical height challenge, resulting in an increased cardiovascular exercise challenge. No participant effectively exceeded the threshold for achieving a positive impact on bone density (100 or more accelerations/day >3.6g) on track 1, and only two of the nine participants intermittently achieved this threshold on tracks 2 and 3.

Incidence of injuries and factors related to injuries in combat soldiers.

INTRODUCTION: Musculoskeletal injuries to the lower extremities are major factors contributing to drop out from military tasks. The aim of the present study was to determine the incidence of musculoskeletal injuries and the parameters that differentiate between the soldiers who incurred these injuries and those who did not along 14 weeks of an infantry commanders course. METHODS: One-hundred and sixty-eight participants were recruited from an infantry commanders course. The soldiers were tested before (pre), in the middle (middle) and at the end (last) of the course for anthropometric measurements, proprioceptive ability and dynamic postural balance (DPB), and filled out an ankle stability questionnaire (Cumberland Ankle Instability Tool (CAIT). A physiotherapist followed and recorded all musculoskeletal injuries incurred by the participants during the course. RESULTS: Fifty-eight participants out of the 168 (34.5%) reported some pain/injury. Time effects were found for body mass index, DPB asymmetry, DPB in posterior-medial (P-M) direction and proprioception ability. Injury effects were found for DPB asymmetry, DPB in P-M direction, CAIT and proprioception ability. An interaction was found for proprioception ability. The Cox regression showed that the variables that are mostly effecting injuries were pretesting proprioception ability, DPB asymmetry and CAIT. CONCLUSIONS: More than one out of three participants incurred musculoskeletal injuries, with deficits in proprioception ability, DPB and ankle stability in pretesting as major factors contributing to injuries. Further studies should look at the effect of specific exercises such as proprioception, DPB and ankle stability exercises for prevention and treatment of musculoskeletal injuries among combat soldiers.

Microvascular volume in symptomatic Achilles tendons is associated with VISA-A score.

OBJECTIVES: The role of neovascularisation in tendinopathy is still poorly understood, potentially due to technical limitations of conventional power Doppler ultrasound. This study aimed to investigate the association between contrast-enhanced ultrasound (CEUS) microvascular volume (MV), Victorian Institute of Sports Assessment-Achilles (VISA-A) scores and intrinsic Achilles tendon tenderness, as well as two different Power Doppler modes. DESIGN: Cross-sectional study. METHODS: 20 individuals with uni- or bilateral Achilles tendinopathy completed a VISA-A questionnaire, and underwent microvascular volume measurements of the Achilles tendon mid-portion using both conventional, ultrasensitive (SMI™) power Doppler ultrasound and CEUS. Intrinsic tendon tenderness was assessed with sensation detection threshold to extracorporeal shock waves (ESW). Linear Mixed Model analysis was used to determine the association between microvascular volume (MV), VISA-A, and ESW-detection threshold for both symptomatic and asymptomatic Achilles tendons. RESULTS: There was a significant association between VISA-A and MV (B=-5.3, 95%CI=[-8.5; -2.0], P=0.0004), and between MV and symptom duration (B=-1.7, 95%CI=[-3.2; -5.0], P=0.023). No significant associations were found between power Doppler ultrasound and CEUS-based MV or between CEUS-based MV and ESW-detection threshold. In comparison with conventional power Doppler ultrasound, SMI™ showed on average similar detection capacity for neovessels in the mid-portion of the Achilles tendon, whilst being superior for detecting neovessels within Kager's fat pad (t=3.46, 95%CI=[0.27; 1.03], P<0.005). CONCLUSIONS: Our results indicate that CEUS-based MV of the Achilles tendon is moderately associated with Achilles tendon symptoms. In accordance, CEUS-detected MV could be a novel target for treatment as it seems to be more sensitive than PDU and is correlated with symptoms.

Association between Berg Balance, Physiological Profile Assessment and Physical Activity, Physical Function and Body Composition: A Cross-sectional Study.

BACKGROUND: Falls are of great concern to older adults and costly to the health system. In addition the relationship between falls risk and falls risk predictor characteristics is complex. OBJECTIVE: This study aimed to explore the relationship between two objective fall-risk measures tools, the Physiological Profile Assessment and the Berg Balance Scale and to determine how an individual's sex, level of physical function, health-related and body composition characteristics impact these objective falls risk measures. DESIGN: A cross-sectional, observational study. PARTICIPANTS: 245 community-dwelling older adults (M age=68.12 years, SD=6.21; 69.8% female). MEASUREMENTS: Participants were assessed for falls-risk (Physiological Profile Assessment and the Berg Balance Scale), physical activity, physical functional and body composition characteristics. Pearson product-moment correlation coefficients were calculated to examine bivariate relationships and hierarchical multiple linear regression modelling was used to estimate the contribution of each predictor in explaining variance in falls-risk. RESULTS: In females, there was a weak association between the two objective falls-risk measures (r =-0.17 p <0.05). The number of falls in the previous 12 months explained 6% of variance in Physiological Profile Assessment scores, with bone density of the lumbar spine contributing a further 1%. In males and females, variance in the Berg Balance Scale showed that age (25%) and physical function (16% for females, 28% for males) contributed significantly to the explaining variance in the falls-risk measure. CONCLUSION: Sex differences are apparent and as such males and females should be assessed (and potentially treated) differently with regards to falls risk. Results indicate that both falls risk assessment tools measure aspects of balance but are not interchangeable. The Berg Balance Scale may be more discriminative in older, less functioning adults and the Physiological Profile Assessment is more useful in assessing falls risk in females.

Hand-held dynamometry strength measures for internal and external rotation demonstrate superior reliability, lower minimal detectable change and higher correlation to isokinetic dynamometry than externally-fixed dynamometry of the shoulder.

OBJECTIVES: To investigate inter and intra-rater reliability of hand held (HHD) and externally fixed (EFD) dynamometry for shoulder internal (IR) and external rotation (ER) strength and their correlation to isokinetic testing. DESIGN: Within participant, inter and intra-rater reliability study. PARTICIPANTS: Twenty active, healthy male and female participants underwent testing by two examiners. OUTCOME MEASURES: Intra-class coefficients (ICC), percentage standard error of measurement (%SEM), and percentage minimal detectable change (%MDC) were calculated for inter-rater, intra-day and intra-rater, inter-week reliability. Maximum and average of three repetitions were compared to the isokinetic results at three speeds (60°/sec, 180°/sec, 240°/sec) for both concentric and eccentric contractions. RESULTS: Inter and intra-tester values demonstrated good to high agreement (HHD, ICC range = 0.89-0.97, %SEM = 4.80-8.60%, %MDC = 13.29-23.70%; EFD, ICC = 0.88-0.96, %SEM = 6.60-11.00%, %MDC = 18.40-30.04%). HHD and EFD showed moderate to very strong correlations to the isokinetic testing (HHD, r = 0.45-0.86; EFD, r = 0.49-0.83). CONCLUSIONS: The results of this study indicate that both EFD and HHD are suitable for clinical practice and research. Hand-held dynamometry is preferred due to its higher intra- and inter-rater reliability and smaller MDC and lower SEM.

A simple operative technique for chronically severing te cerebellar peduncles in neonatal rats.

The method of anaesthesia and a new operative approach to allow chronic cutting of the cerebellar peduncles in neonatal rats by a relatively atraumatic method is described in detail. The operation allows a very quick postoperative recovery time, does not cause necrosis of the cerebellum, allows choice of partial or complete pedunclectomy, and there is no incidence of infection. A postoperative regime which has yielded a very low incidence of savaging by the mother is also discussed.

Comparing wobble board and jump-landing training effects on knee and ankle movement discrimination.

The effects of two training programs on movement discrimination ability, at the ankle and knee, were assessed from the left and right lower limbs of forty-four football players. All players in three Under 18 Victorian Football League (VFL) squads were allocated to either wobble board training, jump landing training, or no-training conditions. Pre-tests to assess discrimination of extent for active movements made while standing were carried out on both ankles and knees of all subjects, using an automated device to accurately set the different movement stop points. Five distances were used, between 10.5 degrees and 14.5 degrees from horizontal for ankle inversion, and between 30.3 degrees and 31.7 degrees from vertical for knee flexion. From a series of 50 inversion movements and 50 knee flexion movements, matrices of absolute judgement by actual movement extent were produced. Non-parametric signal detection analysis was applied to the discrimination score. All subjects were retested after eight weeks. Improvement in discrimination of ankle movements into inversion from pre-test (0.65) to post test (0.70) for the wobble board trained group was significantly larger than the change in the jump-landing trained and the untrained groups (Jump Landing: Pretest: 0.64 to Post-test: 0.64 and Control; Pretest: 0.63 to Post-test: 0.64). Discrimination of knee flexion movements improved significantly from pre-test to post-test in all three groups. These data demonstrate that wobble board training can improve discrimination of discrete ankle inversion movements, an effect interpreted as enabling greater accuracy in the making of inversion movements in foot preparation prior to ground contact.

Ability to discriminate movements at the ankle and knee is joint specific.

Measures of discrimination for movements of different extent at the ankle (inversion) and knee (flexion) were obtained for the right and left legs from 59 male footballers. The finding of significant association between discriminability scores at common joints was interpreted in terms of the motor program.

Football boot insoles and sensitivity to extent of ankle inversion movement.

BACKGROUND: The capacity of the plantar sole of the foot to convey information about foot position is reduced by conventional smooth boot insoles, compared with barefoot surface contact. OBJECTIVE: To test the hypothesis that movement discrimination may be restored by inserting textured replacement insoles, achieved by changing footwear conditions and measuring the accuracy of judgments of the extent of ankle inversion movement. METHODS: An automated testing device, the ankle movement extent discrimination apparatus (AMEDA), developed to assess active ankle function in weight bearing without a balance demand, was used to test the effects of sole inserts in soccer boots. Seventeen elite soccer players, the members of the 2000 Australian Women's soccer squad (34 ankles), took part in the study. Subjects were randomly allocated to start testing in: bare feet, their own football boots, own football boot and replacement insole, and on the left or right side. Subjects underwent six 50 trial blocks, in which they completed all footwear conditions. The sole inserts were cut to size for each foot from textured rubber "finger profile" sheeting. RESULTS: Movement discrimination scores were significantly worse when subjects wore their football boots and socks, compared with barefoot data collected at the same time. The substitution of textured insoles for conventional smooth insoles in the football boots was found to restore movement discrimination to barefoot levels. CONCLUSIONS: The lower active movement discrimination scores of athletes when wearing football boots with smooth insoles suggest that the insole is one aspect of football boot and sport shoe design that could be modified to provide the sensory feedback needed for accurate foot positioning.

The development of pre- and postsynaptic components of the noradrenergic system in the rat cerebellum.

Evidence based on the ability to accumulate [3H]noradrenaline by a mechanism sensitive to desmethylimipramine suggests that there is a period of hyperinnervation of the cerebellum by noradrenergic fibres around the beginning of the second postnatal week. Different developmental profiles for specific noradrenaline uptake and noradrenaline content indicate that invasion of the tissue by noradrenergic fibres precedes their full acquisition of transmitter. Developmental increases in the density of beta-receptors and adenyl cyclase responsiveness to isoproterenol lags behind those of the presynaptic components and does not begin until the hyperinnervation is declining around day 12.

The effects of neonatal pedunclectomy on [3H]noradrenaline uptake and the development of beta-adrenergic receptors in the rat cerebellum.

A newly developed method for cutting the cerebellar peduncles in neonatal rats has allowed the study of the development of cerebellar beta-adrenergic receptors in the absence of noradrenergic afferents. Cutting the cerebellar peduncles of neonatal animals did not affect the pattern of development of the beta-adrenergic receptors, nor their final numbers. Pedunclectomy induced a decline in the ability of slices of cerebellar cortex to accumulate [3H]noradrenaline although high-affinity noradrenaline uptake, was never completely abolished. It is suggested that the remaining high-affinity noradrenaline uptake cannot be attributed to noradrenergic fibres from the locus coeruleus.