Effectiveness of a Back School and Postural Education Program on the improvement of literacy about postures and low back pain in adolescents: A 1-year follow-up study.

BACKGROUND: Some health problems can be associated with the school environment and lifestyles, so it is necessary to carry out intervention actions that promote health and problem prevention. This study evaluates the effects of a Back School and Postural Education on improving short-term and long-term ergonomic knowledge of postures adopted at school and home, as well as reducing low back pain (LBP) in adolescents. METHODS: The sample comprises 98 students, aged 10-16 years (11.61 ± 1.28 years), with 63 (64.3%) girls. The measuring instruments included a theoretical and a practical test, a low back pain (LBP) questionnaire and a scale. The tests and the scale have been applied 1 week before the intervention, 1 week following the Back School and Postural Education Program, and a 1 year later. The questionnaire was applied 1 week before of intervention and after 1 year. The intervention included three sessions of a theoretical and practical nature, each lasting 45 min, with intervals of 1 week. RESULTS: The values of the theoretical test before the intervention, 1 week, and 1 year after the intervention were, respectively, 8.67 ± 2.64, 11.37 ± 1.93, and 11.11 ± 1.92 (p ≤ 0.001), and the practical test were 6.42 ± 2.47, 12.48 ± 2.25, and 12.83 ± 1.78 (p ≤ 0.001). The presence of LBP fell by 42.9%-25.5% after the 1-year period. CONCLUSIONS: Our data show an improvement of ergonomic knowledge of postures adopted at school and home as a result of the education program and a decrease of self-reported LBP.

Effects of therapeutic exercise and aerobic exercise programmes on pain, anxiety and oral health-related quality of life in patients with temporomandibular disorders.

BACKGROUND: Pain and anxiety contribute to decreasing quality of life related to oral health in patients with temporomandibular disorders (TMD). Evidence-based practice has shown that therapeutic and aerobic exercise programmes are adequate strategies for modifying these factors. OBJECTIVE: To assess the effects of aerobic exercise on pain, anxiety and quality of life related to oral health in patients with TMD. METHODS: Forty-five patients diagnosed with TMD were divided into three groups of 15 participants: a therapeutic exercise programme (G1, mean 26.9 ± 5.5 years), a therapeutic and aerobic exercise programme (G2, mean 26 ± 4.4 years) and an aerobic exercise programme (G3, mean 24.9 ± 3.4 years). Pain intensity was assessed using a numerical rating scale (NRS), anxiety level and quality of life related to oral health through GAD-7 and OHIP-14, respectively. These parameters were evaluated twice at baseline (T0a/T0b), ending 8-week intervention period (T1) and 8-12 weeks after ending intervention (T2). RESULTS: NRS significantly decreased in G1 (mean difference T0a/T1 = 5.2, p Ë‚ .001), G2 (mean difference T0a/T1 = 6.0, p Ë‚ .001) and G3 (mean difference T0a/T1 = 2.2, p = 0.001). OHIP-14 significantly decreased in G1 (mean difference T0a/T1 = 13.5, p Ë‚ .001) and G2 (mean difference T0a/T1 = 15.8, p ˂ 0.001) but not in G3 (mean difference T0a/T1 = 1.2, p = 0.55). There were no significant differences between groups regarding GAD-7. Between T1 and T2, there were no significant differences in variables. CONCLUSION: Therapeutic exercises and therapeutic excercises combined with aerobic exercise groups had a significant decrease in pain and oral health-related quality of life at 8 and 12 weeks. These decreases were not seen for the aerobic exercise group.

Shear Wave Elastographic Investigation of the Immediate Effects of Slump Neurodynamics in People With Sciatica.

OBJECTIVES: Neurodynamic techniques are often used to treat people with sciatica pain, but their mechanical effects on the sciatic nerve are unknown. Shear wave elastography (SWE) has been shown to effectively estimate the stiffness of peripheral nerves in real time. The aim of this study was to use SWE to assess the effects of slump neurodynamics in the sciatic stiffness of people with sciatica. METHODS: Sixteen participants volunteered for this study. The sciatic stiffness of 8 patients with unilateral chronic sciatica and 8 healthy control participants was measured by SWE, with the participants in a prone position and during a dynamic condition (ie, ankle dorsiflexion). These measurements were performed before and immediately after the neurodynamic intervention, which consisted of a static slump position applied to the symptomatic limb of the patients with sciatica and in a randomly chosen limb of the healthy participants. RESULTS: The 8 patients with sciatica included 6 male and 2 female patients, and the 8 healthy control participants included 5 male and 3 female volunteers. Slump neurodynamics resulted in an immediate decrease in the sciatic nerve stiffness of the symptomatic limb in people with sciatica by 16.1% (effect size = 0.65; P = .019). The intervention showed no significant changes in the sciatic nerve stiffness of the healthy participants (effect size = 0.05; P = .754). CONCLUSIONS: Slump neurodynamics have the potential of decreasing the sciatic nerve stiffness in people with sciatica, and this effect can be quantified by SWE, which may provide valuable information for health professionals.

Is Biceps Femoris Aponeurosis Size an Independent Risk Factor for Strain Injury?

This study examined whether professional footballers with previous biceps femoris long head (BFLH) injury in the last 3-years present a smaller proximal aponeurosis (Apo-BFLH) size compared to footballers with no previous injury. We examined the Apo-BFLH and BFLH size using magnetic resonance imaging and tested the knee flexor maximal isometric strength in 80 thighs of 40 footballers. Apo-BFLH size parameters were processed using a semi-automated procedure. Outcomes were compared between thighs with (n=9) vs. without (n=71) previous BFLH injury. No differences were observed between injured and non-injured thighs for the Apo-BFLH and BFLH size parameters (p>0.05) except for Apo-BFLH volume, which was higher in the non-injured thighs of athletes with previous injury (3692.1±2638.4 mm3, p<0.006) compared to the left (2274.1±798.7 mm3) thighs of athletes without previous injury. A higher knee flexor isometric strength was observed in the injured limb of athletes with previous BFLH injury (196.5±31.9 Nm, p<0.003) compared to the left (156.2±31.4 Nm) and right (160.0±31.4 Nm) thighs of non-injured athletes. The present results suggest that BFLH proximal aponeurosis size should not be considered as an independent risk factor for strain injury.

Noninvasive Measurement of Sciatic Nerve Stiffness in Patients With Chronic Low Back Related Leg Pain Using Shear Wave Elastography.

OBJECTIVES: The purpose of this study was to determine whether sciatic nerve stiffness is altered in people with chronic low back-related leg pain by using shear wave elastography. METHODS: In this cross-sectional study, the sciatic nerve shear wave velocity (ie, an index of stiffness) was measured in both legs of 16 participants (8 with unilateral low back-related leg pain and 8 healthy controls). Sciatic stiffness was measured during a passive ankle dorsiflexion motion performed at 2°/s in an isokinetic dynamometer. The ankle range of motion and passive torque, as well as muscle activity, were also measured. RESULTS: In people with low back-related leg pain, the affected limb showed higher sciatic nerve stiffness compared to the unaffected limb (+11.3%; P = .05). However, no differences were observed between the unaffected limb of people with low back-related leg pain and the healthy controls (P = .34). CONCLUSIONS: People with chronic low back-related leg pain have interlimb differences in sciatic nerve stiffness, as measured by a safe and noninvasive method: shear wave elastography. The changes found may be related to alterations in nerve mechanical properties, which should be confirmed by future investigations.

Hamstring stiffness pattern during contraction in healthy individuals: analysis by ultrasound-based shear wave elastography.

PURPOSE: To assess the stiffness of hamstring muscles during isometric contractions in healthy individuals, using ultrasound-based shear wave elastography to (1) determine the intra- and inter-day assessment repeatability, (2) characterize the stiffness of semitendinosus (ST) and biceps femoris long head (BFlh) along the contraction intensity, and (3) characterize stiffness distribution among the hamstring muscles and inter-limb symmetry. METHODS: Two experiments were conducted. In experiment I (n = 12), the intra-day repeatability in assessing the BFlh and ST stiffness were determined at intensities between 10-60% of maximal voluntary isometric contraction (MVIC) in a single session. In experiment II (n = 11), the stiffness of the hamstring muscles of both thighs was assessed at 20% of MVIC in the first session; and retested (for one randomly chosen thigh) in a second session. Isometric contraction of knee flexors was performed with the knee flexed at 30° and with the hip in a neutral position. RESULTS: Moderate-to-very-high intra- and inter-day repeatability was found (ICC = 0.69-0.93). The BFlh/ST stiffness ratio increased with contraction intensity. At 20% of MVIC, the ST showed the highest stiffness among the hamstring muscles (p < 0.02), with no differences between the remaining hamstring muscles (p > 0.474). No differences were found between limbs (p = 0.12). CONCLUSIONS: The stiffness distribution among the hamstring muscles during submaximal isometric contractions is heterogeneous, but symmetric between limbs, and changes depending on the contraction intensity. Shear wave elastography is a reliable tool to assess the stiffness of hamstring muscles during contraction.

The Relationship Between Muscular Strength and Dance Injuries: A Systematic Review.

BACKGROUND: The physical demands placed on dancers put them at significant risk for injury, with rates similar to ones sustained by athletes in sports at the same level of performance. Muscle strength has been suggested to play a preventative role against injury in dancers. OBJECTIVE: To systematically search and examine the available evidence on the protective role of muscle strength in dance injuries. METHODS: Five electronic databases and two dance-specific science publications were screened up to September 2015. Study selection was based on a priori inclusion criteria on the relation between muscle strength components and injuries. Methodologic quality and level of evidence were assessed using the Downs and Black (DB) checklist and the Oxford Centre of Evidence-Based Medicine (OCEBM) 2011 model. RESULTS: From 186 titles found, only 8 studies met the inclusion criteria and were considered for review. Because of the significant heterogeneity of the included studies, meta-analysis was deemed inappropriate. The DB quality assessment results ranged from 18.7% to 75% (mean 42.3±16.9) and the OCEBM between 2b and 4. Some level 2b evidence from 2 studies suggested that pre-professional ballet dancers who get injured exhibit lower overall muscle strength scores on the lower extremity, and that lower extremity power gains may be associated with decreased bodily pain but not injury rate. CONCLUSIONS: Although there might be an association trend toward low muscle strength and dance injuries, the nature of that relation remains unclear, and presently the state of knowledge does not provide a solid basis for designing interventions for prevention.

Efficacy of suit therapy on functioning in children and adolescents with cerebral palsy: a systematic review and meta-analysis.

AIM: This systematic review and meta-analysis presents an overview of the efficacy of suit therapy on functioning in children and adolescents with cerebral palsy (CP). METHOD: A systematic review with meta-analysis was conducted. A comprehensive search of peer-reviewed articles was performed on electronic databases, from their inception to May 2014. Studies included were rated for methodological quality using the Physiotherapy Evidence Database scale. Effects of suit therapy on functioning were assessed using meta-analytic techniques. RESULTS: From the 46 identified studies, four met the inclusion criteria and were included in the meta-analysis. Small, pooled effect sizes were found for gross motor function at post-treatment (g=0.46, 95% confidence interval [CI] 0.10-0.82) and follow-up (g=0.47, 95% CI 0.03-0.90). INTERPRETATION: The small number of studies, the variability between them, and the low sample sizes are limitations of this review. Findings suggest that to weigh and balance benefits against harms, clinicians, patients, and families need better evidence to examine and prove the effects of short intensive treatment such as suit therapy on gross motor function in children and adolescents with CP. Therefore, more research based on high-quality studies focusing on functioning in all dimensions of the International Classification of Functioning, Disability and Health perspective is necessary to clarify the impact of suit therapy.

Body surface posture evaluation: construction, validation and protocol of the SPGAP system (Posture evaluation rotating platform system).

BACKGROUND: Several posture evaluation devices have been used to detect deviations of the vertebral column. However it has been observed that the instruments present measurement errors related to the equipment, environment or measurement protocol. This study aimed to build, validate, analyze the reliability and describe a measurement protocol for the use of the Posture Evaluation Rotating Platform System (SPGAP, Brazilian abbreviation). METHODS: The posture evaluation system comprises a Posture Evaluation Rotating Platform, video camera, calibration support and measurement software. Two pilot studies were carried out with 102 elderly individuals (average age 69 years old, SD = ±7.3) to establish a protocol for SPGAP, controlling the measurement errors related to the environment, equipment and the person under evaluation. Content validation was completed with input from judges with expertise in posture measurement. The variation coefficient method was used to validate the measurement by the instrument of an object with known dimensions. Finally, reliability was established using repeated measurements of the known object. RESULTS: Expert content judges gave the system excellent ratings for content validity (mean 9.4 out of 10; SD 1.13). The measurement of an object with known dimensions indicated excellent validity (all measurement errors <1 %) and test-retest reliability. A total of 26 images were needed to stabilize the system. Participants in the pilot studies indicated that they felt comfortable throughout the assessment. The use of only one image can offer measurements that underestimate or overestimate the reality. To verify the images of objects with known dimensions the values for the width and height were, respectively, CV 0.88 (width) and 2.33 (height), SD 0.22 (width) and 0.35 (height), minimum and maximum values 24.83-25.2 (width) and 14.56 - 15.75 (height). In the analysis of different images (similar) of an individual, greater discrepancies were observed in the values found. The cervical index, for example, presented minimum and maximum values of 15.38 and 37.5, a coefficient of variation of 0.29 and a standard deviation of 6.78. CONCLUSIONS: The SPGAP was shown to be a valid and reliable instrument for the quantitative analysis of body posture with applicability and clinical use, since it managed to reduce several measurement errors, amongst which parallax distortion.

Reliability of the Active-Knee-Extension and Straight-Leg-Raise Tests in Subjects With Flexibility Deficits.

CONTEXT: The active-knee-extension test (AKE) and the straight-leg-raise test (SLR) are widely used for flexibility assessment. A number of investigations have tested the reliability of these measures, especially the AKE. However, in most studies, the sample involved subjects with normal flexibility. In addition, few studies have determined the standard error of measurement (SEM) and minimal detectable difference (MDD), which can provide complementary and more clinically relevant information than the intraclass correlation coefficient (ICC) alone. OBJECTIVES: This study aimed to determine the AKE and SLR intrarater (test-retest) reliability in subjects with flexibility deficits, as well as the correlation between the 2 tests. DESIGN: Reliability study, test-retest design. SETTING: Academic laboratory. SUBJECTS: 102 recreationally active participants (48 male, 54 female) with no injury to the lower limbs and with flexibility deficits in the hamstrings muscle group. MAIN OUTCOMES: Intrarater reliability was determined using the ICC, complemented by the SEM and MDD. MEASURES: All participants performed, in each lower limb, 2 trials of the AKE and the SLR. RESULTS: The ICC values found for AKE and SLR tests were, respectively, .87-.94 and .93-.97. The values for SEM were low for both tests (2.6-2.9° for AKE, 2.2-2.6° for SLR), as well as the calculated MDD (7-8° for AKE; 6-7° for SLR). A moderate to strong, and significant, correlation between AKE and SLR was determined for the dominant limb (r = .71) and the nondominant limb (r = .67). CONCLUSIONS: These findings suggest that both AKE and SLR have excellent intrarater reliability. The SEMs and MDDs recorded are also very encouraging for the use of these tests in subjects with flexibility deficits.

Non-specific low back pain in adolescents from the south of Portugal: prevalence and associated factors.

BACKGROUND: Low back pain (LBP) is a common condition in children and adolescents, and the prevalence has been increasing over the years. Most cases of LBP are due to non-specific causes; however, the role of these risk factors is still controversial. This study determined the prevalence of LBP in Portuguese adolescents and characterized the associated factors. METHODS: The design of this study was observational, analytical and cross-sectional. The sample included 966 adolescents from southern Portugal, aged between 10 and 16 years. The assessments included a questionnaire to characterize the presence of LBP, postural habits, body mass index (BMI) and backpack weights and to use a scoliometer to evaluate the presence of scoliosis. RESULTS: One hundred fifty-two (15.7 %) students had LPB at the present time, 456 (47.2 %) had experienced it in the last year, and 600 (62.1 %) had lifetime prevalence of LBP. Girls have 2.05 more probability of presenting LBP than boys (95 % CI 1.58-2.65; p < 0.001), and older students have a 1.54 greater probability (95 % CI 1.19-1.99; p = 0.001). Students who sit with the spine incorrectly positioned presented 2.49 greater probability of having LBP (95 % CI 1.91-3.2; p < 0.001), students using improper positions for watching TV or playing games have 2.01 greater probabilities (95 % CI 1.55-2.61; p < 0.001), and those who adopt an incorrect standing posture have a 3.39 greater chance of experiencing LBP (95 % CI 2.19-5.23; p < 0.001). CONCLUSIONS: This study found a high prevalence of LBP in adolescents, with higher values in older students, female students and those who adopted incorrect positions when sitting or standing.

Body mass index and waist circumference to define thinness, overweight and obesity in Portuguese adolescents: comparison between CDC, IOTF, WHO references.

OBJECTIVES: This study compared the criteria or classification of Body Mass Index (BMI) by Centers for Disease Control and Prevention (CDC), International Obesity Task Force (IOTF) and World Health Organization (WHO) references and by waist circumference (WC). METHODS: The sample involved 966 students aged 10 to 16 years. The evaluation of weight status was verified according to CDC, IOTF, WHO criteria and WC curves for Portuguese adolescents. RESULTS: For classification of overweight and obesity, the agreement between the criteria of CDC and IOTF was the and WC (K = 0.34). In regard to evaluation of thinness, the agreement between all criteria of BMI was considered moderated to fair (K = 0.33-0.51) and a poor level of agreement between the BMI and WC (K = 0.14-0.16). CONCLUSION: The highest level of agreement for thinness, overweight and obesity classification in adolescents was obtained with the IOTF and CDC criteria.

Prevalence of scoliosis in southern Portugal adolescents.

OBJECTIVES: This study determines the prevalence of scoliosis in southern Portugal adolescents and characterizes possible factors associated with this disorder. METHODS: The sample consisted of 966 students, aged between 10 and 16 years. The instruments involved were a scoliometer and a questionnaire of postural habits. RESULTS: Scoliosis was present in 41 (4.2%) students. The girls showed the highest prevalence (4.5%) and the same was observed in those with delayed menarche (8.6%) that was thin (7.1%), which adopted incorrect sitting posture (4.4%), who remained in the upright posture wrongly (5.3%) and pick up the objects incorrectly (4.4%). However no statistically significant association between these characteristics and the presence of scoliosis was observed. CONCLUSIONS: The study revealed a lower prevalence of scoliosis in a representative and stratified sample of southern Portugal adolescents. The development of longitudinal studies is essential and must be carefully developed to validate these results.

Semitendinosus and biceps femoris long head activity during the single leg bridge test in healthy individuals.

INTRODUCTION: The single leg bridge test (SLBT) has been suggested as a clinical test to examine function, screen injury risk, and monitor the effectiveness of rehabilitation programes targeting the hamstring. This study aimed to determine the inter-day reliability and repeatability of both SLBT performance, semitendinosus (ST), and biceps femoris long head (BFlh) surface electromyography (sEMG) responses and characterise the BFlh and ST electrical activity during the SLBT performed until exhaustion in healthy individuals. METHODS: Twelve physically active young men without previous hamstring injury were tested for the number of repetitions attained, and sEMG signal median frequency and amplitude in both ST and BFlh of each lower limb, randomly in two sessions, with a seven-day interval between sessions. RESULTS: High reliability [ICC = 0.85] was found for the number of SLBT repetitions attained. Reliability of sEMG outcomes showed better results for ST (ICC = 0.62-0.91) than for BFlh (ICC = 0.39-0.81), and a high to very-high repeatability was found for both ST (ICC = 0.91-0.84) and BFlh (ICC = 0.91-0.85). sEMG median frequency decreased and amplitude increased for both BFlh (p ≤ 0.001) and ST (p ≤ 0.039) at the end of SLBT, suggesting localised fatigue. CONCLUSIONS: The SLBT performed by healthy individuals until exhaustion proved to be reliable and to induce fatigue in both BFlh and ST, where the sEMG median frequency and amplitude can be measured on different days with acceptable reliability and high repeatability, suggesting its potential future use in both practical and clinical settings.

Effect of Glycerol and Sisal Nanofiber Content on the Tensile Properties of Corn Starch/Sisal Nanofiber Films.

Currently, petroleum-derived plastics are widely used despite the disadvantage of their long degradation time. Natural polymers, however, can be used as alternatives to overcome this obstacle, particularly cornstarch. The tensile properties of cornstarch films can be improved by adding plant-derived nanofibers. Sisal (Agave sisalana), a very common low-cost species in Brazil, can be used to obtain plant nanofibers. The goal of this study was to obtain sisal nanofibers using low concentrations of sulfuric acid to produce thermoplastic starch nanocomposite films. The films were produced by a casting technique using commercial corn starch, glycerol, and sisal nanofibers, accomplished by acid hydrolysis. The effects of glycerol and sisal nanofiber content on the tensile mechanical properties of the nanocomposites were investigated. Transmission electron microscopy findings demonstrated that the lowest concentration of sulfuric acid produced fibers with nanometric dimensions related to the concentrations used. X-ray diffraction revealed that the untreated fibers and fibers subjected to acid hydrolysis exhibited a crystallinity index of 61.06 and 84.44%, respectively. When the glycerol and nanofiber contents were 28 and 1%, respectively, the tensile stress and elongation were 8.02 MPa and 3.4%. In general, nanocomposites reinforced with sisal nanofibers showed lower tensile stress and higher elongation than matrices without nanofibers did. These results were attributed to the inefficient dispersion of the nanofibers in the polymer matrix. Our findings demonstrate the potential of corn starch nanocomposite films in the packaging industry.

Automatic mapping of high-risk urban areas for Aedes aegypti infestation based on building facade image analysis.

BACKGROUND: Dengue, Zika, and chikungunya, whose viruses are transmitted mainly by Aedes aegypti, significantly impact human health worldwide. Despite the recent development of promising vaccines against the dengue virus, controlling these arbovirus diseases still depends on mosquito surveillance and control. Nonetheless, several studies have shown that these measures are not sufficiently effective or ineffective. Identifying higher-risk areas in a municipality and directing control efforts towards them could improve it. One tool for this is the premise condition index (PCI); however, its measure requires visiting all buildings. We propose a novel approach capable of predicting the PCI based on facade street-level images, which we call PCINet. METHODOLOGY: Our study was conducted in Campinas, a one million-inhabitant city in São Paulo, Brazil. We surveyed 200 blocks, visited their buildings, and measured the three traditional PCI components (building and backyard conditions and shading), the facade conditions (taking pictures of them), and other characteristics. We trained a deep neural network with the pictures taken, creating a computational model that can predict buildings' conditions based on the view of their facades. We evaluated PCINet in a scenario emulating a real large-scale situation, where the model could be deployed to automatically monitor four regions of Campinas to identify risk areas. PRINCIPAL FINDINGS: PCINet produced reasonable results in differentiating the facade condition into three levels, and it is a scalable strategy to triage large areas. The entire process can be automated through data collection from facade data sources and inferences through PCINet. The facade conditions correlated highly with the building and backyard conditions and reasonably well with shading and backyard conditions. The use of street-level images and PCINet could help to optimize Ae. aegypti surveillance and control, reducing the number of in-person visits necessary to identify buildings, blocks, and neighborhoods at higher risk from mosquito and arbovirus diseases.

Hamstring Stiffness and Strength Responses to Repeated Sprints in Healthy Nonathletes and Soccer Players With Versus Without Previous Injury.

BACKGROUND: The effect of 10 × 30 m repeated sprints on passive and active stiffness of semitendinosus (ST) and biceps femoris long head (BFlh), and knee flexor maximal voluntary isometric contraction (MVIC) and rate of force development (RFD), and whether athletes with previous hamstring injury have a different response, is unknown. HYPOTHESIS: Repeated sprints would (1) increase BFlh stiffness and decrease ST stiffness and knee flexors MVIC and RFD in healthy participants; and (2) greater magnitude of response would be seen in athletes with previous hamstring injury. STUDY DESIGN: Case series (experiment I) and case control (experiment II) study designs. LEVEL OF EVIDENCE: Level 3. METHODS: Healthy nonathletes attended 2 replicated sessions (experiment I, n = 18), while soccer players with (n = 38) and without (n = 67) previous hamstring injury attended 1 testing session (experiment II). RESULTS: In both experiments, the knee flexors MVIC and RFD decreased after the sprints (P < 0.05). In experiment I, the ST and BFlh passive stiffness reduced after the sprints (P < 0.02), while a small BFlh active stiffness increase was noted (P = 0.02); however, no correlation was observed between the 2 testing sessions for the postsprint muscle stiffness responses (r = -0.07-0.44; P > 0.07). In experiment II, only an ST passive stiffness reduction was observed after the sprints (P < 0.01). No differences were noted between injured and noninjured lower limbs for any variable (P > 0.10). CONCLUSION: Repeated sprints are likely to decrease the knee flexor's maximal and rapid strength, and to alter the hamstring stiffness in the nonathlete population. Previous hamstring injury does not apparently affect the footballer's hamstring functional and mechanical responses to repeated sprints. CLINICAL RELEVANCE: The responses of hamstring stiffness and knee flexor strength to repeated sprints are unlikely to be associated with hamstring injury.

Prevalence of musculoskeletal disorders among dental students: A systematic review and meta-analysis.

Objectives: This study aimed to determine the prevalence of work-related musculoskeletal disorders (WMSDs) in dental students and analyze the potential associated risk factors. Methods: This review was registered in PROSPERO with the number CRD42022349864. We performed a meta-analysis calculating event rates with relative 95% confidence intervals for each body region. Two investigators systematically searched Cochrane, Pubmed, Scopus, and EBSCO databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results: Sixteen studies, with 3761 dental students, were included. The highest 7-day prevalence was in the lower back (27.2%; 95% CI 20-35), neck (27%; 95% CI 19.1-35.8), and upper back (24.2%; 95% CI 17.2-32). Yearly occurrence was mainly in the neck (51%; 95% CI 41-61), followed by shoulders (45.3%; 95% CI 37.6-53.1) and lower back (42%; 95% CI 34.1-50.2) and a fraction of these reported that symptoms in lower-back (15.2%; 95% CI 12.1-18.5), neck (13.9%; 95% CI 10.6-17.5) and shoulders (12.2%; 95% CI 8.7-16.3) affected work or normal activities. Associated contributing factors include female sex, poor posture habits, inadequate ergonomics knowledge, sedentary lifestyle, high physical activity levels, poor quality of life, and smoking. In contrast, engaging in physical exercise has positively impacted mitigating the risk of musculoskeletal disorders. Conclusions: WMSDs have a high prevalence among dental students, particularly in the cervicothoracic, lumbar, and shoulder regions, having a significant impact since training years. Further research with a multidimensional approach with psychosocial and physical assessments is recommended to understand this issue thoroughly.

Irish Dancing Injuries and Associated Risk Factors: A Systematic Review.

Irish dance is growing in popularity, evolving to a more athletic and demanding dance style. The aim of this study is to conduct a systematic review, previously registered with PROSPERO, to identify the prevalence, incidence, and the injury pattern among Irish dancers and analyse the associated risk factors. Six online databases and two dance-specific science publications were searched systematically. Studies were included if the patterns of injuries among Irish dancers were evaluated or the factors associated with injury were analysed, published in English or Portuguese, in peer-reviewed scientific journals. Four reviewers assessed the quality and level of evidence using the Downs and Black criteria and a modified Oxford Centre of Evidence-Based Medicine 2009 model, respectively. Eleven articles were included, eight of Level 3c (cross-sectional) and three of Level 3b (prospective). Mean DB percentage score was 63% ± 7.2%. Prevalence ranged from 72.2% to 92.6%, affecting mostly the foot/ankle complex. Only two articles reported incidence, which ranged from 3.4 to 10.6 injuries/1000 h danced depending on injury definition. Psychological factors, elite level, and insufficient/poor sleep were associated with musculoskeletal injury. Injury prevalence and incidence is high in Irish dancers, with the foot and ankle being more affected. Due to heterogeneity in injury definitions, methods, and populations, along with the need for improvement in studies quality, recommendations were made for future research.

Immediate and short-term effects of eccentric muscle contractions on structural, morphological, mechanical, functional and physiological properties of peripheral nerves: A protocol for a systematic review and meta-analysis.

BACKGROUND: It is widely acknowledged that eccentric muscle contractions may cause skeletal muscle damage. However, there is little knowledge about the impact of eccentric contractions on non-muscular structures. Animal and human studies revealed that eccentric contractions can also induce immediate and short-term nerve dysfunction. The purpose of this review is to examine whether eccentric muscle contractions induce immediate and short-term effects on structural, morphological, mechanical, functional and physiological properties of peripheral nerves, from both animal and human studies. METHODS AND ANALYSIS: A systematic review of randomised (RCTs) and non-randomised controlled trials will be conducted. Four electronic databases (i.e., Medline/Pubmed, Science Direct, PEDro and Cochrane) will be searched using predefined search terms to identify relevant studies. Eligible studies have to comprise any type of eccentric contraction of upper or lower limb muscles. Primary outcomes will include measures related to structure, morphology, mechanical, functional and physiological properties of peripheral nerves. Two independent reviewers will assess eligibility, evaluate risk of bias, and extract relevant data. In human studies, the risk of bias will be assessed by the Cochrane Collaboration risk of bias tool (RoB 2.0 tool) for RCTs and by risk of bias in non-randomised studies of interventions (ROBINS-I) for non-randomised controlled trials; while for animal studies, the risk of bias will be assessed using the SYRCLE's RoB tool. A narrative synthesis will be conducted for all included studies. Also, if appropriate, a meta-analysis will be performed, where the effect size of each outcome will be determined by the standardized mean difference as well as the 95% confidence intervals. I2 statistics will be used to assess heterogeneity. ETHICS AND DISSEMINATION: For this study, no ethical approval is required. Findings will be disseminated widely through peer-reviewed publication and conference presentations. SYSTEMATIC REVIEW REGISTRATION: The protocol has been registered at the International Prospective Register of Systematic Reviews (PROSPERO). Registration number: CRD42021285767.