Effects of Foot Position during Squatting on the Quadriceps Femoris: An Electromyographic Study

International Journal of Exercise Science 6(2) : 114-125, 2013. Weightlifters have commonly believed that changing joint position can alter specific muscle activation. The magnitude of force produced by a muscle is highly dependent upon the length of the muscle. The purpose of this study was to determine the effect of foot positioning on muscle activation of the superficial quadriceps as measured by surface electromyography (sEMG) during a functional squatting movement in healthy adults. Twenty physically active asymptomatic adults (7 females and 13 males) were included in the study while four different foot positions (Neutral, Internally Rotated, Externally Rotated, and Staggered) were assessed. Three quadriceps muscles (Rectus Femoris (RF), Vastus Medialis Oblique (VMO), and Vastus Lateralis Oblique(VLO) were measured. Raw EMG was transformed using a root mean square algorithm. Six one-way repeated measure ANOVAs were conducted to examine the peak and average RMS amplitude for each muscle across each condition, with an alpha level of 0.05 set a priori. Across all foot positions only the Staggered foot position reached statistical significance when compared to all other foot positions for each muscle group. Results suggest that altering the foot position during a partial weight squat has little to no effect on the EMG amplitudes of the quadriceps. However, more research is needed to examine the concentric and eccentric phases of the squatting motion separately with the addition of full weight bearing squats

Optogenetic Interrogation of Functional Synapse Formation by Corticospinal Tract Axons in the Injured Spinal Cord

To restore function after injury to the CNS, axons must be stimulated to extend into denervated territory and, critically, must form functional synapses with appropriate targets. We showed previously that forced overexpression of the transcription factor Sox11 increases axon growth by corticospinal tract (CST) neurons after spinal injury. However, behavioral outcomes were not improved, raising the question of whether the newly sprouted axons are able to form functional synapses. Here we developed an optogenetic strategy, paired with single-unit extracellular recordings, to assess the ability of Sox11-stimulated CST axons to functionally integrate in the circuitry of the cervical spinal cord. Initial time course experiments established the expression and function of virally expressed Channelrhodopsin (ChR2) in CST cell bodies and in axon terminals in cervical spinal cord. Pyramidotomies were performed in adult mice to deprive the left side of the spinal cord of CST input, and the right CST was treated with adeno-associated virus (AAV)–Sox11 or AAV–EBFP control, along with AAV–ChR2. As expected, Sox11 treatment caused robust midline crossing of CST axons into previously denervated left spinal cord. Clear postsynaptic responses resulted from optogenetic activation of CST terminals, demonstrating the ability of Sox11-stimulated axons to form functional synapses. Mapping of the distribution of CST-evoked spinal activity revealed overall similarity between intact and newly innervated spinal tissue. These data demonstrate the formation of functional synapses by Sox11-stimulated CST axons without significant behavioral benefit, suggesting that new synapses may be mistargeted or otherwise impaired in the ability to coordinate functional output. SIGNIFICANCE STATEMENT As continued progress is made in promoting the regeneration of CNS axons, questions of synaptic integration are increasingly prominent. Demonstrating direct synaptic integration by regenerated axons and distinguishing its function from indirect relay circuits and target field plasticity have presented technical challenges. Here we force the overexpression of Sox11 to stimulate the growth of corticospinal tract axons in the cervical spinal cord and then use specific optogenetic activation to assess their ability to directly drive postsynaptic activity in spinal cord neurons. By confirming successful synaptic integration, these data illustrate a novel optogenetic-based strategy to monitor and optimize functional reconnection by newly sprouted axons in the injured CNS

Athletes Who Train on Unstable Compared to Stable Surfaces Exhibit Unique Postural Control Strategies in Response to Balance Perturbations

Background Athletes have been shown to exhibit better balance compared to non-athletes (NON). However, few studies have investigated how the surface on which athletes train affects the strategies adopted to maintain balance. Two distinct athlete groups who experience different types of sport-specific balance training are stable surface athletes (SSA) such as basketball players and those who train on unstable surfaces (USA) such as surfers. The purpose of this study was to investigate the effects of training surface on dynamic balance in athletes compared to NON. Methods Eight NON, eight SSA, and eight USA performed five 20-s trials in each of five experimental conditions including a static condition and four dynamic conditions in which the support surface translated in the anteroposterior (AP) or mediolateral (ML) planes using positive or negative feedback paradigms. Approximate entropy (ApEn) and root mean square distance (RMS) of the center of pressure (CoP) were calculated for the AP and ML directions. Four 3 × 5 (group × condition) repeated measures ANOVAs were used to determine significant effects of group and condition on variables of interest. Results USA exhibited smaller ApEn values than SSA in the AP signals while no significant differences were observed in the ML CoP signals. Generally, the negative feedback conditions were associated with significantly greater RMS values than the positive feedback conditions. Conclusion USA exhibit unique postural strategies compared to SSA. These unique strategies seemingly exhibit a direction-specific attribute and may be associated with divergent motor control strategies

Relationship between the Romberg Test and the Wii Basic Balance Test and Cognition in Athletes with Concussion

Background: Approximately 30% of individuals with a sport-related concussion present with postural instability. Multiple clinical balance tests exist to diagnose postural instability; yet little is known about the potential relationship between these type of postural assessments and cognition post-concussion. Aim: The purpose of the current study was to assess the relationship between the Romberg test, the Wii Fit basic balance test (WBBT), and the composite scores on the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) test in a sample of athletes with concussions. Methods: 55 post-concussed athletes (40 male) completed the Romberg Test (RT) (−/+), the WBBT, and ImPACT test. Wii Fit basic balance test performance was operationalized as the number of successfully completed trials (of 5 trials of increasing difficulty) within 30 seconds. Pearson’s and point-biserial correlations examined univariate associations among the variables. Results: The RT and WBBT were not significantly related (r = −0.029, p = 0.832). The RT weakly correlated with ImPACT impairment scores (r= 0.26, p= 0.041), whereas WBBT the number of trials did not (r = − 0.20, p = 0.155). Romberg Test scores were significantly correlated with ImPACT Visual Processing Speed Score (r = 0.27, p = 0.036) and Reaction Time score (r = 0.34, p = 0.006). In contrast, WBBT trials were significantly correlated with the ImPACT Visual Memory Score (r = − 0.41, p = 0.003). Conclusions: These results suggest that the WBBT and RT assess unique aspects of postural control. The RT may relate directly to single sensory cognitive and motor processing, while the WBBT may relate to multi-sensory visually driven cognitive and motor processing. Relevance for patients: Clinical balance tests could point to different cognitive impairments post-concussion

Return-to-Play Clinical Milestones: Fail-Rate for Those Claiming to Be Fully Symptom Free

Sport-related concussion remains a concerning public health issue. A multifaceted test battery is recommended for clinical judgments, including return-to-play (RTP). Initiation of RTP testing is based on the athletes\u27 honesty with their current symptoms and is confirmed by the multifaceted test battery. PURPOSE: Examine the rates of test failure in NCAA Division I athletes when they present as being symptom free for 24 hours. METHODS: 36 Division I athletes (18 male, 18 female; avg. age=20.1 years) were evaluated at pre-season baselines (BL), within 48 hours of a diagnosed concussion (CON), and when they reported being symptom free (SF) for 24 hours. At each time point, they were evaluated on a symptom severity score (TS), the vestibular/ocular motor screening (VOMS) exam, and tandem gait (TG) under single-task (ST) and dual-task (DT) conditions (serial-7s subtraction). Neurocognitive testing using the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) was only performed at BL and again if they were clinically clear on the VOMS and TG. Lastly, the Buffalo Concussion Treadmill Test (BCTT) was administered at CON and SF using the standard recommended procedures. Concussions were diagnosed using the international consensus criteria alongside symptom presentation and a mechanism of injury. The fail rate was determined if they presented with one or more of the following: 1) a TS of \u3e7 or physiological symptoms (i.e. headaches, dizziness) not present at BL, 2) VOMS change score \u3e2, 3) NPC \u3e5.0cm, 4) ST outside of 1.5s of their BL, 5) DT outside of 1.7s of their BL, 6) declined ImPACT test results determined by a trained clinician using minimal detectable change score, and 7) symptom provocation during the BCTT. RESULTS: A total of 67% (n=23/36) successfully cleared all the testing criteria and moved onto an RTP protocol once subjectively considered SF. 67% (n=12/18) of females and 61% (n=11/18) of males successfully cleared all the testing at their respective impressions of being SF. The average time from CON to SF was 16.8±16.91 days with no significant difference (p=.56) between males (18.50±17.72 days) and females (15.11±16.41 days). CONCLUSION: These results suggest that a multifaceted concussion assessment battery is heavily warranted to determine the athletes\u27 concussion status and readiness for RTP

Circulating microRNAs as biomarkers to assist the management of the malignant germ-cell-tumour subtype choriocarcinoma.

Germ-cell-tumours (GCTs) are heterogeneous and management is complex. The current conventional biomarkers, alpha-fetoprotein and human-chorionic-gonadotropin (HCG), have limited utility for diagnosis/follow-up as secretion is restricted to specific malignant-GCT subtypes and long half-life can make interpretation and clinical decision-making challenging. We sought to identify circulating microRNAs that reflected choriocarcinoma disease activity more accurately than HCG in a metastatic primary mediastinal nonseminomatous-GCT (PMNSGCT) case with elevated diagnostic serum HCG (>250,000U/L), consistent with pure choriocarcinoma. We undertook comprehensive microRNA profiling (n=754 microRNAs) using two 384-well TaqMan Low-Density-Array cards in 16 serum samples; 10 from PMNSGCT diagnosis/follow-up and six controls. Key findings underwent confirmatory qRT-PCR. We identified a serum panel of choriocarcinoma-specific ‘chromosome-19-microRNA-cluster’ (C19MC) microRNAs that were highly elevated at diagnosis but fell rapidly on treatment and normalised before the second full chemotherapy course. We also re-confirmed serum elevation of the previously identified malignant-GCT marker miR-371a-3p at diagnosis. These circulating microRNA markers reflected choriocarcinoma disease activity more accurately than serum HCG and real-time knowledge would have assisted clinical decision-making. With further study, these microRNA markers will facilitate future management of such patients and are likely to result in improved outcomes.Acknowledgment of research support: The authors acknowledge grant funding from the St. Baldrick’s Foundation [reference 358099], the Isaac Newton Trust [reference 15.40f], the Medical Research Council [reference MR/R001146/1] and Addenbrooke’s Charitable Trust [reference 23/17 B (iv)]. We are grateful for support from the Max Williamson Fund and from Christiane and Alan Hodson, in memory of their daughter Olivia. The funders were not involved in study design, data collection or interpretation, or decision to submit for publication

Correlating tephras and cryptotephras using glass compositional analyses and numerical and statistical methods:Review and evaluation

We define tephras and cryptotephras and their components (mainly ash-sized particles of glass ± crystals in distal deposits) and summarize the basis of tephrochronology as a chronostratigraphic correlational and dating tool for palaeoenvironmental, geological, and archaeological research. We then document and appraise recent advances in analytical methods used to determine the major, minor, and trace elements of individual glass shards from tephra or cryptotephra deposits to aid their correlation and application. Protocols developed recently for the electron probe microanalysis of major elements in individual glass shards help to improve data quality and standardize reporting procedures. A narrow electron beam (diameter ~3-5 μm) can now be used to analyze smaller glass shards than previously attainable. Reliable analyses of ‘microshards’ (defined here as glass shards <32 µm in diameter) using narrow beams are useful for fine-grained samples from distal or ultra-distal geographic locations, and for vesicular or microlite-rich glass shards or small melt inclusions. Caveats apply, however, in the microprobe analysis of very small microshards (<=~5 µm in diameter), where particle geometry becomes important, and of microlite-rich glass shards where the potential problem of secondary fluorescence across phase boundaries needs to be recognised. Trace element analyses of individual glass shards using laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS), with crater diameters of 20 μm and 10 μm, are now effectively routine, giving detection limits well below 1 ppm. Smaller ablation craters (<10 μm) can be subject to significant element fractionation during analysis, but the systematic relationship of such fractionation with glass composition suggests that analyses for some elements at these resolutions may be quantifiable. In undertaking analyses, either by microprobe or LA-ICP-MS, reference material data acquired using the same procedure, and preferably from the same analytical session, should be presented alongside new analytical data. In part 2 of the review, we describe, critically assess, and recommend ways in which tephras or cryptotephras can be correlated (in conjunction with other information) using numerical or statistical analyses of compositional data. Statistical methods provide a less subjective means of dealing with analytical data pertaining to tephra components (usually glass or crystals/phenocrysts) than heuristic alternatives. They enable a better understanding of relationships among the data from multiple viewpoints to be developed and help quantify the degree of uncertainty in establishing correlations. In common with other scientific hypothesis testing, it is easier to infer using such analysis that two or more tephras are different rather than the same. Adding stratigraphic, chronological, spatial, or palaeoenvironmental data (i.e. multiple criteria) is usually necessary and allows for more robust correlations to be made. A two-stage approach is useful, the first focussed on differences in the mean composition of samples, or their range, which can be visualised graphically via scatterplot matrices or bivariate plots coupled with the use of statistical tools such as distance measures, similarity coefficients, hierarchical cluster analysis (informed by distance measures or similarity or cophenetic coefficients), and principal components analysis (PCA). Some statistical methods (cluster analysis, discriminant analysis) are referred to as ‘machine learning’ in the computing literature. The second stage examines sample variance and the degree of compositional similarity so that sample equivalence or otherwise can be established on a statistical basis. This stage may involve discriminant function analysis (DFA), support vector machines (SVMs), canonical variates analysis (CVA), and ANOVA or MANOVA (or its two-sample special case, the Hotelling two-sample T² test). Randomization tests can be used where distributional assumptions such as multivariate normality underlying parametric tests are doubtful. Compositional data may be transformed and scaled before being subjected to multivariate statistical procedures including calculation of distance matrices, hierarchical cluster analysis, and PCA. Such transformations may make the assumption of multivariate normality more appropriate. A sequential procedure using Mahalanobis distance and the Hotelling two-sample T² test is illustrated using glass major element data from trachytic to phonolitic Kenyan tephras. All these methods require a broad range of high-quality compositional data which can be used to compare ‘unknowns’ with reference (training) sets that are sufficiently complete to account for all possible correlatives, including tephras with heterogeneous glasses that contain multiple compositional groups. Currently, incomplete databases are tending to limit correlation efficacy. The development of an open, online global database to facilitate progress towards integrated, high-quality tephrostratigraphic frameworks for different regions is encouraged

Exploring views on satisfaction with life in young children with chronic illness: an innovative approach to the collection of self-report data from children under 11

The objective of this study was to explore young children’s views on the impact of chronic illness on their life in order to inform future development of a patient-based self-report health outcome measure. We describe an approach to facilitating self-report views from young children with chronic illness. A board game was designed in order to obtain qualitative data from 39 children with a range of chronic illness conditions and 38 healthy controls ranging in age from 3 to 11 years. The format was effective in engaging young children in a self-report process of determining satisfaction with life and identified nine domains. The board game enabled children aged 5–11 years with chronic illness to describe the effects of living with illness on home, family, friends, school and life in general. It generated direct, non-interpreted material from children who, because of their age, may have been considered unable or limited their ability to discuss and describe how they feel. Obtaining this information for children aged 4 and under continues to be a challenge

Improved physical health in middle-older aged golf caddies following 24-weeks of high-volume physical activity

Background: The physical demands of golf caddying, including walking while carrying a golf bag, may potentially affect body composition, and markers of metabolic, cardiovascular, and musculoskeletal health. Therefore, this study examined the impact of 24 weeks of caddying on physical health in middle-older aged males. Methods: Eleven full-time experienced male caddies (age: 59 [8] y; caddying experience: 14 [12] y) were recruited from a local golf course. The following were assessed at preseason and after 24 weeks of caddying (March–September 2022): body composition, heart rate, blood pressure, blood lipids, and performance tests (static and dynamic balance, strength, and submaximal fitness). Physical activity (PA) levels were assessed at preseason and at the mid-point of the caddying season. Across the caddying season, participants completed a monthly average of 24.0 (3.8) rounds. Results: Following the caddying season, improvements in static balance (Δ = 13.5 s), dynamic balance (Δ = −1.8 s), and lower back absolute strength (Δ = 112.8 N), and muscle quality (Δ = 2.0 N·kg−1) were observed (all P &lt; .05). Additionally, blood lipids, including total cholesterol (Δ = −0.6 mmol·L−1), high-density lipoprotein cholesterol (Δ = 0.1 mmol·L−1), low-density lipoprotein cholesterol (Δ = −0.6 mmol·L−1) (all P &lt; .05), and body composition, including body mass (Δ = −2.7 kg), fat mass (Δ = −1.9 kg), fat percentage (Δ = −1.4%), fat-to-muscle ratio (Δ = −0.03), and body mass index (Δ = −0.9 kg·m−2) (all P &lt; .05) improved. Caddying did not offer beneficial changes to cardiovascular variables or cardiorespiratory fitness (P &gt; .05), while coronary heart disease risk score decreased (Δ = −3.3%) (P &lt; .05). In relation to PA, light- (Δ = 145 min) and moderate-intensity (Δ = 71 min) PA, moderate to vigorous PA (Δ = 73 min), and total PA (Δ = 218 min) between preseason and the mid-point of the caddying season increased, while sedentary time (Δ = −172 min) decreased (all P &lt; .05). Conclusion: Golf caddying can provide several physical health benefits such as improvements in various markers of cardiometabolic health, lower back absolute strength, and static and dynamic balance. The physical health improvements that caddying offers is likely contributed to by increased PA volume and intensity through walking on the golf course. Therefore, caddying may represent a feasible model for increasing PA volume and intensity and achieve physical health–related benefits

Improving the normalization of complex interventions: measure development based on normalization process theory (NoMAD): study protocol

&lt;b&gt;Background&lt;/b&gt; Understanding implementation processes is key to ensuring that complex interventions in healthcare are taken up in practice and thus maximize intended benefits for service provision and (ultimately) care to patients. Normalization Process Theory (NPT) provides a framework for understanding how a new intervention becomes part of normal practice. This study aims to develop and validate simple generic tools derived from NPT, to be used to improve the implementation of complex healthcare interventions.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Objectives&lt;/b&gt; The objectives of this study are to: develop a set of NPT-based measures and formatively evaluate their use for identifying implementation problems and monitoring progress; conduct preliminary evaluation of these measures across a range of interventions and contexts, and identify factors that affect this process; explore the utility of these measures for predicting outcomes; and develop an online users’ manual for the measures.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt; A combination of qualitative (workshops, item development, user feedback, cognitive interviews) and quantitative (survey) methods will be used to develop NPT measures, and test the utility of the measures in six healthcare intervention settings.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Discussion&lt;/b&gt; The measures developed in the study will be available for use by those involved in planning, implementing, and evaluating complex interventions in healthcare and have the potential to enhance the chances of their implementation, leading to sustained changes in working practices