Current Issue : July - September Volume : 2012 Issue Number : 3 Articles : 5 Articles
The aim of this study was to assess the reliability of a novel field test of critical running speed (CS). Ten trained male distance runners completed a familiarisation trial plus three separate experimental trials on a standard 400 m athletics track. Each trial consisted of three distances (1200, 2400 and 3600 metres) that were selected to produce finishing times in the region of 3, 7 and 12 minutes respectively. Participants were instructed to cover the set distance in the fastest time possible. Participants rested for 30 minutes between efforts. Data were modelled using the linear distance-time model, described by the equation: d = (CS x t) ARC, where: d = distance run (m), t = running time (s), and ARC = anaerobic running capacity (m). Results demonstrated a coefficient of variation (CV) of 2.0% (95% confidence limit (95% CL): 1.4-3.8%) for trials 2-1 and 1.3% (95% CL: 0.9-2.4%) for trials 3-2. There was no significant difference in CS (m�·s-1) across trials (P<0.05). The limits of agreement were �±0.27 m�·s-1 of the measure for trials 2-1 and �±0.18 m�·s-1 for trials 3-2. ARC proved to be less reliable with a group CV of 18.4% (95% CL: 13.5- 39.9%) for trials 2-1 and 9.8% (95% CL: 7.0-19.6%) for trials 3-2. Although the assessment of ARC is less reliable, CV data are similar to those reported previously during laboratory-based testing....
Background: Habitual physical activity (PA) is associated with higher cardiorespiratory fitness values, but additional information is needed on the contributions of specific types and amounts of PA. Therefore the main aim of this study was to analyze the heart and lung function of a large cohort of men and compare these outcomes with various modes and volumes of PA.\r\n Methods: We used data from 30,594 men from the Aerobics Center Longitudinal Study who were categorized into sedentary, swimmer, walker, and runner groups using self-report PA data collected during 1970-2005. Additional PA categories using MET-minutes/week were used to group men into 5 distinct levels of activity (0 MET-min, 1-499 MET-min, 500-999 MET-min, 1000-1499 MET-min, and = 1500 MET-min). Each participant also completed a maximal treadmill exercise test to quantify their fitness level. Cross-sectional analyses included general linear modeling and multiple comparisons adjusted for age, smoking status, and histories of myocardial infarction, stroke, diabetes, and hypertension.\r\n Results: A dose-response linear effect was found for heart function variables across PA MET-min categories. Stronger associations for resting heart rate (HR), heart rate recovery (HRR), exercise HR, and exercise blood pressure were found with the runner and swimming groups when compared to the walkers and sedentary groups. Walkers had significantly better heart function than the sedentary group but only about half the effect seen in the swimmers and runners. Lung function findings showed greater absolute values in FVC and FEV1 across PA categories, but found no difference in lung function ratios (e.g FEV1/FVC%).\r\n Conclusions: We found beneficial linear associations with resting HR, exercise HR, HRR, fitness values, FVC, and FEV1 over increasing MET-min categories. This implies that habitual PA, such as walking, but especially swimming and running, when performed with adequate volume, are viable ways to gain benefits for heart health....
Sports chiropractic within Australia has a chequered historical background of unorthodox\r\nindividualistic displays of egocentric treatment approaches that emphasise specific technique\r\npreference and individual prowess rather than standardised evidence based management. This\r\nsituation has changed in recent years with the acceptance of many within sports chiropractic to\r\noperate under an evidence informed banner and to embrace a research culture. Despite recent\r\ndevelopments within the sports chiropractic movement, the profession is still plagued by a minority\r\nof practitioners continuing to espouse certain marginal and outlandish technique systems that\r\nbeleaguer the mainstream core of sports chiropractic as a cohesive and homogeneous group.\r\nModern chiropractic management is frequently multimodal in nature and incorporates components\r\nof passive and active care. Such management typically incorporates spinal and peripheral\r\nmanipulation, mobilisation, soft tissue techniques, rehabilitation and therapeutic exercises.\r\nExternally, sports chiropractic has faced hurdles too, with a lack of recognition and acceptance by\r\norganized and orthodox sports medical groups. Whilst some arguments against the inclusion of\r\nchiropractic may be legitimate due to its historical baggage, much of the argument appears to be\r\nanti-competitive, insecure and driven by a closed-shop mentality.sequently, chiropractic as a\r\nprofession still remains a pariah to the organised sports medicine world. Add to this an uncertain\r\ncontinuing education system, a lack of protection for the title ''sports chiropractor'', a lack of a\r\nrecognized specialist status and a lack of support from traditional chiropractic, the challenges for\r\nthe growth and acceptance of the sports chiropractor are considerable. This article outlines the\r\nhistorical and current challenges, both internal and external, faced by sports chiropractic within\r\nAustralia and proposes positive changes that will assist in recognition and inclusion of sports\r\nchiropractic in both chiropractic and multi-disciplinary sports medicine alike....
Gymnasts are exposed to a high incidence of impact landings due to the execution of repeated dismount\r\nperformances. Biomechanical research can help inform recent discussions surrounding a proposed rule change in\r\npotentially injurious gymnastic dismounting. The review examines existing understanding of the mechanisms\r\ninfluencing the impact loads incurred in gymnastic-style landings achieved using biomechanical approaches.\r\nLaboratory-based and theoretical modelling research of inherent and regulatory mechanisms is appraised. The\r\nintegration of the existing insights into injury prevention interventions studies is further considered in the\r\nappraisals. While laboratory-based studies have traditionally been favoured, the difficulty in controlling and isolating\r\nmechanisms of interest has partially restricted the understanding gained. An increase in the use of theoretical\r\napproaches has been evident over the past two decades, which has successfully enhanced insight into less readily\r\nmodified mechanisms. For example, the important contribution of mass compositions and ââ?¬Ë?tunedââ?¬â?¢ mass coupling\r\nresponses to impact loading has been evidenced. While theoretical studies have advanced knowledge in impact\r\nlanding mechanics, restrictions in the availability of laboratory-based input data have suppressed the benefits\r\ngained. The advantages of integrating laboratory-based and theoretical approaches in furthering scientific\r\nunderstanding of loading mechanisms have been recognised in the literature. Since a multi-mechanism\r\ncontribution to impact loading has been evident, a deviation away from studies examining isolated mechanisms\r\nmay be supported for the future. A further scientific understanding of the use of regulatory mechanisms in\r\nalleviating a performerââ?¬â?¢s inherent injury predisposition may subsequently be gained and used to inform potential\r\nrule changes in gymnastics. While the use of controlled studies for providing scientific evidence for the\r\neffectiveness of gymnastics injury counter measures has been advocated over the past decade, a lack of\r\ninformation based on randomised controlled studies or actual evaluation of counter measures in the field setting\r\nhas been highlighted. The subsequent integration of insight into biomechanical risk factors of landing with clinical\r\npractice interventions has been recently advocated....
Objective: To summarise the available evidence for the efficacy of neuromuscular training in enhancing\r\nsensorimotor and functional deficits in subjects with chronic ankle instability (CAI).\r\nDesign: Systematic review with best evidence synthesis.\r\nData Sources: An electronic search was conducted through December 2009, limited to studies published in the\r\nEnglish language, using the Pubmed, CINAHL, Embase, and SPORTDiscus databases. Reference screening of all\r\nincluded articles was also undertaken.\r\nMethods: Studies were selected if the design was a RCT, quasi RCT, or a CCT; the patients were adolescents or\r\nadults with confirmed CAI; and one of the treatment options consisted of a neuromuscular training programme.\r\nThe primary investigator independently assessed the risk of study bias and extracted relevant data. Due to clinical\r\nheterogeneity, data was analysed using a best-evidence synthesis.\r\nResults: Fourteen studies were included in the review. Meta-analysis with statistical pooling of data was not\r\npossible, as the studies were considered too heterogeneous. Instead a best evidence synthesis was undertaken.\r\nThere is limited to moderate evidence to support improvements in dynamic postural stability, and patient\r\nperceived functional stability through neuromuscular training in subjects with CAI. There is limited evidence of\r\neffectiveness for neuromuscular training for improving static postural stability, active and passive joint position\r\nsense (JPS), isometric strength, muscle onset latencies, shank/rearfoot coupling, and a reduction in injury recurrence\r\nrates. There is limited evidence of no effectiveness for improvements in muscle fatigue following neuromuscular\r\nintervention.\r\nConclusion: There is limited to moderate evidence of effectiveness in favour of neuromuscular training for various\r\nmeasures of static and dynamic postural stability, active and passive JPS, isometric strength, muscle onset latencies,\r\nshank/rearfoot coupling and injury recurrence rates. Strong evidence of effectiveness was lacking for all outcome\r\nmeasures. All but one of the studies included in the review were deemed to have a high risk of bias, and most\r\nstudies were lacking sufficient power. Therefore, in future we recommend conducting higher quality RCTs using\r\nappropriate outcomes to assess for the effectiveness of neuromuscular training in overcoming sensorimotor deficits\r\nin subjects with CAI....
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