920 resultados para knee articulation


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Corporate sponsorship of events contributes significantly to marketing aims, including brand awareness as measured by recall and recognition of sponsor‐event pairings. Unfortunately, resultant advantages accrue disproportionately to brands having a natural or congruent fit with the available sponsorship properties. In three cued‐recall experiments, the effect of articulation of sponsorship fit on memory for sponsor‐event pairings is examined. While congruent sponsors have a natural memory advantage, results demonstrate that memory improvements via articulation are possible for incongruent sponsor‐event pairings. These improvements are, however, affected by the presence of competitor brands and the way in which memory is accessed.

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Objective: To critically appraise the Biodex System 4 isokinetic dynamometer for strength assessment of children. Methods: Appraisal was based on experiences from two independent laboratories involving testing of 213 children. Issues were recorded and the manufacturer was consulted regarding appropriate solutions. Results: The dynamometer had insufficient height adjustment for alignment of the knee for some children, requiring the construction of padding to better fit the child within the dynamometer. Potential for entrapment of the non-testing leg was evident in the passive and eccentric modes and a leg bracket restraint was constructed. Automated gravity correction did not operate when protocols were linked or data was exported to an external device. Conclusions: Limitations were noted, some of which were applicable to knee strength testing in general and others which were specific to use with children. However, most of these obstacles could be overcome, making the Biodex System 4 suitable for assessment of knee strength in children.

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The purpose of this study was to determine the effects of cryotherapy, in the form of cold water immersion, on knee joint position sense. Fourteen healthy volunteers, with no previous knee injury or pre-existing clinical condition, participated in this randomized cross-over trial. The intervention consisted of a 30-min immersion, to the level of the umbilicus, in either cold (14 ± 1°C) or tepid water(28 ± 1°C). Approximately one week later, in a randomized fashion, the volunteers completed the remaining immersion. Active ipsilateral limb repositioning sense of the right knee was measured, using weight-bearing and non-weight bearing assessments, employing video-recorded 3D motion analysis. These assessments were conducted immediately before and after a cold and tepid water immersion. No significant differences were found between treatments for the absolute (P = 0.29), relative (P = 0.21) or variable error (P = 0.86). The average effect size of the outcome measures was modest (range –0.49 to 0.9) and all the associated 95% confidence intervals for these effect sizes crossed zero. These results indicate that there is no evidence of an enhanced risk of injury, following a return to sporting activity, after cold water.

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Introduction: The ability to regulate joint stiffness and coordinate movement during landing when impaired by muscle fatigue has important implications for knee function. Unfortunately, the literature examining fatigue effects on landing mechanics suffers from a lack of consensus. Inconsistent results can be attributed to variable fatigue models, as well as grouping variable responses between individuals when statistically detecting differences between conditions. There remains a need to examine fatigue effects on knee function during landing with attention to these methodological limitations. Aim: The purpose of this study therefore, was to examine the effects of isokinetic fatigue on pre-impact muscle activity and post-impact knee mechanics during landing using singlesubject analysis. Methodology: Sixteen male university students (22.6+3.2 yrs; 1.78+0.07 m; 75.7+6.3 kg) performed maximal concentric and eccentric knee extensions in a reciprocal manner on an isokinetic dynamometer and step-landing trials on 2 occasions. On the first occasion each participant performed 20 step-landing trials from a knee-high platform followed by 75 maximal contractions on the isokinetic dynamometer. The isokinetic data was used to calculate the operational definition of fatigue. On the second occasion, with a minimum rest of 14 days, participants performed 2 sets of 20 step landing trials, followed by isokinetic exercise until the operational definition of fatigue was met and a final post-fatigue set of 20 step-landing trials. Results: Single-subject analyses revealed that isokinetic fatigue of the quadriceps induced variable responses in pre impact activation of knee extensors and flexors (frequency, onset timing and amplitude) and post-impact knee mechanics(stiffness and coordination). In general however, isokinetic fatigue induced sig nificant (p<0.05) reductions in quadriceps activation frequency, delayed onset and increased amplitude. In addition, knee stiffness was significantly (p<0.05) increased in some individuals, as well as impaired sagittal coordination. Conclusions: Pre impact activation and post-impact mechanics were adjusted in patterns that were unique to the individual, which could not be identified using traditional group-based statistical analysis. The results suggested that individuals optimised knee function differently to satisfy competing demands, such as minimising energy expenditure, as well as maximising joint stability and sensory information.

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Introduction: Evidence concerning the alteration of knee function during landing suffers from a lack of consensus. This uncertainty can be attributed to methodological flaws, particularly in relation to the statistical analysis of variable human movement data. Aim: The aim of this study was to compare single-subject and group analysis in quantifying alterations in the magnitude and within-participant variability of knee mechanics during a step landing task. Methods: A group of healthy men (N = 12) stepped-down from a knee-high platform for 60 consecutive trials, each trial separated by a 1-minute rest. The magnitude and within-participant variability of sagittal knee stiffness and coordination of the landing leg during the immediate postimpact period were evaluated. Coordination of the knee was quantified in the sagittal plane by calculating the mean absolute relative phase of sagittal shank and thigh motion (MARP1) and between knee rotation and knee flexion (MARP2). Changes across trials were compared between both group and single-subject statistical analyses. Results: The group analysis detected significant reductions in MARP1 magnitude. However, the single-subject analyses detected changes in all dependent variables, which included increases in variability with task repetition. Between-individual variation was also present in the timing, size and direction of alterations to task repetition. Conclusion: The results have important implications for the interpretation of existing information regarding the adaptation of knee mechanics to interventions such as fatigue, footwear or landing height. It is proposed that a familiarisation session be incorporated in future experiments on a single-subject basis prior to an intervention.

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The anticoagulant effect of apixaban is due to direct inhibition of FXa in the coagulation cascade. The main advantages apixaban has over the current anti-coagulant drugs is that it is active after oral administration, and its coagulation effect does not require monitoring. Apixaban has been compared to enoxaparin in the prevention of venous thromboembolism associated with knee and hip replacement, where it is as efficacious as enoxaparin, but causes less bleeding. However, apixaban is not the only FXa inhibitor that could replace enoxaparin for this indication, as the FXa inhibitor rivaroxaban is as efficacious and safe as enoxaparin in preventing thromboembolism associated with these surgical procedures. Until the results of the AMPLIFY Phase III trial are known, it is too early to consider apixaban as an alternative to enoxaparin in symptomatic thromboembolism. Apixaban should not be used to prevent thromboembolism in medical immobilised subjects or acute coronary syndromes, as it causes excess bleeding in these conditions without benefit.

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This paper will present program developers and institutional administrators with a program delivery model suitable for cross cultural international delivery developing students from industry through to master’s level tertiary qualifications. The model was designed to meet the needs of property professionals from an industry where technical qualifications are the norm and tertiary qualifications are emerging. A further need was to develop and deliver a program that enhanced the University’s current program profile in both the domestic and international arenas. Early identification of international educational partners, industry need and the ability to service the program were vital to the successful development of Master of Property program. The educational foundations of the program rest in educational partners, local tutorial support, international course management, cultural awareness of and in content, online communication fora, with a delivery focus on problem-based learning, self-directed study, teamwork and the development of a global understanding and awareness of the international property markets. In enrolling students from a diverse cultural background with technical qualifications and/or extensive work experience there are a number of educational barriers to be overcome for all students to successfully progress and complete the program. These barriers disappear when the following mechanisms are employed: individual student pathways, tutorial support by qualified peers, enculturation into tertiary practice, assessment tasks that recognise cultural norms and values, and finally that value is placed on the experiential knowledge, cultural practices and belief systems of the students.

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The aim of this study was to determine if athletes with a history of hamstring strain injury display lower levels of surface EMG (sEMG) activity and median power frequency in the previously injured hamstring muscle during maximal voluntary contractions. Recreational athletes were recruited, 13 with a history of unilateral hamstring strain injury and 15 without prior injury. All athletes undertook isokinetic dynamometry testing of the knee flexors and sEMG assessment of the biceps femoris long head (BF) and medial hamstrings (MH) during concentric and eccentric contractions at ± 180 and ± 600.s-1. The knee flexors on the previously injured limb were weaker at all contraction speeds compared to the uninjured limb (+1800.s-1 p = 0.0036; +600.s-1 p = 0.0013; -600.s-1 p = 0.0007; -1800.s-1 p = 0.0007) whilst sEMG activity was only lower in the BF during eccentric contractions (-600.s-1 p = 0.0025; -1800.s-1 p = 0.0003). There were no between limb differences in MH sEMG activity or median power frequency from either BF or MH in the injured group. The uninjured group showed no between limb differences in any of the tested variables. Secondary analysis comparing the between limb difference in the injured and the uninjured groups, confirmed that previously injured hamstrings were mostly weaker (+1800.s-1 p = 0.2208; +600.s-1 p = 0.0379; -600.s-1 p = 0.0312; -1800.s-1 p = 0.0110) and that deficits in sEMG were confined to the BF during eccentric contractions (-600.s-1 p = 0.0542; -1800.s-1 p = 0.0473) Previously injured hamstrings were weaker and BF sEMG activity was lower than the contralateral uninjured hamstring. This has implications for hamstring strain injury prevention and rehabilitation which should consider altered neural function following hamstring strain injury.

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INTRODUCTION: Hamstring strain injuries (HSI) are the predominant non-contact injury in many sports. Eccentric hamstring muscle weakness following intermittent running has been implicated within the aetiology of HSI. This weakness following intermittent running is often greater eccentrically than concentrically, however the cause of this unique, contraction mode specific phenomenon is unknown. AIM: To determine if this preferential eccentric decline in strength is caused by declines in voluntary hamstring muscle activation. METHODS: Fifteen recreationally active males completed 18 × 20m overground sprints. Maximal strength (concentric and eccentric knee flexor and concentric knee extensor) was determined isokinetically at the velocities of ±1800.s-1 and ±600.s- while hamstring muscle activation was assessed using surface electromyography, before and 15 minutes after the running protocol. RESULTS: Overground intermittent running caused greater eccentric (27.2 Nm; 95% CI = 11.2 to 43.3; p=0.0001) than concentric knee flexor weakness (9.3 Nm; 95% CI = -6.7 to 25.3; P=0.6361). Following the overground running, voluntary activation levels of the lateral hamstrings showed a significant decline (0.08%; 95% CI = 0.045 to 0.120; P<0.0001). In comparison, medial hamstring activation showed no change following intermittent running. CONCLUSION: Eccentric hamstring strength is decreased significantly following intermittent overground running. Voluntary activation deficits in the biceps femoris muscle are responsible for some portion of this weakness. The implications of this finding are significant because the biceps femoris muscle is the most frequently strained of all the hamstring muscles and because fatigue appears to play an important part in injury occurrence.