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The Effects of Injury on Running Status and Gait Biomechanics
No full textOver the past several decades, endurance running has grown steadily as a popular form of physical activity. Running is easily accessible, does not require expensive equipment, and can be performed without specific skill training. Individuals who run also experience health benefits like increased cardiovascular health and reduced risk of all-cause morbidity. Despite these benefits, running is also associated with high rates of musculoskeletal injury. Although researchers have attempted to identify injury risks and mitigate the incidence of running injury, there is still no consensus as to why runners become injured. Research has also attempted to identify biomechanical movement patterns that occur as a result of injury, though definitive causal relationships have not been established.
Running injury research is further complicated by several factors related to research design. There are few longitudinal or prospective studies, thus there is little evidence to support the identification of causal relationships between proposed risk factors and the development of running injuries. Recruiting homogenous groups comprised of individuals with similar injury history, running experience, and training level is also difficult. Moreover, there is no universal definition of injury for researchers to utilize when recruiting injured populations. In addition to a lack of definitive causes and definitions of injury, the individual response to injury varies. While some runners may continue running while injured, others may alter their training or stop running completely. Running participation is also influenced by life events that are not related to the sport or the development of injury. Additionally, many runners do not seek medical care for all injuries, thus not all instances of pain are classified as an injury. These discrepancies may influence the reported injury rates in the literature. Therefore, there exists a need for longitudinal or prospective research studies which clearly define injury and consider the homogeneity of the groups of runners recruited.
The overall purpose of this dissertation is to investigate how running injury may affect running status and biomechanical movement characteristics. To address this purpose, three studies were developed to determine: 1) how injury and running and history influences the individual response to injury; 2) how movement characteristics may be influenced by the development of injury over time; and 3) how injury status may influence gait mechanics.
The purpose of study one was to analyze injury and running history among current and former runners. A survey was developed to assess injury incidence, consequences of injury such as time off, and reported injury diagnoses and treatments. 312 participants completed the survey. Most participants reported that they had experienced at least one running injury. Of those who reported no history of injury, about half reported that they had experienced pain while running. The most common location of pain was the foot, followed by the knee. All participants were also asked to report any specific injuries they had experienced, and 775 specific injuries were reported. The four most common injuries were iliotibial band syndrome, plantar fasciitis, strained thigh/hip muscle, and medial tibial stress syndrome. About 40% of participants continued to run with these injuries. The results of this study demonstrated that the response to any given injury varied by individual. Despite feeling pain while running, some individuals did not consider themselves injured, and many participants continued running while injured. This study also supports the notion that running injuries exist on a continuum of severity and that the individual response to injury is complex and determined by various factors.
Study two aimed to assess the incidence of running injuries and investigate movement characteristics as they relate to injury development in Division-I cross-country athletes over a two-year period. While research on running injuries is common, there is a lack of definitive causal relationships between running injuries and gait mechanics. For this study, cross-country runners were evaluated at pre- and post-season each year with three-dimensional kinematic and kinetic gait analyses. Participants also provided data regarding injury occurrence via self-report questionnaires, while injury reports were obtained from the team’s athletic training staff. This study was approached as an exploratory study, thus various statistical analyses were utilized to determine if movement characteristics were influenced by injury status, injury location, or year. First, self-reported injury incidence rates were higher than medically-reported injury incidence rates. This further supports the notion that the method of reporting injuries is an important consideration when examining injury incidence rates. There were no statistically significant results in movement characteristics between groups, though these statistical results were accompanied by large effect sizes. Interestingly, the most common location of pain in this group of runners was the foot, which supports the findings of the first study.
The results of the first two studies supported the development of the third study, which analyzed the effect of plantar fasciitis on movement characteristics. The study design included participants with current plantar fasciitis, resolved plantar fasciitis, and no history of plantar fasciitis. This group design was developed to better assess movement characteristics which may exist before, during, and after an injury. Additionally, the study was designed to investigate foot characteristics, thus the foot was analyzed using a multi-segment foot model. Participants in the current plantar fasciitis group exhibited foot characteristics during gait which were indicative of a lower, less rigid arch. Participants in the resolved plantar fasciitis group demonstrated foot characteristics during gait which were indicative of a higher, more rigid arch. These results are meaningful because there were no differences between groups in static measures of foot characteristics, yet during gait, foot mechanics differed. These findings highlight the importance of modeling the foot as a multi-segment structure, rather than a rigid segment. The results of this study support the hypothesis that the movement of the foot during gait may contribute to the development of plantar fasciitis and that runners who have plantar fasciitis move differently than runners with resolved plantar fasciitis
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
AGE-RELATED DIFFERENCES IN THE ACUTE EFFECTS OF MUSCLE FATIGUE ON STABILITY
No full textPostural stability is necessary for maintaining body position, achieving coordination, and reducing fall risk. With advancing age, fall risk increases, due in part to a decreasing ability to maintain postural stability. Muscular fatigue, which results from activities of daily life or exercise, may further intensify instability and increase risk of falls. Some research indicates older individuals develop muscular fatigue sooner than younger adults, but less is known about the differences in the time to recover stability. PURPOSE: To compare the acute effects of muscular fatigue on stability and time to recover stability between older and younger adults. METHODS: Participants from two age groups (n = 30; younger, 18-28 y; and older, 55-65 y) will be recruited. Four participants, two per group, have completed the study. Limits of Stability (LOS) testing and a fatiguing protocol, comprised of sit-to-stand to volitional fatigue, were performed. LOS tests were conducted at baseline and 0, 5, 10, 15, and 20 minutes after the fatiguing protocol. The variables of interest from LOS include reaction time (RT) and maximum excursion (MXE). The effects of age and recovery time on RT and MXE were analyzed with a 2 (group) by 6 (time) ANCOVA, with time to fatigue as a covariate (α = .05). RESULTS: Preliminary analysis indicates that after adjusting for time to fatigue for MXE, there was no significant group by time interaction (p = .11), and no main effect of time (p = .07) or group (p = .07). For RT there was no significant interaction (p= .71) or main effect of time (p = .34), but there was a significant group effect (p = .002), with younger participants exhibiting faster reaction times (0.45 ± 0.14 s) compared to older participants (0.53 ± 0.11 s) on average. CONCLUSION: Based on these early results, balance measures were not significantly affected by fatigue. However, given the low sample size currently, these results may differ as additional data are collected. Between groups, there was no difference in maximum excursion based on age, which indicates that both groups were effective in reaching their limits of stability. There was a significant difference in reaction times between groups, with younger participants having faster reaction times at all testing points. This is to be expected with changes in the neuromuscular system that occur with age
Hips Don\u27t Lie: Analyzing Frontal Plane Kinematics in Adults of Varying Ages During Step Tasks
No full textAging is linked to reduced physical activity, which can lead to a loss of strength and coordination. Older individuals display greater asymmetries and altered kinematic patterns in fundamental movements, which can contribute to injury. PURPOSE: To assess the relationships between age and frontal plane kinematics of the hip and knee during step-up and step-down tasks. METHODS: Eighteen participants completed the study (6 males, age 38.89±16.24). Participants completed three single-leg step-ups and step-downs on each limb from a 25 cm height while 2D kinematics were recorded. Contralateral hip drop and knee valgus angles were identified. The average maximum and minimum values of the dominant limb were calculated across trials. Range of motion (ROM) for each angle was calculated as the average minimum value minus the average maximum value. The relationships between age and hip drop ROM, knee valgus ROM, and contralateral hip drop were assessed using bivariate correlations (α=0.05). RESULTS: No significant correlation was found between age and contralateral hip drop (Right: r=.070, p\u3e0.05; Left: r=-0.032, p\u3e 0.05) or knee valgus (Right: r=-152, p\u3e0.05; Left: r=-0.239, p\u3e0.05) during the single-leg step-up. No significant correlation was found between age and contralateral hip drop (Right: r=-0.112, p\u3e0.05; Left: r=-0.400, p\u3e0.05) or knee valgus on the left limb (r=0.184, p\u3e0.05) during the single-leg step-down. A moderate correlation was observed between age and knee valgus during the single-leg step-down on the right limb (r=0.497,
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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