Stress and risk for depression in competitive athletes suffering from back pain – Do age and gender matter?†

Back pain (BP), a prominent problem for competitive athletes, is a primary reason for limitations in athletic performance and daily life restrictions. As studies on the relationship between psychological variables and BP in athletes are scarce, the aim of this study was to investigate stress and depression in competitive athletes with BP. In a cross-sectional design, data of 154 competitive athletes (51% female; M_age?=?18.81 years, SD_age?=?5.05 years) were collected, assessing Performance stress, Socio-emotional stress, Risk for depression and Psychological well-being and the two BP parameters BP Intensity and Disability. Two multiple linear regressions were conducted to predict (1) BP Intensity and (2) Disability from Performance stress, Socio-emotional stress, Risk for depression and Psychological well-being. Multiple linear regressions demonstrated that Performance stress (β?=?.21, p?=?.01) was the only significant predictor of BP Intensity (F_1,142?=?6.68, p?=?.01, R²?=?.05), whilst Risk for depression (β?=?.24, p?=?.01) was the only significant predictor of Disability (F_1,142?=?8.46, p?=?.01, R²?=?.06). Neither gender nor age explained a significant amount of variance in the models. Study results showed that, as in the general population, the variables stress and depression are related to BP in competitive athletes. In particular, BP intensity was found to be associated with stress and BP-related disability was associated with depression, whereas age and gender showed no association with the BP parameters. A longitudinal investigation is warranted to determine the direction of the observed relationships.     

特厚、突出、极松软、大应力、极复杂地质条件下跟煤底施工技术研究

青东矿82采区8煤层首采工作面为828工作面,煤层厚度6.2～13.2m,平均厚度为9.2m,回采工艺为综放,工作面巷道施工采取跟底留顶煤施工,由于煤体松散破碎,同时过上覆726工作面收作线应力集中区、频繁过断层、过构造,在施工期间遇到很多了困难,特别是极松散的煤顶在超前管理上、支护上,和现场施工管理上采取非常有价值的举措,成功的克服了各种困难,巷道单进达100m/月,减少了工作面准备时间,回提前回采产出的煤炭而带来巨大的经济效益和社会效益。     

An examination of psychosocial variables moderating the relationship between life stress and injury time-loss among athletes of a high standard

Based on Williams and Andersen's model of stress and athletic injury, six psychosocial variables were assessed as possible moderators of the relationship between life stress and injury among 121 athletes (65 males, 56 females) competing in a variety of sports at state, national or international level. No significant effects of the sex of the participants were evident. Correlational analyses revealed moderator effects of several variables. Specifically, dispositional optimism and hardiness were related to decreased injury time-loss in athletes when positive life change increased, and global self-esteem was associated with decreased injury time-loss when both negative life change and total life change increased. The results indicate that athletes with more optimism, hardiness or global self-esteem may cope more effectively with life change stress, resulting in reduced injury vulnerability and recovery rates.     

Stress reactivity after maximal exercise: The effect of manipulated performance feedback in endurance athletes

This study was designed to assess the effect of performance feedback on stress reactivity after recovery from maximal exercise. Forty competitive athletes were recruited to complete a maximal exercise test. Performance feedback was manipulated after the exercise test to give four groups: (1) high performance, (2) low performance, (3) accurate feedback and (4) no exercise control. Cardiovascular reactivity was assessed during psychological stress. The results indicate that accurate feedback participants experienced lower relative reactivity to stress (lower mean arterial pressure) than their no-exercise counterparts. These results demonstrate that the stressbuffering effect of exercise extends to maximal exercise. In addition, high-performance participants experienced lower relative reactivity than low-performance participants. Thus, low-performance feedback was sufficient to remove the buffering effect of exercise. There were no differences between the high-performance and accurate feedback conditions, or between the low-performance and control conditions.     

The influence of crank rate on peak oxygen consumption during arm crank ergometry

The aim of this study was to assess the influence of three imposed crank rates on the attainment of peak oxygen consumption ( V O 2peak ) and other physiological responses during incremental arm crank ergometry. Twenty physically active, although non-specifically trained, males volunteered for the study. They completed an exercise protocol using an electrically braked arm ergometer (Lode Angio, Groningen, Netherlands) at crank rates of 60, 70 and 80 rev·min -1 . The order of tests was randomized and they were separated by at least 2 days. Peak V O 2 was significantly higher ( P ? 0.05) at 70 and 80 rev·min -1 than at 60 rev·min -1 . Peak ventilation volume increased as a function of crank rate and was higher ( P ? 0.05) at 80 than at 60 rev·min -1 . Peak heart rate was higher ( P ? 0.05) at 70 and 80 rev·min -1 than at 60 rev·min -1 . Furthermore, 70 and 80 rev·min -1 resulted in an extended test time compared with 60 rev·min -1 . The greater physiological responses observed during the tests at the two faster crank rates might have been the result of a postponement of acute localized neuromuscular fatigue, allowing for more work to be completed. We recommend, therefore, that an imposed crank rate between 70 and 80 rev·min -1 should be used to elicit V O 2peak and other physiological responses in arm crank ergometry.     

Fluid ingestion and exercise hyperthermia: Implications for performance,thermoregulation, metabolism and the development of fatigue

The development of fatigue during exercise and the subsequent onset of exhaustion occur earlier in the heat than in cooler environments. The underlying mechanisms responsible for the premature development of fatigue in the heat have yet to be clearly identified. However, the proposed mechanisms include metabolic, cardiovascular and central nervous system perturbations, together with an elevated core temperature. Fluid ingestion is one of three strategies that have been shown to be successful in enhancing the performance of endurance exercise in the heat, with the other interventions being precooling and acclimatization. However, like the development of fatigue in the heat, the mechanisms by which fluid ingestion allows for improved exercise performance remain unclear. We propose that fluid ingestion enhances exercise performance in the heat by increasing the heat storage capacity of the body. We suggest that the thermoregulatory, metabolic and cardiovascular alterations that occur as a result of this increased heat storage capacity contribute to performance enhancement when fluid is ingested during exercise heat stress.     

Personal and situational factors that predict coping strategies for acute stress among basketball referees

The aim of this study was to establish the ways in which coping style and situational appraisals are related to the consistency of using approach and avoidance coping strategies for skilled Australian basketball referees (n = 133) after three game-related stressful events. The events, ‘making a mistake’, ‘aggressive reactions by coaches or players’ and ‘presence of important others’, were determined from previous research on sources of acute stress among basketball officials. Our findings indicated that: referees exhibited consistent avoidance, but not approach, coping styles; they used more avoidance than approach strategies; and they perceived stress to be positively correlated with approach, and negatively associated with avoidance, coping strategies. These findings suggest that individual differences exist in perceptions of stress (i.e. situational appraisals), controllability and coping styles among moderately and highly skilled basketball referees. The implications for teaching cognitive and behavioural strategies for effective coping with acute stress in basketball officiating are discussed.     

Sources of stress,burnout and intention to terminate among rugby union referees

We examined sources of stress, burnout and intention to terminate among rugby union referees. Questionnaires were returned by 682 of 1175 referees (58%) from Wales, Scotland and England. Exploratory and confirmatory factor analyses revealed four correlated sources of stress factors (performance concerns, time pressure, interpersonal conflict and fear of physical harm), which accounted for 49.6% of the variance. Referees believed the first three factors to be mildly related to their stress. They believed fear of physical harm to be unrelated to their stress. A structural model hypothesizing that time pressure and interpersonal conflict predict burnout, and that age and burnout predict intention to terminate refereeing, fit the observed data. The goodness-of-fit index for this model was 0.96. Our results and those of other studies indicate that interpersonal conflict and time pressure are common sources of stress for sport officials and are frequently related to their burnout experiences. Also, age and burnout are frequently, although only marginally, related to intention to terminate.     

一个新的等参数奇异单元

本文推导得到了一个新的等参数奇异单元,它仍然是四边形四分之一节点奇异元。数值实验表明,它要比常用的四边形四分之一节点奇异元精度更好,使用这种单元可以使断裂问题的有限元计算效果更好。在计算过程中还利用到改进等参变换。     

外踝短缩对踝关节面应力分布的影响

目的：探讨外踝短缩所致创伤性踝关节炎发生的生物力学机制。方法：选取8只新鲜冷冻尸体下肢，分别在外踝正常长度、短缩113、短缩213和短缩313的情况下，测量和分析踝关节面应力分布的变化。结果：踝关节应力接触区大致呈三角形，外踝短缩后踝关节面应力分布发生变化，以向前、内、外侧压力增高最为显著。结论：外踝短缩后踝关节面应力分布发生明显变化。这可能是导致创伤性关节炎发生的重要机制。