Evidence for data missing at random in youth physical activity monitoring research

This study examined whether or not activity monitor data collected as part of a typical 7-day physical activity (PA) measurement protocol can be expected to be missing at random. A total of 315 participants (9–18 years) each wore a SenseWear Armband monitor for 7 consecutive days. Participants were classified as “compliant” (86 boys and 124 girls) if they had recorded accelerometer data during 70% or more of the predefined awake time (7 AM–10 PM) on four different days; and “non-compliant” (44 boys and 51 girls) when not meeting these criteria. Linear mixed models were used to examine differences in energy expenditure (EE) levels by compliance across 10 different time periods. The results indicated that non-compliant girls were older (13.4 ± 2.9 vs. 12.2 ± 2.5) and taller (156.8 ± 10.3 vs. 152.8 ± 11.3) than their same gender compliant peers (P < .05). Comparisons of EE rates at segmented portions of the day revealed no differences between compliant and non-compliant groups (P ≥ .05). Differences in EE ranged from ?0.32 kcal · kg^?1 · h^?1 (before school time) to 0.62 kcal · kg^?1 · h^?1 (physical education class) in boys and ?0.39 kcal · kg^?1 · h^?1 (transportation from school) to 0.37 kcal · kg^?1 · hour^?1 (recess) in girls. The results showed that compliant and non-compliant individuals differed in a few demographic characteristics but exhibited similar activity patterns. This suggests that data were considered to be missing at random, but additional work is needed to confirm this observation in a representative sample of children using other types of activity monitors and protocols.     

Association of different types of playing surfaces with bone mass in growing girls

The aim of this cross-sectional study was to compare bone mass in young female athletes playing ball games on different types of playing surfaces. About 120 girls, 9–13 years of age (10.6 ± 1.5 years old Tanner I–III) were recruited and divided into prepubertal and pubertal groups. The sample represented 3 groups of athletes: soccer (N = 40), basketball (N = 40), and handball (N = 40); and 6 different playing surfaces (soccer – ground, soccer – artificial turf, basketball – synthetic, basketball – parquet, handball – synthetic, and handball – smooth concrete). Total and regional body composition (bone mass, fat mass, and lean mass) were measured by dual-energy X-ray absorptiometry (DXA). The mechanical properties of the surfaces (force reduction, vertical deformation, and energy return) were measured with the Advanced Artificial Athlete (Triple A) method. The degree of sexual development was determined using Tanner test. The pubertal group showed that soccer players on the ground, basketball players on synthetic, and handball players on smooth concrete had higher values of bone mineral content (BMC) and bone mineral density (BMD) (P < 0.05) than the soccer players on the artificial turf, basketball players on parquet, and handball players on synthetic. In conclusion, a hard playing surface, with less vertical deformation and force reduction, and greater energy return, is associated with higher levels of BMD and BMC in growing girls, regardless of the sport they practice.     

Sexual dimorphism in bone–muscle relationship in young adults

The purpose of this study was to analyse associations between lean soft tissue (LST), a surrogate of skeletal muscle mass and key fracture-related geometric characteristics of the proximal femur. Moreover, we examined the role that muscle played on the proximal femur geometry in response to physical activity (PA). Participants were 83 young adults. Leg LST (exposure) was assessed by dual energy X-ray absorptiometry (DXA). Proximal femur geometry was derived from a left hip DXA scan. Geometric variables (outcomes) included the femoral neck axis length (FNAL), the femoral neck width (FNW), the neck–shaft angle and FNW|FNAL (an index of robustness). PA was evaluated by accelerometry. Linear regression was used to analyse relationships. Additional exposure variables included body height and mass. In males, leg LST explained 17.4% of variation in FNAL (P < 0.001) and 15% in FNW (P = 0.015). In females, it explained 8.8% of the variance in FNAL (P = 0.020). Associations remained significant in males, but not in females, when vigorous PA was added to the models. These results suggest that public health approaches to promote PA may be particularly important in females since vigorous PA seems to convey advantages in femur geometry and consequently in bone strength.     

Long-term endurance training increases serum cathepsin S and decreases IL-6 and hsCRP levels

Cathepsin S (CS) was shown to play a key role in cancer progression, atherosclerosis, heart valve disease, insulin resistance and diabetes mellitus. The present prospective study aimed to investigate the influence of sports on CS, interleukin-6 (Il-6) and high-sensitivity C-reactive protein (hsCRP) levels.

Ninety-eight of 109 participants completed the study. Ergometries were performed at baseline and after 8 months to evaluate/quantify the performance gain. Blood samples were taken at baseline and every 2 months. CS was measured by ELISA (enzyme-linked immunosorbent assay). Compared to the control group (mean performance gain ?3.41 ± 4.62%) we observed a significant physical-activity-induced increase of CS levels (3.45–3.73 ng · ml^?1; P = 0.027) and a significant decrease of Il-6 (2.43–1.91 pg · ml^?1; P = 0.031) and hsCRP-levels (0.11–0.09 mg · dl^?1; P = 0.001) in the intervention group (mean performance gain: 12.13 ± 6.32%). Furthermore, the tendency of the progression was significant for CS and Il-6 (P = 0.002/0.033).

We could show a significant sports-induced decrease of the classic inflammation parameters hsCRP/Il-6, probably expressing a downregulation of permanently prevalent inflammation processes. Simultaneously CS levels increased significantly. Our results show that increasing CS amounts are not simply to equal with an enhanced inflammation status and might even have beneficial effects on inflammation and angiogenesis.     

Postpartum Mothers’ Leisure-Time Exercise Behavior is Linked to Positive Emotion During Partner Discussions

Purpose: Marital dissatisfaction and conflict often increase for couples after the birth of a child and are evident in fewer positive family interactions and more negative family interactions. Because exercise is known to increase positive emotions and decrease negative emotions, the current study examined the extent to which higher levels of mothers’ exercise during the postpartum period were related to more positive and fewer negative emotion-expressive behaviors with their infants’ fathers. Method: Mothers’ (N = 46; M = 8 months postpartum) positive and negative expressive behaviors were coded during couples’ discussions of current conflict and positive family experiences. Mothers self-reported their leisure-time exercise behavior. Results: First-time mothers and mothers with higher levels of leisure-time exercise behavior displayed higher levels of positive expressive behaviors during couples’ discussions. Conclusions: Exercise may be associated with increased positive emotion and, in turn, can have great potential to improve family relationships during the postpartum period when marital stress normatively increases, particularly for mothers with more than 1 child. Future longitudinal studies are needed to understand exercise patterns across the postpartum period to identify the most effective timing and optimal level of exercise that lead to more positive expressive behaviors.     

生活方式干预对心血管疾病危险因素的影响——美国HELPS项目成果

摘要：心血管疾病（CVD）一直是全世界最主要的死因。由于CVD等慢性疾病对健康的威胁越来越大,有必要开展生活方式干预项目以控制这些疾病的危险因素。本研究的目的是评估美国的重要慢病干预项目—HELPS治疗型生活方式改变（TLC）项目对减少CVD危险因素和其他慢性疾病的有效性。方法：140位大学教职工参加为期12周的HELPS TLC项目,干预前后用配对t检验对其体重、BMI、腰围（WC）、6分钟步行距离（6MWD）、空腹血脂和血糖进行测定和比较。结果：干预后6MWD显著增加,总胆固醇（TC）和WC显著下降。对“高危”参与者进一步分析显示：BMI（-1.5±0.5,-3.9%）、TC（- 22.8±4.0,-9.0%）、LDL（- 14.1±4.9,9.3%）和血糖（-6.9±2.2,-6.1%）均显著下降;男性腰围（-4.5±0.8,-10%）显著减小,女性未见显著改变（-1.5±0.5,-4.0%）。此外,体重的变化与TC（r=0.43）、LDL（r=0.35）和血糖（r=0.44）的变化均显著相关。结论：参加12周的生活方式干预项目可以使CVD危险因素减少,特别是在CVD“高危”个体中。HELPS TLC项目的远期效果还待进一步深入研究。     

第64届美国运动医学会年会关于“运动益处的生物网络”研究热点与趋势

摘要：概述美国运动医学第64th年会的主要内容和目标;归纳“机体对运动反应/适应的生物网络”研究的报告热点;介绍美国国立卫生院资助项目,“人类体力活动的分子传感器”的研究设计和组成。建立各取所长、分工合作的研发联盟是进行运动促进健康分子机制研究的必要途径;基于集合最新研究技术和分析方法,从宏观到微观再到宏观,从整体到局部再到整体的整合性系统实验设计是链接运动益处与其作用机制的桥梁。在未来,该领域的研究成果不仅仅是精准运动的实现、运动依存性的提高和对慢性病的辅助治疗,同时如果能够发现传递运动益处的分子,研发成产品,这必将会为人类健康产生深远影响。     

厌氧氨氧化菌活性的快速恢复及运行

为研究厌氧氨氧化(anaerobic ammonium oxidizing,ANAMMOX)菌的活性恢复,采用SBR工艺对长时间(100 d左右)停止运行的反应器中ANAMMOX菌进行活性培养。经过22 d的恢复试验,ANAMMOX菌活性基本恢复,在第17天,NH+4—N和NO-2—N的转化率均在90%以上,TN的去除率在80%以上。在培养过程中,载体的颜色由白色逐渐变成淡黄色。结果表明,在常温闲置较长时间的反应器中ANAMMOX菌的活性可恢复性强,恢复周期短,恢复后的脱氮性能良好;ANAMMOX反应器通过对生物膜载体的培养可以使ANAMMOX菌的活性快速恢复。     

身体活动对改善药物成瘾戒断者脑功能损伤的研究——来自抑制加工及脑功能静息态的证据

目的：探讨身体活动对药物成瘾戒断者抑制能力及静息态脑功能的改善,拟为药物成瘾提供有效的辅助治疗手段。方法：将药物成瘾戒断者按身体活动量分为活动组和久坐组,首先进行Go/NoGo抑制能力测试,然后采集他们的静息态功能磁共振数据。选取静息态的两项重要分析方法——低频振幅（amplitude of low frequency fluctuations,ALFF）和局部一致性（regional homogeneity,ReHo）来探讨身体活动对药物成瘾戒断者脑功能损伤的改善。结果：①Go/NoGo测试：活动组NoGo正确率显著高于久坐组。②ALFF分析：活动组在双侧脑岛、左侧额下回眶部、双侧额内侧回、左侧前扣带回、右侧背外侧前额叶、左侧枕上回、左侧辅助运动区、双侧内侧扣带回ALFF显著高于久坐组。③ReHo分析：活动组在左侧枕中回、双侧背外侧前额叶、左侧辅助运动区ReHo显著高于久坐组。这些显著差异脑区主要与成瘾的抑制能力有关。结论：①身体活动能有效地提高药物成瘾戒断者的抑制能力。②身体活动是修复药物成瘾戒断者大脑功能损伤的关键因素之一。身体活动可通过增加药物成瘾戒断者静息状态下脑功能的低频振幅和局部一致性,改善药物成瘾戒断者大脑功能损伤。     

腰痛羽毛球运动员的功能评估

研究目的：对腰痛羽毛球运动员的部分功能进行测试,观察其活动范围、肌肉力量、肌电活动以及相应对称性。为了解羽毛球运动员损伤机制发生提供科学依据。研究对象：6名腰痛羽毛球运动员（男运动员4名,女运动员2名）。研究方法：对研究对象分别进行日本矫正外科协会（JOA）评分量表、躯干旋转、胸椎旋转、髋关节内外旋活动度、躯干等速旋转力量、等长背伸活动的肌电活动测试,并观察两侧差异比的平均值。研究结果：（1）腰痛运动员的躯干旋转、胸椎旋转以及髋关节外旋活动度平均差异比为（31.98±21.53）%,（19.8±17.08）%,（13.81±4.43）%大于10%,仅髋关节内旋活动度平均差异比为（5.62±5.63）%小于10%。胸椎和髋关节旋转动度有减小的趋势;（2）等速躯干旋转两侧峰力矩和平均功率差异没有显著性意义,峰力矩平均差异比为（5.45±1.78）%小于10%,而平均功率平均差异比为（12.78±11.40）%大于10%;（3）在等长背伸活动中,竖脊肌肌电活动的平均两侧差异比为（14.18±9.84）%大于10%,而多裂肌肌电活动的平均两侧差异比（9.90±7.92）%接近10%;竖脊肌和多裂肌的中位频率斜率（Median Frequency slope,MFs）均出现下降的趋势,但两侧差异比为（4.68±3.17）%,（5.35±5.40）%小于10%。结论：（1）腰痛羽毛球运动员躯干旋转、胸椎旋转、髋关节外旋活动范围存在对称性问题,且胸椎旋转、髋关节旋转有减少趋势;（2）躯干等速旋转平均功率存在对称性问题;（3）等长背伸任务中,竖脊肌和多裂肌出现疲劳,肌电活动存在对称性问题。