The effect of time of day and recovery type after a football game on muscle damage and performance in anaerobic tests on young soccer players

The purpose of this study was to investigate the effect of time of day and different modalities of recovery (active vs. passive recovery) after intermittent exercise in young soccer players. In randomized order, 16 boys participated in the study, divided into two groups: passive recovery (PRG, n?=?8) and active recovery (ARG, n?=?8). Both groups performed tests at 07:00 and 17:00 h. The results showed that performance in the Sargent jump test (SJT), 10-m sprint, and agility were higher in the evening (17:00 h), around the presumed peak of body temperature. SJT and agility performance decreased after the match. The better performance in SJT and agility were found in ARG rather than PRG (p?p?p?p?p?p?相似文献   

Effects of an active warm-up on variation in bench press and back squat (upper and lower body measures)

The present study investigated the magnitude of diurnal variation in back squat and bench press using the MuscleLab linear encoder over three different loads and assessed the benefit of an active warm-up to establish whether diurnal variation could be negated. Ten resistance-trained males underwent (mean ± SD: age 21.0 ± 1.3?years, height 1.77 ± 0.06?m, and body mass 82.8 ± 14.9?kg) three sessions. These included control morning (M, 07:30?h) and evening (E, 17:30?h) sessions (5-min standardized warm-up at 150?W, on a cycle ergometer), and one further session consisting of an extended active warm-up morning trial (M_E, 07:30?h) until rectal temperature (T_rec) reached previously recorded resting evening levels (at 150?W, on a cycle ergometer). All sessions included handgrip, followed by a defined program of bench press (at 20, 40, and 60?kg) and back squat (at 30, 50, and 70?kg) exercises. A linear encoder was attached to an Olympic bar used for the exercises and average force (AF), peak velocity (PV), and time to peak velocity (tPV) were measured (MuscleLab software; MuscleLab Technology, Langesund, Norway) during the concentric phase of the movements. Values for T_rec were higher in the E session compared to values in the M session (Δ0.53?°C, P < 0.0005). Following the extended active warm-up in the morning (M_E), T_rec and T_m values were no different to the E values (P < 0.05). Values for T_m were lower in the M compared to the E condition throughout (P < 0.05). There were time-of-day effects for hand grip with higher values of 6.49% for left (P = 0.05) and 4.61% for right hand (P = 0.002) in the E compared to the M. Daily variations were apparent for both bench press and back squat performance for AF (3.28% and 2.63%), PV (13.64% and 11.50%), and tPV (?16.97% and ?14.12%, where a negative number indicates a decrease in the variable from morning to evening). There was a main effect for load (P < 0.0005) such that AF and PV values were larger at higher masses on the bar than lower ones and tPV was smaller at lower masses on the bar than at higher masses for both bench press and back squat. We established that increasing T_rec in the M–E values did not result in an increase of any measures related to bench press and back squat performance (P > 0.05) to increase from M to E levels. Therefore, MuscleLab linear encoder could detect meaningful differences between the morning and evening for all variables. However, the diurnal variation in bench press and back squat (measures of lower and upper body force and power output) is not explained by time-of-day oscillations in T_rec.     

Jumping ability is related to change of direction ability in elite handball players

PurposeThis study investigated the relationship between vertical and horizontal jumping ability and change of direction (COD) to measure athletic performance in 51 elite male handball players.Scope.Countermovement jump (CMJ), peak power, and standing long jump (SLJ) were measured. Participants performed a 20-m sprint test (time measured at 5, 10, and 20 m) and a zigzag test (COD: 135°, 90°, and 45°). The COD deficit, an index of the time required for COD, was calculated. The correlations between CMJ height and zigzag test times were relatively large (at 135°, r =  − 0.607; at 90°, r =  − 0.594; at 45°, r =  − 0.613; p < 0.01), whereas those between CMJ height and COD deficit were moderate (at 135°, r =  − 0.399, p < 0.01; at 90°, r =  − 0.350, p < 0.05; at 45°, r =  − 0.323, p < 0.05). SLJ showed a negative moderate correlation with COD deficit (at 135°, r =  − 0.439, p < 0.01; at 90°, r =  − 0.469, p < 0.01; at 45°, r =  − 0.380, p < 0.01).ConclusionsThis study is the first to analyse SLJ ability and COD deficit parameters of handball players. We found that SLJ ability is moderately related to COD time and deficit; therefore, SLJ measurement may be a useful predictor of athletic performance.     

The effects of 12-week progressive strength training on strength,functional capacity,metabolic biomarkers,and serum hormone concentrations in healthy older women: morning versus evening training

ABSTRACT

Previous findings suggest that performing strength training (ST) in the evening may provide greater benefit for young individuals. However, this may not be optimal for the older population. The purpose of this study was to compare the effects of a 12-week ST program performed in the morning vs. evening on strength, functional capacity, metabolic biomarker and basal hormone concentrations in older women. Thirty-one healthy older women (66 ± 4 years, 162 ± 4 cm, 75 ± 13 kg) completed the study. Participants trained in the morning (M) (07:30, n = 10), in the evening (E) (18:00, n = 10), or acted as a non-training control group (C) (n = 11). Both intervention groups performed whole-body strength training with 3 sets of 10–12 repetitions with 2–3 minutes rest between sets. All groups were measured before and after the 12-week period with; dynamic leg press and seated-row 6-repetition maximum (6-RM) and functional capacity tests (30-second chair stands and arm curl test, Timed Up and Go), as well as whole-body skeletal muscle mass (SMM) (kg) and fat mass (FM-kg, FM%) assessed by bioelectrical impedance (BIA). Basal blood samples (in the intervention groups only) taken before and after the intervention assessed low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), blood glucose (GLU), triglycerides (TG), high-sensitive C-reactive protein (hsCRP) concentrations and total antioxidant status (TAS) after a 12 h fast. Hormone analysis included prolactin (PRL), progesterone (P) estradiol (ESTR), testosterone (T), follicle stimulating hormone (FSH), and luteinizing hormone (LH). While C showed no changes in any variable, both M and E significantly improved leg press (+ 46 ± 22% and + 21 ± 12%, respectively; p < 0.001) and seated-row (+ 48 ± 21% and + 42 ± 18%, respectively; p < 0.001) 6-RM, as well as all functional capacity outcomes (p < 0.01) due to training. M were the only group to increase muscle mass (+ 3 ± 2%, p < 0.01). Both M and E group significantly (p < 0.05) decreased GLU (–4 ± 6% and –8 ± 10%, respectively), whereas significantly greater decrease was observed in the E compared to the M group (p < 0.05). Only E group significantly decreased TG (–17 ± 25%, p < 0.01), whereas M group increased (+ 15%, p < 0.01). The difference in TG between the groups favored E compared to M group (p < 0.01). These results suggest that short-term “hypertrophic” ST alone mainly improves strength and functional capacity performance, but it influences metabolic and hormonal profile of healthy older women to a lesser extent. In this group of previously untrained older women, time-of-day did not have a major effect on outcome variables, but some evidence suggests that training in the morning may be more beneficial for muscle hypertrophy (i.e. only M significantly increased muscle mass and had larger effect size (M: g = 2 vs. E: g = 0.5).     

The effect of temperature on the development and life cycle regulation of the pine weevil Hylobius abietis and the potential impacts of climate change

• 1 The pine weevil Hylobius abietis is widely distributed in the Palaearctic region where it is a major pest. Although predominantly semi‐voltine, with a 2‐year life cycle, the generation time across its range can vary from 1 to 4 years. The duration of the life cycle and the seasonal timing of weevil activity affect the economic impact and management of this pest, all of which are likely to change in a warming climate.
• 2 To determine the effect of temperature and tree species on weevil growth and development, laboratory experiments were performed with eggs, larvae, prepupae, pupae and adults, using, as appropriate, the host species Scots pine Pinus sylvestris L. and Sitka spruce Picea sitchensis (Bong.) Carr. under constant or alternating temperatures.
• 3 The development rate was linearly related to temperature, with developmental thresholds for eggs, larvae and pupae of 8, 4.5 and 7.3 °C, respectively. Day‐degrees were estimated for each life stage. Larval development was affected by tree species, being slower on Sitka spruce than on Scots pine, and was faster under alternating than constant temperatures.
• 4 The development time for prepupae was highly variable, with an apparent facultative prepupal diapause initiated by temperature. The temperature range 20–17.5 °C marked the transition between median prepupal development times of approximately 25 and 90 days. The prepupal stage may serve to minimize the risk of overwintering mortality in the pupal stage and help to synchronize the life cycle.
• 5 Larval and adult mass was positively related to developmental temperature, demonstrating an inverse temperature size rule, and weevils were heavier when developing on Scots pine than Sitka spruce. Development in alternating temperatures reduced weevil mass on Scots pine. The influence of temperature on weevil mass is likely to have a positive effect on fecundity and overwintering survival. The effects of climate change on development, voltinism and weevil mass are discussed.

     

青年教师卓越教学能力的提升对留学生人体解剖与组织胚胎学教学的影响

高校留学生教育迅速发展,我国高校青年教师教学能力的发展还存在诸多问题,"卓越计划"背景下高校青年教师的留学生教学能力亟待提高。根据我校青年教师的发展特点以及留学生教学现状,我们通过组织精彩示范课、教师系列培训等活动以及加强基础教师实践能力培养等一系列措施,形成了一套切实可行的提高青年教师人体解剖与组织胚胎学教学能力的有效策略。经过统计分析发现,教学效果显著提高。     

大小龄红松木质部解剖特征的年龄效应及其对气候变化的响应差异

树龄是影响树木生长的最重要因素之一。在气候变暖背景下,利用树干木质部解剖特征,分析不同树龄生长-气候关系,对准确评估树木对气候变化的响应和适应策略、预测气候变化下的森林动态至关重要。利用木材解剖学方法,比较了小兴安岭溪水地区针阔混交林内大、小龄红松(Pinus koraiensis)木质部解剖特征及其对气候变化的响应异同。结果表明:大龄红松主要管胞特征值随年龄增加而呈上升趋势,但小龄红松的变化趋势并不明显,两者均在1840-1890年和1980-2010年间出现剧烈的波动。大、小年龄红松部分管胞特征与气候因子的关系具有一致性,管胞数量和理论导水率分别与月最高温度负相关和正相关;总管胞面积(负相关)、理论导水率(正相关)、平均水力直径(正相关)与月最低温度的关系一致;理论导水率与月总降水正相关;管胞占比、平均管胞面积、理论导水率、平均水力直径均与平均相对湿度正相关,且大龄红松相关性更强。大、小年龄红松管胞特征与气候因子的关系的不一致表现在,大龄红松管胞占比、平均管胞面积、总管胞面积和平均水力直径与月最高温度正相关,而这些关系在小龄红松则表现为负相关。大龄红松管胞数量与7-9月最低温度正相关,而在小龄红松表现为显著负相关;大、小龄红松除理论导水率外其他管胞特征与降水关系基本相反,其中管胞数量的相关性更强;大龄红松与7月、9月、年总降水量显著正相关,而小龄红松与6月和年总降水显著负相关;与月平均相对湿度的相关关系大龄红松表现为正相关或不显著,而小龄红松呈负相关关系。温度是限制大、小龄红松管胞特征生长的主要气候因子,降水的影响相对较弱,平均相对湿度对大小龄红松的影响差异不大。近几十年,小兴安岭地区气候暖干化趋势逐渐增强,这种暖干化会造成大、小龄红松生长的响应差异。若气候持续变暖或加剧,小龄红松会出现严重生长衰退。     

Effects of strength training with elastic band programme on fitness components in young female handball players: a randomized controlled trial

This study examined the effect of a 10-week programme of strength training with elastic band (STEB) on fitness components in young female handball players. Twenty-six young female handball players (aged 15.8 ± 0.2 years) from the same club participated in this study. They were randomly assigned between experimental (EG; n = 13) and control (CG; n = 13) groups. The EG performed the STEB, replacing some handball-specific drills in the regular handball training. The CG followed the regular handball training (i.e., mainly technical-tactical drills, small sided and simulated games, and injury prevention drills). Two-way analyses of variance were used to assess: handgrip; back extensor strength; medicine ball throw; 30 m sprint times; Modified Illinois change-of-direction (Illinois-MT); four jump tests: squat jump (SJ), countermovement jump (CMJ), countermovement jump with arm swing (CMJA) and five-jump test (5JT); static (Stork test) and dynamic balance (Y Balance Test); and repeated sprint T-test (RSTT). Results revealed significant gains in handgrip - right (p < 0.001, d = 1.75: large), handgrip - left (p < 0.001, d = 2.52: large), back extensor (p < 0.001, d = 2.01: large), and medicine ball throw (p = 0.002, d = 0.95: large) with EG compared to the CG. The EG also demonstrated greater improvement in sprint performance over 20 m (Δ = 10.6%, p = 0.001, d = 1.07: large) and 30 m (Δ = 7.2%, p < 0.0001, d = 1.56: large) compared to the CG. The EG showed better Illinois-MT (Δ = 5.6%, p = 0.034, d = 0.62: medium) compared to the CG. Further, EG posted significant improvements in the SJ (Δ = 17.3%, p = 0.048, d = 0.58: medium), CMJ (Δ = 17.7%, p = 0.017 d = 0.71: medium), and CMJA (Δ = 16.3%, p = 0.019, d = 0.69: medium) compared to the CG. Similarly, the EG exhibited significant improvement in RSTT best time [p = 0.025, d = 0.66 (medium)], RSTT mean time [p = 0.019, d = 0.69 (medium)] and RSTT total time [p = 0.019, d = 0.69 (medium)] compared to the CG. In conclusion, the 10-week STEB improved the physical abilities in young female handball players.     

Secular change in body height and cephalic index of Croatian medical students (University of Rijeka)

An investigation of body height and cephalic measurements was performed among five groups of first-year medical students of the University of Rijeka School of Medicine (Rijeka, Croatia). Body height and different cephalic measurements showed normal distribution, both in male and female students. Differences between measured variables were statistically analyzed by ANOVA. No significant difference with regard to year of birth was found in either males or females. The cephalic index showed no statistically significant difference between sexes or with regard to body height, while head breadth and length correlated significantly with birth year and body height, both in males and females. Head breadth decreased within the study period, while head length increased. Results were compared with those of similar studies from the mid-20th century. Student's t-test showed a significant change of cephalic indices and other head measurements, but not of body height, in males. The frequency difference between various head shapes was tested using the chi-square test. A significant increase of dolichocephalic and mesocephalic and a significant decrease of brachycephalic head shape were found in both sexes. These results suggest a continuity of the debrachycephalization process observed in our population at the past midcentury.     

The impact of climate change on the physical characteristics of the larger lakes in the English Lake District

1. The larger lakes of the English Lake District have been the subject of intensive scientific study for more than 60 years. Year‐to‐year variations in the weather have recently been shown to have a major effect on their physical characteristics. The area is mild but very wet and the dynamics of the lakes are strongly influenced by the movement of weather systems across the Atlantic. 2. Here, we combine the results of long‐term measurements and the projections from a Regional Climate Model (RCM) to assess the potential impact of climate change on the surface temperature and residence times of the lakes. 3. The RCM outputs used were produced by the U.K. Hadley Centre and are based on the IPCC ‘A2’ scenario for the emission of greenhouse gases. These suggest that winters in the area will be very much milder and wetter by the 2050s and that there will be a pronounced reduction in the summer rainfall. 4. An analysis of the meteorological data acquired between 1940 and 2000 shows that there have been progressive increases in the winter air temperature and in the rainfall which are correlated with the long‐term change in the North Atlantic Oscillation. The trends reported during the summer were less pronounced and were correlated with the increased frequency of anticyclonic days and a decrease in the frequency of westerly days in the British Isles. 5. A simple model of the year‐to‐year variations in surface temperatures showed that the highest winter temperatures were recorded in the deeper lakes and the highest summer temperatures in the lakes with the shallowest thermoclines. When this model was used to predict the surface temperatures of the lakes in the 2050s, the greatest winter increase (+1.08 °C) was observed in the shallowest lake and the greatest summer increase (+2.18 °C) in the lake with the shallowest thermocline. 6. The model used to estimate the seasonal variation in the residence time of the lakes showed that the most pronounced variations were recorded in lakes with a short residence time. Average winter residence times ranged from a minimum of 10 days to a maximum of 436 days and average summer values from a minimum of 23 days to a maximum of 215 days. When this model was used to predict the residence time of the lakes in the 2050s, the greatest winter decrease (−20%) was observed in the smallest lake and the greatest summer increase (+92%) in the lake with the shortest residence time. 7. The results are discussed in relation to trends reported elsewhere in Europe and the impact of changes in the atmospheric circulation on the dynamics of the lakes. The most serious limnological effects were those projected for the summer and included a general increase in the stability of the lakes and a decrease in the flushing rate of the lakes with short residence times.     

The effect of local change in habitat quality on populations of migratory species

1. Habitat deterioration is a major problem world-wide as a result of processes such as change in land use, introduced species, human disturbance and exploitation of food supplies. Many studies have shown that habitat change can have considerable effect on the numbers of individuals using a site. For migratory species, however, the consequences for the total population cannot be deduced from local studies.
2. For a migratory species, the change in total population size Δ N , as a consequence of habitat change in the wintering area, can be calculated from Δ N  =  LM γ d '/( b ' +  d '), where γ is the expected proportional change in the number of birds using a site as a result of the habitat change, L is the area affected, M is the density of individuals using the site prior to habitat change, b ' is the strength of the per capita density-dependent breeding output, and d ' is the strength of the per capita density-dependent winter mortality. Similarly the consequences of habitat change in the breeding area can be calculated from Δ N  =  LM γ b '/( b ' +  d ').
3. The same approach can be used for predicting the consequences of improvements in habitat quality.
4. A worked example is given to illustrate how this approach could be used to predict the consequences for the total population of changes in the food supply of oystercatchers within one estuary.
5. There is a need for more measures of γ, the expected proportional change in the number of birds using a site as a result of various forms of habitat deterioration, and the strengths of density dependence.     

Effect of Pedal Rate on Diurnal Variations in Cardiorespiratory Variables

Recently, it was observed that the freely chosen pedal rate of elite cyclists was significantly lower at 06:00 than at 18:00 h, and that ankle kinematics during cycling exhibits diurnal variation. The modification of the pedaling technique and pedal rate observed throughout the day could be brought about to limit the effect of diurnal variation on physiological variables. Imposing a pedal rate should limit the subject's possibility of adaptation and clarify the influence of time of day on physiological variables. The purpose of this study was to determine whether diurnal variation in cardiorespiratory variables depends on pedal rate. Ten male cyclists performed a submaximal 15 min exercise on a cycle ergometer (50% W_max). Five test sessions were performed at 06:00, 10:00, 14:00, 18:00, and 22:00 h. The exercise bout was divided into three equivalent 5 min periods during which different pedal rates were imposed (70 rev · min^?1, 90 rev · min^?1 and 120 rev · min^?1). No significant diurnal variation was observed in heart rate and oxygen consumption, whatever the pedal rate. A significant diurnal variation was observed in minute ventilation (p=0.01). In addition, the amplitude of the diurnal variation in minute ventilation depended on pedal rate: the higher the pedal rate, the greater the amplitude of its diurnal variation (p=0.03). The increase of minute ventilation throughout the day is mainly due to variation in breath frequency (p=0.01)—the diurnal variation of tidal volume (all pedal rate conditions taken together) being non‐significant—but the effect of pedal rate×time of day interaction on minute ventilation specific to the higher pedal rate conditions (p=0.03) can only be explained by the increase of tidal volume throughout the day. Even though an influence of pedal rate on diurnal rhythms in overall physiological variables was not also evidenced, high pedal rate should have been imposed when diurnal variations of physiological variables in cycling were studied.     

Effect of pedal rate on diurnal variations in cardiorespiratory variables

Recently, it was observed that the freely chosen pedal rate of elite cyclists was significantly lower at 06:00 than at 18:00 h, and that ankle kinematics during cycling exhibits diurnal variation. The modification of the pedaling technique and pedal rate observed throughout the day could be brought about to limit the effect of diurnal variation on physiological variables. Imposing a pedal rate should limit the subject's possibility of adaptation and clarify the influence of time of day on physiological variables. The purpose of this study was to determine whether diurnal variation in cardiorespiratory variables depends on pedal rate. Ten male cyclists performed a submaximal 15 min exercise on a cycle ergometer (50% W_max). Five test sessions were performed at 06:00, 10:00, 14:00, 18:00, and 22:00 h. The exercise bout was divided into three equivalent 5 min periods during which different pedal rates were imposed (70 rev · min^-1, 90 rev · min^-1 and 120 rev · min^-1). No significant diurnal variation was observed in heart rate and oxygen consumption, whatever the pedal rate. A significant diurnal variation was observed in minute ventilation (p=0.01). In addition, the amplitude of the diurnal variation in minute ventilation depended on pedal rate: the higher the pedal rate, the greater the amplitude of its diurnal variation (p=0.03). The increase of minute ventilation throughout the day is mainly due to variation in breath frequency (p=0.01)—the diurnal variation of tidal volume (all pedal rate conditions taken together) being non-significant—but the effect of pedal rate×time of day interaction on minute ventilation specific to the higher pedal rate conditions (p=0.03) can only be explained by the increase of tidal volume throughout the day. Even though an influence of pedal rate on diurnal rhythms in overall physiological variables was not also evidenced, high pedal rate should have been imposed when diurnal variations of physiological variables in cycling were studied.     

Effects of room temperature and body position change on cerebral blood volume and center-of-foot pressure in healthy young adults

This study aimed to examine the effects of room temperature and body position changes on cerebral blood volume, blood pressure and center-of-foot pressure (COP). Cerebral oxygenation kinetics and blood pressure were measured by near infrared spectroscopy (NIRS) and volume-compensation, respectively, in 9 males and 9 females after rapid standing from sitting and supine positions in low (12 degrees C) or normal (22 degrees C) room temperatures. COP was also measured in a static standing posture for 90 s after rapid standing. The total hemoglobin (Hb) decreased just after standing. Blood pressure after standing at normal temperature tended to decrease immediately but at low temperature tended to decrease slightly and then to increase greatly. The decreasing ratio of total Hb and blood pressure upon standing from a supine position at normal room temperatures was the largest of any condition. Total Hb recovered to a fixed level approximately 25 sec after standing from a sitting position and approximately 35 sec after standing from a supine position. All COP parameters after standing tended to change markedly in the supine position compared to the sitting position, especially at normal temperatures. The COP parameters after standing in any condition were not significantly related to the decreasing ratio of total Hb but were related to the recovery time of total Hb after standing. In conclusion, decreasing ratios of total Hb and blood pressure after standing from a supine position at normal temperatures were large and may affect body sway.     

近40年中国干旱特征及其对植被变化的影响

全球变暖影响下,中国干旱事件发生愈加频繁。过去半个世纪里,中国半干旱和半湿润地区的分界线总体南移,干旱面积呈增加趋势,因此了解中国干旱变化趋势对区域生态环境保护具有重要意义。基于GLASS数据产品、ERA5-Land数据,采用游程理论和多元线性回归等方法,探究1982—2018年间多尺度干旱事件基本特征(干旱持续时间、干旱严重度、干旱强度等),并分析植被生产力变化趋势,揭示干旱对植被变化的累积影响。结果表明：(1)新疆、青藏高原以及东南地区干旱较为严峻,而华中、华东大部分区域处于轻旱或无旱状态;(2)1982—2018年间,中国植被生产力整体呈改善态势,显著改善区集中在中国中部,而退化区集中在东南部、内蒙古和西藏南部;(3)中国大部分区域干旱与植被呈正相关,且干旱对植被多为累积影响,在干旱区和半干旱区尤为明显;(4)随着植被覆盖度的增加,植被与近短期尺度干旱的相关性也逐渐增加,由干旱区到湿润区,近短尺度干旱对植被变化的影响逐步增大。其中,SPEI-6(标准化降水蒸散发指数—中期尺度)对植被轻微变化累积影响最显著,而SPEI-12(标准化降水蒸散发指数—长期尺度)对植被显著变化累积影响更...     

Analysis of the effects of hypothalamic-pituitary-adrenal axis activity in menstrual cycle on ankle proprioception,dynamic balance scores and visual-auditory reaction times in healthy young women

Objectives:Menstrual cycle (MC) can affect not only the female reproductive system, but also functions such as neuromuscular performance. For this reason, the aim of this study is to investigate the effect of hypothalamic-pituitary-adrenal axis (HPA) activity in MC on proprioception, balance and reaction times.Methods:For cortisol analysis, saliva samples were taken from the same women (n=43) in the four phases of MC. While State Trait Anxiety Inventory-I (STAI-I) was applied in each phase to support cortisol analysis, pain was measured with visual analogue scale (VAS). Proprioception, dynamic balance, visual and auditory reaction times (VRT-ART) measurements were made in the four phases of MC.Results:Cortisol, STAI-I and VAS scores, angular deviations in proprioception measurements, dynamic balance scores, VRT and ART measurements were found to show statistically significant difference between MC phases (p<0.05). As a result of the post hoc test conducted to find out which MC phase the statistical difference resulted from, it was found that statistically significant difference was caused by the mensturation (M) phase (p<0.05).Conclusions:It was found that neuromuscular performance and postural control was negatively affected by HPA axis activity in M phase of MC and by pain, which is a significant menstrual symptom.     

Caffeine reversal of sleep deprivation effects on alertness,mood and repeated sprint performances in physical education students

The aim of this study was to evaluate the effects of caffeine ingestion and partial sleep deprivation on mood and cognitive and physical performances. In randomised order, 12 healthy male physical education students completed four test sessions at 18:00 h after placebo or 5 mg/kg of caffeine ingestion during a baseline night (RN) (bed time: from 22:00 to 07:00 h), or during a night of partial (four hrs) sleep deprivation (PSD). During each test session, participants performed a reaction time test, a vigilance test, the 10 s Wingate cycling test during (measuring peak power (PP) and anaerobic capacity), and the 5 m multiple shuttle test (measuring peak distance (PD), total distance (TD), and fatigue index (FI)). Compared to RN, simple reaction time, vigilance, PP, PD, TD, and FI were altered by PSD the following day after placebo ingestion with increased reaction time and FI and reduced PP, PD, TD, and vigilance (p < 0.001). Moreover, during PSD condition, PP, PD, and TD were significantly higher after caffeine ingestion in comparison with placebo ingestion (p < 0.05). However, both simple reaction times and vigilance were significantly lower after caffeine ingestion in comparison with placebo during PSD (p < 0.05). Caffeine is an effective strategy to maintain physical and cognitive performances the day after PSD.     

未来气候变化对河南省冬小麦需水量和缺水量的影响预估

采用美国农业部土壤保持局推荐的方法计算有效降水量,应用Penman-Monteith模型和作物系数法计算需水量,在对河南省1981—2010年冬小麦生育期内有效降水量、需水量和缺水量分析的基础上,结合《排放情景特别报告》的两种排放情景A2(强调经济发展)和B2(强调可持续发展)预估的未来气候情景,探讨了未来气候情景下河南省冬小麦的有效降水量、需水量和缺水量的时空演变规律及其主要气候影响因素.结果表明: 从整体上看,相对于基准时段(1981—2010年),A2和B2情景下,不同时段冬小麦全生育期的有效降水量、需水量和缺水量均表现出增加趋势,有效降水量均以2030s时段增加最多,分别增加33.5%和39.2%;需水量均以2010s时段增加最多,分别增加22.5%和17.5%,年代间呈现明显递减趋势;缺水量在A2情景下以2010s时段增加(23.6%)最多,B2情景下以2020s时段增加(13.0%)最多.偏相关分析表明,A2和B2情景下,太阳总辐射是影响河南省冬小麦需水量和缺水量变化的主要气候因素.由于地理环境和气候条件的差异,不同时段河南省冬小麦全生育期有效降水量、需水量和缺水量的距平百分率在空间分布上具有差异.未来河南省水资源可能更趋于短缺.