Parental beliefs concerning development and education, family educational practices and children’s intellectual and academic performances

The present study examines the relationships between parental beliefs relating to development and education, parenting practices, and the intellectual and academic performances of children. Data were collected for 128 families with a child in the second or third year of primary school. Investigations of the factors affecting the children’s performances were carried out using two models that combined the different study variables. Compliance between the data and the theoretical models was tested by path analysis, using LISREL software. The results show a good fit between the data and the models and partly confirm the hypothesis that family educational practices are intermediary variables between parenting beliefs and a child’s intellectual and academic performances.     

Reading in French-speaking adults with dyslexia

This study investigated the reading and reading-related skills of 15 French-speaking adults with dyslexia, whose performance was compared with that of chronological-age controls (CA) and reading-level controls (RL). Experiment 1 assessed the efficiency of their phonological reading-related skills (phonemic awareness, phonological short-term memory, and rapid automatic naming (RAN)) and experiment 2 assessed the efficiency of their lexical and sublexical (or phonological) reading procedures (reading aloud of pseudowords and irregular words of different lengths). Experiment 1 revealed that adults with dyslexia exhibited lower phonological reading-related skills than CAs only, and were better than RL controls on the RAN. In experiment 2, as compared with RL controls, only a deficit in the sublexical reading procedure was observed. The results of the second experiment replicated observations from English-language studies but not those of the first experiment. Several hypotheses are discussed to account for these results, including one related to the transparency of orthographic systems.     

1900年以来贝加尔湖水位变化及其原因分析

水位变化作为湖泊水文过程和水量平衡的动态反映,是湖泊生态环境的重要影响因素。全球最大的淡水湖——贝加尔湖,在自然变化与人为活动的双重影响下,过去100多年水位表现出较大的年内、年际和多年变化。贝加尔湖水位变化与入湖径流量变化密切相关,与贝加尔湖最大支流色楞格河的径流量变化较为一致。气候变暖带来的气温上升和降水减少使得入湖径流量减少,贝加尔湖水位下降。人类活动对贝加尔湖水位变化影响表现在两个方面：一方面,全球变暖条件下耕地面积扩张和灌溉用水增加导致贝加尔湖流域用水增加,使得入湖径流量减少,贝加尔湖水位下降;另一方面,1958年伊尔库茨克水电站投入运营之后,贝加尔湖水位变化受到了安加拉河水位顶托的影响。在下游水电站人为调控影响下,贝加尔湖年平均水位升高,年内水位波动幅度增加,年最低和最高水位出现日期推迟。地处全球气候与环境变化敏感区的贝加尔湖,其水位变化对湖泊及周边生态环境影响显著。因此,探究在全球变化背景下贝加尔湖的水位变化及影响因素对保护当地生态环境具有重要意义。     

The relation to time in the family business and in the start-up company: A comparative study

The “relation to time” refers to the way time is apprehended. Despite calls to further integrate the time variable in family business research, studies remain few and do not compare with other organizational forms. This conceptual study highlights the largely antithetical relation to time of family businesses and start-up companies to deduct proposals in terms of governance, investment, innovation and socioemotional wealth. The discussion looks at the positive and negative impacts of these two types of relation to time and suggests that leaders develop the absorptive capacity of their businesses to enrich their practices with approaches proven in other forms of organizations.     

Fatigue-related changes in technique emerge at different timescales during repetitive training

Training consisting of numerous repetitions performed as closely as possible to ideal techniques is common in sports and every-day tasks. Little is known about fatigue-related technique changes that emerge at different timescales when repeating complex actions such as a karate front kick. Accordingly, 15 karatekas performed 600 kicks (1 pre-block and 9 blocks). The pre-block comprised 6 kicks (3 with each leg) at maximum intensity (K-100%). Each block comprised 60 kicks (10 with each leg) at 80% of their self-perceived maximum intensity (K-80%) plus 6 K-100%. In between blocks, the participants rested for 90 seconds. Right leg kinematics (peak joint angles, peak joint angular velocities, peak joint linear resultant velocities, and time of occurrence of peaks) and kick duration corresponding to the K-80% were measured resulting in numerous variations with fatigue. At the timescale of tens of seconds, the changes involved variables that were related to velocity of execution (slowed down), while variables related to movement form were hardly affected. At the timescale of tens of minutes, the opposite results were observed. These findings challenge the long-standing rationale underlying repetitive training, suggesting instead that such involuntary variations in technique might play a crucial role in motor skill training     

Effect of different velocity loss thresholds during a power-oriented resistance training program on the mechanical capacities of lower-body muscles

This study compared the effects of two velocity loss thresholds during a power-oriented resistance training program on the mechanical capacities of lower-body muscles. Twenty men were counterbalanced in two groups (VL10 and VL20) based on their maximum power capacity. Both groups used the same exercises, relative intensity and repetition volume, only differing in the velocity loss threshold of each set (VL10: 10% vs. VL20: 20%). Pre- and post-training assessments included an incremental loading test and a 15-m linear sprint to assess the force- and load-velocity relationships and athletic performance variables, respectively. No significant between-group differences (P > 0.05) were observed for the force-velocity relationship parameters (ES range = 0.15–0.42), the MPV attained against different external loads (ES range = 0.02–0.18) or the 15-m sprint time (ES = 0.09). A high between-participants variability was reported for the number of repetitions completed in each training set (CV = 30.3% for VL10 and 29.4% for VL20). These results suggest that both velocity loss thresholds induce similar changes on the lower-body function. The high and variable number of repetitions completed may compromise the velocity-based approach for prescribing and monitoring the repetition volume during a power-oriented resistance training program conducted with the countermovement jump exercise.     

Effects of resistance training on performance in previously trained endurance runners: A systematic review

The aim of this work was to identify, synthesize and evaluate the results of randomized controlled trials examining the effects of resistance training on performance indicators in previously trained endurance runners. A database search was carried out in PubMed, Science Direct, OvidSPMedLine, Wiley, Web of Science, ProQuest and Google Scholar. In accordance with the PRISMA checklist, 18 published articles dated prior to May 2016 involving 321 endurance runners were reviewed using the PEDro scale. Resistance training led to general improvements in muscular strength, running economy, muscle power factors, and direct performance in distances between 1,500 and 10,000 m. Such improvements were not accompanied by a significant increase in body mass or signs of overtraining. However, improvements did not occur in all cases, suggesting that they might depend on the specific characteristics of the resistance training applied. Although current evidence supports the effectiveness of resistance training to improve performance in already trained endurance runners, the methodological inconsistencies identified suggest that the results should be interpreted with caution. Future studies ought to investigate the benefits of resistance training in endurance runners while considering the existence of possible differentiated effects based on the specific characteristics of the resistance training carried out.     

Reliability of power and velocity variables collected during the traditional and ballistic bench press exercise

This study aimed to examine the reliability of different power and velocity variables during the Smith machine bench press (BP) and bench press throw (BPT) exercises. Twenty-two healthy men conducted four testing sessions after a preliminary BP one-repetition maximum (1RM) test. In a counterbalanced order, participants performed two sessions of BP in one week and two sessions of BPT in another week. Mean propulsive power, peak power, mean propulsive velocity, and peak velocity at each tenth percentile (20–70% of 1RM) were recorded by a linear transducer. The within-participants coefficient of variation (CV) was higher for the load–power relationship compared to the load–velocity relationship in both the BP (5.3% vs. 4.1%; CV ratio = 1.29) and BPT (4.7% vs. 3.4%; CV ratio = 1.38). Mean propulsive variables showed lower reliability than peak variables in both the BP (5.4% vs. 4.0%, CV ratio = 1.35) and BPT (4.8% vs. 3.3%, CV ratio = 1.45). All variables were deemed reliable, with the peak velocity demonstrating the lowest within-participants CV. Based upon these findings, the peak velocity should be chosen for the accurate assessment of BP and BPT performance.     

Larger strength losses and muscle activation deficits in plantar flexors induced by backward downhill in reference to distance-matched forward uphill treadmill walk

We tested the hypothesis that backward downhill walking (eccentric component) impairs both voluntary activation and muscle contractile properties in the plantar flexors and delays recovery as compared to a gradient and distance-matched uphill walk. Fourteen males performed two 30-min walking exercises (velocity: 1?m/?s; grade: 25%; load: 12% of body weight), one downhill (DW) and one uphill (UP), in a counterbalanced order, separated by 6?weeks. Neuromuscular test sessions were performed before, after, 24-, 48- and 72-h post-exercise, including motor nerve stimulations during brief (5?s) and sustained (1?min) maximal isometric voluntary contractions of the plantar flexors. DW (?18.1?±?11.1%, P?P?=.15), decreased torque production during brief contractions for at least three days post-exercise (P?P?P?=?.024) and DW (?25.6?±?10.3%, P?P?=?.001) was lower in DW than UP. Peak twitch torque and maximum rates of torque development and relaxation were equally reduced after UP and DW (P?P?P?>?.05). Using a direct comparison, the capacity to drive the plantar flexors during sustained contractions remains sub-optimal during the three-day recovery period in response to non-exhaustive, downhill backward walking in reference to an uphill exercise matched for distance covered.     

The effect of sex and localised fatigue on triceps surae musculoarticular stiffness

Purpose: The main purpose of this study was to investigate the influence of fatigue on musculoarticular stiffness (MAS) of the ankle joint across sexes. Methods: Twenty-seven males and 26 females participated in the study. After baseline assessment of MAS and related variables, localised fatigue was induced in triceps surae using the standing heel-rise test during which the subjects were instructed to lift and drop the heel at a frequency of 0.5?Hz. When subjects were unable to continue due to exhaustion the test was terminated and another MAS test was performed soon after. Results: Significant higher triceps surae MAS was found in men compared to women (p?p??1 and from 14.5 to 13.9?KN?m^?1 in men and women, respectively. Percentage changes revealed, however, that in relative terms the changes in all the variables evaluated were similar (p?>?.01) between sexes, with MAS less than 5%. Conclusion: Despite the sex-related differences at baseline, fatigue seems to affect biomechanical properties of the ankle joint similarly in men and women.