Time-course of running treadmill adaptation in novice treadmill runners

ABSTRACT

Studies on running biomechanics and energetics are usually conducted on a treadmill. To ensure that locomotion on a treadmill is comparable to locomotion overground, participants need to be expert in the use of the device. This study aimed to identify the number and duration of sessions needed to obtain stable measurements for spatiotemporal and metabolic parameters in unexperienced treadmill runners. Fourteen male recreational runners performed three 15-min treadmill running trials in different days at a submaximal speed. Spatiotemporal and metabolic parameters were registered at minutes: 5, 10, 15 and their within-trial and between-trial changes were analysed using a two-way repeated measures ANOVA and Bonferroni post-hoc test. Within-trial differences were found in step frequency (decreased over time), Step Length and Contact Time (increased), reaching stability at different time points. Ventilator parameters increased, reaching stability after 5–10 min, while heart rate increased progressively over time. The only between-trial differences were an increase in step length and a decrease in step frequency at min 1, between trials 1 and 3. In conclusion, at least three running trials of 15 min are required to familiarize with the device. The last 5 min of the third trial can be regarded as stable measurements.     

Are Method Effects Permanent or Ephemeral in Nature? The Case of the Revised Life Orientation Test

This research investigated the nature of the method effect associated with positively worded items of the Life Orientation Test–Revised. In a first cross-sectional study (N?=?11,028) the best fitting model posits 2 factors, representing general optimism and a specific factor associated with positive items. In a second longitudinal study (N?=?203), a unified latent curve latent state–trait model was used to assess the developmental trajectory of the specific factor from 16 to 20 years. This factor contains a prevalence of trait versus state variance, and presents a relationship pattern with external criteria (e.g., depression) that differ from the one involving general optimism.     

Parental risk attitudes and children's secondary school track choice

Although it is well-known that individuals’ risk attitudes are related to behavioral outcomes such as smoking, portfolio decisions, and educational attainment, there is virtually no evidence of whether parental risk attitudes affect the educational attainment of their dependent children. We add to this literature and examine children's secondary school track choice in Germany where tracking occurs at age ten and has a strong binding character. Using risk indicators for different domains, we mainly find evidence of an inverse relation between parental risk aversion and children's secondary school track, with some heterogeneity depending on whether parents’ risk willingness is modeled separately or jointly, by child gender, or by the risk measure used.     

A 3D kinematic analysis of breathing patterns in competitive swimmers

Abstract

The purpose of this paper was to understand which differences long-term swimming training can cause on trunk mechanics during breathing and how these differences are related to the years of swimming training. The variations and coordination among trunk compartments were considered as target movement patterns. Video-based plethysmography was utilised for data acquisition and pre-processing. A group of swimmers, who followed a long-term intensive swimming training previously to this study, was compared with a non-swimmer control group. The participants of both groups performed quiet breathing and vital capacity tests. From the compartmental volumes associated with each breathing curves, the relative amplitude and cross-correlation among these volumetric time-varying signals were calculated, in order to analyse the relative partial volume variation and the coordination among trunk compartments involved in respiration. The results of a Mixed-ANOVA test (P ≤ 0.05) revealed higher coefficient of variation (P < 0.001) and correlations among trunk compartments in the swimmers group when vital capacity was performed. Significant linear regression was found between the years of swim training and the coefficients of variation and correlation. The results suggest that after long periods of intensive swim training, athletes might develop specific breathing patterns featuring higher volume variations in the abdominal region and more coordination among compartments involved in forced respiratory tasks such as vital capacity.     

Senior citizens and the ethics of e-inclusion

The ageing society poses significant challenges to Europe’s economy and society. In coming to grips with these issues, we must be aware of their ethical dimensions. Values are the heart of the European Union, as Article 1a of the Lisbon Treaty makes clear: “The Union is founded on the values of respect for human dignity…”. The notion of Europe as a community of values has various important implications, including the development of inclusion policies. A special case of exclusion concerns the gap between those people with effective access to digital and information technology and those without access to it, the “digital divide”, which in Europe is chiefly age-related. Policies to overcome the digital divide and, more generally speaking, e-inclusion policies addressing the ageing population raise some ethical problems. Among younger senior citizens, say those between 65 and 80 years old, the main issues are likely to be universal access to ICT and e-participation. Among the older senior citizens, say those more than 80 years old, the main issues are mental and physical deterioration and assistive technology. An approach geared towards the protection of human rights could match the different needs of senior citizens and provide concrete guidance to evaluate information technologies for them.     

Muscle morphology of the vastus lateralis is strongly related to ergometer performance,sprint capacity and endurance capacity in Olympic rowers

Rowers need to combine high sprint and endurance capacities. Muscle morphology largely explains muscle power generating capacity, however, little is known on how muscle morphology relates to rowing performance measures. The aim was to determine how muscle morphology of the vastus lateralis relates to rowing ergometer performance, sprint and endurance capacity of Olympic rowers. Eighteen rowers (12♂, 6♀, who competed at 2016 Olympics) performed an incremental rowing test to obtain maximal oxygen consumption, reflecting endurance capacity. Sprint capacity was assessed by Wingate cycling peak power. M. vastus lateralis morphology (volume, physiological cross-sectional area, fascicle length and pennation angle) was derived from 3-dimensional ultrasound imaging. Thirteen rowers (7♂, 6♀) completed a 2000-m rowing ergometer time trial. Muscle volume largely explained variance in 2000-m rowing performance (R² = 0.85), maximal oxygen consumption (R² = 0.65), and Wingate peak power (R² = 0.82). When normalized for differences in body size, maximal oxygen consumption and Wingate peak power were negatively related in males (r = ?0.94). Fascicle length, not physiological cross-sectional area, attributed to normalized peak power. In conclusion, vastus lateralis volume largely explains variance in rowing ergometer performance, sprint and endurance capacity. For a high normalized sprint capacity, athletes may benefit from long fascicles rather than a large physiological cross-sectional area.     

Drivers of spin-off performance in industry clusters: Embodied knowledge or embedded firms?

Numerous studies attest to the distinctive performance of intra-industry spin-offs located in agglomerated regions. Besides entrepreneurs’ pre-entry experience, both superior hires and regional embeddedness have been suggested as factors contributing to this pattern. We employ linked employer-employee data to assess their relevance in the empirical context of the Portuguese plastic injection molds industry. We find that the longevity of entrants is associated with the number and quality of early employees hired from within the industry, consistent with the importance of embodied knowledge flows. Our findings do not suggest that entrants’ centrality in the regional industry network enhances their longevity.