Zoekresultaten

Using the apple watch to teach and learn about heart rate variability while vacationing.

Individual variability in heart rate recovery after standardized submaximal exercise

To optimize performance, coaches and athletes are always looking for the right balance between training load and recovery. Therefore, closely monitoring of athletes is important. Heart rate recovery (HRR) after standardized sub maximal exercise has been proposed as a useful variable to monitor (Lamberts et al., 2004). However, it is well known that heart rate, next to biological variability, is influenced by several factors such as training load and psychosocial stress. So, the purpose was to look at individual variability in HRR from one week to another using the heart rate interval monitoring system (HIMS). Methods Eight elite Dutch female indoor hockey players (age: 23.9±3.91yr, length: 155.0±7.01cm, weight: 56.6±6.16kg) completed the HIMS two weeks in a row (Lamberts et al., 2004). The heart rate at the end of the last stage (HRend) was determined and the HRR was calculated one minute after the end of the last stage. Furthermore, training load and psychosocial stress and recovery were monitored using the Foster-method (1998) and the RESTQ-Sport (Nederhof et al., 2008), respectively. Results A strong correlation was found between the HRend from one week to the other (r=0.984 p.

Considering Human Interaction and Variability in Automatic Text Simplification

Research into automatic text simplification aims to promote access to information for all members of society. To facilitate generalizability, simplification research often abstracts away from specific use cases, and targets a prototypical reader and an underspecified content creator. In this paper, we consider a real-world use case – simplification technology for use in Dutch municipalities – and identify the needs of the content creators and the target audiences in this scenario. The stakeholders envision a system that (a) assists the human writer without taking over the task; (b) provides diverse outputs, tailored for specific target audiences; and (c) explains the suggestions that it outputs. These requirements call for technology that is characterized by modularity, explainability, and variability. We argue that these are important research directions that require further exploration

The effect of work pace on workload, motor variability and fatigue during simulated light assembly work

This study investigated the effect of work pace on workload, motor variability and fatigue during light assembly work. Upper extremity kinematics and electromyography (EMG) were obtained on a cycle-to-cycle basis for eight participants during two conditions, corresponding to "normal" and "high" work pace according to a predetermined time system for engineering. Indicators of fatigue, pain sensitivity and performance were recorded before, during and after the task. The level and variability of muscle activity did not differ according to work pace, and manifestations of muscle fatigue or changed pain sensitivity were not observed. In the high work pace, however, participants moved more efficiently, they showed more variability in wrist speed and acceleration, but they also made more errors. These results suggest that an increased work pace, within the range addressed here, will not have any substantial adverse effects on acute motor performance and fatigue in light, cyclic assembly work.STATEMENT OF RELEVANCE: In the manufacturing industry, work pace is a key issue in production system design and hence of interest to ergonomists as well as engineers. In this laboratory study, increasing the work pace did not show adverse effects in terms of biomechanical exposures and muscle fatigue, but it did lead to more errors. For the industrial engineer, this observation suggests that an increase in work pace might diminish production quality, even without any noticeable fatigue being experienced by the operators.

Variability of inter-team distances associated with match events in elite-standard soccer

In soccer, critical match events like goal attempts can be preceded by periods of instability in the balance between the two teams' behaviours. Therefore, we determined periods of high variability in the distance between the teams' centroid positions longitudinally and laterally in an international-standard soccer match and evaluated corresponding match events. Position data were collected with AMISCO Pro®. Inter-team distance variability was calculated over a 3-s moving window. Out of the 242 match periods that exceeded the variability criterion, 51 were dead-ball situations. Match events identified through longitudinal inter-team distance primarily related to defending players moving forward-backward after a longitudinal pass. Match events identified through lateral inter-team distance mainly corresponded with defending players moving laterally following sideways passing. One of two goals and two of fourteen goal-attempts were preceded by a period of high variability. Together, periods of highly variable inter-team distance were associated with collective defensive actions and team reorganisation in dead-ball moments rather than goals or goal attempts. Inter-team dynamics quantified (mutual) reorganisation of the teams and marked teams' collective defensive ability to respond to attacking explorations. doi: 10.1080/02640414.2012.703783

Creative Motor Actions As Emerging from Movement Variability

In cognitive science, creative ideas are defined as original and feasible solutions in response to problems. A common proposal is that creative ideas are generated across dedicated cognitive pathways. Only after creative ideas have emerged, they can be enacted to solve the problem. We present an alternative viewpoint, based upon the dynamic systems approach to perception and action, that creative solutions emerge in the act rather than before. Creative actions, thus, are as much a product of individual constraints as they are of the task and environment constraints. Accordingly, we understand creative motor actions as functional movement patterns that are new to the individual and/or group and adapted to satisfy the constraints on the motor problem at hand. We argue that creative motor actions are promoted by practice interventions that promote exploration by manipulating constraints. Exploration enhances variability of functional movement patterns in terms of either coordination or control solutions. At both levels, creative motor actions can emerge from finding new and degenerate adaptive motor solutions. Generally speaking, we anticipate that in most cases, when exposed to variation in constraints, people are not looking for creative motor actions, but discover them while doing an effort to satisfy constraints. For future research, this paper achieves two important aspects: it delineates how adaptive (movement) variability is at the heart of (motor) creativity, and it sets out methodologies toward stimulating adaptive variability.