排序方式： 共有8条查询结果，搜索用时 125 毫秒
1
1.
Lotte L. Lintmeijer Gert S. Faber Hessel R. Kruk A. J. “Knoek” van Soest Mathijs J. Hofmijster 《European Journal of Sport Science》2018,18(7):940-946
For a valid determination of a rower’s mechanical power output, the anterior–posterior (AP) acceleration of a rower’s centre of mass (CoM) is required. The current study was designed to evaluate the accuracy of the determination of this acceleration using a full-body inertial measurement units (IMUs) suit in combination with a mass distribution model. Three methods were evaluated. In the first two methods, IMU data were combined with either a subject-specific mass distribution or a standard mass distribution model for athletes. In the third method, a rower’s AP CoM acceleration was estimated using a single IMU placed at the pelvis.Experienced rowers rowed on an ergometer that was placed on two force plates, while wearing a full-body IMUs suit. Correspondence values between AP CoM acceleration based on IMU data (the three methods) and AP CoM acceleration obtained from force plate data (reference) were calculated. Good correspondence was found between the reference AP CoM acceleration and the AP CoM accelerations determined using IMU data in combination with the subject-specific mass model and the standard mass model (intraclass correlation coefficients [ICC] >?0.988 and normalized root mean square errors [nRMSE]?3.81%). Correspondence was lower for the AP CoM accelerations determined using a single pelvis IMU (0.877?Based on these results, we recommend determining a rower’s AP CoM acceleration using IMUs in combination with the standard mass model. Finally, we conclude that accurate determination of a rower’s AP CoM acceleration is not possible on the basis of the pelvis acceleration only. 相似文献
2.
Eline van der Kruk Marco M. Reijne Bjorn de Laat DirkJan Veeger 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(5):527-538
This study performed an analysis of the push-off forces of elite-short-track speed skaters using a new designed instrumented short-track speed skate with the aim to improve short-track skating performance. Four different skating strokes were distinguished for short-track speed skaters at speed. The strokes differed in stroke time, force level in both normal and lateral directions, and the centre of pressure (COP) on the blade. Within the homogeneous group of male elite speed skaters (N = 6), diversity of execution of the force patterns in the four phases of skating was evident, while skating at the same velocities. The male participants (N = 6) with a better personal record (PR) kept the COP more to the rear of their blades while hanging into the curve (r = 0.82, p < 0.05), leaving the curve (r = 0.86, p < 0.05), and entering the straight (r = 0.76, p < 0.10). Furthermore, the male skaters with a better PR showed a trend of a lower lateral peak force while entering the curve (r = 0.74, p < 0.10). Females showed a trend towards applying higher body weight normalised lateral forces than the males, while skating at imposed lower velocities. 相似文献
3.
Letter orientation confusions (reversals) in the reading and writing of 10-year-old children with and without reading disability were investigated to determine whether reading disability is associated with letter orientation errors and to identify the nature of the errors. In a variety of tasks measuring letter orientation confusions in reception (reversal detection and recognition) and production (controlled writing, copying), individuals with reading disability made more orientation confusions than average readers. Orientation errors were more frequent for reversible than for nonreversible items in tasks involving long-term memory processes. The results did not appear to be related to group differences in attention or speed of motor responding. Possible sources of orientation confusions, including deficient magnocellular system processing, mislabeling, and overreliance on visual strategies, are discussed. 相似文献
5.
Joanna Kruk 《Journal of sports sciences》2013,31(5):437-445
Abstract Physical activity is associated with a lower risk of breast cancer, although research findings are inconsistent regarding the type, duration, intensity, and frequency of activities that are necessary to reduce the risk, as well as dependence on menopausal status. To address these issues, I examined the effect of physical activity on breast cancer risk among 858 Polish invasive breast cancer cases and 1085 controls. Data on components of lifetime household, occupational, and recreational activities were collected in 2003–2007, using a self-administered questionnaire. Odds ratios with 95% confidence intervals were estimated using unconditional logistic regression analyses and a full assessment of confounding variables. For all types of physical activity, odds ratios were calculated for self-reported and compendium-based assigned levels of activity. Moderate- and vigorous-intensity total and recreational activities, as well as moderate- and long-lasting low-intensity household activities, lowered the risk by at least 44% for the highest versus lowest quartiles of activity in both menopausal groups. The associations were linear (Ptrend≤ 0.009). There was a suggestion of a risk reduction for occupational activity among post-menopausal women. These findings show that a risk reduction can be achieved by vigorous-intensity activities or by longer-lasting activities of moderate-intensity. 相似文献
6.
Objective: Sport research often requires human motion capture of an athlete. It can, however, be labour-intensive and difficult to select the right system, while manufacturers report on specifications which are determined in set-ups that largely differ from sport research in terms of volume, environment and motion. The aim of this review is to assist researchers in the selection of a suitable motion capture system for their experimental set-up for sport applications. An open online platform is initiated, to support (sport)researchers in the selection of a system and to enable them to contribute and update the overview. Design: systematic review; Method: Electronic searches in Scopus, Web of Science and Google Scholar were performed, and the reference lists of the screened articles were scrutinised to determine human motion capture systems used in academically published studies on sport analysis. Results: An overview of 17 human motion capture systems is provided, reporting the general specifications given by the manufacturer (weight and size of the sensors, maximum capture volume, environmental feasibilities), and calibration specifications as determined in peer-reviewed studies. The accuracy of each system is plotted against the measurement range. Conclusion: The overview and chart can assist researchers in the selection of a suitable measurement system. To increase the robustness of the database and to keep up with technological developments, we encourage researchers to perform an accuracy test prior to their experiment and to add to the chart and the system overview (online, open access). 相似文献
7.
We investigated influences of non‐alphanumeric rapid naming on decoding skill growth for regularly and irregularly spelled English words. In a longitudinal study, 52 at‐risk and 69 not‐at‐risk readers were tracked from Grade 1 to Grade 3. Non‐alphanumeric rapid naming ability measured in Grade 1 accounted for unique variance in irregular word decoding in early Grade 2 – strong rapid naming was associated with strong irregular word decoding. An interaction between reading risk status and Grade 1 rapid naming indicated that the influence of Grade 1 rapid naming ability on growth in irregular word decoding was different for at‐risk than not‐at‐risk readers. Non‐alphanumeric rapid naming can have predictive validity as a marker for identifying specific difficulties in learning to read irregular words in at‐risk readers. Results indicate that rapid naming plays a general role in irregular word reading and a specific role in at‐risk readers' growth in irregular word decoding. 相似文献
8.
E. van der Kruk O. den Braver A. L. Schwab F. C. T. van der Helm H. E. J. Veeger 《Sports Engineering》2016,19(4):273-281
In the current project, we aim to provide speed skaters with real-time feedback on how to improve their skating performance within an individual stroke. The elite skaters and their coaches wish for a system that determines the mechanical power per stroke. The push-off force of the skater is a crucial variable in this power determination. In this study, we present the construction and calibration of a pair of wireless instrumented klapskates that can continuously and synchronously measure this push-off force in both the lateral direction and normal direction of the skate and the centre of pressure of these forces. The skate consists of a newly designed rigid bridge (0.6 kg), embedding two three-dimensional force sensors (Kistler 9602, Kistler Group, Winterthur, Switzerland), which fits between most individual skate shoes and Maple skate blades. The instrumented klapskates were calibrated on a tensile testing machine, where they proved to be unaffected to temperature conditions and accurate up to an RMS of 42 N (SEM = 1 N) in normal and up to an RMS of 27 N (SEM = 1 N) in lateral direction. Furthermore, the centre of pressure of these forces on the blade was determined up to a mean error of 10.1 mm (SD = 6.9 mm). On-ice measurements showed the possibility of recording with both skates simultaneously and synchronously, straights as well as curves. The option to send data wirelessly and real-time to other devices makes it possible to eventually provide skaters and coaches with visual real-time feedback during practice. 相似文献
1