Researchers and clinicians have suggested that overuse injuries to the lower back and lower extremities of figure skaters may be associated with the repeated high impact forces sustained during jump landings. Our primary aim was to compare the vertical ground reaction forces (GRFs) in freestyle figure skaters (n = 26) and non-skaters (n = 18) for the same barefoot single leg landing on a force plate from a 20 cm platform. Compared with non-skaters, skaters exhibited a significantly greater normalised peak GRF (3.50 ± 0.47 × body weight for skaters vs. 3.13 ± 0.45 × body weight for non-skaters), significantly shorter time to peak GRF (81.21 ± 14.01 ms for skaters vs. 93.81 ± 16.49 ms for non-skaters), and significantly longer time to stabilisation (TTS) of the GRF (2.38 ± 0.07 s for skaters vs. 2.22 ± 0.07 s for non-skaters). Skaters also confined their centre of pressure (CoP) to a significantly smaller mediolateral (M-L) (25%) and anterior-posterior (A-P) (40%) range during the landing phase, with the position of the CoP located in the mid to forefoot region. The narrower and more forward position of the CoP in skaters may at least partially explain the greater peak GRF, shorter time to peak, and longer TTS. Training and/or equipment modification serve as potential targets to decrease peak GRF by distributing it over a longer time period. More comprehensive studies including electromyography and motion capture are needed to fully characterise the unique figure skater landing strategy.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1080/02640414.2013.877593 | DOI Listing |
Patients with anterior cruciate ligament reconstruction frequently present asymmetries in the sagittal plane dynamics when performing single leg jumps but their assessment is inaccessible to health-care professionals as it requires a complex and expensive system. With the development of deep learning methods for human pose detection, kinematics can be quantified based on a video and this study aimed to investigate whether a relatively simple 2D multibody model could predict relevant dynamic biomarkers based on the kinematics using inverse dynamics. Six participants performed ten vertical and forward single leg hops while the kinematics and the ground reaction force "GRF" were captured using an optoelectronic system coupled with a force platform.
View Article and Find Full Text PDFSci Rep
January 2025
Chair of Applied Mechanics, Technical University of Munich, Garching, 85748, Germany.
Ankle push-off is important for efficient, human-like walking, and many prosthetic devices mimic push-off using motors or elastic elements. The knee is extended throughout the stance phase and begins to buckle just before push-off, with timing being crucial. However, the exact mechanisms behind this buckling are still unclear.
View Article and Find Full Text PDFBackground: Kettlebell (KB) swing exercises, whether performed using shoulder height (SHS) or overhead (OHS) swing variations in therapeutic or strength and conditioning settings, are posterior chain dominant exercises that require hip extension contributions when performed correctly.
Purpose/ Hypothesis: The primary purpose of this study was to evaluate the effect of swing style (SHS, OHS) and KB mass on hip extension kinematics and kinetics in young adult females. A secondary purpose was to determine the effects of swing style and KB mass on the forces applied to the total body center of mass and KB.
Sports (Basel)
November 2024
Sport, Performance, and Nutrition Research Group, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, VIC 3086, Australia.
Ground reaction forces (GRFs) are known to be high during front foot contact of fast bowling deliveries in cricket. There is a lack of published data on the GRFs during follow through foot contacts. The aim of this study was to quantify and compare peak GRFs and impulse of the delivery stride and the follow through of fast bowling deliveries.
View Article and Find Full Text PDFJ Sci Food Agric
December 2024
Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology, Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China.
Background: Nitrogen application is recognized as a principal factor influencing rice quality. However, there remains a paucity of research on the effects of different N levels on quality, particularly within the context of the improvement of rice varieties.
Results: This study examined 14 mid-season japonica rice varieties cultivated in Jiangsu province over the past 80 years under five N application levels (0, 90, 180, 270, and 360 kg N ha).
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!