The purpose of this study was to investigate the differences of knee concentric and eccentric strength and impact related knee biomechanics between jumpers and non-jumpers during step-off landing tasks. Ten male college swimming athletes (non-jumpers) and 10 track and volleyball athletes (jumpers) were recruited to participate in two test sessions: a muscle strength testing session of concentric and eccentric extension for dominant knee joint at 60°/s and 180°/s and a landing testing session. The participants performed five trials of step-off landing in each of four conditions: soft and stiff landing from 0.4m and 0.6m landing heights. The three-dimensional kinematics and ground reaction force were recorded simultaneously during step-off landing conditions. The results showed that the jumpers had significantly greater peak knee eccentric extension and concentric flexion torques compared to the non-jumpers. No significant group effects were found for peak vertical ground reaction force and knee range of motion during landing. The jumpers had significantly greater knee contact flexion angle, maximum knee flexion angle and initial knee extension moment compared to the non-jumpers. These results suggest that these athletes adopted a favorable impact attenuation strategy that is related to the greater knee eccentric muscle strength and training.
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http://dx.doi.org/10.1016/j.humov.2013.03.008 | DOI Listing |
Eur J Sport Sci
February 2025
Department of Sport and Health Sciences and Social Work, Oxford Brookes University, Oxford, UK.
Some technical limitations to using the eccentric mode to measure peak eccentric strength of the hamstrings (PTH) were raised. PTH also has limited validity to predict performance or injury risk factor. Therefore, our aim was to compare PTH and other isokinetic variables tested in the eccentric and passive modes.
View Article and Find Full Text PDFJ Electromyogr Kinesiol
January 2025
Centro Polifunzionale di Scienze Motorie, Università degli Studi di Genova, Genoa, Italy; Department of Experimental Medicine, Section of Human Physiology, Università degli Studi di Genova, Genoa, Italy.
This study investigated proprioceptive acuity using the conventional joint position reproduction (JPR) task and a modified version, the Dynamic JPR task (D-JPR), during Concentric and Eccentric muscle contractions. Seventeen participants were recruited and received a tactile stimulus indicating the position cue at Initial (INI), Intermediate (INT), and Final (FIN) phases of movements, during either the concentric or eccentric phases. After the movement, they replicated the position where they received the stimulus.
View Article and Find Full Text PDFSensors (Basel)
January 2025
School of Athletic Performance, University of Sport, Shanghai 200438, China.
This study investigates the effects of electrical stimulation (EMS) combined with strength training on lower limb muscle activation and badminton jump performance, specifically during the "jump smash" movement. A total of 25 male badminton players, with a minimum of three years of professional training experience and no history of lower limb injuries, participated in the study. Participants underwent three distinct conditions: baseline testing, strength training, and EMS combined with strength training.
View Article and Find Full Text PDFInt J Environ Res Public Health
January 2025
Study Design and Scientific Writing Laboratory, Centro Universitario FMABC, Santo André 09060-870, SP, Brazil.
The trained heart adapts through geometric changes influenced by concentric and eccentric hypertrophy, depending on the predominance of the isometric or dynamic components of the exercise performed. Additionally, alterations in heart rhythm may occur due to increased vagal system activity. Cardiological evaluation with an electrocardiogram (ECG) aims to identify cardiac conditions that could temporarily or permanently disqualify an athlete from competition.
View Article and Find Full Text PDFFront Physiol
January 2025
Liberal Arts Department, American University of the Middle East, Egaila, Kuwait.
Introduction: The aim of the present study was to investigate the effects of eccentric phase tempo in squats on hypertrophy, strength, and contractile properties of the quadriceps femoris (QF) muscle.
Methods: Eighteen participants (10 males and 8 females, age 24.0 ± 1.
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