Search results for "force"
showing 10 items of 3423 documents
Older adults who have previously fallen due to a trip walk differently than those who have fallen due to a slip
2014
Studying the relationships between centre of mass (COM) and centre of pressure (COP) during walking has been shown to be useful in determining movement stability. The aim of the current study was to compare COM-COP separation measures during walking between groups of older adults with no history of falling, and a history of falling due to tripping or slipping. Any differences between individuals who have fallen due to a slip and those who have fallen due to a trip in measures of dynamic balance could potentially indicate differences in the mechanisms responsible for falls. Forty older adults were allocated into groups based on their self-reported fall history during walking. The non-faller …
Biomechanical Comparison Between Sprint Start, Sled Pulling, and Selected Squat-Type Exercises
2013
The purpose of this study was to compare kinetics, kinematics, and muscle activity among sprint start, sled pulling, and selected squat-type exercises (countermovement jumps [CMJs] and 1/2-squats with various loads) and also to examine how these exercises correlate with the performance time of the block start (10 m). Nine male athletes (4 sprinters, 3 decathlonists, 1 long jumper, and 1 triple jumper: age = 24.9 ± 3.9 years; 100-m record = 11.35 ± 0.29 seconds; track and field training years = 11.8 ± 3.1 years) volunteered as subjects. The comparisons were made with regard to the block phase (the phase of force production toward starting blocks) of the block start. In nearly all exercises, …
Long-term effects of repeated social stress on the conditioned place preference induced by MDMA in mice.
2015
Previous studies have demonstrated that social defeat stress increases the rewarding effects of psychostimulant drugs such as cocaine and amphetamine. In the present study we evaluated the long-term effects of repeated social defeat (RSD) on the rewarding effects of ±3,4-methylenedioxymethamphetamine (MDMA) hydrochloride in the conditioned place preference (CPP) paradigm. Adolescent and young adult mice were exposed to four episodes of social defeat (on PND 29-40 and PND 47-56, respectively) and were conditioned three weeks later with 1.25 or 10mg/kg i.p. of MDMA (experiment 1). The long-term effects of RSD on anxiety, social behavior and cognitive processes were also evaluated in adult mic…
Acute neuromuscular responses to short and long roundhouse kick striking paces in professional Muay Thai fighters.
2019
International audience; BACKGROUND: Muay Thai fighters strongly rely on the use of the roundhouse kick due to its effectiveness (i.e. power) and implications on the final score. Therefore, different striking tempos at full power are used during training as a method to enhance kicking power. However, the neuromuscular responses are unknown. Thus, the goal of this study was to investigate neuromuscular responses to a single bout of shorter (every second = H1) and longer (every 3s = H3) kick striking time intervals, measured with the countermovement jump (CMJ).METHODS: Nine professional Muay Thai fighters participated in this randomized, cross-over trial. CMJs were measured on force plates bef…
Relationship between body composition and vertical ground reaction forces in obese children when walking.
2016
Abstract Background Obesity is now a serious worldwide challenge, especially in children. This condition can cause a number of different health problems, including musculoskeletal disorders, some of which are due to mechanical stress caused by excess body weight. The aim of this study was to determine the association between body composition and the vertical ground reaction force produced during walking in obese children. Methods Sixteen children participated in the study, six females and ten males [11.5 (1.2) years old, 69.8 (15.5) kg, 1.56 (0.09) m, and 28.36 (3.74) kg/m 2 of body mass index (BMI)]. Total weight, lean mass and fat mass were measured by dual-energy X-ray absorptiometry and…
A year in the life of German patients with COPD: the DACCORD observational study
2016
Roland Buhl,1 Carl-Peter Criée,2 Peter Kardos,3 Claus Vogelmeier,4,5 Nadine Lossi,6 Claudia Mailänder,6 Heinrich Worth7 1Pulmonary Department, Mainz University Hospital, Mainz, 2Department of Sleep and Respiratory Medicine, Evangelical Hospital Göttingen-Weende, Bovenden, 3Group Practice and Centre for Allergy, Respiratory and Sleep Medicine, Red Cross Maingau Hospital, Frankfurt am Main, 4Department of Medicine, Pulmonary, and Critical Care Medicine, University Medical Center Giessen and Marburg, Philipps-University Marburg, 5German Center for Lung Research, Marburg, 6Clinical Research Primary Care, Novartis Pharma GmbH, Nürnberg, 7Facharztforum F&…
Central Contribution to Electrically Induced Fatigue depends on Stimulation Frequency
2017
International audience; PURPOSE: This study analyzed the impact of several protocols of neuromuscular electrical stimulation (NMES), matched with a similar total torque-time integral, on muscle activation pathways and neuromuscular fatigue.METHODS: Ten young healthy participants (age: 24.6 +/- 4.2) performed 3 randomized NMES sessions on the triceps surae muscles with 20 Hz, 60 Hz or 100 Hz stimulation frequencies (pulse duration: 1 ms), with pulse amplitude (IES) set at 20 % of isometric maximal voluntary contraction (MVC). Muscle activity during NMES was assessed by means of the twitch, the soleus H-reflex and M wave responses evoked by single muscle stimulation at IES. Neuromuscular fati…
GOLD and the fixed ratio
2012
We thank Dr Vestbo for his interest in our manuscript “Diagnosis of airway obstruction in the elderly: contribution of the SARA study” and for the opportunity to clarify some points. As mentioned in the title and aims, the intent of the paper is to offer a contribution to the open issue of identification of airway obstruction in elderly people.1 We agree with Dr Vestbo about the utility of distinguishing between the clinical and functional aspects of chronic obstructive pulmonary disease (COPD). We stress that, until the term COPD is used, diagnosis needs clinical evidence of a chronic pulmonary disease and functional evidence of airway obstruction. Given that symptoms compatible with COPD …
Should we individualize training based on force-velocity profiling to improve physical performance in athletes?
2021
The present study aimed to examine the effectiveness of an individualized training program based on force-velocity (FV) profiling on jumping, sprinting, strength, and power in athletes. Forty national level team sport athletes (20 ± 4years, 83 ± 13 kg) from ice-hockey, handball, and soccer completed a 10-week training intervention. A theoretical optimal squat jump (SJ)-FV-profile was calculated from SJ with five different loads (0, 20, 40, 60, and 80 kg). Based on their initial FV-profile, athletes were randomized to train toward, away, or irrespective (balanced training) of their initial theoretical optimal FV-profile. The training content was matched between groups in terms of set x repet…
Loading and gait symmetry during level and stair walking in asymptomatic subjects with knee osteoarthritis: importance of quadriceps femoris in reduc…
2007
Repetitive impulsive forces during walking are claimed to result in joint osteoarthritis (OA). The aim of this study was to investigate impact loading and gait symmetry during level and stair walking in asymptomatic elderly subjects with knee OA. It was hypothesised that pre-activity of the quadriceps femoris muscle (QF) would be an important factor reducing impulsive loading when walking on level ground. Subjects [21 female, six men, 66.2 (7.6) years] were studied. The subjects had no knee pain or diminished functional capacity, but showed radiographically light or moderate bilateral knee OA changes. Ground reaction forces (GRFs), plantar pressure distribution, muscle activation pattern [v…