Search results for "cycle"
showing 10 items of 3119 documents
Effects of exhaustive stretch-shortening cycle exercise on muscle blood flow during exercise
2006
Aim: The influence of exhaustive stretch-shortening cycle exercise (SSC) on skeletal muscle blood flow (BF) during exercise is currently unknown. Methods: Quadriceps femoris (QF) BF was measured in eight healthy men using positron emission tomography before and 3 days after exhaustive SSC exercise. The SSC protocol consisted of maximal and submaximal drop jumps with one leg. Needle biopsies of the vastus lateralis muscles were taken immediately and 2 days after SSC for muscle endothelial nitric oxide synthase (eNOS) and interleukin-1-beta (IL-1β) mRNA level determinations. Results: All subjects reported subjective muscle soreness after SSC (P < 0.001), which was well in line with a decre…
Aurora-A overexpression as an early marker of reflux-related columnar mucosa and Barrett's oesophagus.
2007
Abstract BACKGROUND: The development of oesophageal adenocarcinoma is generally closely associated with the presence of a specialised intestinal-type epithelium such as that found in Barrett's oesophagus (BO). A particular histological condition is when the distal oesophagus showing cardiac and/or fundic mucosa without intestinal metaplasia cannot be defined as 'Barrett's mucosa' [condition that we call 'columnar-lined oesophagus' (CLO)] and up till now, there has been no agreement in literature about the management of this condition. Aurora-A overexpression leads to centrosome amplification, chromosomal instability and aneuploidy in mammalian cells. PATIENTS AND METHODS: A prospective stud…
Differential effects of exhaustive cycle ergometry on concentric and eccentric torque production.
2001
The purpose of this study was to investigate the potential differences in peak isokinetic concentric end eccentric torque following low- and high-intensity cycle exercise fatigue protocols. Ten healthy, recreationally-active men were tested in a balanced, randomized testing sequence for peak eccentric and concentric isokinetic torque (60 degrees/sec) immediately before and after three experimental conditions each separated by 48 hours: 1) a bout of high intensity cycling consisting of a maximal 90-second sprint; 2) a bout of low-intensity cycling at 60 rpm equated for total work with the high-intensity protocol: and 3) no exercise (control bout). Blood was drawn from an antecubital vein and…
Left ventricular ejection fraction calculation from automatically selected and processed diastolic and systolic frames in short-axis cine-MRI
2005
International audience; Abstract: The calculation of the left ventricular ejection fraction (LVEF) is dependent upon the accurate measurement of diastolic and systolic left ventricular volumes. Although breath-hold cine magnetic resonance imaging (MRI) allows coverage of the whole cardiac cycle with an excellent time resolution, many authors rely on the visual selection of diastolic and the systolic short-axis slices in order to reduce the postprocessing time. An automatic method was developed to detect the endocardial contour on each image, allowing an automatic selection of the systolic frame. The calculated ejection fraction was compared with radionuclide ventriculography (RNV). Sixty-fi…
The mechanical efficiency of locomotion in men and women with special emphasis on stretch-shortening cycle exercises.
1986
The mechanical efficiency of the leg extensor musculature of men and women was examined with a special "sledge ergometer". The subjects (ten males and ten females) performed pure positive work, pure negative work and a combination of negative and positive work (stretch-shortening cycle). The mechanical efficiency of pure positive work was on average 19.8 +/- 1.2% for female subjects and 17.4 +/- 1.2% for male subjects (t = 4.12, P less than 0.001), although the work intensity was equal in both groups. The mechanical efficiency of pure negative work was slightly lower in women than in men (59.3 +/- 14.4% vs 75.6 +/- 29.3%). The mechanical efficiency of positive work (eta +) in a stretch-shor…
Heart rate and perceptual response to exercise with different pedalling speed in normal subjects and patients.
1977
The perceived exertion rating (RPE) scale of Borg was used to investigate the relationship between perceived exertion and pedalling rate. Normal subjects and patients with chronic obstructive lung disease (Cold) were studied in repeated test series. Work load, applied in a random order, varied from 2.5 to 10 mkp/s (patients) and 5 to 20 mkp/s (normals). Pedalling rate varied from 2.5 to 10 mkp/s (patients) and 5 to 20 mkp/s (normals). Pedalling rate varied from 40 to 60, 80, 100 rpm. At constant work load, RPE decreases during increasing pedalling rate. With respect to validity, RPE, showing a closer relationship to work load than to heart rate, seems to reflect perception of physical stres…
Visual quality differences between orthokeratology and LASIK to compensate low-moderate myopia.
2013
PURPOSE: To assess the differences in visual performance between orthokeratology (ortho-k) and laser in situ keratomileusis (LASIK) for the treatment of low-to-moderate myopia. METHODS: An adaptive optics visual simulator (Imagine Eyes) was used to simulate the wavefront aberration patterns induced by ortho-k and LASIK for low and moderate myopia on 10 healthy eyes. Visual acuity (VA) at 100%, 50%, and 10% contrast levels and contrast sensitivity (CS) at 10, 20 and 25 cycles per degree (cpd) were then measured for 3- and 6-mm pupil sizes. RESULTS: Differences in VA for 3-mm pupil diameter were not found between ortho-k and LASIK. For 6-mm pupil size, LASIK provided significantly better VA v…
Differences in mechanical efficiency between power- and endurance-trained athletes while jumping
1995
Mechanical efficiency (ME) of jumping exercises was compared between power-trained (n = 11) and endurance-trained athletes (n = 10) using both a biomechanical and a physiological approach. In drop jumps and in stretch-shortening cycle exercise on a special sledge (sledge jumps), the subjects performed 60 muscle actions from a dropping height of optimum minus 40 cm (O − 40), as well as from dropping heights of optimum (O) and optimum plus 40 cm (O + 40). Thus, they were tested in six different tests which lasted for a total of 3 min for each. The mean ME values in the drop jumps from the lowest dropping height upwards were as follows: 23.8 (SD 5.3)%, 35.5 (SD 10.8)% and 39.2 (SD 6.6)% for th…
Interaction between pre-landing activities and stiffness regulation of the knee joint musculoskeletal system in the drop jump: implications to perfor…
2002
The purpose of the present study was to investigate the interaction between the pre-landing activities and the stiffness regulation of the knee joint musculoskeletal system and the takeoff speed during a drop jump (DJ). Nine healthy male subjects performed a DJ test from the height of 50 cm. The surface electromyographic (EMG) activity of the vastus lateralis (VL) muscle was recorded to evaluate both the pre-landing and post-landing muscle activation levels. Simultaneous recording of the jumping motion and ground reaction force was performed by a high-speed video camera (100 frames x s(-1)), and a force platform was employed to allow joint moment analysis. Joint stiffness was calculated by …
Bicycling to university: Evaluation of a bicycle-sharing program in Spain
2013
: This study examined the change in behavioral stages (e.g. contemplation, action and maintenance) of cycling to university before and after the implementation of a new public bicycle share program (PBSP) and promotion of its use. The study also determined the change in the prevalence, correlates of PBSP use and potential role in the promotion of healthy weight. An 8-month follow-up cross-sectional study (September 2010-April 2011) was carried out among undergraduate students during the first season of implementation of the PBSP in Valencia, Spain. The sample was 173 students (68.2% female) with a mean age of 21.3 years (SD 3.06) who attended a PBSP promotional session. The data were collec…