Publications by authors named "Lennart Gullstrand"

Background: Exercise training is suggested to have a stress-buffering effect on physiological reactions to acute stress. The so-called cross-stressor adaptation hypothesis is one of many theories behind the plausible effects, proposing that the attenuated physiological reaction seen in trained individuals in response to acute exercise is also seen when the individual is exposed to acute psychosocial stress. However, few randomized controlled trials (RCT) are available in this field.

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Objective: Modern hatha yoga exercises (YE) provide an alternative form of physical activity which may reduce stress, facilitate recovery and improve health. This study investigated the short-term effects of high intensity hatha yoga exercises (HIY) on health-related outcomes.

Methods: A 6-week randomized controlled study was performed to compare HIY with a control group not changing their exercise behavior.

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Background: This paper describes the protocol and methodological prerequisites for a randomised controlled exercise intervention. Selected baseline data from the study are also presented, demonstrating some methodological challenges related to exercise intervention trials. The aim of the trial was to study the effects of exercise training on physiological responses to acute psychosocial stress in untrained individuals.

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Background: Yoga exercises are often used as a form of body and mind exercise to increase performance. However, knowledge about the physiologic effects of performing high-intensity Hatha yoga exercises over a longer time period remains limited.

Objective: To investigate the effects of high-intensity yoga (HIY) on cardiovascular fitness (maximal oxygen consumption, estimated from the Cooper running test), ratings of perceived exertion (RPE), heart rate (HR), heart rate recovery (HRR), blood pressure (BP), adipocytokines, apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), and glycosylated hemoglobin (HbA1c) in healthy students.

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This work studies the immediate effects of altering the vertical displacement of the center of mass (VD) and step frequency (SF) on the metabolic cost of level treadmill running at 16 km · h(-1) on 16 male runners. Alterations of VD, SF, and the product VD × SF was induced using a novel feedback system, which presents target and current values to the runner by visual or auditory display. Target values were set to 5 and 10% reductions from individual baseline values.

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The correlation between mechanical factors of running and running economy as measured by metabolic cost is a subject of much interest in the study of locomotion. However, no change in running technique has been shown to result in an immediate improvement in running economy on an intra-individual basis. To evaluate the effect of a modified running technique, it is probably necessary that the individual trains with the new technique for a longer period using a feedback system to control the new kinematics.

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The aim of this study was to evaluate two versions of the Oxycon Mobile portable metabolic system (OMPS1 and OMPS2) in a wide range of oxygen uptake, using the Douglas bag method (DBM) as criterion method. The metabolic variables VO2, VCO2 respiratory exchange ratio and VE were measured during submaximal and maximal cycle ergometer exercise with sedentary, moderately trained individuals and athletes as participants. Test-retest reliability was investigated using the OMPS1.

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The purpose was to study the validity of a recently proposed method [Forsell C, Halvorsen K. A method for determining minimal sets of markers for the estimation of center of mass, linear and angular momentum. Journal of Biomechanics 2009;42(3):361-5] for estimating the trajectory of the whole-body center of mass (CoM) in the case of running at velocities ranging from 10 to 22 km h(-1).

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The aim was (1) to evaluate measurements of vertical displacements (V(disp)) of a single point on sacrum as an estimate of the whole body centre of mass (CoM) V(disp) during treadmill running and (2) to compare three methods for measuring this single point. These methods were based on a position transducer (PT), accelerometers (AMs) and an optoelectronic motion capture system. Criterion method was V(disp) of the whole body CoM measured with the motion capture system.

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Purpose: To investigate whether sessions of glossopharyngeal pistoning (GP) to lung volumes exceeding maximum inspiratory capacity in a group of extremely well-trained elite swimmers would affect maximum lung volumes and buoyancies.

Methods: Ten female and 16 male swimmers performed GP four times a week for 5 wk in addition to their regular swimming training program. Pulmonary function, chest expansion, hydrostatic weights (maximally inhaled and exhaled), and body composition (relative amounts of fat, bone, muscle, and fat-free tissue) were measured.

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The aim of the study was to examine submaximal and maximal physiological responses and perceived exertion during deep-water running with a vest compared with the responses during treadmill running in healthy elderly women. Eleven healthy women 70 +/- 2 years old participated. On two different occasions they performed a graded maximal exercise test on a treadmill on land and a graded maximal exercise test in water wearing a vest.

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The aim of this study was to examine work-time profiles, blood lactate concentrations and perceived exertion among Greco-Roman wrestlers in the 1998 World Championship. Forty-two senior wrestlers from nine nations were studied in 94 matches. Each match was recorded with a video camera (Panasonic AG 455, film rate: 25 Hz) and analysed for duration of work (wrestling) and rest (interrupt) periods.

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