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Biomedical subjects

V Niinimaa

Publications and source records attributed to V Niinimaa.

14 recordsLinked to original sources
PubMed1983

Oronasal airway choice during running.

The choice of oronasal airway was studied in 984 subjects participating in a 10 km run. Subject's age and sex was obtained from entry forms, degree of mouth opening by videotaping the subjects' upper body as they approached the camera, and average running speed from elapsed time. The degree of mouth opening was evaluated independently by three observers. Results indicated that only three (0.3%) of the 917 analyzed subjects breathed nasally during running, 96.3% breathed oronasally, 2.3% opened and closed their mouths rhythmically with breathing, and in 10 subjects it could not be determined whether the mouth was open or closed. No relationship existed between degree of mouth opening and subjects' age, sex or running speed. It was concluded that the incidence of nasal breathing during self-paced endurance running is less frequent than indicated by previous laboratory studies.

Adolescent↗
PubMed1983

Influence of exercise on body sway in the standing rifle shooting position.

Standing stability was measured in 16 male subjects during standing at rest, and aiming an air rifle at both rest and after an exercise bout simulating cross-country ski racing. Subjects consisted of a control group with no previous shooting experience, groups of rookie and established biathletes, and experienced position rifle shooters. Anteriposterior and lateral positions of the subject's centre of pressure were determined by a force platform, sampled at 30 Hz over a 60 second period. Horizontal movement was calculated digitally from the anteriposterior and lateral position data. Body sway was greater (p less than 0.05) during aiming at rest than while standing at rest, and also greater during aiming after exercise than at rest. Body sway was significantly smaller (p less than 0.05) in the position shooters compared to subjects with 4 months or less of shooting training. The contribution of anteriposterior movement to body sway while standing at rest was approximately twice that of lateral movement. Greater increases in lateral movement with aiming and after exercise lead to similar contributions by both components of body sway.

Humans↗
PubMed1981

Oronasal distribution of respiratory airflow.

The oronasal distribution of respiratory airflow was determined during incrementally graded submaximal exercise in 30 (14 M, 16 F) healthy adult volunteers. Nasal airflow was measured by a pneumotachograph attached to a nasal mask. Oral airflow was determined as the difference between nasal airflow and total pulmonary airflow, the latter being measured by a head-out exercise body plethysmograph. The two airflow signals were sampled every 20 msec by a microprocessor, which calculated the oral and nasal minute volumes (separating inspiration and expiration) and produced an on-line print-out of the results. Twenty subjects ("normal augmenters") switched from nasal to oronasal breathing at a VE of 35.3 +/- 10.8 1 . min-1, four subjects ("mouth breathers") habitually breathed oronasally, five subjects ("nose breathers") persistently breathed through the nose only, and one subject showed no consistent nose/mouth breathing pattern. After the switch to oronasal breathing, the nasal portion of VE decreased suddenly to 57% of total VE. With a further increase of VE, oral minute volume increased rapidly, equalling nasal minute volume at a VE of 45 1 . min-1, and accounting for 61% of the total ventilation at high respiratory minute volumes (90 1 . min-1). During oronasal breathing, normal augmenters inspired some 2 1 . min-1 more nasally than they expired. Similarly, the nasal inspiration of mouth breathers exceeded expiration by 2 1 . min-1 at rest, but the difference increased to 13.51 . min-1 at a VE of 81.51 . min-1.

Adolescent↗
PubMed1980

The switching point from nasal to oronasal breathing.

The switching point from nasal to oronasal breathing during incrementally graded submaximal exercise was determined in 30 (14 M, 16 F) healthy adult volunteers. Nasal airflow was measured by a pneumotachograph attached to a nasal mask. Oral airflow was determined as the difference between nasal airflow and total pulmonary airflow, the latter being measured by a head-out exercise body plethysmograph. The airflow and pressure signals were sampled every 20 msec by a micropressor, which calculated respiratory volumes and nasal work of breathing, and produced an on-line print-out. Twenty of the 30 subjects (normal augmenters) switched from nasal to oronasal breathing at submaximal exercise of 105.0 W (SD = 30.1), four subjects (mouth breathers) breathed habitually oronasally, five subjects (nose breathers) persistently breathed through the nose only, and one subject showed no consistent nose/mouth breathing pattern. In normal augmenters, the onset of oronasal breathing (VE 35.3 +/- 10.81 . min-1) was quite consistent individually, but varied considerably between inividuals without showing a significant sex difference. The factors most closely related to the switching point were rating of perceived exertion of breathing and nasal work of breathing.

Adolescent↗
PubMed1980

Computer-aided rhinometry. A research rhinometer for clinical trial.

The effects of several variables on work of nasal breathing and nasal resistance were investigated. Sampling of pressure and flow of nasal respiratory air was performed by posterior rhinometry every 20 msec with a microprocessor and standard respiratory laboratory equipment. This technique enables work of nasal breathing and mean nasal resistance to be determined on line. The relationship between work-litre-1 and ventilation was always near-linear and its slope is the dimensional equivalent of resistance. Slope and linearity remained constant for several hours at a time and were unaffected by moderate hyperventilation, exercise, or change in breathing pattern. The slope of the line--but not its linearity--was altered by vasoactive medication exercise and nasal obstruction. Mean nasal resistance determined by this technique may be employed as a measure of nasal obstruction, its stability and independence from the moderate changes in breathing pattern which occur spontaneously suggest a useful clinical application.

Airway Obstruction↗
PubMed1979

Determinations of performance and mechanical efficiency in nordic skiing.

Determinants of performance and mechanical efficiency of effort have been made on a group of ten male nordic skiers, all participants in the University of Toronto ski-team. The oxygen intake at the maximum attainable speed of skiing on a level course averaged 89.6 percent of the maximum oxygen intake observed during uphill treadmill running; the latter (average 63.9 ml.kg-1 min-1) may be compared with values greater than 80 ml.kg1 min-1 for international competitors. Maximum heart rates and respiratory gas exchange ratios were generally lower during skiing than running, and it is suggested that the maximum oxygen intake attained during skiing is limited by the individual's skill. In support of this the more experienced skiers were able to reach close to 100 percent of the treadmill maximum oxygen intake during level skiing. A multiple regression analysis indicated that the skiing speed sustained over a one-hour period was related to experience of skiing, maximum oxygen intake, and the percentage of body fat. Assuming a dynamic friction coefficient of 0.075, a drag area of 0.7 m2 and a drag coefficient of 1.0, the gross mechanical efficiency of the university-class skier averaged a little under 20 percent, with a net efficiency of 21.3 percent.

Biomechanical Phenomena↗
PubMed1979

A head-out exercise body plethysmograph.

A head-out exercise body plethysmograph has been developed to facilitate investigations of the extrathoracic airways. An airtight seal around the neck is provided by a pliable sheet of dental dam braced by a tubular bean bag. A set of bicycle pedals is connected by a chain drive, axle, and wall-mounted sealed ball bearing to an external ergometer. The box is air-conditioned to allow exercise up to work loads of 200 W with a temperature increase of less than 1 degree C above ambient laboratory readings. Nose, mouth, and extrathoracic airways are easily accessible for airflow and pressure measurements. O2, CO2, and humidity levels of respired air are not disturbed, verbal communication with the subject is possible, and the subject is unlikely to feel claustrophobic. The plethysmograph has a flat frequency response to 4.2 Hz; it thus functions accurately in both resting and exercise measurements of respiratory minute ventilation. The plethysmograph can also be used for determinations of nasal and oral airflow and pressure, and the study of breathing patterns.

Humans↗
PubMed1979

Work of nasal breathing: measurement of each nostril independently using a split mask.

The work of nasal breathing was determined in human subjects as a measure of impedance to respiratory airflow. The nasal cavities were examined separately and simultaneously with a split mask; flow and pressure signals were fed to a microprocessor for on-line computation and printout of respired volumes and work of nasal breathing. An alternating resistive nasal cycle of 3--4 hours' duration was demonstrated in the majority of normal, resting subjects. Reciprocity of the resistive changes in each nasal cavity maintained a constant total nasal respiratory work load of about 0.2 Joules/litre. Moderate changes in breathing rate and tidal volume had little influence on work. Inspiratory work was 1.6 times that of expiration. Increases in resistance of the dependent nostril were seen when the lateral decubitus position was adopted. Increase in cephalic venous pressure and pathological nasal obstruction increased the work of nasal breathing.

Airway Obstruction↗
PubMed1979

Nasal aerodynamics.

The historical development of nasal aerodynamic measurement is discussed. Attention is drawn to the absence of a consensus on adequate rhinometric techniques and standards, which hampers the elevation of rhinometry to the universal clinical status of audiometric, impedance, or nystagmus measurement. A computer-aided technique is described which overcomes some problems of rhinometry, by measurement of the amount of energy the body devotes to moving respiratory air through each separate nasal cavity. Although the approach is different, our preliminary results confirm previous work and suggest that assessment of the work of breathing is a promising technique in the investigation of nasal respiratory airflow.

Airway Obstruction↗
PubMed1978

Training and oxygen conductance in the elderly. I. The respiratory system.

Static lung volumes, closing volumes and pulmonary diffusing capacity have been measured in a group of 19 subjects (9 M, 10 F) 60 - 76 years old, all volunteers for an exercise training program (nominal 4 hours per week for 11 weeks). Initial static lung volumes were larger than in some previous series, perhaps because our sample was health-conscious and mainly nonsmokers. Training produced no significant changes in any of the pulmonary variables tested, despite a 10% increase of maximum oxygen intake seen in those members of the group who progressed to intensive training (heart rate 145 - 155/min). This reflects the fact that oxygen transport depends more on blood transport than on the respiratory system.

Age Factors↗
PubMed1978

Training and oxygen conductance in the elderly. II. The cardiovascular system.

CO2 rebreathing measurements of cardiac output have been made in 8 men and 7 women aged 60--76 years, before and immediately after participation in an 11-week endurance training programme. Initial values showed a lower heart rate than in younger subjects at a given percentage of maximum oxygen intake. Stroke volume decreased slightly over the range of 40--80% of maximum oxygen intake. Relative to younger subjects, metabolic needs were thus met to a larger extent by a widening of arterio-venous oxygen difference and redistribution of blood flow. Over the period of observation, training induced a decrease in heart rate and cardiac output at a given sub-maximum work load, with no change in stroke volume or arterio-venous oxygen difference.

Age Factors↗
PubMed1978

Performance and efficiency of intercollegiate cross-country skiers.

Ten male intercollegiate cross-country skiers were studied to identify factors influencing competitive performance and to estimate the efficiency of energy expenditure in skiing. The variables examined were maximum oxygen intake, as determined by both uphill treadmill running and by maximal level skiing, physical characteristics, strength and experience in cross-country skiing and racing. Multiple regression analysis showed that racing experience, cardiorespiratory fitness, and body fat percentage were significant factors in racing success. The net mechanical efficiency at this level of competition was estimated at 21.3%.

Adolescent↗
PubMed1976

Some reactions to a dry-land training programme for dinghy sailors.

A dry-land winter training programme for dinghy-sailors is described. Individual elements include circuit training, specific exercises for muscle strength and endurance, and distance running. Ten international-class sailors followed a progressive regimen of this type for 14 weeks after completion of the 1973 season. Excess weight and skinfold thicknesses were reduced, while muscle strength, endurance and anaerobic capacity increased. Aerobic power remained substantially unchanged, although a smaller oxygen debt was incurred in reaching maximum effort. Team members were enthusiastic about the benefits gained from the training, commenting on their greater tolerance of the hiking position and all proposed to continue or to increase their efforts during subsequent winters. Racing results during 1974 were also an improvement on the 1973 record. However, it was difficult to link physiological gains to improvements in the relative rankings of individual competitors under either light or high wind conditions; the main factor changing relative standings seems to have been the additional year of competitive experiences in younger team members.

Body Weight↗