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Biomedical subjects

G Hedberg

Publications and source records attributed to G Hedberg.

At least 19 recordsLinked to original sources
PubMed2006

Relationships between physical activity and physical capacity in adolescent females and bone mass in adulthood.

This study investigates whether physical activity and physical performance in adolescence are positively related to adult bone mineral density (BMD). In 1974, physical activity, endurance, and muscular strength were measured in 204 randomly selected female students, age 16.1 +/- 0.3 year (range 15-17 years). Twenty years later, 36 of the women volunteered to undergo a measurement of their BMD. Women who were members in a sports club in adolescence had significantly higher adult BMD (mean differences of 5% to 17% depending on site) compared with subjects who were not engaged in a sports club. Furthermore, women with persistent weight-bearing activity in adulthood had significantly higher BMD compared with women who had stopped being active or had never been active. The differences ranged between 5% and 19% with the highest difference found in trochanter BMD. Stepwise regression analyses showed that membership in a sports club at baseline was a significant independent predictor of BMD in the total body, lumbar spine, legs, trochanter, and femoral neck, explaining 17-26% of the variation in BMD. Change in body weight was a strong independent predictor of BMD of the total body and arms, explaining 8% of the variation in both sites. In addition, running performance at baseline was an independent predictor of total body BMD, whereas the two-hand lift performance significantly predicted BMD of the total body, legs and trochanter. The hanging leg-lift and handgrip were both significant predictors of arm BMD. In conclusion, membership in a sports club and site-specific physical performance in adolescence together with the change in body weight were significantly associated with adult BMD in premenopausal women.

Adolescent↗
PubMed2003

Secular trends in body dimensions and physical fitness among adolescents in Sweden from 1974 to 1995.

AIM: To investigate changes over time in body dimensions, and muscular and aerobic fitness in a representative sample of 16-year-old-girls and boys in secondary schools in Sweden from 1974 to 1995 (n = 855). METHOD: Height and weight were measured and five tests were performed: run-walk, two-hand-lift, Sargent jump, sit-ups, and bench-press. RESULTS: In 1995, girls and boys had higher body mass index (BMI) than in 1974. Girls and boys performed less well in bench-press, sit-ups, and run-walk-tests in 1995. Boys, but not girls, performed better in Sargent jump in 1995 than in 1974. Girls and boys performed better in two-hand-lift in 1995 than in 1974. However, after adjustment for body dimensions, there were no differences in performance in two-hand-lift or run-walk-tests between 1974 and 1995. CONCLUSION: There was a decreased aerobic fitness and an increased maximal static strength among adolescents in Sweden between 1974 and 1995. These changes were partly due to increased BMI. However, decreased daily physical activity level cannot be excluded as a contributing factor to the decreased aerobic fitness. The reduced performance in muscular endurance in 1995 was not related to increased BMI. Instead, it is suggested that it is to be related to a specific decrease in hip flexion and arm muscle endurance.

Adolescent↗
PubMed2003

Secular trends in sports: participation and attitudes among adolescents in Sweden from 1974 to 1995.

AIM: To study the secular trend (time changes) in participation in leisure-time sports activities and in attitudes towards sports activities and physical education in a representative sample of Swedish adolescents between 1974 and 1995. METHODS: A questionnaire was distributed to 16-y-old girls and boys (n = 395 in 1974, n = 542 in 1995) to assess participation in leisure-time sports activity, attitudes towards sports activities and attitudes towards physical education at school. Height and weight were measured and body mass index (BMI) was calculated. RESULTS: Compared with 1974, more subjects in 1995 answered that they were engaged in leisure-time sports activities, and that they were members of sports clubs. BMI increased from 1974 to 1995. By 1995, adolescents participated in and had become more interested in individual sports activities, including keep-fit activities (e.g. strength training and aerobics) compared with 1974. A gender difference in the feeling of anxiety towards physical education, with more girls experiencing it, appeared in 1995, but not in 1974. CONCLUSION: Although more adolescents participated in leisure-time sports activity in 1995 than in 1974, the lifestyle of adolescents between sports training sessions may have become more sedentary. This is negative in a health perspective, since the benefits of physical activity on health are largely correlated to the total energy expenditure. However, the increased interest in keep-fit activities is important, since these activities have the potential to be continued into adulthood.

Adolescent↗
PubMed2001

Adolescent determinants of cardiovascular risk factors in adult men and women.

AIMS: To investigate how physical activity, physical performance and sociodemographic characteristics at the age of 16 are related to adult health habits (physical activity, dietary intake, smoking) and biological risk factors for cardiovascular diseases (being overweight, low aerobic fitness, unfavorable levels of serum lipids, high blood pressure). METHODS: A randomly selected group of 220 male and 205 female students at 16 years of age was tested in 1974, and reinvestigated 18 years later. RESULTS: The predictive health profiles for adult lifestyle and biological risk factors were different in men and women. Leisure sports activity along with high performance in the nine-minute run among the boys and in the two-hand lift test among the girls were significant predictors of adult physical activity. A positive attitude to aerobic exercise and high performance in the nine-minute run test among the boys and high marks in physical education among the girls decreased the risk of smoking. Leisure sports activities together with body mass index at young ages were the most powerful predictors of adult biological risk factors, but attitudes to sports and educational level were also significant determinants. CONCLUSION: These results contribute to the knowledge of which factors at young ages may promote adult healthy habits in particular physical activities.

Adolescent↗
PubMed1998

High thigh muscle strength but not bone mass in young horseback-riding females.

To evaluate whether the type of weight-bearing loading subjected to the skeleton during horseback-riding was associated with differences in bone mass and muscle strength of the thigh, we investigated bone mass and isokinetic muscle strength in 20 female horse riders (age 17.9 +/- 0.6 years) who were riding 7.0 +/- 3.4 hours/week, and 20 nonactive females (age 17.8 +/- 1.1 years). The groups were matched according to age, weight, and height. Areal bone mineral density was measured in total body, head, lumbar spine, right femoral neck, Ward's triangle, and trochanter, the whole dominant and nondominant humerus, and in specific sites in the right femur diaphysis, distal femur, proximal tibia, and tibia diaphysis using dual X-ray absorptiometry. Isokinetic concentric and eccentric peak torque of the quadricep and hamstring muscles were measured using an isokinetic dynamometer. There were no significant differences in bone mass between the horseback riders and nonactives at any site measured. The horse riders were significantly (P < 0.05-0.01) stronger in concentric hamstrings strength at 90 degrees/second and 225 degrees/second and in eccentric quadricep and hamstring strength at 90 degrees/second. Horseback riding in young females is associated with a high muscle strength of the thigh, but not with a high bone mass.

Adolescent↗
PubMed1998

Prediction of physical fitness and physical activity level in adulthood by physical performance and physical activity in adolescence--an 18-year follow-up study.

The aim of the study was to investigate relationships between physical fitness and self-reported physical activity in adulthood and to what extent the level of physical fitness and leisure-time physical activity in adulthood can be explained by anthropometric measures, physical performance, physical activity, attitudes to sports activities and socio-demographic characteristics at the age of 16. A group of 157 men and 121 women was tested at the ages of 16 and 34 by means of questionnaires and fitness tests. Physically active men and women had higher estimated VO2 max and performed better in curl ups and bench press than those who were inactive. Performance in physical tests, height, weight and physical activity at the age of 16 contributed best to explain adult physical performance and physical activity. The magnitude of explanation varied between 10% (9-min run test) and 56% (bench press test); it was in general lower in the men than in the women. The various fitness tests and physical activity were explained by different predictors and the predictors also differed between men and women. The findings about attitudes to sports and socio-demographic factors at a young age that influence adult physical activity habits and fitness are very complex and further research is required to identify specific inactivity risks.

Adolescent↗
PubMed1996

Development of muscular endurance and strength from adolescence to adulthood and level of physical capacity in men and women at the age of 34 years.

This study investigated the development of muscular endurance and strength from the age of 16 to the age of 34 and the fitness components at the age of 34 in men and women. A randomly selected group consisting of 220 boys and 205 girls was tested in 1974 and reinvestigated 18 years later. Muscular endurance and strength increased significantly in 4 of the 5 remeasured tests for the men; bench press increased by 58%, two-hand lift by 20%, hand grip by 16% and Sargent jump by 8%. For the women there was a significant increase in bench press and two-hand lift by 25% and 7% respectively, but hand grip and Sargent jump decreased with a few per cent. The hip and trunk flexion test, sit-up, decreased remarkably in both men (58%) and women (78%). At the age of 16 physical capacity was significantly higher in all tests in the men. This was also the situation at the age of 34 except for VO2 max in ml.kg-1.min-1 and muscular endurance in the back muscles. There were no differences in flexibility between men and women except for less flexibility in the hamstring muscles in the men. The result of the balance test was significantly better in the men.

Adolescent↗
PubMed1996

Physical activity pattern in men and women at the ages of 16 and 34 and development of physical activity from adolescence to adulthood.

The aim of this study was to investigate gender-related differences in physical activity patterns at the ages of 16 and 34 and to analyse those factors that might contribute to an explanation of physical activity habits in adulthood. A randomly selected group, consisting of 220 boys and 205 girls, was tested in 1974 and reinvestigated in 1992 by means of a questionnaire. Eighty-eight per cent participated in the reinvestigation. At the age of 16 more boys (69%) than girls (51%) participated in some sports activity in their leisure time. The results showed an overall decrease in participation in vigorous physical activity, although participation in light physical activity remained relatively constant. At the age of 34, there was no difference in overall physical activity between men and women, but the men exercised more vigorously (44% vs. 29%). Early experience of physical activity at the age of 16 decreased the risk of becoming inactive in adulthood. At the age of 34 cohabiting for the men, and having children and high socio-economic class for the women, increased the risk of being physically inactive in adulthood, whereas positive beliefs about health effects of exercise decreased the risk for both men and women.

Adolescent↗
PubMed1994

Prediction of physical activity level in adulthood by physical characteristics, physical performance and physical activity in adolescence: an 11-year follow-up study.

The purpose of the study was to investigate to what extent the physical activity pattern in adulthood can be predicted by physical characteristics, performance and activity in adolescence. A group of 62 men and 43 women completed a questionnaire concerning physical activity during their leisure time at the ages of 16 and 27 years. An activity index produced from the questionnaire. At the age of 16 years, the subjects were also tested for strength (strength test battery) and running performance (9-min run). Maximal oxygen uptake (VO2max) was estimated from a submaximal test and a muscle biopsy specimen was taken and analysed for fibre types (percentages of types I, IIA, IIB). The proportion of subjects engaged in some kind of physical activity during their leisure time was approximately 70% among the women and 80% among the men at both ages. The time spent on physical activity (minutes per week) decreased with age for the men but not for the women. The women devoted less time to physical activity than the men both at age 16 and 27 years. The attitude to endurance activities had changed to a more positive attitude among the women and to a less positive attitude among the men at age 27 years. The aerobic potential (VO2max and percentage of type I fibre), running performance, strength performance, physical activity and marks in physical education at age 16 years explained 82% of the physical activity level in adulthood for the women and 47% for the men.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Muscle strength from adolescence to adulthood--relationship to muscle fibre types.

The aim of the present study was to reinvestigate muscle strength and the relationship to muscle fibre and the level of physical activity in adult men and women previously studied during adolescence. A group of 55 men and 26 women were tested for maximal strength (handgrip, Sargent jump and two-hand lift) and completed a questionnaire concerning physical activity during their leisure time (activity index) at the ages of 16 and 27 years. Biopsy specimens were taken from the vastus lateralis and analysed for fibre type (percentage of I, IIA, IIB) and fibre area (area I, area IIA, area IIB). The sex differences in strength increased from age 16 to 17 years. Body dimension, sex, percentage of type II, mean fibre area and the activity index contributed to explaining 50-75% of the strength at both ages. Different changes in relationship between fibre type composition and strength in women and men was seen with increasing age. In the women, the relationship between strength and the percentage of type II fibres changed with age (from 16 to 27 years of age) from a positive correlation (only Sargent jump) to negative correlations for all the strength tests, i.e. the more type I fibres the stronger the subject. A positive correlation between strength and the level of physical activity during leisure time was revealed in the women at both ages. The positive correlation between strength and type II fibres in the 16-year-old men had disappeared at age 27. No systematic relationships between strength and the level of physical activity were seen in the men at either 16 or 27 years of age. It is suggested that women may be more dependent on physical activity than adult men to develop strength and the percentage of type I fibres reflects the degree of physical activity among adult women but not among adolescent women.

Adolescent↗
PubMed1993

Running capacity from adolescence to adulthood. Relationship to physical characteristics.

It has been shown earlier that the proportion of slow twitch (type I) fibres in the leg musculature is directly related to running performance in boys but not in girls at the age of 16. The purpose of the present study was to determine whether this pattern remains in adulthood. Forty-one men and 19 women were tested at the age of 16 and 27 years. Muscle biopsy specimens were obtained from the vastus lateralis and analysed for fibre type (I%, IIA%, IIB%). Maximal oxygen uptake (VO2max) was estimated from a submaximal exercise test. Running performance (9-min run) was assessed in a modified Cooper test. At age 16, the 9-min run was positively correlated with type I% and VO2max for the men. For the women, the 9-min run was positively correlated with VO2max but not with type I%. At age 27, the 9-min run was positively correlated with type I % and VO2max for both men and women. The appearance at the age of 27 of a relationship between running performance and type I% in the women could be related to the increase with age in the VO2max found in the women in the present study. These results support an earlier formulated hypothesis that a certain level of VO2max must be reached before peripheral factors such as the muscle fibre type composition are of any significance for the performance in a 9-min run.

Adolescent↗
PubMed1992

Changes in muscle fibre type from adolescence to adulthood in women and men.

Age-related changes in muscle fibre characteristics have been presented in cross-sectional studies previously. The aim of the present study was to investigate longitudinally whether the muscle fibre type composition and muscle fibre area change from adolescence to adulthood. Fifty-five men and 28 women were studied at the age of 16 and again at the age of 27. Biopsies were taken from the vastus lateralis muscle and analysed for fibre types (I, IIA, IIB, IIC) and fibre areas. Different development of fibre type composition with increased age were seen in women and men: the type I percentage tended to increase in the women (51 +/- 9 to 55 +/- 12) and decrease significantly in the men (55 +/- 12 to 48 +/- 13). The fibre areas remained unchanged in both sexes. It is suggested that there is a sex-related fibre adaptation to increased age.

Adolescent↗
PubMed1991

Mortality in circulatory diseases, especially ischaemic heart disease, among Swedish professional drivers: a retrospective cohort study.

The aim of the investigation was to study mortality from circulatory diseases, especially ischaemic heart disease (IHD), in a cohort of Swedish professional drivers. The cohort included 1,731 male members of the Swedish Transport Workers Union. During the follow-up period, 1974-1985, 123 drivers died. Information concerning the cause of death was acquired from the Cause-of-Death Register. Standardized Mortality Ratio (SMR) for circulatory diseases and ischaemic heart disease were significantly higher among professional drivers (SMR = 127 and 138, respectively) than in the reference group consisting of Swedish males.

Adolescent↗
PubMed1987

Evaluation of the driver's cab in the Rc5 engine.

The opinion of engine drivers concerning the design of the cab in a new engine (Rc5, ASEA, Sweden) is surveyed in the present study, which is aimed at recommendations for further improvements of the new cab. Fifty engine drivers from the northern part of Sweden (Ange, Vannas and Boden), who had been driving the new engine, were selected at random to answer a specially designed questionnaire. Most of the drivers considered the new cab as better than the old one (Rc4) in several respects. Particularly appreciated was an adjustable footrest, on which the safety regulator pedal was fitted, which enabled an individually adjusted position for driving. They also preferred the automatic brake valve located close to the driver and with its movements in a sagittal direction. A number of proposals for further improvement of the cab are presented in order to attain an optimally designed driver's cab.

Journal Article↗
PubMed1981

Rheumatic complaints among Swedish engine drivers in relation to the dimensions of the driver's cab in the Rc engine.

This paper compares the occurrence of rheumatic complaints among male engine drivers with their body measurements and with the dimensions of the cab in the Rc Swedish engine. 150 Swedish engine drivers were interviewed regarding symptoms from the musculoskeletal system. Relevant anthropometric measurements were obtained from each subject and compared with similar dimensions on a symptom free group of drivers matched for age. Data concerning the dimensions of the cab in the Rc engine were obtained from drawings and measurements of the cab. The results indicate that engine drivers with complaints in the lower back, neck and/or shoulders and/or the lower extremities were significantly shorter than controls in those anthropometric measurements related to correct sitting posture. Since the cab of the Rc engine is designed for tall engine drivers, the shorter driver appears to be at risk. Recommendations for cab designs suitable for all potential male and female drivers are appended.

Journal Article↗