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- Nordström, Peter, et al.
(författare)
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Type of physical activity, muscle strength, and pubertal stage as determinants of bone mineral density and bone area in adolescent boys.
- 1998
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Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 0884-0431 .- 1523-4681. ; 13:7, s. 1141-8
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Tidskriftsartikel (refereegranskat)abstract
- The present study was conducted to evaluate the influence of different types of weight-bearing physical activity, muscle strength, and puberty on bone mineral density (BMD, g/cm2) and bone area in adolescent boys. Three different groups were investigated. The first group consisted of 12 adolescent badminton players (age 17.0 +/- 0.8 years) training for 5.2 +/- 1.9 h/week. The second group consisted of 28 ice hockey players (age 16.9 +/- 0.3 years) training for 8.5 +/- 2.2 h/week. The third group consisted of 24 controls (age 16.8 +/- 0.3 years) training for 1.4 +/- 1.4h/week. The groups were matched for age, height, and pubertal stage. BMD, bone mineral content (BMC, g), and the bone area of the total body, lumbar spine, hip, femur and tibia diaphyses, distal femur, proximal tibia, and humerus were measured using dual-energy X-absorptiometry. When adjusting for the difference in body weight between the groups, the badminton players were found to have significantly higher BMD (p < 0.05) of the trochanter and distal femur compared with the ice hockey players despite a significantly lower weekly average training. The badminton players had higher BMD compared with the control with the control group at all weight-bearing BMD sites, except at the diaphyses of the femur and tibia and lumbar spine. The independent predictors of bone density were estimated by adjusting BMC for the bone area in a multivariate analysis among all subjects (n = 64). Accordingly, the bone density of all sites except the spine was significantly related to muscle strength and height, and the bone density of the total body, neck, trochanter, distal femur, and proximal tibia was significantly related to type of physical activity (beta = 0.09-0.33, p < 0.05). The bone area values at different sites were strongly related to muscle strength and height and less strongly related to the type of physical activity and pubertal stage. In conclusion, it seems that during late puberty in adolescent boys the type of weight-bearing physical activity is an important determinant of bone density, while the bone area is largely determined by parameters related to body size. The higher BMD at weight-bearing sites in badminton players compared with ice hockey players, despite significantly less average weekly training, indicates that physical activity including jumps in unusual directions has a great osteogenic potential.
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- Pahlm, Ulrika, et al.
(författare)
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Comparison of teaching the basic electrocardiographic concept of frontal plane QRS axis using the classical versus the orderly electrocardiogram limb lead displays
- 1997
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Ingår i: American Heart Journal. - 1097-6744. ; 134:6, s. 1014-1018
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Tidskriftsartikel (refereegranskat)abstract
- This study compares the effectiveness of teaching the calculation of frontal plane QRS axis with the use of the classical versus the orderly electrocardiographic limb lead display. Eighty-three students from two environments were randomized into two groups and were taught to determine frontal plane axis with one of the methods. The accuracy and time to determine the axis were tested on 10 electrocardiograms. In the United States the group using the classical display achieved 4.2 (+/-2.7) correct answers, whereas those using the orderly method achieved 6.8 (+/-3.0) (p = 0.0006). The classical group used 9.2 (+/-2.8) minutes to complete the test, whereas the orderly group needed 7.2 (+/-2.0) minutes (p = 0.015). The results achieved in Sweden were similar. The use of the orderly electrocardiographic limb lead display results in greater diagnostic accuracy in less time than the classical display when determining the frontal plane QRS axis.
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- Pettersson, Ulrika, et al.
(författare)
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A comparison of bone mineral density and muscle strength in young male adults with different exercise level.
- 1999
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Ingår i: Calcified Tissue International. - 0171-967X .- 1432-0827. ; 64:6, s. 490-8
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate any differences in bone mass at different sites between young adults subjected to a high physical activity and a group of young adults with a low level of physical activity. In addition, we compared the relationship among bone mass, muscle strength, and body constitution in these two groups. The reference group consisted of 20 men, age 24.6 +/- 2.3 years, not training for more than 3 hours per week. The ice hockey players consisted of 20 players, age 23.4 +/- 4.9 years, from an ice hockey team in the second highest national Swedish league, training for about 10 hours per week. The groups were matched according to age, height, and weight. Areal bone mineral density (BMD) was measured in total body, head, humerus, spine, pelvis, femur, femoral neck, Ward's triangle, trochanter, femur diaphysis, proximal tibia, and tibia diaphysis using dual energy X-ray absorptiometry. BMD was significantly higher in the total body (8.1%), humerus (11.4%), spine (12.7%), pelvis (12.4%), femoral neck (10.3%), femur (7.4%), proximal tibia (9.8%), and tibia diaphysis (7.5%) in the high activity group. Fat mass was significantly lower in the high activity group (18.7%). The high activity group also had a significantly higher lean body mass (5.4%) and a significantly higher isokinetic muscle strength of the quadriceps muscle compared with the reference group. In the reference group, there was a general strong independent relationship between muscle strength of the thigh and all BMD sites, except for the head, tibia diaphysis, and proximal tibia. Furthermore, in the same group, body mass index (BMI) independently predicted pelvis BMD. On the contrary, in the high activity group, muscle strength did not predict any BMD site at all. In the same group, body constitutional parameters (weight, height, and fat mass) independently predicted pelvis BMD, and BMI was shown to be an independent predictor of humerus BMD. The differences in BMD between the groups seem to be site-specific and may be associated with the type and magnitude of loading during off season training and preferentially during ice hockey. High physical activity seems to weaken the relationship between BMD and muscle strength. Hence, impact forces may be of greater importance in regulating bone mass than muscle strength in itself in highly trained athletes.
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- Pettersson, Ulrika, 1970-
(författare)
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Bone mass in the young athlete
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bone mass and bone size accumulate during childhood and adolescence and peak in the twenties. The obtained peak bone mass has been suggested to be a major determinant of bone mass even in the very elderly. Although, genetic factors are the main determinants, environmental and lifestyle factors also play a crucial role in modulating maximal bone mass. Assessing these lifestyle factors would be of great importance for the intervention strategies against osteoporosis. The first aim of this thesis was to compare the bone mass and bone size in male and female young adults on a high level of physical activity with males or females on a low level of physical activity. Furthermore, it also aimed to investigate the influence of pubertal maturity, menstrual disturbances, and different body constitutional factors on bone mass and size during adolescence and young adulthood. The female activity groups consisted of cross-county skiers, soccer players, and rope skippers. Compared to their age-matched inactive controls, all these athletic groups demonstrated a significantly higher bone mineral density (BMD) at those sites subjected to the sport-specific loading. Rope-skipping, a very high impact activity was associated with a higher bone size, preferentially in the lower extremity, suggesting an effect of weight-bearing activity also on bone geometry. The effect of menstrual disturbances was evaluated in a group of long-distance runners, where amenorrheic runners had significantly lower BMD in both trabecular and also cortical bone in the lower extremity compared to eumenorrheic runners, suggesting that weight-bearing activity cannot compensate for the shortfall of reduced estrogen levels. The male activity groups consisted of ice hockey players and badminton players. Compared to their age-matched controls, both athletic groups demonstrated a significantly higher BMD at those sites subjected to the sport-specific loading. Especially badminton was associated with a high BMD, suggesting that physical activity, including jumps in unusual directions has a great osteogenic potential. The main determinants of BMD in both male and females were, except for type of physical activity, activity, muscle strength, height, and different body constitutional factors. However, the relationships with muscle strength and body constitution were somewhat weaker in the athletic groups, especially in the males, indicating that impact forces may be of greater importance in regulating bone mass in highly trained athletes. Yet bone size was largely determined by parameters related to body size and less strongly to physical activity. In a prospective study on adolescent boys, the changes in bone mass during late puberty were mainly accounted for by growth and development, including height and pubertal maturation, and less to physical activity level. Thus, the osteogenic effect from physical activity seems to be of importance for bone mass achievement predominantly before late puberty.
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- Pettersson, Ulrika, et al.
(författare)
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Low bone mass density at multiple skeletal sites, including the appendicular skeleton in amenorrheic runners
- 1999
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 64:2, s. 117-125
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate any difference in bone mass at different sites between female long-distance runners with amenorrhea and those with eumenorrhea. We compared 10 amenorrheic and 10 eumenorrheic athletes to determine whether athletes with amenorrhea have lower BMD in multiple skeletal regions, including weight-bearing lower limbs. The amenorrheic group had experienced menstrual dysfunction ranging from 3 to 43 months. As a further control group, 16 eumenorrheic soccer players were compared with the former two running groups regarding their BMD measurements. The two groups were matched for age, height, and amount of training. Areal bone mineral density (BMD) was measured and was found to be significantly lower in the total body, humerus, spine, lumbar spine, pelvis, femoral neck, trochanter, total femur, femur diaphysis, tibia diaphysis and in the nonweight-bearing head of the femur in the amenorrheic group. Body weight, BMI, fat mass, and body fat percent were significantly lower in the amenorrheic group. The differences in the BMD of the head, humerus, femoral neck, total femur, femur diaphysis, and tibia diaphysis disappeared when adjusted for body weight. Compared with the soccer group, the amenorrheic subjects had significantly lower BMD values at all sites except for the head, Ward's triangle, and femur diaphysis. Blood samples were obtained in the two running groups for analysis of osteocalcin, carboxy terminal telopeptide (ICTP), procollagen I (PICP), and estradiol. There were no significant differences between the groups but there was a strong tendency towards a lower estradiol level and a higher osteocalcin level in the amenorrheic group. A free estradiol index (FE2) was derived as the ratio of estradiol to sex hormone binding globulin (SHBG) and was significantly lower in the amenorrheic group. No difference in their daily intake of total energy, protein, carbohydrates, fiber, calcium, and vitamin D was observed. However, both groups showed a surprisingly low energy intake in relation to their training regimens. Stepwise regression analyses revealed that weight was the best predictor of spine BMD in both groups. Estradiol and FE2 were significant predictors of the BMD of the proximal femur in the eumenorrheic group, but did not predict any BMD site in the amenorrheic group. In conclusion, amenorrhea in athletic women affects trabecular and cortical bone in both axial and appendicular skeleton. However, some of the discrepancy can be explained by a lower body weight. Physical weight-bearing activity does not seem to completely compensate for the side effects of reduced estrogen levels even in weight-bearing bones in the lower extremity and spine.
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