Changes in physical activity, maximal isometric strength and maximal oxygen uptake from late teenage to adulthood: an eight‐year follow‐up study of adolescents in Denmark

Abstract

Changes in physical activity, maximal .ts i n -Denmark Andersen LB, Haraldsdottir J. Changes in physical activity, maximal isometric strength and maximal oxygen uptake from late teenage to adulthood: an eight-year follow-up study of adolescents in Denmark.A randomly selected group of 88 men and 115 women, aged 23-27 years in 1991, were tested as teenagers in 1983, and then followed-up in 1991. A mean increase of 15% in maximal voluntary isometric strength was found in men, and no change was found in women over the 8 years. Body weight increased 14% in men and 6% in women. Strength in relation to body weight (N . kg-') did not change in men, but a small decrease of 3% was found in women. Strength in abdominal muscles decreased iq blue-collar workers but increased in students. Maximal oxygen uptake ( V , A (ml . min-lkg-') decreased 9% in men and 3% in women. The values in 1991 were 47.9 and 39.5 ml-min-lkg-' for men and women, respectively.Participation in leisure sport activities decreased 1.7 h . week-' in men and 1.2 h . week-' in women. Seventy percent of the men and 74% of the women participated in regular leisure sport activity, which was a marked increase from 8 years before, when only 54% of the men and 57% of the women were similarly active. The overall decrease in V , , in men was due pnmanly to a decrease among blue-collar workers and unemployed men: 19% vs 4% in other occupational groups. Only 20% of the blue-collar workers participated in sport activities for more than 4 h . week.-], and 47% did not participate at all. In women, changes in strength and V , , ,were related to motherhood. Abdominal muscle strength decreased, but arm flexor strength increased in women who had become mothers. Vdecreased 14% in mothers vs 2% in other women. Changes over 8 years in V , , and strength did not relate to changes in physical activity, but a significant relationship between decrease in physical activity and gain in body fat was found in men. Changes in body weight and body fat were the only variables that correlated with changes in strength. None of the observed changes related to changes in V , -(ml . min-lkg-'). For the 23-to 27-year-olds, the level of physical actmty assessed in h . week-' was almost as high in women as in men.

School fitness tests as predictors of adult health‐related fitness

“…The sit-up results, by contrast, decreased significantly from adolescence to adulthood in women but not in men, whereas the hand-grip test results increased significantly in men but not in women. All these findings are supported by previous studies (Kemper et al, 1990;Andersen and Haraldsdóttir, 1994). The sex difference in the development of the hand-grip and sit-up tests may be due to biological differen- ces, such as higher testosterone levels or growth in men (Andersen and Haraldsdóttir, 1994;Ramos et al, 1998;Round et al, 1999).…”

“…All these findings are supported by previous studies (Kemper et al, 1990;Andersen and Haraldsdóttir, 1994). The sex difference in the development of the hand-grip and sit-up tests may be due to biological differen- ces, such as higher testosterone levels or growth in men (Andersen and Haraldsdóttir, 1994;Ramos et al, 1998;Round et al, 1999). Another reason could be that men are more interested in strength-demanding activities at work or during leisure time (Glenmark et al, 1994).…”

“…Strengths of the study include a longer follow-up time than in most previous studies (Rutenfranz, 1986;Beunen et al, 1992;Andersen and Haraldsdóttir, 1994;BarnekowBergkvist et al, 1996;Kemper et al, 2001). The sample also included both sexes from the same age group, and all of them had complete baseline and follow-up data on all fitness test results.…”

“…Some studies followed the development of physical fitness from childhood or adolescence to ages 20-34 years (Rutenfranz, 1986;Beunen et al, 1992;Andersen and Haraldsdóttir, 1994;Barnekow-Bergkvist et al, 1996;Kemper et al, 2001). Test methods, number of subjects, follow-up periods, and testing ages varied in different studies, making it difficult to compare results.…”

Are children of today less active than before and is their health in danger? What can we do?

“…We need to perform multiple longitudinal studies for the assessment of secular trend in fitness. Even if this is accomplished now, there are only few older studies with direct measurement of aerobic fitness to compare the data with, and only two earlier studies have assessed a representative sample of adolescents with direct measured VO 2 max (Andersen & Haraldsdóttir, 1994). Also, we need to assess physical activity objectively in order to describe secular trend of physical activity in the population, and to describe what types of activity that have decreased most and in which groups.…”