Longitudinal changes in physical capacity from adolescence to middle age in men and women.

The aim was to investigate how physical capacity changes from adolescence through early adulthood to middle age with focus on early aging. The aim was also to study if physical capacity in middle age could be predicted by factors in adolescence or early adulthood. A cohort of men and women in Sweden (SPAF-1958, n = 425) have been followed for 36 years, at 16, 34, and 52 years of age. The study includes, among other variables, objective measures of physical capacity. At age 52, 50% of the original cohort participated in exercise testing. Physical capacity increased from 16 to 34 years. From 34 to 52 years, physical capacity decreased in both genders by 15-20% in all but one test. Physical capacity at 16 and 34 years of age were better predictors of physical capacity at age 52 than body dimensions, school grades and life style factors. In conclusion, present data confirm earlier cross-sectional studies regarding the decrease in aerobic capacity and muscular strength during the early ageing period in both genders. The study has also generated novel data that show a smaller decline in muscular endurance than previously reported. Finally, physical capacity is fairly stable from adolescence to middle age.

The Swedish physical activity and fitness cohort born in 1958 - dropout analysis and overview at 36-year follow-up.

The main aim of the Swedish physical activity and fitness cohort study (SPAF-1958) was to describe physical fitness, physical activity, health, and lifestyle across part of the lifespan, and to assess the influences on these factors from the environment, personal factors, and genetics. There is inevitable dropout from longitudinal studies, and it may be systematic. The aim of this first paper of the second follow-up of SPAF-1958 was to provide a dropout analysis to consider to what extent the participants, at 52 years of age, remain a representative sample of the original adolescent study population. Additional aims were to provide an overview of the study protocol and the ongoing study population. Ongoing study participants in SPAF born in 1958 were, at the second follow-up at the age of 52, still representative of the study cohort in terms of sex, adolescent geographical area, upper secondary school program, adolescent body composition, muscular strength, and muscular endurance. However, a higher physical activity and, among women, a higher aerobic capacity in adolescence decreased the risk for dropout. It is important when interpreting results from longitudinal studies to adjust for the systematic dropout that could bias the conclusions drawn from the results.

Prediction of development of fatigue during a simulated ambulance work task from physical performance tests.

The aims of this study were (1) to identify which physical performance tests could best explain the development of fatigue during a simulated ambulance work task, (2) to investigate the effect of height and weight and (3) to investigate in what respects these findings differ between female and male ambulance personnel. Forty-eight male and 17 female ambulance personnel completed a test battery assessing cardio-respiratory capacity, muscular strength and endurance, and co-ordination. The subjects also completed a simulated ambulance work task -- carrying a loaded stretcher. The work task was evaluated by development of fatigue. Univariate and multiple regression analyses were used to investigate to what extent the tests in the test battery were able to explain the variance of developed fatigue. The explained variance was higher for female than for male ambulance personnel (time > 70% of HRpeak: R2 = 0.75 vs 0.10, accumulated lactate: R2 = 0.62 vs 0.42, perceived exertion: R2 = 0.75 vs 0.10). Significant predictors in the models were VO2max, isometric back endurance, one-leg rising, isokinetic knee flexion and shoulder extension strength. Height, but not weight, could further explain the variance. The high physical strain during carrying the loaded stretcher implies the importance of investigating whether improved performance, matching the occupational demands, could decrease the development of fatigue during strenuous tasks.