Tracking of physical fitness from childhood to adulthood.

The purpose of the present study was to investigate the tracking of selected aspects of physical fitness (peak handgrip force, sit-ups, aerobic fitness, and blood pressure) from childhood to adulthood. The investigation studied a randomly selected subgroup from the original participants in the Trois-Rivières growth and development study, 95 women (57 experimental and 38 control) and 96 men (56 experimental and 40 control). During their primary-school education, the experimental group had received 5 hours of physical education each week whereas the control group had received 40 minutes per week. Data were gathered when subjects were 10-12 years old (baseline) and during follow-up around the age of 35 years. Tracking between 10, 11, 12, and 35 years of age was assessed by correlation analysis. In females the tracking of grip strength increased from the interval 10-35 to the intervals 11-35 and 12-35 years of age (r = 0.54 to 0.69 and 0.67, respectively, all p < 0.001). In males the tracking of grip strength was less consistent, but also increased over the same intervals to become significant for the correlation between 12 and 35 years of age (r = 0.32, p < 0.05). Tracking for sit-ups also increased, from 0.29 to 0.38 for females and from 0.23 to 0.54 for males. The tracking of PWC 170/kg between 11 and 35 years was significant but low in females (r = 0.24) as well as in males (r = 0.34). The ability of childhood blood pressure to predict adult values was low in females (r = 0.24 for diastolic, ns; and r = 0.26 for systolic, p < 0.05) and absent in males. Presumably because some of the influence of the added physical education was lost by adulthood, the tracking of PWC 170/kg and grip strength was weaker for experimental than for control subjects. In conclusion, data from the Trois-Rivières longitudinal study showed limited tracking of PWC170/kg and situps in both sexes. The tracking of grip strength was moderately high in females but less consistent in males. This may reflect the larger influence of sex hormones on the muscle strength of males at puberty.