Mathieu F. McKinnon¹, Angela M. Kolen^1,

It is important to recognize or control for the impact of physical growth to evaluate changes in children’s physical performance as they get older particularly when involved in an exercise or training program. This study examined the effect of growth in height on four physical competency tasks in children. Data were collected twice from 206 children, aged 8 to 11 years at first data collection. These participants completed the Progressive Aerobic Cardiorespiratory Endurance Run [PACER], a timed plank, left- and right-hand grip strength, and had their height and mass measured in consecutive years. Growth in height was used in dimensional analyses to predict the participants’ expected improvement in their physical competency measures. The expected improvement in PACER, timed plank and left- and right-hand grip strength was compared to actual differences in the children’s performance using repeated measures t-tests. Significantly greater improvements than expected were found for left (t(167)=-4.731, p=0.000) and right-hand grip (t(168)=-4.579, p=0.000). Actual performance was significantly less than expected for the timed plank (t(172)=-2.743, p=0.003). No significant differences in actual versus expected performance were found for the PACER (t(164)=-1.023, p=0.154). Although children’s growth in height accounted for a proportion of their performance, it was inconsistent suggesting other biologic and non-biologic factors also impact their physical competencies over time.

dimensional analysis, grip strength, plank, PACER