The Influence of Isokinetic Trunk Flexor and Extensor Strength on Dynamic Balance in Children

This study assessed whether trunk flexor and extensor strength were predictors of time to stability (TTS) and center of pressure (CoP) during hop and hold tasks in children. Seventeen boys (age, 10.1 ± 1.6 years; height, 1.45 ± 0.11 m; mass, 26.7 ± 7.83 kg) undertook isokinetic strength assessments of concentric and eccentric trunk flexors/extensors at 60°/s, and anterior/medial hop tasks. Hierarchical multiple regressions determined whether concentric and eccentric trunk flexor/extensor peak torques predict TTS using a composite score (CompX CompY CompZ) and CoPX and CoPY. Concentric trunk flexors were the strongest predictor for TTS CompXY, with concentric flexion and eccentric extension predicting TTS CompY. All muscle actions were also strong predictors for CoPY during hop tasks. These findings have implications for the assessment of trunk musculature strength and measures of postural control within a young healthy population. The development of trunk musculature strength may aid improvements in dynamic balance tasks in children, with implications for fall and injury risk. To improve trunk musculature strength and the potential to maintain postural control, a combination of concentric and eccentric exercises with other training modalities appears relevant due to the increased relevance to the demands of balance maintenance.