Upper and lower limb loading during weight-bearing activity in children: reaction forces and influence of body weight

Area of Science:

• Pediatrics
• Biomechanics
• Skeletal Development

Background:

• Weight-bearing (WB) activity is essential for healthy skeletal development in children.
• Quantifying the impact forces during upper limb WB activities in children remains largely unexamined.

Purpose of the Study:

• To quantify ground reaction forces (GRF) during various WB activities in children.
• To investigate the contribution of body weight (BW) to these GRF.
• To explore sex differences in GRF and the association between peak forces and BW.

Main Methods:

• Fifty children (aged 8-12) participated.
• Ground reaction forces (GRF) were measured using force plates during 20 upper and lower limb activities.
• Statistical analyses included independent sample t-tests and linear regressions.

Main Results:

• Lower limb GRF ranged from 2-6 times body weight (BW) with no significant sex differences.
• Upper limb GRF ranged from 1/3-1.7 times BW; males had significantly higher GRF in 25% of activities.
• BW was associated with peak force, but explained a wide range of GRF variation, independent of limb or activity type.

Conclusions:

• While body weight influences forces during pediatric WB activities, it does not solely determine them.
• Factors such as technique are critical and should be considered in designing WB activity interventions for children.
• Further research into technique's role can optimize skeletal health interventions.