School-aged children often carry significant weight due to the school supplies required for daily activities. This overload can lead to biomechanical, structural, and strength changes, impacting musculoskeletal development and posture.

Compare the propulsive ankle torque during walking without load and with 10% of the body mass in children aged 8 to 10 years.

A cross-sectional study approved by the local ethics committee was conducted with healthy children. Fifteen children (53.3% boys) (9,6 ± 0,5 years; 33.1 ± 4.5 kg; 1.36 ± 0.5 m) participated in the study. Gait analysis was performed at a 5km/h control speed in a biomechanics laboratory equipped with a motion capture system (Vicon, EUA) using reflective markers, specifically the Plug-in-Gait model from Vicon Motion Systems. The system&apos;s cameras recognized these markers, and the children were evaluated under two conditions: walking without a backpack and walking with a backpack carrying a load equivalent to 10% of their body weight. Familiarization with the testing area was conducted, and data from seven valid trials were collected for each proposed condition. A trial was considered valid when the child walked a distance of 10 meters and stepped on a force platform. The ankle plantarflexion torque without and with a backpack with 10% were compared using a paired Student’s t-test and the effect size was calculated by Hedges’ g, with a significance level set at p < 0.05, using the Statistical Package for the Social Sciences.

The ankle plantarflexion torque with a backpack with 10% of the body weight was significantly higher (1.2 ± 0.1 N.m/kg) compared to the ankle plantarflexion torque without a backpack (1.1 ± 0.1 N.m/kg) (p < 0.001; Hedge&apos;s g = 0.94, 95% CI = 0,36 to 1,43).

A slight increase in plantarflexion torque was observed when children walked while carrying an additional 10% body weight in a backpack. During prolonged walking, this may lead to increased energy consumption, potentially causing overload and fatigue, even with a relatively small load. This suggests that carrying a backpack with an additional 10% of their body weight may cause muscular overload.

Children&apos;s weight in their daily activities should be kept below 10% of their body weight to prevent high biomechanical loads and muscular overload during gait.