Excess weight affects foot loading, peak pressure even in young kids
Weight loss may improve function
By Katie Bell
Overweight and obese children present with higher overall foot loading and a disproportional impact on the midfoot and longitudinal arch, with those as young as 1 or 2 years of age affected, according to research from Germany that may have implications for abnormal foot loading prevention in children.
Lead author Steffen Müller, PhD, research associate at the University Outpatient Clinic, Sports Medicine & Sports Orthopaedics, at the University of Potsdam in Germany, remarked, “In our data we cannot really see a well-adapted gait strategy for these children [for foot loading] since no real compensation is visible. Therefore, it could be speculated that the obese children are not capable [of adapting] their gait sufficiently to extra weight, leading to higher and disproportional foot loading.”
The study included 7575 children aged 1 to 12 years and examined foot-loading characteristics during gait. Of the participants, 6458 were categorized as normal weight, 746 as overweight, and 371 as obese, according to a German reference system based on age- and gender-specific body mass indices.
Plantar pressure measurements were taken during gait with a pressure measurement platform that was mounted on an instrumented walkway. The researchers calculated the contact area, arch index, peak pressure, and force time integral for the total foot, forefoot, midfoot, and hindfoot.
Weight-related differences in peak plantar pressure, while relatively small, were present at the mid- and forefoot by age 2 years.
The data suggested a mean walking velocity of .95 m/s was evident in normal-weight, overweight, and obese children. However, obese and normal-weight children presented with the highest and lowest foot contact area, respectively, in all age groups. This was also the case for the arch index in children aged 5 to 12 years.
Müller suggested that prevention strategies, such as strengthening and sensorimotor exercises for the foot and lower extremity, should start at a young age. “Additionally, we should try to enhance the compliance of these children to participate in an active lifestyle and reduce weight,” he added.
Meanwhile, overall foot loading and peak pressures increased consistently with age and were highest in the obese children and lowest in the normal-weight children. Increased foot loading for the total foot and forefoot was present from the age of 3 to 4 years, while excess foot loading at the rearfoot and midfoot was visible from age 5 to 6 years.
Müller said, “Since pros and cons for active versus passive treatments in the long run are well known, active interventions should be preferred in contrast to shoe and insole adaptations to address disproportional foot loading and/or foot stress/pain.”
The differences in peak pressure at the toes, rearfoot, and total foot were relatively small between normal-weight, overweight, and obese children, but were present at the forefoot and midfoot at age 2 years. PLoS One published the findings in February.
Commenting on the study data, Sharon Bout-Tabaku, MD, assistant professor of pediatrics at Nationwide Children’s Hospital in Columbus, OH, said: “The implications are important because we can hypothesize that walking speed, lower extremity strength, and altered forces around the knee and hips will be affected.”
She added that, “Early foot changes may affect the morphology of the bones and joints due to sustained low-level systemic and local joint inflammation. Finally, we can guess that it may interfere with optimal physical function and can be associated with pain.”
She also emphasized weight management. “Certainly maintaining a healthy weight or weight loss early is important because it can minimize alterations in morphology, forces, and gait across the entire lower extremity,” she said. “Physical activity and normal childhood play is equally important to maintain bone development, strength and neuromuscular development.”
She added that “in children who are symptomatic, orthotics, heel cups, and cushioning may provide some relief.”
The study authors concluded the plantar pressure values assessed in this trial could serve as reference data to identify suspicious foot-loading patterns in children. Bout-Tabaku agreed, and noted, “This article provides nice reference data in a large sample and serves as a starting point for other studies: longitudinal studies; studies exploring associations with foot pressure and function, gross motor skills, and pain; and longitudinal studies looking at bone and joint development radiographically.”
Bout-Tabaku added that “the take-home is that obesity is modifiable. Similarly, during childhood and adolescence, the musculoskeletal system is dynamic and very responsive to change, and can be positively modified with weight loss in childhood. The degree of positive changes in the musculoskeletal system is harder to attain with increasing age.”
Katie Bell is a freelance writer based in New York City.
Müller S, Carlsohn A, Müller J, et al. Influence of obesity on foot loading characteristics in gait for children aged1 to 12 years. PLoS One 2016;11(2):e0149924.