Ultrasound radiomics reveals that the macrochamber layer of the heel fat pad shows significant exercise-associated textural differences, with 19 radiomic features differing among low-, moderate-, and high-exercise-volume groups, while the microchamber layer shows limited variation.
Key Findings
Results
The macrochamber layer of the heel fat pad showed significant radiomic differences associated with exercise volume, with 19 features differing among the three groups.
51 healthy young adults aged 18-35 years were classified into high-exercise-volume (HEV, n=18), moderate-exercise-volume (MEV, n=15), and low-exercise-volume (LEV, n=18) groups based on weekly physical activity energy expenditure.
A total of 101 radiomic features were extracted from each layer to characterize intensity, heterogeneity, and spatial texture patterns.
19 features in the macrochamber layer differed significantly among the three groups (P < 0.05).
Six representative features were retained after LASSO feature selection.
Intergroup differences were analyzed using one-way ANOVA or the Kruskal-Wallis test, followed by Bonferroni-adjusted pairwise comparisons.
Results
The main pairwise radiomic differences in the macrochamber layer occurred between the LEV group and the MEV or HEV groups, with no significant differences detected between MEV and HEV groups in the main distinguishing features.
Pairwise comparisons used Bonferroni adjustment to control for multiple testing.
The LEV group was distinguishable from both MEV and HEV groups based on the six LASSO-selected features.
MEV and HEV groups were not significantly different from each other in the main distinguishing macrochamber features, suggesting a possible threshold effect of exercise volume.
Results
The microchamber layer showed limited radiomic variation associated with exercise volume, with only the feature Uniformity differing significantly.
Only one feature, Uniformity, differed significantly in the microchamber layer.
This difference was observed between the LEV group and the MEV/HEV groups.
The limited variation in the microchamber layer contrasted sharply with the 19 significant features found in the macrochamber layer.
Discussion
The macrochamber layer appears more sensitive to activity-associated radiomic texture differences than the microchamber layer.
The macrochamber layer yielded 19 significantly differing radiomic features compared to only 1 in the microchamber layer.
This layer-specific sensitivity suggests that long-term mechanical loading from exercise may preferentially alter the structural and textural properties of the macrochamber layer.
The authors describe this as suggesting the macrochamber layer 'may be more sensitive to activity-associated radiomic texture differences than the microchamber layer.'
Conclusions
Ultrasound radiomics demonstrated potential as a non-invasive approach for quantifying subtle, layer-specific texture patterns in the heel fat pad.
Ultrasound images were obtained from all 51 participants and analyzed by extracting radiomic features characterizing intensity, heterogeneity, and spatial texture patterns.
The approach allowed differentiation between the macrochamber and microchamber layers of the heel fat pad.
The authors conclude that 'ultrasound radiomics shows potential as a non-invasive approach for quantifying subtle, layer-specific texture patterns in the heel fat pad.'
What This Means
This research suggests that the heel fat pad — the cushioning tissue on the bottom of the heel — shows measurable structural differences associated with how much exercise a person does. Using ultrasound imaging combined with a technique called radiomics (which extracts detailed mathematical features from medical images), researchers analyzed the heel fat pads of 51 healthy young adults divided into low-, moderate-, and high-exercise groups. They found that the outer, larger-chambered layer of the fat pad (called the macrochamber layer) had 19 different textural characteristics that varied according to exercise level, while the inner, finer-chambered layer (the microchamber layer) showed very little variation.
Interestingly, the differences were mainly between people who exercised little (low-exercise group) and those who exercised at moderate or high levels, while the moderate and high exercise groups looked similar to each other. This could suggest that even moderate levels of regular physical activity are associated with detectable changes in heel fat pad structure, but that increasing exercise beyond a moderate level may not produce further measurable textural differences. The macrochamber layer appears to be the more 'responsive' layer to mechanical loading from physical activity.
This research matters because the heel fat pad is important for absorbing shock during walking and running, and understanding how it changes with activity could eventually help clinicians better assess foot health or identify people at risk for heel-related problems. The use of ultrasound radiomics is notable because it is a non-invasive and widely available imaging method, suggesting it could be a practical tool for studying soft tissue changes in clinical or research settings without requiring more invasive or expensive procedures.
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Wang Y, Li Y, Duan Y, Cui L, Sun Y, Zhao X, et al.. (2026). Radiomic analysis reveals exercise-induced textural changes in the heel fat pad macrochamber layer.. Journal of biomechanics. https://doi.org/10.1016/j.jbiomech.2026.113533