Foot Pressure Analysis for Pedography and Gait Assessment

library(pressR)

Plantar-pressure measurement is used in pedography, gait analysis, and diabetic-foot risk assessment. This vignette demonstrates the workflow using a synthetic in-shoe insole trial.

trial <- pr_example_trial("insole")
trial
#> 
#> ── pr_trial ────────────────────────────────────────────────────────────────────
#> • System: "insole"
#> • Layout: "insole_standard"
#> • Frames: 250
#> • Duration: 5 s
#> • Sampling: 50 Hz
#> • Sensors: 99
#> • Subject: "EX01"
#> • Date: "2026-05-04"
#> • Condition: "walking"

Gait cycle detection

cycles <- pr_calc_gait_cycles(trial)
cycles
#> # A tibble: 5 × 8
#>   cycle heel_strike_frame toe_off_frame heel_strike_time toe_off_time
#>   <int>             <int>         <int>            <dbl>        <dbl>
#> 1     1                 1            30             0           0.582
#> 2     2                51            80             1.00        1.59 
#> 3     3               101           130             2.01        2.59 
#> 4     4               151           180             3.01        3.59 
#> 5     5               201           230             4.02        4.60 
#> # ℹ 3 more variables: stance_duration <dbl>, start_frame <int>, end_frame <int>

Force vs time with cycles

pr_plot_force_time(trial, show_cycles = TRUE)

Center of pressure and rollover

pr_plot_cop(trial)

pr_plot_cop_butterfly(trial)

Regional analysis

pr_calc_regional(trial)
#> # A tibble: 7 × 6
#>   region           mpp   mvp max_force contact_area pti_mean
#>   <chr>          <dbl> <dbl>     <dbl>        <dbl>    <dbl>
#> 1 heel            220.  15.0     357.          42       40.2
#> 2 midfoot         646.  59.6    1248.          61.5    155. 
#> 3 metatarsal_1    130.  23.0      41.9          6       65.4
#> 4 metatarsal_2_3  224.  43.3     116.           9      127. 
#> 5 metatarsal_4_5  137.  15.9      49.1          9       43.8
#> 6 hallux          265.  29.9     120.           6       83.8
#> 7 lesser_toes     190.  12.9      73.1         12       30.0

Diabetic foot thresholds

pr_ref_diabetic_foot()
#> # A tibble: 4 × 6
#>   region      parameter threshold unit  interpretation                    source
#>   <chr>       <chr>         <dbl> <chr> <chr>                             <chr> 
#> 1 any plantar mpp             200 kPa   Elevated ulceration risk (Armstr… Armst…
#> 2 any plantar pti_mean         70 kPa*s Pressure-time integral associate… Casel…
#> 3 forefoot    mpp             400 kPa   High-risk forefoot peak pressure… Veves…
#> 4 heel        mpp             250 kPa   Heel threshold reported in mixed… Frykb…

Composite foot report

pr_plot_foot_report(trial)