## 2 Methods
### Outcome Measures  
The first primary outcome was DPN symptoms, measured using the Brazilian version of the Michigan Neuropathy Screening Instrument questionnaire (MNSI) [35]. The sum of the scores ranged from 0 to 13, with the greater scores indicating worse DPN. The second primary outcome was DPN severity measured by the Decision Support System for Classification of Diabetic Polyneuropathy [9](www.usp.br/labimph/fuzzy, accessed on 28 December 2022). Scores ranged from 0 to 10, with greater values representing a more severe DPN.  
Secondary outcomes comprised DPN-related and biomechanical variables. The clinical variables were: (1) tactile sensitivity by the 10 g monofilament at four plantar areas [36], and (2) vibration perception using a 128 Hz tuning fork at the first metatarsophalangeal joint [37].  
The biomechanical variables included plantar pressure parameters and joint kinetics and kinematics during gait, as well as toes and hallux strength. Toes and hallux isometric muscle strength were measured orthostatically by a pressure plate (emed q-100; Novel GmbH, Munich, Germany), following the protocol of [PERSON] et al. (2008) [38]. The toes and hallux maximum force (N) was normalized by the participant's body weight and analyzed using a standard mask from novel Multimask software v.9.35 (Novel GmbH). Contact area, pressure-time integral, and peak pressure were collected by the pressure plate at 100 Hz. The participants were asked to walk barefoot three times over the platform at a comfortable speed. Seven plantar areas (heel, midfoot, medial forefoot, central forefoot, lateral forefoot,hallux, and toes) were assessed by a geometrical mask using the novel Multimask software v.9.35 (Novel GmbH, Munich, Germany) [39].  
Hip, knee, and foot-ankle kinematics and kinetics during gait were also secondary outcomes. We used 42 reflective markers (diameter = 9.5 mm) placed on both lower limbs of the participant following the Plug-In Gait and Oxford Foot Model [40] setup protocols and were tracked by 8 infrared cameras at 100 Hz (VERO; Vicon Motion System Ltd., Oxford, UK). To calculate the net joint moments, we acquire ground reaction forces by a force platform (AMTI OR-6-1000) at 1 kHz. Kinematic and ground reaction force data were sampled and synchronized by an A/D board (192 kHz, 24 bits; Lock Control Box; Vicon Motion System Ltd.). Participants walked barefoot five times over the force platform at a self-selected speed. Gait speed was checked between assessments (baseline, 8 weeks, and 16 weeks) by two photo cells (Model Speed Test Fit; Cefise, Nova Odessa, Brazil) in order to make sure it stayed the same throughout the study assessments.  
Force data were processed using a zero-lag low-pass Butterworth fourth-order filter with cutoff frequency of 50 Hz. Gait kinematics data were processed using a zero-lag second-order low-pass filter with cutoff frequency of 6 Hz. The net moments of the ankle, knee, and hip in the sagittal plane were calculated using the bottom-up inverse dynamics method. Gait kinematics (angles) and kinetics (joint moments and power) variables were calculated with the open-source Python package pyCGM2 (www.pycgm2.github.io, accessed on 28 December 2022) (Python Software Foundation, USA) using the Vicon Plug-In Gait protocol and Oxford Foot Model.