Feasibility of Force-Sensing Insoles for Measuring Lower Limb Loading in Older Adults With Obesity

Research Objectives: To determine the feasibility of using force-sensing insoles to measure lower limb loading in older adults living with obesity enrolled in a clinical weight loss program.

Design: Ancillary study to the Incorporating Nutrition, Vests, Education and Strength Training (INVEST) randomized controlled trial. Bilateral lower limb loading was measured using force-sensing insoles (Loadsol, Novel) at baseline and 6-month follow up while participants walked for 2-minutes at their usual speed for three trials. At follow-up, participants completed a satisfaction survey. Limb loading outcomes included peak force, loading rate, total cumulative force, and step time.

Setting: Wake Forest University research laboratory.

Participants: 44 overweight or obese participants [age: 67 (5.1) years; sex: 11 males; BMI: 33.7 (3.1) kg/m2] 60-85 years old completed baseline testing. Thirty-seven completed follow-up.

Interventions: Intentional weight loss (WL) plus weighted vest wear, WL plus resistance training, or WL alone. Assessors were blinded to participant groups.

Main Outcome Measures: Feasibility was defined as: 1) ≥80% usable data at baseline and follow-up visits; 2) ≥80% satisfaction from participant surveys; and 3) ≤15 minutes to collect and analyze data per participant.

Results: All limb loading data was found to be usable. At baseline across all participants, average (standard deviation) peak force was 1.07 (0.04) N/kg, loading rate was 0.07 (0.02) N/s/kg, total cumulative force was 17.5 kN*s/kg, and step time was 0.74 (0.04) secs.
At follow up, peak force was 1.12 (0.04) N/kg, loading rate was 0.08 (0.02) N/s/kg, total cumulative force was 17.2 kN*s/kg, and step time was 0.71 (0.05) secs. Average satisfaction was 80% (6.3%). All data collection was completed in under 10 minutes, and data analysis was completed in under 5 minutes per participant.

Conclusions: Force-sensing insoles appear to be feasible to measure limb loading in the lab within a clinical research trial.

Author(s) Disclosures: This work was supported by the National Institute on Aging (Grant No. R01 AG059186 & P30 AG021332). Jason Pharmaceuticals, a wholly owned subsidiary of Medifast, Inc. made an in-kind product donation for the meal replacements used in this study.