Modulation of vertical ground reaction impulse with real-time biofeedback: A feasibility study

Pawel R. Golyski, Elizabeth M. Bell, Elizabeth M. Husson, Erik J. Wolf, Brad D. Hendershot*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Given its apparent representation of cumulative (vs peak) loads, this feasibility study investigates vertical ground reaction impulse (vGRI) as a real-time biofeedback variable for gait training aimed at reducing lower limb loading. Fifteen uninjured participants (mean age = 27 y) completed 12 2-min trials, 1 at each combination of 4 walking speeds (1.0, 1.2, 1.4, and 1.6 m/s) and 3 targeted reductions in vGRI (5, 10, and 15%) of the assigned (“target”) limb, with the latter specified relative to an initial baseline (no feedback) condition at each speed. The ability to achieve targeted reductions was assessed using step-by-step errors between measured and targeted vGRI. Mean (SD) errors were 5.2% (3.7%); these were larger with faster walking speeds but consistent across reduction targets. Secondarily, we evaluated the strategy used to modulate reductions (ie, stance time or peak vertical ground reaction force [vGRF]) and the resultant influences on knee joint loading (external knee adduction moment [EKAM]). On the targeted limb, stance times decreased (P < .001) with increasing reduction target; first and second peaks in vGRF were similar (P > .104) across all target conditions. While these alterations did not significantly reduce EKAM on the target limb, future work in patients with knee pathologies is warranted.

Original languageEnglish
Pages (from-to)134-140
Number of pages7
JournalJournal of Applied Biomechanics
Issue number2
StatePublished - Apr 2018
Externally publishedYes


  • Biomechanics
  • Gait training
  • Knee
  • Rehabilitation


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