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Table 2 Aggregate simulation results during stabilization against postural disturbances for 5 muscle excitation test cases

From: Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation

  CONST:OPT CONST: MAX JT Control ACC Control JT + ACC Control
Mean muscle excitation level 0.521 0.908 0.623 0.564 0.664
PERFORMANCE RESULTS: MEAN UPPER EXTREMITY LOADING (Newtons)
Perturbation Direction
Forward 66 47 19 (-60%) 27 (-44%) 18 (-62%)
Backward 32 22 17 (-23%) 25 (+14%) 17 (-23%)
Side (Left or Right) 51 36 16 (-54%) 14 (-61%) 13 (-63%)
Perturbation Location (Segment)
Thorax 61 48 31 (-35%) 34 (-27%) 30 (-36%)
Pelvis 58 41 22 (-47%) 20 (-49%) 19 (-53%)
Thigh (Left or Right) 52 35 16 (-54%) 19 (-44%) 14 (-61%)
Shank (Left or Right) 39 22 6 (-72%) 8 (-63%) 5 (-77%)
Total Body COM 70 52 27 (-48%) 31 (-40%) 23 (-55%)
Support Conditions
Two-Arm Support 32 28 19 (-32%) 20 (-29%) 17 (-39%)
One-Arm Support 73 44 16 (-64%) 21 (-52%) 15 (-66%)
One-arm FTP* 11 11 3 (-70%) 7 (-39%) 3 (-71%)
Overall Upper Extremity Loading (N)** 52.7 ± 25 35.9 ± 8 17.6 ± 3 (-51%) 20.7 ± 6 (-43%) 15.3 ± 3 (-56%)
KINEMATICS RESULTS (During One-Arm Support)
COM Position (cm) 7.3 ± 5.6 4.5 ± 1.3 1.8 ± 0.4 3.4 ± 1.6 1.8 ± 0.4
COM Acceleration (cm/sec2) 37 ± 15 21 ± 4 25 ± 4 20 ± 4 24 ± 4
Joint Position Error (deg) 1.3 ± 0.9 0.83 ± 0.2 0.27 ± 0.05 0.55 ± 0.2 0.25 ± 0.04
Joint Velocity Error (deg/sec) 3.0 ± 1.0 2.0 ± 0.6 1.2 ± 0.1 2.1 ± 0.7 1.3 ± 0.2
  1. CONST: OPT = Constant Muscle Excitations, Optimal Levels; CONST: MAX = Constant Muscle Excitations, Maximal Levels; JT = Joint Feedback Control of Excitation Levels; ACC = Center of Mass Acceleration Feedback Control of Excitation Levels; JT + ACC = Combined Feedback Control of Excitation Levels.
  2. Notes: (X%) = %Change from CONST:MAX case.
  3. *Mean UE loading calculated for zeroed RMS only during “steady-state” portion of FTP.
  4. **Overall values based on average of UE loading against discrete perturbations across two-arm and one-arm support conditions (i.e., does not include FTP) taken to additional significant digit.