Skip to main content

Table 2 Absolute and relative sensors kinematics accuracy assessed on multiple segments and Joints during different tasks

From: Inertial measurement systems for segments and joints kinematics assessment: towards an understanding of the variations in sensors accuracy

STS (n = 120) Walk (n = 240) Turn (n = 120)
RMSD Errpeak CMC RMSD Errpeak CMC RMSD Errpeak CMC
Absolute sensor kinematics  
 Head
  4.0° [2.3°–6.8°] 8.0° [5.3°–13.6°] 0.900 [0.740–0.966] 3.7° [2.2°–5.5°] 8.9° [5.6°–12.7°] 0.819 [0.778–0.879] 4.4° [2.9°–5.7°] 6.8° [5.0°–9.2°] 0.998 [0.998–0.999]
 Upper Trunk
  1.5° [1.1°–2.1°] 3.7° [2.5°–4.9°] 0.996 [0.992–0.997] 2.9° [1.8°–4.4°] 6.8° [4.5°–9.6°] 0.853 [0.779–0.897] 3.1° [1.6°–4.7°] 5.6° [3.4°–8.9°] 0.999 [0.998–1.000]
 Pelvis
  1.0° [0.8 ° –1.5°] 2.9° [2.1°–4.1°] 0.997 [0.988–0.999] 2.2° [1.4°–3.6°] 5.1° [3.6°–8.4°] 0.842 [0.646–0.946] 1.7° [1.4°–2.9°] 4.0° [3.0°–6.4°] 1.000 [0.998–1.000]
 Thigh
  0.9° [0.7°–1.4°] 2.4° [1.8°–3.2°] 0.999 [0.997–1.0] 1.6° [1.1°–3.0°] 4.4° [3.2°–7.7°] 0.981 [0.918–0.991] 1.3° [0.8°–1.9°] 3.3° [2.4°–4.9°] 1.000 [1.000–1.000]
 Shank
  1.3° [0.9°–1.7°] 3.2° [2.5°–4.4°] 0.983 [0.974–0.989] 2.4° [1.7°–3.2°] 5.6° [4.0°–7.7°] 0.990 [0.987–0.994] 2.4° [1.7°–2.9°] 4.9° [3.8°–6.6°] 1.000 [0.999–1.000]
 Foot
  1.1° [0.6°–2.3°] 2.9° [1.6°–5.7°] 0.935 [0.629–0.986] 2.1° [1.4°–3.2°] 5.7° [4.0°–8.6°] 0.996 [0.967–0.997] 1.7° [1.1°–2.8°] 4.5° [3.2°–8.3°] 1.000 [0.999–1.000]
 Global
1.3° [0.9°–2.2°] 3.3° [2.2°–5.5°] 2.4° [1.5°–3.9°] 5.8° [3.9°–9.2°] 2.2° [1.4°–3.8°] 4.8° [3.3°–7.5°]
Relative sensor kinematics
 Trunk
  2.8° [1.9°–4.4°] 6.4° [4.1°–9.7°] 0.808 [0.744–0.891] 3.5° [2.3°–5.6°] 8.5° [6.1°–12.9°] 0.501 [0.343–0.741] 4.1° [2.6°–6.2°] 8.4° [6.4°–11.8°] 0.598 [0.470–0.663]
 Hip
  1.5° [1.1°–2.2°] 3.7° [2.9°–5.0°] 0.997 [0.992–0.998] 2.7° [1.8°–4.4°] 7.1° [5.1°–10.2°] 0.951 [0.910–0.975] 3.4° [2.4°–5.4°] 8.3° [6.0°–11.8°] 0.926 [0.861–0.954]
 Knee
  1.4° [1.0°–2.0°] 3.6° [2.8°–4.7°] 0.999 [0.998–0.999] 3.3° [2.5°–4.5°] 8.4° [6.3°–11.2°] 0.982 [0.974–0.988] 3.9° [2.3°–5.4°] 8.1° [5.7°–12.1°] 0.981 [0.965–0.986]
 Ankle
  2.5° [1.5°–4.0°] 6.3° [4.1°–10.6°] 0.881 [0.623–0.928] 7.8° [5.7°–11.3°] 20.6° [15.3°–30.4°] 0.712 [0.643–0.772] 9.4° [6.5°–16.6°] 23.5° [16.7°–37.0°] 0.517 [0.219–0.678]
 Global
  1.9° [1.3°–3.1°] 4.5° [3.3°–7.4°] 3.9° [2.5°–6.7°] 9.7° [6.4°–16.5°] 4.6° [2.8°–7.7°] 10.4° [6.7°–18.6°]
  1. RMSD root mean squared difference, median [IQR]; Err peak peak error, median [IQR]; CMC coefficient of multiple correlation, median [IQR]