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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]
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