Table 1.
Studies involving automatic activity recognition in youth from accelerometers
| De Vries (9) | Ruch et al. (23) | Trost et al. (28) | Hikihara et al. (13) | Del Rosario et al. (10) | Nam and Park (19) | Trost et al. (29) | Hagenbuchner et al (12) | This study | |
|---|---|---|---|---|---|---|---|---|---|
| Year | 2011 | 2011 | 2012 | 2014 | 2014 | 2013 | 2014 | 2015 | |
| Number of participants | 58 | 41 | 100 | 68 | 37 elderly, E 20 young adults, YA | 10 | 52 | 11 | 33 adults. A 20 youth, Y |
| Age of participants | 9 to 12 | 10.8 ± 1.3 (mean ± std dev.) | 5 to 15 (11.0 ± 2.7) | 6 to 12 | E: 83.9 ± 3.4 YA: 21.9 ± 1.7 | toddlers: 1.3 to 2.4 | 13.7 ± 3.1 | Pre-school: 4.8 ± 0.87 | A: 18 to 75 Y: 11 to 15 |
| Classes | 7 classes: sitting, standing, walking, running, rope skipping, playing soccer, and cycling | 10 classes: biking, crawling, walking, scooter, horseback riding, jumping and floor exercise | 12 activities merged to 5 classes: sedentary, walking, running, light intensity household activities or games, moderate-to-vigorous intensity games or sports | 11 activities merged to 2 classes: non-locomotive, locomotive | 9 classes: stand, sit, lie, walk, walk upstairs, walk downstairs | 11 classes: wiggling, rolling, standing still, standing up, sitting down, walking, toddling, crawling, climbing up / down and stopping | 12 activities merged to 7 classes: lying down, sitting, standing, walking, running, basketball, dancing | 12 activities merged to 5 classes: sedentary activities, light activities, moderate to vigorous activities, walking, and running | 23 activities for youth and 26 for adults merged to 4 classes: sedentary, ambulation, cycling and others |
| Sensor site | ankle or hip | hip and wrist | hip | waist | smartphone in truosers pocket | waist (diaper) | wrist or hip | hip | ankle or wrist |
| Raw data vs activity counts | AC | AC | AC | custom counts from acc. data (32 Hz) | Raw acc. and gyr. (100 Hz), barometer (10 Hz) | Raw acc. and barometer (95 Hz) | Raw acc. (30 Hz) | AC | Raw acc. (90 Hz) |
| AC epoch | 1 s | 1 s | 1 s | 10 s | n.a. | n.a. | n.a. | 1 s | n.a. |
| Windowing approach | 10 s, non overlapping | 1 s | 10 s to 60 s tested | 10 s | 2.5 s 50% overlapping | 2.7 s, 50% overlapping | 10 s | 10, 30 or 60 s, non overlapping | 12.8 s non overlapping |
| Acquired data (minutes) | 20 per subject (tot. 1160) | 438 on average per participant | 5 per activity acquired (tot. 6000) | 3-7 per activity (tot. 2244-5236) | 10-15 per subject for the young adults and 30 for elderly (tot. 1310-1410) | 3000 | 5 per activity acquired (tot. 3120) | 4-5 per activity per participant (tot. 528-660) | 3-5 per activity: Yankle 1848 Ywrist 1809 A ankle2976 A wrist 2917 |
| Classified data (minutes) | not disclosed | 108 | 2 per activity used (tot. 2400) | not disclosed | YA: 189, E: 683 | not disclosed | 2 per activity used (tot. 1248) | 264 | Yankle 1257 Ywrist 1248 A ankle1609 A wrist 1633 |
| Features | time domain | time domain | time domain | time domain | time domain | time and frequency domain | time domain | time domain | time and frequency domain |
| Classifier | ANN | kNN + DT + NDTF + voting | ANN | threshold | decision tree | NB, SVM, kNN, DT, ANN | logistic regression | ANN or deep learning network | SVM |
| Validation approach | LOSO | split in two subset with half participants each | subjects were split into three groups: one for training one for validation and one for testing. 10 random splits tested. | split in two subset (48 participants for training, 20 participants for testing) | LOSO | 10-fold cross validation | subjects were split in three groups: one for training one for validation and one for testing. 10 random splits tested. | LOSO | LOSO |
| Accuracy | ankle: 68.0% hip: 77.0% | 67.0 % | 88.4 % | 99,10% | E: 82,0% YA: 79.9% | Acc. only: 88.3% (DT) acc.+ barometer: 98.4% (SVM) | hip: 91.0 ± 3.1% wrist: 88.4 ± 3.0% | ANN: 69.7% DLN: 82.6% | Yankle: 92.4% Ywrist: 90.7% A ankle: 94.5% A wrist: 86.9% |