{'fraction_non_alphanumeric': 0.03098106712564544, 'fraction_numerical': 0.01721170395869191, 'mean_word_length': 5.025906735751295, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Construct validity of RT3 accelerometer: a comparison of level-ground and treadmill walking at self-selected speeds.

This study examined differences in accelerometer output when subjects walked on level ground and on a treadmill. We asked 25 nondisabled participants to wear an RT3 triaxial accelerometer (StayHealthy, Inc; Monrovia, California) and walk at their "normal" and "brisk" walking speeds for 10 minutes. These activities were repeated on a treadmill using the individual speeds from level-ground walking on two occasions 1 week apart. Paired t-tests found a difference in RT3 accelerometer vector magnitude (VM) counts/min between the two walking speeds on both surfaces on days 1 and 2 (p < 0.001). Although we found no significant differences between VM counts/min on the two surfaces at normal and brisk speeds on days 1 and 2 (p > 0.05), we found wide limits of agreement between level ground and treadmill walking at both speeds. Measurement and discrimination of walking intensity employing RT3 accelerometer VM counts/min on the treadmill demonstrated reasonable validity and stability over two time points compared with level-ground walking.