Article

Time to stabilization (TTS) is the time it takes for an individual to return to a
baseline or stable state following a jump or hop landing. A large variety exists
in methods to calculate the TTS. These methods can be described based on four
aspects: (1) the input signal used (vertical, anteroposterior, or mediolateral
ground reaction force) (2) signal processing (smoothed by sequential averaging, a
moving root-mean-square window, or fitting an unbounded third order polynomial),
(3) the stable state (threshold), and (4) the definition of when the (processed)
signal is considered stable. Furthermore, differences exist with regard to the
sample rate, filter settings and trial length. Twenty-five healthy volunteers
performed ten 'single leg drop jump landing' trials. For each trial, TTS was
calculated according to 18 previously reported methods. Additionally, the effects
of sample rate (1000, 500, 200 and 100 samples/s), filter settings (no filter,
40, 15 and 10 Hz), and trial length (20, 14, 10, 7, 5 and 3s) were assessed. The
TTS values varied considerably across the calculation methods. The maximum effect
of alterations in the processing settings, averaged over calculation methods,
were 2.8% (SD 3.3%) for sample rate, 8.8% (SD 7.7%) for filter settings, and
100.5% (SD 100.9%) for trial length. Differences in TTS calculation methods are
affected differently by sample rate, filter settings and trial length. The
effects of differences in sample rate and filter settings are generally small,
while trial length has a large effect on TTS values.
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Langue : ANGLAIS