Rate of force development

Computes sequential interval RFD from contraction onset and the maximum moving-window slope. RFD is expressed in N m/s.

Usage

rateOfForceDevelopment(
  torque,
  sampling_rate,
  onset = NULL,
  onset_method = c("absolute", "sd"),
  onset_threshold = 7.5,
  baseline_ms = 100,
  baseline_sd_k = 5,
  windows_ms = c(50, 100, 200),
  peak_window_ms = 20
)

Arguments

torque

Numeric torque trace in N m.

sampling_rate

Sampling rate in Hz.

onset

Optional 1-based integer onset sample. When NULL, onset is detected from the baseline.

onset_method

Either a fixed "absolute" increase above baseline or a baseline "sd" rule.

onset_threshold

Absolute onset threshold in N m above baseline.

baseline_ms

Baseline duration in milliseconds.

baseline_sd_k

Number of baseline SDs used by the "sd" method.

windows_ms

Positive interval widths in milliseconds.

peak_window_ms

Positive moving-window width in milliseconds.

Value

An rfd object containing onset details, interval RFD values, and peak moving-window RFD.

References

Aagaard P, Simonsen EB, Andersen JL, Magnusson P, Dyhre-Poulsen P (2002). Increased rate of force development and neural drive of human skeletal muscle following resistance training. Journal of Applied Physiology, 93:1318-1326. doi:10.1152/japplphysiol.00283.2002

Maffiuletti NA, Aagaard P, Blazevich AJ, Folland J, Tillin N, Duchateau J (2016). Rate of force development: physiological and methodological considerations. European Journal of Applied Physiology, 116:1091-1116. doi:10.1007/s00421-016-3346-6

Examples

torque <- c(rep(0, 100), seq(0.4, 120, by = 0.4), rep(120, 100))
rateOfForceDevelopment(torque, sampling_rate = 1000, onset_method = "sd")
#> <rfd> onset 0.100 s (sample 101)
#>   0-50 ms: 400.000 N m/s
#>   0-100 ms: 400.000 N m/s
#>   0-200 ms: 400.000 N m/s
#>   peak (20 ms): 400.000 N m/s