Title:	Tools for Analyzing Lactate Thresholds
Version:	0.2.0
Description:	Set of tools for analyzing lactate thresholds from a step incremental test to exhaustion. Easily analyze the methods Log-log, Onset of Blood Lactate Accumulation (OBLA), Baseline plus (Bsln+), Dmax, Lactate Turning Point (LTP), and Lactate / Intensity ratio (LTratio) in cycling, running, or swimming. Beaver WL, Wasserman K, Whipp BJ (1985) <doi:10.1152/jappl.1985.59.6.1936>. Heck H, Mader A, Hess G, Mücke S, Müller R, Hollmann W (1985) <doi:10.1055/s-2008-1025824>. Kindermann W, Simon G, Keul J (1979) <doi:10.1007/BF00421101>. Skinner JS, Mclellan TH (1980) <doi:10.1080/02701367.1980.10609285>. Berg A, Jakob E, Lehmann M, Dickhuth HH, Huber G, Keul J (1990) PMID 2408033. Zoladz JA, Rademaker AC, Sargeant AJ (1995) <doi:10.1113/jphysiol.1995.sp020959>. Cheng B, Kuipers H, Snyder A, Keizer H, Jeukendrup A, Hesselink M (1992) <doi:10.1055/s-2007-1021309>. Bishop D, Jenkins DG, Mackinnon LT (1998) <doi:10.1097/00005768-199808000-00014>. Hughson RL, Weisiger KH, Swanson GD (1987) <doi:10.1152/jappl.1987.62.5.1975>. Jamnick NA, Botella J, Pyne DB, Bishop DJ (2018) <doi:10.1371/journal.pone.0199794>. Hofmann P, Tschakert G (2017) <doi:10.3389/fphys.2017.00337>. Hofmann P, Pokan R, von Duvillard SP, Seibert FJ, Zweiker R, Schmid P (1997) <doi:10.1097/00005768-199706000-00005>. Pokan R, Hofmann P, Von Duvillard SP, et al. (1997) <doi:10.1097/00005768-199708000-00009>. Dickhuth H-H, Yin L, Niess A, et al. (1999) <doi:10.1055/s-2007-971105>.
License:	MIT + file LICENSE
Encoding:	UTF-8
LazyData:	true
RoxygenNote:	7.2.3
Suggests:	bsplus, covr, datapasta, glue, knitr, miniUI, rhandsontable, rmarkdown, shiny, shinyjs, shinyWidgets, spelling, testthat (≥ 3.0.0)
Imports:	magrittr, broom, dplyr, ggplot2, ggtext, patchwork, lubridate, minpack.lm, pracma, rlang, segmented, stringr, tidyr, forcats
Depends:	R (≥ 2.10)
Language:	en-US
Config/testthat/edition:	3
NeedsCompilation:	no
Packaged:	2023-11-16 13:40:44 UTC; fmattioni
Author:	Felipe Mattioni Maturana [aut, cre]
Maintainer:	Felipe Mattioni Maturana <felipe.mattioni@med.uni-tuebingen.de>
Repository:	CRAN
Date/Publication:	2023-11-16 15:40:02 UTC

lactater: Tools for Analyzing Lactate Thresholds

Description

Set of tools for analyzing lactate thresholds from a step incremental test to exhaustion. Easily analyze the methods Log-log, Onset of Blood Lactate Accumulation (OBLA), Baseline plus (Bsln+), Dmax, Lactate Turning Point (LTP), and Lactate / Intensity ratio (LTratio) in cycling, running, or swimming. Beaver WL, Wasserman K, Whipp BJ (1985) doi:10.1152/jappl.1985.59.6.1936. Heck H, Mader A, Hess G, Mücke S, Müller R, Hollmann W (1985) doi:10.1055/s-2008-1025824. Kindermann W, Simon G, Keul J (1979) doi:10.1007/BF00421101. Skinner JS, Mclellan TH (1980) doi:10.1080/02701367.1980.10609285. Berg A, Jakob E, Lehmann M, Dickhuth HH, Huber G, Keul J (1990) PMID 2408033. Zoladz JA, Rademaker AC, Sargeant AJ (1995) doi:10.1113/jphysiol.1995.sp020959. Cheng B, Kuipers H, Snyder A, Keizer H, Jeukendrup A, Hesselink M (1992) doi:10.1055/s-2007-1021309. Bishop D, Jenkins DG, Mackinnon LT (1998) doi:10.1097/00005768-199808000-00014. Hughson RL, Weisiger KH, Swanson GD (1987) doi:10.1152/jappl.1987.62.5.1975. Jamnick NA, Botella J, Pyne DB, Bishop DJ (2018) doi:10.1371/journal.pone.0199794. Hofmann P, Tschakert G (2017) doi:10.3389/fphys.2017.00337. Hofmann P, Pokan R, von Duvillard SP, Seibert FJ, Zweiker R, Schmid P (1997) doi:10.1097/00005768-199706000-00005. Pokan R, Hofmann P, Von Duvillard SP, et al. (1997) doi:10.1097/00005768-199708000-00009. Dickhuth H-H, Yin L, Niess A, et al. (1999) doi:10.1055/s-2007-971105.

Author(s)

Maintainer: Felipe Mattioni Maturana felipe.mattioni@med.uni-tuebingen.de (ORCID)

Pipe operator

Description

See magrittr::%>% for details.

Usage

lhs %>% rhs

Add external resources

Description

This function was copied from golem

Usage

add_external_resources()

Adjust x-axis

Description

Adjusts the x-axis to show rest value at the beginning. Internal use only.

Usage

adjust_x_axis_plot(.data, plot)

Arguments

Bsln+ helper

Description

For internal use only and it won't be exported.

Usage

bsln_plus_helper(.data, data_augmented, fit, model, plus)

Arguments

Value

The results (intensity, lactate, heart rate) from the lactate threshold method.

Convert m/s to s/100m

Description

It converts speed, in m/s, to pace, in s/100m.

Usage

convert_to_pace(speed)

Arguments

Value

the converted pace

Demo data

Description

A dataset containing the lactate and heart rate data collected from a step-incremental test as an example

Usage

demo_data

Format

A data frame with 8 rows and 5 variables:

step

the number of the step, starting at zero for the baseline.

length

the length of each step.

intensity

the intensity performed on each step (in this case in watts).

lactate

the blood lactate concentration.

heart_rate

the heart rate associated with that step.

Produce data protocol skeleton

Description

This is an internal function used in run_data_input().

Usage

helper_data_protocol(
  input_steps,
  input_length_steps,
  input_starting_load,
  input_step_increase,
  input_heart_rate_data,
  input_completed,
  input_last_length_step,
  sport
)

Arguments

Helper - Dmax

Description

For internal use only and it won't be exported.

Usage

helper_dmax_dmax(data_prepared, sport, plot)

Arguments

Helper - Exp-Dmax

Description

For internal use only and it won't be exported.

Usage

helper_dmax_exp_dmax(data_prepared, sport, plot)

Arguments

Helper - Log-Exp-ModDmax

Description

For internal use only and it won't be exported.

Usage

helper_dmax_log_exp_moddmax(data_prepared, sport, loglog_restrainer, plot)

Arguments

Helper - Log-Poly-ModDmax

Description

For internal use only and it won't be exported.

Usage

helper_dmax_log_poly_moddmax(data_prepared, sport, loglog_restrainer, plot)

Arguments

Helper - ModDmax

Description

For internal use only and it won't be exported.

Usage

helper_dmax_moddmax(data_prepared, sport, plot)

Arguments

Calculate length of last step

Description

For internal use only.

Usage

helper_last_length_step(last_length_step)

Arguments

Render table for data input

Description

For internal use only.

Usage

helper_render_table(.data, sport)

Arguments

Interpolate intensity

Description

Interpolate intensity

Usage

interpolate_intensity(.data, interpolation_factor)

Arguments

Check if all suggested packages are installed

Description

Check if all suggested packages are installed

Usage

is_installed()

Value

a boolean

Lactate curve

Description

It retrieves the lactate curve for plotting purposes.

Usage

lactate_curve(
  .data,
  intensity_column,
  lactate_column,
  heart_rate_column,
  fit = c("3rd degree polynomial", "4th degree polynomial", "B-spline"),
  include_baseline = FALSE,
  sport = c("cycling", "running", "swimming")
)

Arguments

Value

a list with the following elements:

Examples

## Not run: 
lactate_curve(
  .data = demo_data,
  intensity_column = "intensity",
  lactate_column = "lactate",
  heart_rate_column = "heart_rate",
  fit = "3rd degree polynomial",
  include_baseline = TRUE,
  sport = "cycling"
)

## End(Not run)

Lactate threshold

Description

This is a general function that applies several lactate threshold methods at the same time.

Usage

lactate_threshold(
  .data,
  intensity_column,
  lactate_column,
  heart_rate_column,
  method = c("Log-log", "OBLA", "Bsln+", "Dmax", "LTP", "LTratio"),
  fit = c("3rd degree polynomial", "4th degree polynomial", "B-spline"),
  include_baseline = FALSE,
  sport = c("cycling", "running", "swimming"),
  loglog_restrainer = 1,
  plot = TRUE
)

Arguments

Details

Log-log

The lactate response (i.e., log of lactate vs intensity) is divided into two segments. A segmented regression is then performed such that the lactate curve would present one breaking point. The exercise intensity at which the breaking point occurs is then considered as Log-log (Beaver et al., 1985). Caution: this method might require a double-check via a visual inspection, depending in some cases.

OBLA

The Onset of Blood Lactate Accumulation (OBLA) is the exercise intensity at fixed lactate of 2.0, 2.5, 3.0, 3.5, and 4.0 mmol/L (Heck et al., 1985, Kindermann et al., 1979; Skinner & Mclellan, 1980). The lactate curve is usually fitted using a 3rd order polynomial regression curve, but the user can define another method (4th degree polynomial or B-spline).

Bsln+

In the baseline plus method (Bsln+), the exercise intensity at which lactate increases to 0.5, 1.0, and 1.5 mmol/L above baseline (resting) values is considered (Berg et al., 1990; Zoladz et al., 1995). The lactate curve is usually fitted using a 3rd order polynomial regression curve, but the user can define another method (4th degree polynomial or B-spline).

Dmax

Dmax

The exercise intensity that yields the maximum perpendicular distance to the straight line between the first and the last data point (Cheng et al., 1992). The lactate curve is fitted using a 3rd order polynomial regression curve, and it can't be changed.

Modified Dmax (ModDmax)

The exercise intensity that yields the maximum perpendicular distance to the straight line between data point preceding the first rise in lactate greater than 0.4 mmol/L and the last data point (Bishop et al., 1998). The lactate curve is fitted using a 3rd order polynomial regression curve, and it can't be changed.

Exponential Dmax (Exp-Dmax)

The exercise intensity on the exponential plus-constant regression lactate curve that yields the maximum perpendicular distance to the straight line between the first and the last data point (Hughson et al., 1987). The lactate curve is fitted using an exponential curve, and it can't be changed.

Log-log modified Dmax (Log-Poly-ModDmax)

The exercise intensity that yields the maximum perpendicular distance to the straight line between Log-log and the last data point in the 3rd order polynomial regression curve (Jamnick et al., 2018). The lactate curve is fitted using a 3rd order polynomial regression curve, and it can't be changed.

Log-log exponential Dmax (Log-Exp-ModDmax)

The exercise intensity that yields the maximum perpendicular distance to the straight line between Log-log and the last data point in the exponential curve (Jamnick et al., 2018). The lactate curve is fitted using an exponential curve, and it can't be changed.

LTP

Lactate Turning Point 1 (LTP1) and Lactate Turning Point 2 (LTP2)

the lactate response is divided into three segments. A segmented regression is performed such that the lactate curve yields two breaking points. The first breaking point, representing the first rise in lactate above resting levels, is considered as LTP1. The second breaking point, representing an accelerated lactate accumulation, is then considered as LTP2 (Hofmann & Tschakert, 2017; Hofmann et al., 1997; Pokan et al., 1997). Caution: this method might require a double-check via a visual inspection, depending in some cases.

LTratio

The lactate response (i.e., ratio of lactate / exercise intensity vs exercise intensity) is interpolated using a B-spline regression curve. LTratio is then defined as the lowest value of the lactate / exercise intensity ratio, which attempts to describe the onset of the lactate increase (Dickhuth et al., 1999).

Value

a tibble with the following columns:

References

Beaver WL, Wasserman K, Whipp BJ. Improved detection of lactate threshold during exercise using a log-log transformation. Journal of Applied Physiology. 1985;59(6):1936–40.

Heck H, Mader A, Hess G, Mücke S, Müller R, Hollmann W. Justification of the 4-mmol/l Lactate Threshold. International Journal of Sports Medicine. 1985;06(03):117–30.

Kindermann W, Simon G, Keul J. The significance of the aerobic-anaerobic transition for the determination of work load intensities during endurance training. European Journal of Applied Physiology and Occupational Physiology. 1979;42(1):25–34.

Skinner JS, Mclellan TH. The Transition from Aerobic to Anaerobic Metabolism. Research Quarterly for Exercise and Sport. 1980;51(1):234–48.

Berg A, Jakob E, Lehmann M, Dickhuth HH, Huber G, Keul J. Current aspects of modern ergometry. Pneumologie. 1990;44(1):2–13.

Zoladz JA, Rademaker AC, Sargeant AJ. Non-linear relationship between O2 uptake and power output at high intensities of exercise in humans. The Journal of Physiology. 1995;488(1):211–7.

Cheng B, Kuipers H, Snyder A, Keizer H, Jeukendrup A, Hesselink M. A New Approach for the Determination of Ventilatory and Lactate Thresholds. International Journal of Sports Medicine. 1992;13(07):518–22.

Bishop D, Jenkins DG, Mackinnon LT. The relationship between plasma lactate parameters, Wpeak and 1-h cycling performance in women. Med Sci Sports Exerc. 1998;30(8):1270–5.

Hughson RL, Weisiger KH, Swanson GD. Blood lactate concentration increases as a continuous function in progressive exercise. Journal of Applied Physiology. 1987;62(5):1975–81.

Jamnick NA, Botella J, Pyne DB, Bishop DJ. Manipulating graded exercise test variables affects the validity of the lactate threshold and VO2peak. PLOS ONE. 2018;13(7):e0199794.

Hofmann P, Tschakert G. Intensity- and Duration-Based Options to Regulate Endurance Training. Front Physiol. 2017;8:337.

Hofmann P, Pokan R, von Duvillard SP, Seibert FJ, Zweiker R, Schmid P. Heart rate performance curve during incremental cycle ergometer exercise in healthy young male subjects. Med Sci Sports Exerc. 1997;29(6):762–8.

Pokan R, Hofmann P, Von Duvillard SP, et al. Left ventricular function in response to the transition from aerobic to anaerobic metabolism. Med Sci Sports Exerc. 1997;29(8):1040–7.

Dickhuth H-H, Yin L, Niess A, et al. Ventilatory, Lactate-Derived and Catecholamine Thresholds During Incremental Treadmill Running: Relationship and Reproducibility. International Journal of Sports Medicine. 1999;20(02):122–7.

Examples

## Not run: 
lactate_threshold(
  .data = demo_data,
  intensity_column = "intensity",
  lactate_column = "lactate",
  heart_rate_column = "heart_rate",
  fit = "3rd degree polynomial",
  include_baseline = TRUE,
  sport = "cycling",
  loglog_restrainer = 1,
  plot = TRUE
)

## End(Not run)

Bsln+

Description

It applies the ⁠Bsln+⁠ methods: ⁠Bsln+ 0.5 mmol/L⁠, ⁠Bsln+ 1.0 mmol/L⁠, and ⁠Bsln+ 1.5 mmol/L⁠.

Usage

method_bsln_plus(data_prepared, fit, sport, plot)

Arguments

Value

a tibble with the following columns:

Dmax

Description

It applies the Dmax methods: "Dmax", "ModDmax", "Exp-Dmax", "Log-Poly-ModDmax", and "Log-Exp-ModDmax".

Usage

method_dmax(data_prepared, sport, loglog_restrainer = 1, plot)

Arguments

Value

a tibble with the following columns:

Log-log

Description

It applies the Log-log method.

Usage

method_loglog(data_prepared, fit, sport, loglog_restrainer = 1, plot)

Arguments

Value

a tibble with the following columns:

Lactate Turning Point (LTP)

Description

It applies the LTP methods: LTP1, and LTP2.

Usage

method_ltp(data_prepared, fit, sport, plot)

Arguments

Value

a tibble with the following columns:

Minimum Lactate-Intensity Ratio (LTratio)

Description

It applies the LTratio method.

Usage

method_ltratio(data_prepared, fit, sport, plot)

Arguments

Value

a tibble with the following columns:

Onset of Blood Lactate Accumulation (OBLA)

Description

It applies the OBLA methods: ⁠OBLA 2.0 mmol/L⁠, ⁠OBLA 2.5 mmol/L⁠, ⁠OBLA 3.0 mmol/L⁠, ⁠OBLA 3.5 mmol/L⁠, and ⁠OBLA 4.0 mmol/L⁠.

Usage

method_obla(data_prepared, fit, sport, plot)

Arguments

Value

a tibble with the following columns:

OBLA helper

Description

For internal use only and it won't be exported.

Usage

obla_helper(.data, data_augmented, fit, model, obla)

Arguments

Value

The results (intensity, lactate, heart rate) from the lactate threshold method.

Plot lactate

Description

Plots the lactate method. For internal use only.

Usage

plot_lactate(data_processed, method)

Arguments

Value

a ggplot2 object.

Combine lactate threshold methods into one plot

Description

Combine lactate threshold methods into one plot

Usage

plot_methods(plots, ...)

Arguments

Value

a patchwork object

Prepare raw data

Description

It organizes and renames the raw data.

Usage

prepare_data(.data, intensity_column, lactate_column, heart_rate_column)

Arguments

Value

a tibble with the following columns:

Prepare fit

Description

This is an obligatory step before applying any lactate threshold method. This function will model the raw data as well as make all the necessary data wrangling.

Usage

prepare_fit(
  .data,
  fit = c("3rd degree polynomial", "4th degree polynomial", "B-spline", "Exponential"),
  include_baseline = FALSE,
  sport = c("cycling", "running", "swimming")
)

Arguments

Value

a tibble with the following nested columns:

Prepare modified Dmax fits

Description

This is a function for internal use only and it won't be exported.

Usage

prepare_fit_dmax_mods(
  .data,
  fit = c("3rd degree polynomial", "Exponential"),
  intensity_to_start,
  sport = c("cycling", "running", "swimming")
)

Arguments

Value

a tibble with the following nested columns:

Retrieve heart rate

Description

Retrieves the heart rate associated to a given intensity value. It is mainly for internal use but it is exported for possible extensions.

Usage

retrieve_heart_rate(raw_data, intensity_value)

Arguments

Value

the heart rate associated with the estimated lactate threshold

Retrieve intensity

Description

Retrieves the intensity associated to a given lactate value. It is mainly for internal use but it is exported for possible extensions.

Usage

retrieve_intensity(data_augmented, fit, model, lactate_value)

Arguments

Value

the intensity associated with the estimated lactate threshold

Retrieve lactate

Description

Retrieves the lactate associated to a given intensity value. It is mainly for internal use but it is exported for possible extensions.

Usage

retrieve_lactate(model, intensity_value)

Arguments

Value

the lactate associated with the estimated lactate threshold

Data input widget

Description

Widget to help with data input.

Usage

run_data_input(width = 1200, height = 900)

Arguments

Value

The code to reproduce the manual data input.