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The single-bout forearm critical force test: a new method to establish forearm aerobic metabolic exercise intensity and capacity.

Kellawan JM, Tschakovsky ME - PLoS ONE (2014)

Bottom Line: There was no systematic difference between test 1 and 2 for fCF(peak) force (p = 0.11) or fCF(impulse) (p = 0.76).TTE predicted by W' showed good agreement with actual TTE during the TTE tests (r = 0.97, ICC = 0.97, P<0.01; typical error 0.98 min, 12%; regression fit slope = 0.99 and y intercept not different from 0, p = 0.31).MVC did not predict fCF(peak force) (p = 0.37), fCF(impulse) (p = 0.49) or W' (p = 0.15).

View Article: PubMed Central - PubMed

Affiliation: School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada.

ABSTRACT
No non-invasive test exists for forearm exercise that allows identification of power-time relationship parameters (W', critical power) and thereby identification of the heavy-severe exercise intensity boundary and scaling of aerobic metabolic exercise intensity. The aim of this study was to develop a maximal effort handgrip exercise test to estimate forearm critical force (fCF; force analog of power) and establish its repeatability and validity. Ten healthy males (20-43 years) completed two maximal effort rhythmic handgrip exercise tests (repeated maximal voluntary contractions (MVC); 1 s contraction-2 s relaxation for 600 s) on separate days. Exercise intensity was quantified via peak contraction force and contraction impulse. There was no systematic difference between test 1 and 2 for fCF(peak) force (p = 0.11) or fCF(impulse) (p = 0.76). Typical error was small for both fCF(peak force) (15.3 N, 5.5%) and fCF(impulse) (15.7 N ⋅ s, 6.8%), and test re-test correlations were strong (fCF(peak force), r = 0.91, ICC = 0.94, p<0.01; fCF(impulse), r = 0.92, ICC = 0.95, p<0.01). Seven of ten subjects also completed time-to-exhaustion tests (TTE) at target contraction force equal to 10%fCF(peak force). TTE predicted by W' showed good agreement with actual TTE during the TTE tests (r = 0.97, ICC = 0.97, P<0.01; typical error 0.98 min, 12%; regression fit slope = 0.99 and y intercept not different from 0, p = 0.31). MVC did not predict fCF(peak force) (p = 0.37), fCF(impulse) (p = 0.49) or W' (p = 0.15). In conclusion, the poor relationship between MVC and fCF or W' illustrates the serious limitation of MVC in identifying metabolism-based exercise intensity zones. The maximal effort handgrip exercise test provides repeatable and valid estimates of fCF and should be used to normalize forearm aerobic metabolic exercise intensity instead of MVC.

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Related in: MedlinePlus

Force tracings from a representative subject.Panel A: Raw force trace depicting the data points used for calculation of the peak force (single *) and force impulse (shaded grey area) Panel B: Raw force trace during constant intensity handgrip exercise at target force of 10%>fCFpeak force. Arrow indicates first of three consecutive contractions where target force was not achieved, and represents the time at which exhaustion occurred.
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pone-0093481-g002: Force tracings from a representative subject.Panel A: Raw force trace depicting the data points used for calculation of the peak force (single *) and force impulse (shaded grey area) Panel B: Raw force trace during constant intensity handgrip exercise at target force of 10%>fCFpeak force. Arrow indicates first of three consecutive contractions where target force was not achieved, and represents the time at which exhaustion occurred.

Mentions: The constant intensity rhythmic handgrip exercise trials were performed at the same duty cycle as the maximal effort fCF test. The target force equal to 10% above or 10% below fCFpeak force was identified on the computer display screen with a target line. Time-to-exhaustion (TTE) was identified as the time of the first of three consecutive contraction efforts where the subject was unable to achieve the target force despite strong encouragement (Fig. 2B). All participants were stopped if they reached 20 min of exercise.


The single-bout forearm critical force test: a new method to establish forearm aerobic metabolic exercise intensity and capacity.

Kellawan JM, Tschakovsky ME - PLoS ONE (2014)

Force tracings from a representative subject.Panel A: Raw force trace depicting the data points used for calculation of the peak force (single *) and force impulse (shaded grey area) Panel B: Raw force trace during constant intensity handgrip exercise at target force of 10%>fCFpeak force. Arrow indicates first of three consecutive contractions where target force was not achieved, and represents the time at which exhaustion occurred.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3974771&req=5

pone-0093481-g002: Force tracings from a representative subject.Panel A: Raw force trace depicting the data points used for calculation of the peak force (single *) and force impulse (shaded grey area) Panel B: Raw force trace during constant intensity handgrip exercise at target force of 10%>fCFpeak force. Arrow indicates first of three consecutive contractions where target force was not achieved, and represents the time at which exhaustion occurred.
Mentions: The constant intensity rhythmic handgrip exercise trials were performed at the same duty cycle as the maximal effort fCF test. The target force equal to 10% above or 10% below fCFpeak force was identified on the computer display screen with a target line. Time-to-exhaustion (TTE) was identified as the time of the first of three consecutive contraction efforts where the subject was unable to achieve the target force despite strong encouragement (Fig. 2B). All participants were stopped if they reached 20 min of exercise.

Bottom Line: There was no systematic difference between test 1 and 2 for fCF(peak) force (p = 0.11) or fCF(impulse) (p = 0.76).TTE predicted by W' showed good agreement with actual TTE during the TTE tests (r = 0.97, ICC = 0.97, P<0.01; typical error 0.98 min, 12%; regression fit slope = 0.99 and y intercept not different from 0, p = 0.31).MVC did not predict fCF(peak force) (p = 0.37), fCF(impulse) (p = 0.49) or W' (p = 0.15).

View Article: PubMed Central - PubMed

Affiliation: School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada.

ABSTRACT
No non-invasive test exists for forearm exercise that allows identification of power-time relationship parameters (W', critical power) and thereby identification of the heavy-severe exercise intensity boundary and scaling of aerobic metabolic exercise intensity. The aim of this study was to develop a maximal effort handgrip exercise test to estimate forearm critical force (fCF; force analog of power) and establish its repeatability and validity. Ten healthy males (20-43 years) completed two maximal effort rhythmic handgrip exercise tests (repeated maximal voluntary contractions (MVC); 1 s contraction-2 s relaxation for 600 s) on separate days. Exercise intensity was quantified via peak contraction force and contraction impulse. There was no systematic difference between test 1 and 2 for fCF(peak) force (p = 0.11) or fCF(impulse) (p = 0.76). Typical error was small for both fCF(peak force) (15.3 N, 5.5%) and fCF(impulse) (15.7 N ⋅ s, 6.8%), and test re-test correlations were strong (fCF(peak force), r = 0.91, ICC = 0.94, p<0.01; fCF(impulse), r = 0.92, ICC = 0.95, p<0.01). Seven of ten subjects also completed time-to-exhaustion tests (TTE) at target contraction force equal to 10%fCF(peak force). TTE predicted by W' showed good agreement with actual TTE during the TTE tests (r = 0.97, ICC = 0.97, P<0.01; typical error 0.98 min, 12%; regression fit slope = 0.99 and y intercept not different from 0, p = 0.31). MVC did not predict fCF(peak force) (p = 0.37), fCF(impulse) (p = 0.49) or W' (p = 0.15). In conclusion, the poor relationship between MVC and fCF or W' illustrates the serious limitation of MVC in identifying metabolism-based exercise intensity zones. The maximal effort handgrip exercise test provides repeatable and valid estimates of fCF and should be used to normalize forearm aerobic metabolic exercise intensity instead of MVC.

Show MeSH
Related in: MedlinePlus