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The Effects of Load Carriage and Physical Fatigue on Cognitive Performance.

Eddy MD, Hasselquist L, Giles G, Hayes JF, Howe J, Rourke J, Coyne M, O'Donovan M, Batty J, Brunyé TT, Mahoney CR - PLoS ONE (2015)

Bottom Line: In the current study, ten participants walked for two hours while carrying no load or a 40 kg load.There were also shifts in response criterion towards responding yes and decreased sensitivity in responding in the loaded condition compared to the unloaded condition.In the visual target detection there were no reliable effects of load carriage in the overall analysis however, there were slower reaction times in the loaded compared to unloaded condition during the second hour.

View Article: PubMed Central - PubMed

Affiliation: U.S. Army Natick Soldier Research, Development, and Engineering Center, Natick, Massachusetts, United States of America; Department of Psychology, Tufts University, Medford, Massachusetts, United States of America.

ABSTRACT
In the current study, ten participants walked for two hours while carrying no load or a 40 kg load. During the second hour, treadmill grade was manipulated between a constant downhill or changing between flat, uphill, and downhill grades. Throughout the prolonged walk, participants performed two cognitive tasks, an auditory go no/go task and a visual target detection task. The main findings were that the number of false alarms increased over time in the loaded condition relative to the unloaded condition on the go no/go auditory task. There were also shifts in response criterion towards responding yes and decreased sensitivity in responding in the loaded condition compared to the unloaded condition. In the visual target detection there were no reliable effects of load carriage in the overall analysis however, there were slower reaction times in the loaded compared to unloaded condition during the second hour.

No MeSH data available.


Related in: MedlinePlus

Means and standards errors of reaction times (RTs) for go trials after a no-go trials over time and by load condition.
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pone.0130817.g005: Means and standards errors of reaction times (RTs) for go trials after a no-go trials over time and by load condition.

Mentions: Comparing reaction times across the two tasks (go trials with no-go trials and all go trials), there was a main effect of trial type, F(1,9) = 41.15, p < .001, ƞp2 = .82, with the reaction time for trials in the all go blocks being faster than trials with go and no-go trials intermixed; Mallgo = 462.86 ms, SDallgo = 75.29 ms; Mgo/no-go = 565.43 ms, SDgo/no-go = 62.06 ms. However, trial type did not interact with load or trial block (all F’s < 1, p’s > .4). When comparing reaction times for the go/no-go blocks by load condition, there was a interaction between load condition and time block, F(5,45) = 3.39, p = .011, ƞp2 = .27. For this interaction there were no linear, quadratic or cubic elements that reached significance, however, there was a trend towards linear and quadratic elements to this interaction, p’s > .054. To examine the above reported interaction, post-hoc corrected comparisons (p < .0083) were performed, revealing at 65 minutes of walking, in the loaded condition, participants had significantly longer reaction times than in the unloaded condition (t(9) = 3.49, p = .007, d = .24; Mloaded = 605.27 ms, SDloaded = 205.63 ms; Munloaded = 556.18 ms, SDunloaded = 203.88 ms). Examining the reaction time to a go trial after having a no-go trial, the same pattern was observed with load and time block interacting with quadratic elements, F(5,45) = 4.14, p = .004, ƞp2 = .32. Post-hoc corrected comparisons (p < .0083) revealed at 65 minutes of walking, in the loaded condition, participants had significantly longer reaction times than in the unloaded condition (t(9) = 4.97, p = .001, d = .4; Mloaded = 602.83 ms, SDloaded = 188.88 ms; Munloaded = 527.98 ms, SDunloaded = 188.48 ms). The quadratic element of this interaction is reflected by this longer RT at 65 minutes of walking for the loaded condition compared to the unloaded condition (see Fig 5).


The Effects of Load Carriage and Physical Fatigue on Cognitive Performance.

Eddy MD, Hasselquist L, Giles G, Hayes JF, Howe J, Rourke J, Coyne M, O'Donovan M, Batty J, Brunyé TT, Mahoney CR - PLoS ONE (2015)

Means and standards errors of reaction times (RTs) for go trials after a no-go trials over time and by load condition.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496096&req=5

pone.0130817.g005: Means and standards errors of reaction times (RTs) for go trials after a no-go trials over time and by load condition.
Mentions: Comparing reaction times across the two tasks (go trials with no-go trials and all go trials), there was a main effect of trial type, F(1,9) = 41.15, p < .001, ƞp2 = .82, with the reaction time for trials in the all go blocks being faster than trials with go and no-go trials intermixed; Mallgo = 462.86 ms, SDallgo = 75.29 ms; Mgo/no-go = 565.43 ms, SDgo/no-go = 62.06 ms. However, trial type did not interact with load or trial block (all F’s < 1, p’s > .4). When comparing reaction times for the go/no-go blocks by load condition, there was a interaction between load condition and time block, F(5,45) = 3.39, p = .011, ƞp2 = .27. For this interaction there were no linear, quadratic or cubic elements that reached significance, however, there was a trend towards linear and quadratic elements to this interaction, p’s > .054. To examine the above reported interaction, post-hoc corrected comparisons (p < .0083) were performed, revealing at 65 minutes of walking, in the loaded condition, participants had significantly longer reaction times than in the unloaded condition (t(9) = 3.49, p = .007, d = .24; Mloaded = 605.27 ms, SDloaded = 205.63 ms; Munloaded = 556.18 ms, SDunloaded = 203.88 ms). Examining the reaction time to a go trial after having a no-go trial, the same pattern was observed with load and time block interacting with quadratic elements, F(5,45) = 4.14, p = .004, ƞp2 = .32. Post-hoc corrected comparisons (p < .0083) revealed at 65 minutes of walking, in the loaded condition, participants had significantly longer reaction times than in the unloaded condition (t(9) = 4.97, p = .001, d = .4; Mloaded = 602.83 ms, SDloaded = 188.88 ms; Munloaded = 527.98 ms, SDunloaded = 188.48 ms). The quadratic element of this interaction is reflected by this longer RT at 65 minutes of walking for the loaded condition compared to the unloaded condition (see Fig 5).

Bottom Line: In the current study, ten participants walked for two hours while carrying no load or a 40 kg load.There were also shifts in response criterion towards responding yes and decreased sensitivity in responding in the loaded condition compared to the unloaded condition.In the visual target detection there were no reliable effects of load carriage in the overall analysis however, there were slower reaction times in the loaded compared to unloaded condition during the second hour.

View Article: PubMed Central - PubMed

Affiliation: U.S. Army Natick Soldier Research, Development, and Engineering Center, Natick, Massachusetts, United States of America; Department of Psychology, Tufts University, Medford, Massachusetts, United States of America.

ABSTRACT
In the current study, ten participants walked for two hours while carrying no load or a 40 kg load. During the second hour, treadmill grade was manipulated between a constant downhill or changing between flat, uphill, and downhill grades. Throughout the prolonged walk, participants performed two cognitive tasks, an auditory go no/go task and a visual target detection task. The main findings were that the number of false alarms increased over time in the loaded condition relative to the unloaded condition on the go no/go auditory task. There were also shifts in response criterion towards responding yes and decreased sensitivity in responding in the loaded condition compared to the unloaded condition. In the visual target detection there were no reliable effects of load carriage in the overall analysis however, there were slower reaction times in the loaded compared to unloaded condition during the second hour.

No MeSH data available.


Related in: MedlinePlus