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Maxime Deshayes, Corentin Clément-Guillotin and Raphaël Zory

Previous research on the stereotype threat phenomenon has shown that inducing a negative stereotype toward a group debilitates motor performance despite the increase in motivation. Most of the studies focused on tasks requiring technical skills. However, what happens when the task does not require technical skills but focuses on energy expenditure? To examine this question, 34 male and female participants were assigned to a negative stereotype toward women and a nullified-stereotype condition and performed 20 min of self-paced cycling exercise. The authors hypothesized better performances when participants were assigned to the negative stereotype toward women condition than when assigned to the nullified-stereotype condition. As predicted, men and women increased their performances, accompanied by increases in heart rate. Concerning women, this result provides support for the notion that the effect of inducing a negative stereotype is task dependent, but further research is needed to more deeply investigate the mechanisms involved.

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Daniel A. Keir, Raphaël Zory, Céline Boudreau-Larivière and Olivier Serresse

Objectives:

Mechanical efficiency (ME) describes the ratio between mechanical (P MECH) and metabolic (P MET) power. The purpose of the study was to include an estimation of anaerobic energy expenditure (AnE) into the quantification of P MET using the accumulated oxygen deficit (AOD) and to examine its effect on the value of ME in treadmill running at submaximal, maximal, and supramaximal running speeds.

Methods:

Participants (N = 11) underwent a graded maximal exercise test to determine velocity at peak oxygen uptake (vVO2peak). On 4 separate occasions, subjects ran for 6 min at speeds corresponding to 50%, 70%, 90%, and 110% of vVO2peak. During each testing session, P MET was measured from pulmonary oxygen uptake (VO2p) using opencircuit spirometry and was quantified in 2 ways: from VO2p and an estimate of AnE (from the AOD method) and from VO2p only. P MECH was determined from kinematic analyses.

Results:

ME at 50%, 70%, 90%, and 110% of vVO2peak was 59.9% ± 11.9%, 55.4% ± 12.2%, 51.5% ± 6.8%, and 52.9% ± 7.5%, respectively, when AnE was included in the calculation of P MET. The exclusion of AnE yielded significantly greater values of ME at all speeds: 62.9% ± 11.4%, 62.4% ± 12.6%, 55.1% ± 6.2%, and 64.2% ± 8.4%; P = .001 (for 50%, 70%, 90%, and 110% of vVO2peak, respectively).

Conclusions:

The data suggest that an estimate of AnE should be considered in the computation of P MET when determining ME of treadmill running, as its exclusion leads to overestimations of ME values.