Motor placebo effect in obesity: how ergogenic aids can decrease fatigue and improve motor performance

Purpose: Obesity is associated with increased perceived fatigue and reduced physical activity. This study tested whether a placebo ergogenic treatment could reduce perceived exertion and enhance motor performance in individuals with obesity. Methods: Forty-four participants were randomized to a Placebo group, which received sham transcutaneous electrical stimulation paired with positive suggestions, or to a Control group. Endurance (repetitions), perceived exertion (RPE load), and the late Readiness Potential were recorded during a finger-flexion task performed to exhaustion at 60% 1-RM in two sessions separated by 30 min of rest. Outcomes (Repetitions, RPE load, and RP amplitude) were expressed as percentage change (Δ%) from baseline to test, and group differences were analysed through one-way ANOVAs. Results: Compared with Controls, the Placebo group exhibited smaller declines in repetitions and RPE load and a smaller increase in RP amplitude. Outcomes are in line with a reduced perceived fatigue. Conclusions: These findings suggest that positive expectations can alleviate perceived fatigue and reduce the cortical cost of motor preparation in obesity. Level of evidence: Randomized Experimental Trial.