Transcranial Direct Current Stimulation Combined With or Without Caffeine: Effects on Training Volume and Pain Perception.

Purpose: This study aimed to investigate the acute effects of tDCS combined with caffeine intake on training volume and pain perception in the bench press in resistance-trained males. The correlation between training volume and pain perception was also assessed in all interventions. Methods: Sixteen healthy males (age = 25.2 ± 4.7 years, body mass = 82.8 ± 9.1 kg, and height = 178.3 ± 5.7 cm), advanced in RT, were randomized and counterbalanced for the following experimental conditions: Sham tDCS with placebo intake (Sham+Pla), Sham tDCS with caffeine intake (Sham+Caff), anodal tDCS with placebo intake (a-tDCS+Pla), and anodal tDCS with caffeine intake (a-tDCS+Caff). The caffeine or placebo ingestion (both with 5 mg.kg-1) occurred 40 minutes before the tDCS sessions. The tDCS was applied over the left DLPFC for 20 minutes, with a 2 mA current intensity. After the tDCS sessions, participants performed the bench press with an 80% of 1RM load, where training volume and pain perception were measured. Results: Training volume was higher in the 1st and 2nd sets in both a-tDCS+Caff and Sham+Caff conditions, compared to the Sham+Pla condition (P < .05). Both a-tDCS+Caff and a-tDCS+Pla showed an increased pain perception during the third set compared to the first set. Also, no correlation was found between the number of repetitions and pain perception in any condition (P > .05). Conclusion: This research revealed that caffeine intake alone could be used as an ergogenic aid during resistance training programs in resistance-trained males.

Anodal Transcranial Direct Current Stimulation Does Not Affect Velocity Loss During a Typical Resistance Exercise Session.

Purpose: This study investigated the effects of transcranial direct current stimulation (tDCS) on velocity loss in a typical resistance exercise session. Methods: Twelve recreationally resistance-trained males (age = 24.8 ± 3.0 years, body mass = 78.9 ± 13.6 kg, and height = 174.3 ± 7.3 cm) completed two experimental trials in a counterbalanced crossover design: anodal tDCS and sham conditions. The stimuli were applied over the left dorsolateral prefrontal cortex for 20 minutes, using a 2 mA current intensity in anodal tDCS and a 1-minute active stimulus in the sham condition. After stimulation, subjects performed three sets of the bench press at a 70% of 1 maximum repetition intensity and 1 min of inter-set rest. The velocity loss was calculated as the relative difference between the fastest repetition velocity (usually first) and the velocity of the last repetition of each set and averaged over all three sets. Results: The results found no interaction between conditions and sets (P = .122), and no effect for conditions (P = .323) or sets (P = .364) for the velocity loss in each set. Also, no differences were found between the average velocity loss of the three sets in the anodal tDCS (-25.0 ± 4.7%) and sham condition (-23.3 ± 6.4%; P = .323). Conclusion: Anodal tDCS does not affect movement velocity in a typical strength training protocol in recreationally trained subjects.

Effects of Anodal Transcranial Direct Current Stimulation on Training Volume and Pleasure Responses in the Back Squat Exercise Following a Bench Press.

ABSTRACT: Rodrigues, GM, Machado, S, Faria Vieira, LA, Ramalho de Oliveira, BR, Jesus Abreu, MA, Marquez, G, Maranhão Neto, GA, and Lattari, E. Effects of anodal transcranial direct current stimulation on training volume and pleasure responses in the back squat exercise following a bench press. J Strength Cond Res 36(11): 3048-3055, 2022-This study aimed to investigate the effects of anodal transcranial direct current stimulation (a-tDCS) on volume-load and pleasure responses in a back squat following a bench press. Twelve male subjects advanced in resistance training (RT) (age, 25.5 ± 4.4 years) completed 2 experimental trials in a counterbalanced crossover design: a-tDCS and sham conditions. The stimulus was applied over the left dorsolateral prefrontal cortex for 20 minutes using a 2-mA current intensity in a-tDCS condition and 1 minute of active stimulus in the sham condition. Immediately after stimulation, subjects performed the bench press followed by the back squat. The exercise protocol consisted of 3 sets of maximum repetitions at an intensity of 80% of 1 repetition maximum. The volume-load, perceived pleasure, and arousal responses were measured during the RT protocol. The results indicated that volume-load was higher in the a-tDCS condition than in the sham condition for both exercises ( p = 0.02), with large effect for the back squat ( p = 0.045; d = 0.96). The higher volume-load was obtained by increasing the number of repetitions across all sets for the bench press ( p ≤ 0.0001) and only in the first set for the back squat ( p = 0.01). The circumplex model analysis showed a higher pleasure in the bench press and a tendency toward a higher pleasure in the a-tDCS condition. Anodal tDCS may be used as an ergogenic resource for increasing the back squat volume after performing the bench press in resistance-trained male subjects.

Transcranial Direct Current Stimulation (tDCS) Improves Back-Squat Performance in Intermediate Resistance-Training Men.

Purpose: The purpose of this study was to evaluate the effects of anodal tDCS applied over the dorsolateral prefrontal cortex (DLPFC) on muscle endurance in the back-squat exercise. Methods: Eleven healthy males, intermediate in resistance training (RT), aged between 18 and 31 years (25.5 ± 4.4 years) were recruited. In the initial visits (1st and 2nd visits), participants performed a 1RM test to determine the load in the back-squat exercise. Following the two initials visits, participants attended the lab for the two experimental conditions (anodal tDCS and sham), which were completed a week apart, with sessions randomly counterbalanced. The stimulation was applied over the DLPFC for 20 minutes using a 2 mA current intensity. Immediately after the experimental conditions, participants completed three sets of maximum repetitions (80% of 1RM), with a 1-minute recovery interval between each set in the back-squat exercise. Muscle endurance was determined by the total number of repetitions and the number of repetitions in each set. Results: The total number of repetitions was higher in the anodal tDCS condition compared to sham condition (p ≤ .0001). Moreover, the number of repetitions performed in the first set was higher for anodal tDCS condition than in the sham condition (p ≤ .01). Conclusion: This study found improvement in back-squat exercise performance after the application of anodal tDCS. The effects of anodal tDCS applied over DLPFC may be a promising ergogenic resource on muscle endurance in the back-squat exercise.