Cerebellar Transcranial Direct Current Stimulation Improves Maximum Isometric Force Production during Isometric Barbell Squats

Abstract

Maximum voluntary contraction force (MVC) is an important predictor of athletic performance as well as physical fitness throughout life. Many everyday life activities involve multi-joint or whole-body movements that are determined in part through optimized muscle strength. Transcranial direct current stimulation (tDCS) has been reported to enhance muscle strength parameters in single-joint movements after its application to motor cortical areas, although tDCS effects on maximum isometric voluntary contraction force (MIVC) in compound movements remain to be investigated. Here, we tested whether anodal tDCS and/or sham stimulation over primary motor cortex (M1) and cerebellum (CB) improves MIVC during isometric barbell squats (iBS). Our results provide novel evidence that CB stimulation enhances MIVC during iBS. Although this indicates that parameters relating to muscle strength can be modulated through anodal tDCS of the cerebellum, our results serve as an initial reference point and need to be extended. Therefore, further studies are necessary to expand knowledge in this area of research through the inclusion of different tDCS paradigms, for example investigating dynamic barbell squats, as well as testing other whole-body movements.

Effects of Preceding Transcranial Direct Current Stimulation on Movement Velocity and EMG Signal during the Back Squat Exercise

“…Similarly, Kamali et al [ 42 ] have reported not only beneficial effects on sEMG signal after the application of a-tDCS (2 mA) for 13 min on the primary motor cortex (M1) and temporal cortex (TC) in bodybuilders, but also an improvement in performance (muscular strength and endurance). These improvements on neuromuscular performance have also been confirmed in previous research conducted in other types of muscle contractions, such as an isometric squat, where significant improvements in MVIC were shown [ 43 ]. Similar results have been reported in the biceps brachii muscles [ 41 ].…”

Role of the trace amine associated receptor 5 (TAAR5) in the sensorimotor functions

“…First, we observed significantly worse performance in the Rotarod test and the Vertical ladder (90°) test in TAAR5-KO mice, which may be the consequence of the decrease in muscle strength or endurance in this group. It has been shown that muscle strength may depend in part on cerebellar function and can be modulated through the cerebellar neural pathways 30 . A likely reason for the sensorimotor characteristics changes observed in TAAR5-KO animals could be the alterations in the functioning of classical monoaminergic systems 17 , 27 , particularly in histaminergic projections of the cerebellum.…”

Precision strength training: Data-driven artificial intelligence approach to strength and conditioning

“…Easily acquired continuous measurements are not always helpful when the signal has lowdelity, or when the data is not the most relevant for the task in question [113]. [607], testosterone assay for both acute exercise-induced response and global levels [288,484], muscle oxygenation with fNIRS [679], ultrasound SWE for the (real-time) quantication of musculotendon stiness [419,467], cartoon of smart insoles for quantifying center-of-pressure (CoP) and the tripod loading , force plates for measuring ground reaction forces [245], EMG for measuring activation [257] (myoelectric activity more exactly [841]), sweat-based biochemical sensing for detecting metabolic and neuromuscular fatigue from ammonia and lactate levels [697], core body temperature for circadian phase [788] and muscle temperature measurements for training preparedness, subjective rating of eort through RPE logging (https://www.reactivetrainingsystems.com/), cognitive load from electrical (EEG) [396] and hemodynamic (fNIRS) brain activity [395]. Image from Dr. Ben Pollock, reproduced with permission.…”