The Effect of Non-Invasive Brain Stimulation on Running Performance and Inertial Measurement Unit-Derived Spatiotemporal Parameters in Endurance-Trained Runners.

The M1 + DLPFC combined stimulation condition produced the fastest mean 3000 m completion time compared to all other conditions.

• The M1 + DLPFC condition averaged approximately three seconds faster than sham
• Ten endurance-trained runners (7 males) completed four stimulation conditions: M1, DLPFC, M1 + DLPFC, and sham
• The differences in completion time were not statistically significant
• Study used a randomized, sham-controlled, repeated-measures crossover design

Combined M1 + DLPFC stimulation resulted in significantly higher running speeds during the initial phase of the 3000 m time-trial compared to other conditions.

• Significant differences in running speed were found specifically during the initial phase of the run
• Analyses were conducted across initial, steady-state, and final acceleration phases
• The effect was phase-specific, with the initial phase showing the most pronounced differences
• Running performance and spatiotemporal gait parameters were continuously monitored using wearable IMUs

Combined M1 + DLPFC stimulation produced significant alterations in stride time and step frequency during the initial phase of running.

• Stride time and step frequency were significantly altered following combined stimulation compared with the other conditions
• These biomechanical differences were specific to the initial phase of the run
• Spatiotemporal gait parameters were derived from wearable inertial measurement units (IMUs)
• These phase-specific changes suggest early-stage running biomechanics are particularly sensitive to combined neuromodulation

Ratings of perceived exertion (RPE) did not differ significantly between any of the stimulation conditions.

• RPE was measured across the stimulation conditions: M1, DLPFC, M1 + DLPFC, and sham
• No significant differences in RPE were found between any conditions
• This suggests that performance or biomechanical changes observed were not accompanied by changes in subjective effort perception

Spatiotemporal variability in running gait did not differ significantly between stimulation conditions.

• Variability measures were derived from wearable IMU data
• No significant differences in spatiotemporal variability were found across M1, DLPFC, M1 + DLPFC, and sham conditions
• This finding held across the initial, steady-state, and final acceleration phases of the run

Intermittent theta burst stimulation (iTBS) was applied to the primary motor cortex (M1), dorsolateral prefrontal cortex (DLPFC), or both regions as the neuromodulation protocol.

• iTBS was chosen as the non-invasive brain stimulation technique to alter neural excitability
• Target regions included M1 (motor control) and DLPFC (cognitive control)
• Four conditions were tested: M1 alone, DLPFC alone, M1 + DLPFC combined, and sham stimulation
• The crossover design meant all ten participants completed all four stimulation conditions

Wearable IMUs successfully detected subtle, phase-specific changes in running biomechanics that would not have been captured by overall performance measures alone.

• IMUs provided continuous monitoring of running performance and spatiotemporal gait parameters throughout the 3000 m trial
• Phase-specific analyses (initial, steady-state, final acceleration) revealed differences not apparent in overall completion times
• The authors conclude the findings 'demonstrate the utility of wearable IMUs for detecting subtle phase-specific changes in running biomechanics'
• Sensor-derived biomechanical measures revealed significant differences in speed, stride time, and step frequency during the initial phase

The study was limited by a small sample size of ten runners, making all findings preliminary.

• The complete sample consisted of only ten endurance-trained runners (7 males)
• Authors explicitly state 'these findings are preliminary and require confirmation in a larger sample size'
• The small sample size likely contributed to the lack of statistical significance in overall 3000 m completion time despite a ~3 second mean difference
• Authors call for 'further investigation in larger cohorts'