Author(s): ROUSANOGLOU, E., EMMANOUIL, A., BOUDOLOS, K., Institution: NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS, GREECE, Country: GREECE, Abstract-ID: 2578

INTRODUCTION:
Rhythmic acoustic stimuli (AS) are commonly used to regulate movement timing during exercise [1] or rehabilitation [2]. The purpose of this study was to examine the effects of different rhythmic AS on muscle and brain activation during squatting, a fundamental exercise in physical fitness.
METHODS:
Twenty mean and 20 women (physically active, 25.2 ± 4.6 and 24.4 ± 4.4 years; 1.80 ± 0.07 and 1.65 ± 0.05 m; 81.4 ± 11.3 and 70.7 ± 14.6 kg; and 25.5 ± 4.2 and 25.8 ± 5.5 kg/m², respectively) performed squatting trials under five AS conditions: no-AS (N=40 preferred tempo, 27.40 ± 6.34 cycles·min⁻¹), metronome, vocal counting, melodic music (all three at the participant’s preferred tempo) and fitness music (133bpm). Two trials of 8 repetitions each were performed in synchronization with the AS. Muscle activity of the right and left vastus lateralis (R-VL, L-VL) was recorded using surface vibromyography (2000 Hz; TSD250, Biopac Systems Inc., USA). Brain activity was recorded from motor cortex sites (C3, C4) (Biopac EEG system, 2000 Hz). Muscle signals were band-pass filtered (5–100 Hz, 4th-order Butterworth), notch filtered (50 Hz) and processed via linear envelope; EEG signals underwent wavelet denoising, band-pass filtering (2–40 Hz), resampling (200 Hz), and alpha (8–12 Hz) and beta (13–35 Hz) extraction. Muscle and brain activity were quantified using the root mean square. One-way repeated-measures ANOVA (SPSS v29.0, p≤0.05) examined the AS effect.
RESULTS:
In R-VL, metronome (+6%, p=0.021), vocal counting (+6.3%, p=0.014), and
fitness music (+31.3%, p=0.002) increased muscle activity compared to
no-AS, whereas melodic AS had no effect (p=1.000). In L-VL, only fitness
music increased muscle activity (+37.6%, p=0.006). Overall, fitness music
elicited greater activation than all other AS conditions (R-VL ≈20%; L-VL
≈24%; p≤0.05). AS had a significant effect on alpha EEG activity (C3, C4)
with an increase during fitness AS compared to all other AS (p>0.05).
However, beta power at C3 was lower during fitness music than during
melodic (p=0.039) and vocal AS (p=0.023).
CONCLUSION:
Rhythmic AS appears to modulate muscle and brain activity during squatting, a fundamental exercise in physical fitness. This modulation is stimulus-specific, with fitness music eliciting greater muscle activation and distinct brain activity compared to metronome, vocal, and melodic AS. Consistent with evidence supporting the beneficial use of rhythmic AS in running [1] and rehabilitation [2], the present findings extend their application to single-exercise strength tasks.

References
1. Terry, P. C., Karageorghis, C. I., Curran, M. L., Martin, O. V., & Parsons-Smith, R. L. (2020). Effects of music in exercise and sport: A meta-analytic review. Psychological Bulletin, 146 (2), 91-117. https://doi.org/10.1037/bul0000216
2. Thaut, M. H., & McIntosh, G. C. (2014). Neurologic music therapy in stroke rehabilitation. Current Physical Medicine and Rehabilitation Reports, 2(2), 106–113. https://doi.org/10.1007/s40141-014-0049-y