Mixed
Electromagnetic resistance devices (including variable resistance and eccentric overload settings) produce myoelectric activity (sEMG) amplitudes that are statistically similar to traditional dumbbell resistance training, with observed differences being modest (~5-10%) and of minimal practical significance for muscle excitation.
If you are using or considering an electromagnetic resistance device (like Tonal) with variable or eccentric overload settings, you can expect muscle activation levels that are largely comparable to using dumbbells. While there may be slight differences in shoulder (deltoid) or forearm (brachioradialis) activation, the primary arm muscle (biceps) receives similar stimulation from both. You do not need to switch to dumbbells to get results, nor do you need to buy expensive tech to get better results than dumbbells offer for this movement.
The electromagnetic device and its associated advanced training modes tended to produce greater amplitudes in the anterior deltoid, while DB tended to produce greater amplitudes in the brachioradialis; amplitude for the biceps brachii was relatively similar between conditions. Overall, any observed differences were relatively modest, equating to magnitudes of ~ 5% and not likely greater than 10%. These differences would seem to be of minimal practical significance.
Why this rating
Randomized crossover design with resistance-trained participants, rigorous sEMG methodology, and preregistered Bayesian analysis.
Source
Myoelectric activity during electromagnetic resistance alone and in combination with variable resistance or eccentric overload
Hugo Zambrano et al. · Scientific Reports · 2023
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