The purpose of this study is to determine the effect of mental effort on improving muscle
Training that involves heavy loads or resistance strengthens muscles. Recent data suggest
that substantial voluntary strength gains can be achieved with training involving low
resistance and strong mental effort. In contrast, individuals who train with the same low
intensity contractions but with low mental effort show no improvement in strength.
This study will evaluate the relationship between mental effort muscle strength improvements
by comparing the improvement in muscle strength in participants who have trained with
different levels of mental effort. In addition to evaluating muscle strength, this study
will also examine the neural mechanisms underlying muscle strength improvements.
Four groups of volunteers (65 years old and over) will participate in a training program
directed at elbow-flexor muscles. One group will be trained with an intensity near the level
of maximal voluntary contraction (MVC group); a second group will be trained with high
mental effort, low muscle intensity contractions (HME group); a third group will be trained
with low mental effort, low muscle intensity elbow-flexion contractions (LME group); and the
fourth (control) group will not be trained but will participate in the strength tests.
Training will be performed every weekday for 12 weeks. Participants will be evaluated by
functional MRI (fMRI), EEG-derived motor activity-related cortical potential (MRCP), surface
EMG signals, and the MRI T2 relaxation time.
Preliminary analysis of results shows that the HME group gained more than 13% strength, the
LME group showed a statistically insignificant 6% change, and the no-practice control group
did not show any change in elbow flexor muscle strength. We expect the MVC group to have the
highest strength gains among the four groups.
- Healthy individuals free of neurological impairment
- Already involved in regular physical training
- Neuromuscular disorders
- Medications known to affect neuromuscular system (other than moderate alcohol or
- Left-hand dominant