Does repetition and force matter? (Byl et al., Physical Therapy, 77(3), 269-284, 1997)
Trained 2 owl monkeys to repetitively close a handpiece (80-g force) for 1.5 hours (~400 squeezes) a day, for 5 weeks.
Results showed a deterioration in motor control and degradation of hand representation on the somatosensory cortex.