It is interesting that the non-significant EMG amplitude changes after
isotonic training follow a U-shaped curve, but only contribute to
greater torque increases than the middle range of motion at short muscle lengths (30 degrees).
They tested joint angles from long (90 degrees of knee flexion) to short (30 degrees of knee flexion) muscle lengths, expecting to see
greater gains for the
isotonic group at both ends of the range of motion, where loading was higher than in the middle.