Okay. I was just a bit concerned about a rep being characterized as explosive. By definition, an explosive rep employs momentum and therefore has more force at the beginning of the concentric phase and substantially less at the end of the concentric. I would think that a uniform distribution of force throughout the rep would maximize intensity, thereby optimizing results.* So I agree with you about the movement being controlled rather than jerky. Even so, a one-second concentric phase seems rather short for anything other than calf raises.
__________________________
* One researcher suggested that explosive lifts would likely recruit fewer muscle fibres due to momentum and that the diminished recruitment through most of the range of motion would be less effective for enhancing muscle function.
(Johnston BD. Moving too rapidly in strength training will unload muscles and limit full range strength development adaptation: a case study. J Exerc Physiol 2005; 8: 36-45.)
Another study suggests that "persons should maintain steady force production throughout a range of motion and reduce external forces such as momentum; movements should be of a pace that maintains muscular tension, not explosive or ballistic in nature. Faster movements cause greater peaks in both muscular and ground reaction forces which likely transfer through joints and connective tissue, potentially causing injury."
http://ssudl.solent.ac.uk/3127/1/Evidence Based Resistance Training Recommendations.pdf