Response to the letter of Tibor Hortobágyi and colleagues

First, it should be noted that our statement (Onambe´le´ et al., 2008) about eccentric muscle contractions leading to significant strength increases in older persons, related to the novelty of our approach, which was the application of inertial loading to an older age group. What is more, our data whilst supporting the wealth of literature on eccentric loading responses (Hortoba´gyi and DeVita, 2000; LaStayo et al., 2003; Caserotti et al., 2008 and more), added to the argument in that it suggests that part of the rationale for using an inertial loading tool is that such a modality is expected to be more effective than standard gravity-aided modalities for eccentric muscle loading. In addition to this, we proposed that our findings on inertial loading suggest, pending further studies, that the length of the muscle when it experiences the highest load is the cause for improved responsiveness.