Why can the human body raise more resistance on the negative repetition compared to the positive, concentric muscle contraction? T90 Xplode all comes down to 1 work- intra muscular friction. The friction on the regular, concentric muscle contraction is abundant higher as compared to the negative rep. Thus, the human body can lift a lot of throughout the eccentric contraction versus the concentric. This is often why negatives are necessary to incorporate into a successful body building weight lifting program. Read More : http://www.xtgenixau.com/t90-xplode-reviews/