The X-Force Solution

The fundamental point of X-Force, compared to other forms of training, is to deliver a combination of static, concentric and increased eccentric resistance. 

Early machines utilizing pneumatic or electrodynamic resistance failed to provide this combination. The first machine to be constructed was the Eccentric Jo-Jo, developed by Swedish strength-training physiologist Per Tesch at the Karolinska Institute in Stockholm. This machine provided extra eccentric force in leg extensions. However, there was no static component and it was not possible to maintain a constant 40% increase in eccentric force. 
Recent research has now proven that eccentric training improves muscular strength and muscle growth better than concentric training does. As such, eccentric training can be expected to deliver far better results in regard to the development of tendons, ligaments, joint surfaces and skeleton – and the way fat is metabolized. Eccentric strength training is recognized as a principal cause of DOMS (delayed onset muscle soreness). Simply by increasing the intensity in the eccentric phase (instead of decreasing it) a person training eccentrically will be able to work out less frequently and in shorter bouts. 
Attempts have been made to apply these facts in commercial gyms, but up until now no machine has been able to provide a precisely regulated eccentric force combined with concentric and static components in the correct proportions. 
The X-Force is the first machine that actually meets these requirements. X-Force provides modern man with excellent way to get fit and stay in shape, as it helps him achieve greater muscular mass and strength by spending less time at the gym.