Four different workload modes / Spirit / i-Strength

Spirit Fitness built the i-Strength adaptive strength training system around four distinct workout modes. The i-Strength system is powered by an advanced electronic resistance motor that changes how weight behaves in real-time. This is strength training, redefined.

Mode 1: Pure Resistance for hypertrophy

Designed for hypertrophy, Pure Resistance mode follows the natural rhythm of your muscles, delivering consistent, uninterrupted resistance that never drops off, just like the classic bodybuilding movements it's built to replicate.

Mode 2: Eccentric Load for strength

Designed for strength, Eccentric Load mode targets the most overlooked phase of every rep, the lowering. As you descend, resistance automatically increases, forcing your muscles to work harder as they lengthen. It unlocks a deeper level of strength stimulus that traditional iron simply cannot replicate.

Mode 3: Isokinetic control for safety

Designed for safety, i-Strength’s Isokinetic Mode changes everything. In this mode, the speed of movement remains constant, no matter how much force you apply. It responds directly to you: if you give 10% effort, it provides 10% resistance. The moment you stop, the resistance vanishes. There is no risk of being crushed and no danger of losing control.

Mode 4: Elastic Tension for explosive power

Designed for explosive power, Elastic Tension mode acts like a smart rubber band: the further you pull, the stronger the resistance gets. Unlike traditional weights that deliver a flat, static load, elastic resistance compounds with every inch of movement, activating fast-twitch muscle fibers and sharpening neuromuscular response. For athletes chasing peak performance, it's the edge that traditional weights could never provide.

Visit our website to learn more about i-Strength | SPIRIT Commercial Fitness or contact us at [email protected]