The Peak Contraction Intensity Technique

This intensity variant focuses more on the neural component of muscle strength. Peak Contraction requires a high neural drive, and protein synthesis is, relatively speaking, stimulated less strongly.

While it is likely that training with the Peak Contraction method can increase the rate of force development (the increase in force per unit of time), it remains completely unclear what physiological significance this might have for everyday movements.

This is related to the function-dependent recruitment of motor units.

The training weight is moved 10 - 20 times at a rhythm of (1)-3-2-2 (lifting the weight - concentric - isometric shortened - eccentric), and after each repetition the weight is set down slowly (3-second pause). This results in a time under tension of 80'' - 160''.

Terminology

Isometric

Force increases while the muscle stays the same length (static, holding). In the physical sense, no work is done, since the distance covered is zero.

Motor unit

A motor unit consists of a single α motor neuron together with all the muscle fibres it innervates.

Torque

Torque is a physical quantity in classical mechanics. In rotational motion, it plays the same role that force plays in linear motion. A torque can accelerate or slow the rotation of a body, and can twist or bend the body.

Single-joint

A muscle that spans only one joint and moves that joint.

Multi-joint

A muscle that spans several joints and moves them.

Source: update Fitness training concept and Wikipedia