Strength training relies on resistance. Usually, this resistance is fixed. In other words, the amount of force provided by a barbell is constant throughout the range of motion. However, dynamic variable resistance alters the equation. Force changes. When working with free weights, machines and resistance bands, dynamic variable resistance increases external force to match muscle force through the concentric phase and decreases it through the eccentric phase.
Dynamic Resistance Squat
A barbell squat is easily altered for variable resistance by draping chains over the outer parts of the bell (See Ref 2). In fact, try a few sets with just the barbell and chains ranging from 10 to 15 pounds to acclimate yourself to the increased demands on stability before adding plates. Use this to determine your working sets. You won't be able to lift as heavy as under a traditional squat using constant resistance. To ensure proper squatting technique keep legs shoulder width apart. Focus on the glutes as you lower the body. Squeeze them as you drive the legs through the floor, returning to a standing position. Keep the back straight throughout squat. Do not round the lower back.