Variable Resistance Training: Understanding, Methods, Benefits, and Application

What is Variable Resistance Training?

Variable resistance training is a strength training methodology that alters the amount of resistance applied to a muscle throughout its full range of motion, typically to match the natural strength curve of the human body and optimize muscle tension.

Understanding Resistance and Strength Curves

To grasp variable resistance training, it's essential to understand the concept of a strength curve. Every exercise has a unique strength curve, which dictates how much force a muscle can generate at different points in its range of motion. For example, in a bicep curl, you are generally strongest in the mid-range of the movement, and weakest at the very bottom (stretched position) and very top (contracted position).

Traditional free weights (barbells, dumbbells) provide a constant resistance throughout the entire movement. This means the weight remains the same regardless of where you are in the lift. The challenge with constant resistance is that the load is limited by the weakest point in the range of motion. Consequently, muscles may not be maximally challenged at their strongest points, potentially leaving growth and strength potential untapped.

Defining Variable Resistance Training

Variable resistance training (VRT) is a method designed to overcome the limitations of constant resistance. It involves manipulating the resistance so it changes throughout the exercise, aiming to provide greater resistance where the muscle is strongest and less resistance where it is weakest. The primary goal is to maintain a more consistent level of tension on the target muscle throughout the entire range of motion, thereby maximizing muscle fiber recruitment and time under tension.

Common Methods of Implementing Variable Resistance

Several tools and techniques are employed to achieve variable resistance:

• Resistance Bands: When attached to barbells, dumbbells, or directly to the body, resistance bands provide progressively increasing tension as they are stretched. This means the resistance is lowest at the bottom of a lift (where the band is least stretched) and highest at the top (where the band is maximally stretched), often aligning well with ascending strength curves (e.g., squat, bench press).
• Chains: Similar to bands, chains are draped over the ends of a barbell. As the bar is lifted, more links of the chain come off the floor, progressively increasing the total weight lifted. This provides an ascending resistance curve, making the lift heavier as you approach lockout.
• Specialized Machines: Many selectorized gym machines, particularly older designs like Nautilus or Cybex, utilize cams or lever arms designed to alter the resistance throughout the movement. These machines are engineered to match the specific strength curve of the muscles targeted by that particular exercise.
• Water Resistance: In aquatic training, the resistance encountered by movement through water increases with the speed of movement, providing a form of variable resistance often used in rehabilitation or low-impact training.

The Science Behind Variable Resistance: Why It Works

The effectiveness of variable resistance training stems from several biomechanical and physiological principles:

• Optimized Muscle Activation: By providing resistance that closely matches the muscle's natural strength curve, VRT ensures that the muscle is challenged more consistently throughout the entire range of motion. This can lead to greater overall muscle fiber recruitment and more effective training stimulus.
• Overcoming Sticking Points: Many lifts have "sticking points" – positions where the lifter struggles most due to leverage disadvantages. VRT, especially with ascending resistance (bands/chains), allows the lifter to accelerate through the initial, weaker phase of the lift and still be maximally challenged in the stronger, lockout phase, potentially helping to break through plateaus.
• Enhanced Hypertrophy and Strength Gains: The increased "time under tension" at higher loads throughout the movement can promote greater mechanical tension and metabolic stress, two key drivers of muscle hypertrophy (growth) and strength adaptations.
• Improved Power Output: For explosive movements, bands and chains can teach the athlete to accelerate through the entire range of motion, rather than decelerating as they approach lockout with constant resistance. This can lead to greater power development and improved rate of force development.
• Neuromuscular Adaptation: The dynamic nature of variable resistance can challenge the nervous system in new ways, leading to improved motor unit recruitment and synchronization.

Benefits of Incorporating Variable Resistance Training

Integrating VRT into a training regimen can offer several advantages:

• Increased Training Stimulus: Provides a novel stimulus that can help break through plateaus and promote continued adaptations.
• Improved Strength Across the Range of Motion: Trains muscles more effectively at their strongest points, leading to more balanced strength development.
• Enhanced Force Production and Power: Particularly beneficial for athletes requiring explosive strength.
• Versatility and Accessibility: Resistance bands are highly portable and affordable, making VRT accessible to a wide audience.
• Rehabilitation Aid: In clinical settings, variable resistance can be adjusted precisely to accommodate injured joints or muscles, providing appropriate challenge without excessive strain.

Considerations and Potential Drawbacks

While beneficial, VRT is not without its considerations:

• Learning Curve and Setup: Properly setting up bands or chains requires some knowledge and practice. Specialized machines, while convenient, may not be available everywhere.
• Difficulty in Quantifying Load (Bands): The exact resistance provided by bands can be harder to quantify and replicate precisely compared to fixed weights, making progressive overload tracking more challenging.
• Not a Replacement for Free Weights: VRT is best viewed as a complementary tool to traditional free weight training, not a substitute. Free weights are crucial for developing stability, balance, and proprioception.
• Potential for Overload: If not managed correctly, the increased resistance at the top of a lift could potentially lead to excessive joint stress for some individuals, especially in movements with descending strength curves.

Who Can Benefit from Variable Resistance Training?

Variable resistance training can be a valuable addition for a diverse range of individuals:

• Strength Athletes: Powerlifters and weightlifters often use bands and chains to improve lockout strength and develop greater speed-strength.
• Bodybuilders: Can utilize VRT to maximize muscle tension and time under tension, promoting hypertrophy.
• General Fitness Enthusiasts: Seeking to add variety to their workouts, break through plateaus, or enhance specific movements.
• Individuals in Rehabilitation: Under professional guidance, variable resistance (especially with bands or water) can allow for controlled, progressive loading.

Practical Application: How to Integrate Variable Resistance

Integrating VRT into your routine can be done in various ways:

• Accessory Work: Add bands to exercises like push-ups, pull-ups, or glute bridges.
• Main Lifts: Attach bands or chains to barbells for squats, bench presses, and deadlifts. Start with lighter bands/chains and gradually increase the resistance.
• Machine Training: If available, utilize machines designed with variable resistance cams.
• Focus on Technique: Always prioritize proper form, especially when introducing new variables like bands or chains. The added complexity requires diligence.

Conclusion

Variable resistance training is an advanced yet accessible method that offers a powerful way to optimize muscle loading throughout an exercise's range of motion. By strategically matching resistance to the body's natural strength curves, VRT can enhance muscle activation, improve strength and power, and provide a novel stimulus for continued progress. While it requires understanding and proper application, incorporating variable resistance can be a highly effective tool for anyone looking to maximize their training results and break through performance plateaus.