In recent years, stability balls, BOSU balls, and wobble boards have become common sights in gyms worldwide, promoted as tools for “core stability” and “functional strength.” But how effective are they for what they claim to do? Let’s explore why unstable training may be more hype than necessity.
Stability or “unstable” training commonly involves exercises performed on unstable surfaces, such as Bosu balls, balance discs, or Swiss balls. These exercises are often marketed as ways to improve core stability, balance, and functional strength. While they can have specific applications in physical therapy or balance training, they’re not always necessary for strength development, and, in many cases, traditional training methods on stable surfaces are more effective for building muscle and power. In this blog, we’ll break down the science behind stability training, examine its limitations, and explain why focusing on stable training surfaces is the smarter choice.
The Science of Stability and Unstable Training
1. How Stability Training Works:
• In stability training, exercises are performed on wobbly or unstable surfaces, forcing the body to engage additional “stabilizer” muscles to maintain balance. This type of training is said to enhance neuromuscular coordination and core strength by keeping the body stable on an unsteady surface.
2. What is Stability: Stability is control, or the ability to move your limb or body in a specific way. This is done in two main ways-
• Static Stability: The ability to maintain a controlled position when stationary, like holding a plank. Static stability is essential for developing foundational strength, allowing the body to support itself against gravity.
• Dynamic Stability: This involves maintaining control during movement, such as running, lifting, or changing directions. Dynamic stability is crucial for anyone performing multi-joint exercises where the body must remain stable while moving in multiple planes.
3. What muscles do: The largest problem with the concept of “Stability” training is that muscles do not inherently stabilize or can be trained for that function. All muscles have 3 actions they are able to perform-
1. Concentric Contraction
• In a concentric contraction, the muscle shortens as it generates force. This action is commonly seen when lifting weights or moving against resistance.
• Example: During a bicep curl, the biceps muscle shortens as you lift the dumbbell toward your shoulder, creating a concentric contraction.
2. Eccentric Contraction
• An eccentric contraction occurs when the muscle lengthens while still generating force. This type of contraction is essential for controlling movement and absorbing shock.
• Example: When lowering a dumbbell from a curl position, the biceps muscle lengthens under tension, creating an eccentric contraction that controls the descent of the weight.
3. Isometric Contraction
• In an isometric contraction, the muscle generates force without changing its length. This action is useful for maintaining static positions.
• Example: Holding a plank involves an isometric contraction of the core muscles, as they work to maintain a steady position without movement.
This shows that no matter what role a muscle plays during a movement, whether it’s the main muscle doing the work (agonist), the muscle opposing the work (antagonist), or a helper muscle (synergist), the ability to control that movement depends entirely on how much force the muscle can produce in the action it is responsible. In other words, the strength of a muscle determines how stable and controlled the movement can be. Stronger muscles make it easier to direct movements in the way you want, so inherently speaking, real “Stability” training is Strength training, and Unstable training or modalities used to disrupt balance are a completely different thing.
3. What Research Shows:
• Research has shown that while unstable training can engage smaller muscles to a greater degree, this is because it often reduces the force production in primary muscle groups. This means that you’re not able to lift as much weight or generate as much power, making unstable training less effective for building strength and muscle mass compared to traditional, stable training.
Why Stability Training May Be Unnecessary for Most Athletes
1. Reduced Force Production
• When performing exercises on unstable surfaces (squats on a Bosu ball) the body’s ability to produce force is compromised. Since you can’t lift as heavy, you lose out on the muscle and strength-building benefits of resistance training. Working on a stable surface allows for greater intensity, which is essential for progress.
2. Limited Transfer to Real-World Performance
• Stability training is often marketed as “functional,” but research shows that the benefits don’t necessarily translate to sports performance. Most sports movements: running, jumping, lifting, and throwing, are performed on stable ground, not wobbly surfaces. Training on a stable surface with heavier weights more closely mirrors and translates the demands of sports and daily activities by increasing the function of the muscles used for those skills, making it more effective for functional strength development.
3. Better Core Strength from Traditional Exercises
• Many believe stability training improves core strength, but traditional exercises like squats, deadlifts, and overhead presses activate the core much more effectively. When performed on stable ground, these exercises require the core to stabilize heavy loads, promoting real-world core stability without the need for balance equipment.
4. Higher Risk of Injury
• Unstable training increases the risk of injury, especially when weights are added. Balancing on an unstable surface requires constant micro-adjustments, which can strain muscles and joints in unexpected ways. These activities only improve the specific skill of getting used to using those implements and as previously mentioned have little to no carryover into other functions. For most people, the risks often outweigh the limited rewards.
When Stability Training Can Be Useful
While stability training may not be necessary for building strength and muscle, it has some applications where it can be beneficial:
1. Specific Balance and Coordination Goals:
• For athletes who need specific balance skills, such as skaters, surfers, or circus performers, balance training on unstable surfaces can help improve neuromuscular control in ways more relevant to their sport. Ultimately the rule of specificity trumps all, and the best way to improve something is to be as logically specific to that goal as possible
2. Breaking Through Plateaus:
• If you’ve hit a training plateau, incorporating brief, low-load stability exercises could add a new challenge. However, these should be supplementary to the main workout, not a replacement for stable, high-load training.
Alternatives to Stability Training for Core and Functional Strength
Instead of relying on unstable surfaces, you can build core strength and functional power more effectively with these exercises:
1. Compound Movements:
• Exercises like deadlifts, squats, overhead presses, and rows target major muscle groups and engage core stabilizers. These lifts improve stability and functional strength without compromising force production.
2. Single-Leg Exercises:
• Movements like lunges, Bulgarian split squats, and single-leg deadlifts challenge balance and coordination without sacrificing stability. Single-leg exercises build unilateral strength and stability that are valuable for functional performance.
3. Anti-Rotation and Anti-Flexion Exercises:
• Core exercises such as Pallof presses, plank variations, and dead bugs develop core stability without an unstable surface. These exercises require the core to resist movement, promoting real-world stability.
4. Loaded Carries:
• Exercises like farmer’s walks and suitcase carries engage the entire body and build strength in stabilizing muscles. These functional movements promote core and grip strength while enhancing overall stability.
Closing Thoughts:
While stability training is often marketed as essential for core and functional strength, the reality is that traditional strength exercises are more effective in every way. Unstable training may be useful in highly specific rehabilitation scenarios or for activities requiring unique balance skills, but for most people, sticking to stable ground is the best approach.
Want to maximize your training results without unnecessary equipment? Contact us for a customized strength program focused on effective, stable training techniques that build muscle and power safely.
References:
1. National Strength and Conditioning Association. Essentials of Strength Training and Conditioning. 4th ed., Human Kinetics, 2015.
2. Behm, David G., and Anis Chaouachi. “A Review of the Acute Effects of Unstable and Stability Device Exercises on the Performance of Muscular Fitness.” Journal of Strength and Conditioning Research, vol. 25, no. 11, 2011, pp. 3118-3131.
3. McGill, Stuart M., and Craig R. Marshall. “Core Stability: Muscles, Core, and Spine Stabilization.” Strength and Conditioning Journal, vol. 30, no. 2, 2008, pp. 20-24.
4. Anderson, Kurt, and David G. Behm. “The Impact of Instability Resistance Training on Balance and Stability.” Sports Medicine, vol. 35, no. 1, 2005, pp. 43-53.
5. Norwood, Jeffrey T., et al. “The Effects of Stable vs. Unstable Surfaces on Force Output and Muscle Activation in Lower Body Resistance Exercises.” Journal of Strength and Conditioning Research, vol. 21, no. 1, 2007, pp. 345-353. 6. Saeterbakken, Atle H., and Gertjan Ettema. “The Effect of Unstable Surfaces on Lower Limb Muscle Activation during Resistance Exercises.” Journal of Strength and Conditioning Research, vol. 25, no. 9, 2011, pp. 2702-2710.