Unstable Surface Training: Does it work?
What Is Unstable Surface Training?
Unstable surface training (UST) is when an exercise is performed on an unstable surface such as a bosu ball, yoga ball, balance board, etc. But why would one choose movements such as squats and bench on a bosu ball or bench press on a yoga ball?
The Benefits of UST
UST has become a widely used tool in rehabilitation and strength training, particularly for reducing the recurrence of ankle sprains and ACL knee injuries. Balance training on a UST device has been shown to decrease the risk of subsequent injury in individuals recovering from ankle or knee injuries.
UST is often used to increase core muscle activation and stability. By introducing instability to traditional stable surface exercises some core muscles experience increased activation. This has led to the belief that UST can enhance overall stability and functional strength.
Functional Training and UST
UST is sometimes categorized as "functional" strength training because it is believed to enhance stability in ways that transfer to sports and daily activities better than stable surface training. However, being on an unstable surface alters neuromuscular recruitment and diminished force output suggest that UST is less "functional" than traditional stable surface resistance training.
The Limitations of UST
Despite its benefits, UST presents several limitations, particularly when applied to healthy / uninjured individuals. One major concern is that it may counteract the neuromuscular training adaptations produced by stable surface training. Research indicates that muscular force output is significantly reduced when exercises such as squats and bench press are performed on an unstable surface. One study found that maximum isometric force output declined by 59.6% when the bench press was performed on an unstable surface compared to a stable one. This suggests that UST compromises the ability to generate maximal force, which can hinder strength development and progressive overload.
Core Activation and Resistance Training
UST can be effective for engaging the abdominal muscles, particularly the rectus abdominis, when resistance exercises are performed on an unstable surface in a supine position. However, standing resistance exercises on an unstable surface are not as effective for core activation compared to stable surface resistance exercises performed with at least 50% of an individual's one-repetition maximum.
Conclusion
So is UST worth doing? Depends on your goals. While UST is a valuable tool in rehabilitation settings for restoring proprioceptive and reactive deficits in individuals with ankle and knee injuries, its application to healthy adults is limited. The reductions in force output, difficulty in achieving progressive overload, and questionable transfer to functional movements suggest that stable surface training is a better option for strength and athletic performance. UST should be used selectively, primarily for rehabilitation purposes rather than as a primary strength training method.
Sources: https://ace-pt.org/ace-physical-therapy-and-sports-medicine-stable-vs-unstable-exercise-surface/https://journals.lww.com/nsca-scj/fulltext/2010/06000/is_unstable_surface_training_advisable_for_healthy.7.aspx