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Training Stability: Research into Practice

posted Mar 12, 2014, 2:28 PM by Ben Jane   [ updated Aug 14, 2014, 6:09 AM ]
Walk through any gym over the last few years and you will often see someone trying to balance on a swiss ball or precariously balanced on a BOSU while bicep curling a set of 10kg dumbbells. What are they up to and more importantly will it work?

Instability training comes in many forms but the rationale behind it is that training with the sudden inconsistent movements of instability will train the neuromuscular system recruiting and developing the motor units that will create more stability and that this increased stability will then translate into improved performance, either by reducing injury or by directly improving performance. Instability training has also developed out of the research by Hodges and Richardson (1997) that identified muscle firing issues in those that had back problems. This lead to the concept that if we can activate and train the core in the right way we would be less likely to become injured.

The reality is that form and technique can be compromised by instability and that the unstable surfaces create an upper limit of maximal force production and can reduce the rate of force development (RFD) of any muscle contractions. Behm & Colado (2012) illustrated from a sample of instability studies that force or power, on average, decreases 29.3% when using an unstable version of a stable exercise. The combination of core muscles recruited is dependent on the task demand and as most gym based stability exercises are quite novel this will have little chance of transferring to elements of performance. Unstable resisted force activities can result in less force (Anderson & Behm, 2004), power, velocity and range of movement (Drinkwater et al, 2007)

It is worth noting that there is often a functional difference between upper body and lower body requirements where in both life and many sports the upper body functions in predominantly open chain movement patterns while the lower body is producing force more often through closed chain movements. Add to this the fact that in most sports the surface used is pretty stable, albeit slippy sometimes, there appears more need to challenge the lower body in a variety of ways, but with the feet (or foot) firmly on the floor while using either a stable or unstable resistance applied via the upper body in some way.

The origins of instability exercise is in the field of rehabilitation and while a significant body of research has shown that training with instability can be of some use to a rehabilitating individual the evidence that it will be of benefit to a healthy individual is less conclusive.

Some examples of relevant findings
  • chest press on a physio ball demonstrates a reduced activation of prime movers and strength compared to a stable bench press. if instability is required then a balance cushion is preferable over a physio ball (Saeterbakken & Fimland, 2013
  • press up on a ball versus feet raised on a bench does not necessarily increase core activation.The relationship between the participant's center of mass, the location of the unstable surface and the body part contacting the Swiss ball are all relevant but no one position is best all round. (Lehman et al, 2006)
  • standing cable push is limited compared to the bench press by the ability of the core musculature reducing the activation of the chest and shoulder joints (Santana et al, 2007)
  • the more weight lifted, the more the core is activated, irrespective of surface (Li et al, 2013)
  • ground based lifts such as deadlifts and squats require higher core activation than less strenuous lifts executed on an unstable surface (Hamlyn et al, 2007)
  • trunk muscle activation does increase with instability (Anderson & Behm, 2005)
  • resistance training in an unstable environment at an intensity sufficient to elicit strength gains of results in detrimental effects in concentric squat kinetics and squat technique. Such observations are particularly evident on very unstable platforms (Drinkwater et al, 2007)
Guidelines (Behm et al, 2009) suggest that in rehabilitation, the use of unstable exercises has been shown to be of benefit when addressing low-back issues or ankle and knee instabilities (Verhagen et al, 2004) but when training athletes unstable devices should not be used if maximum strength, power or hypertrophy is the primary goal. For the general population, ground based, free-weight exercises should form the basis of any programme aimed at developing the core musculature and unstable exercises should only be a supplementary part of the training.

So trainers should use instability with caution, considering the safety-effectiveness of any exercises very carefully and remain aware of the fact that simply lifting heavy where appropriate will be more effective in recruiting the core than jumping around on a BOSU. If unstable exercise is to be included as part of any periodised programme then trainers should recognise that there are many more exercises than those that use swiss balls and BOSUs and some are listed below.

Examples of unstable activities worth considering include:
Koji squats
Slosh pipes
Bottom-Up KB shoulder press
Offset weights (bench press/squat/shoulder press/deadlift)
Using water to create instability (Colado et al, 2013)

Related articles

Further Online Reading
References and Further Reading
  • Anderson, K., & Behm, D. G. (2005). Trunk muscle activity increases with unstable squat movements. Canadian Journal of Applied Physiology,30(1), 33-45.[full text]
  • Behm, D., & Colado, J. C. (2012). The effectiveness of resistance training using unstable surfaces and devices for rehabilitation. International journal of sports physical therapy, 7(2), 226.[html]
  • Behm, D. G., Drinkwater, E. J., Willardson, J. M., & Cowley, P. M. (2010). Canadian Society for Exercise Physiology position stand: The use of instability to train the core in athletic and nonathletic conditioning. Applied Physiology, Nutrition, and Metabolism, 35(1), 109-112.[full text]
  • Behm, D. G., Anderson, K., & Curnew, R. S. (2002). Muscle force and activation under stable and unstable conditions. The Journal of Strength & Conditioning Research, 16(3), 416-422 [full text]
  • Behm, D. G., Leonard, A. M., Young, W. B., Bonsey, W. A. C., & MacKinnon, S. N. (2005). Trunk muscle electromyographic activity with unstable and unilateral exercises. The Journal of Strength & Conditioning Research,19(1), 193-201. [full text]
  • Colado, J. C., Borreani, S., Pinto, S. S., Tella, V., Martin, F., Flandez, J., & Kruel, L. F. (2013). Neuromuscular Responses During Aquatic Resistance Exercise With Different Devices and Depths. The Journal of Strength & Conditioning Research, 27(12), 3384-3390.[full text]
  • Cosio-Lima, L. M., Reynolds, K. L., Winter, C., Paolone, V., & Jones, M. T. (2003). Effects of physioball and conventional floor exercises on early phase adaptations in back and abdominal core stability and balance in women. The Journal of Strength & Conditioning Research, 17(4), 721-725 [full text]
  • Cowley, P. M., Swensen, T., & Sforzo, G. A. (2007). Efficacy of instability resistance training. International journal of sports medicine, 28(10), 829-835.[full text]
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  • Drinkwater, E. J., Pritchett, E. J., & Behm, D. G. (2007). Effect of instability and resistance on unintentional squat-lifting kinetics. International Journal of Sports Physiology & Performance, 2(4) 400-413 [full text]
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  • Hodges, P.W. and Richardson, C.A. (1997). Contraction of the abdominal muscles associated with movement of the lower limb. Physical Therapy. 77(2): 132-144.
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  • Koshida, S., Urabe, Y., Miyashita, K., Iwai, K., and Kagimori, A. (2008). Muscular outputs during dynamic bench press under stable versus unstable conditions. Journal of Strength and Conditioning Research. 22(5): 1584-1588.[abstract]
  • Lederman, E. (2010). The myth of core stability. Journal of bodywork and movement therapies, 14(1), 84-98. [full text]
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  • Lehman, G. J., MacMillan, B., MacIntyre, I., Chivers, M., & Fluter, M. (2006). Shoulder muscle EMG activity during push up variations on and off a Swiss ball. Dynamic Medicine, 5(1), 7.[full text]
  • Lehman, G.L., Gordon, T., Langley, J., Pemrose, P., and Tregaskis, S. (2005). Replacing a swiss ball for an exercise bench causes variable changes in trunk muscle activity during upper limb strength exercises. Dynamic Medicine. 4(6): 1-7.
  • Li, Y., Cao, C., & Chen, X. (2013). Similar Electromyographic Activities of Lower Limbs Between Squatting on a Reebok Core Board and Ground. The Journal of Strength & Conditioning Research, 27(5), 1349-1353.[abstract]
  • Marshall, P. W., & Murphy, B. A. (2006). Increased deltoid and abdominal muscle activity during Swiss ball bench press. The Journal of Strength & Conditioning Research, 20(4), 745-750.[full text]
  • Marshall, P.W. and Murphy, B.A. (2005). Core stability exercises on and off a swiss ball. Arch Phys Med Rehabil. 86: 242-249.
  • Martins, J., Tucci, H. T., Andrade, R., Araujo, R. C., Bevilaqua-Grossi, D., & Oliveira, A. S. (2008). Electromyographic amplitude ratio of serratus anterior and upper trapezius muscles during modified push-ups and bench press exercises. The Journal of Strength & Conditioning Research, 22(2), 477-484 [full text]
  • McBride, J.M., Cormie, P., and Deane, R. (2006). Isometric squat force output and muscle activity in stable and unstable conditions. Journal of Strength and Conditioning Research. 20(4): 915-918.[full text]
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  • Saeterbakken, A. H., & Fimland, M. S. (2013). Electromyographic Activity and 6RM Strength in Bench Press on Stable and Unstable Surfaces. The Journal of Strength & Conditioning Research, 27(4), 1101-1107.[full text]
  • Saeterbakken, A. H., & Fimland, M. S. (2013). Muscle force output and electromyographic activity in squats with various unstable surfaces. The Journal of Strength & Conditioning Research, 27(1), 130-136.[full text]
  • Saeterbakken, A. H., van den Tillaar, R., & Fimland, M. S. (2011). A comparison of muscle activity and 1-RM strength of three chest-press exercises with different stability requirements. Journal of sports sciences,29(5), 533-538.[abstract]
  • Santana, J. C., Vera-Garcia, F. J., & McGill, S. M. (2007). A kinetic and electromyographic comparison of the standing cable press and bench press. The Journal of Strength & Conditioning Research, 21(4), 1271-1277.[abstract]
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