Comparing Training On Stable Versus Unstable Surfaces

The advantages and disadvantages of unstable surface training have been discussed ad nauseam (e.g. Hubbard, 2010; Behm & Sanchez, 2013). Here, I want to focus on if strength gains are stability-specific. To do this, we can look at studies exploring:

  1. Training with stable vs. unstable surfaces, then testing strength on stable surfaces
  2. Training with stable vs. unstable surfaces, then testing an athletic ability

#1. Comparisons of training on stable vs. unstable surfaces on strength on stable surfaces

Very few studies have compared the effects of training on stable vs. unstable surfaces on strength on stable surfaces. Those that have are summarized in a recent systematic review (Behm et al. 2015), although the measures used to test strength were not differentiated from one another, which makes the results difficult to interpret.

The most stable surface typically measured in studies is maximum isometric force, using a dynamometer. Training on unstable surfaces tends to produce similar gains in maximum isometric force as training on stable surfaces (Kibele & Behm, 2009; Sparkes & Behm, 2010; Prieske et al. 2016).

The second most stable surface typically measured in studies is maximum dynamic force, using the strength exercise used in the stable-surface training group, such as 1RM bench press (Cowley et al. 2007; Marinković et al. 2012; Premkumar et al. 2012; Maté-Muñoz et al. 2014), 3RM bench press (Sparkes & Behm, 2010), 6RM bench press (Saeterbakken et al. 2016), 1RM back squat (Marinković et al. 2012; Maté-Muñoz et al. 2014), and 3RM back squat (Sparkes & Behm, 2010). Training on unstable surfaces seems to produce similar gains in dynamic strength in the exercise used during training, compared to training with the same exercise on stable surfaces.

This suggests that there is no evidence of stability-specific strength when testing strength on stable surfaces after either stable or unstable surface training. However, although not as well-researched, there are some suggestions that gains in strength on unstable surfaces might be greater after training on unstable surfaces (Sparkes & Behm, 2010; Saeterbakken et al. 2016), which would mean that stability-specific strength gains still occur, albeit only in one direction.

Importantly, however, all of these studies were performed in untrained individuals. 

Since there are indications that unstable surface training does not lead to greater EMG amplitudes than stable surface training with the same absolute loads in resistance-trained individuals (Wahl & Behm, 2008; Li et al. 2013), training on unstable surfaces may not be as effective as training on stable surfaces in trained subjects.

#2. Comparisons of training on stable vs. unstable surfaces on athletic performance

Very few studies have compared the effects of training on stable vs. unstable surfaces on athletic performance measures. Those that have are summarized in a recent systematic review (Behm et al. 2015), although the measures used to assess athletic ability are not differentiated, which makes the results difficult to interpret.

Looking only at those studies exploring the effects of lower body strength training on countermovement jump height, a majority have found that performing the exercises on stable surfaces is better than performing the exercises on unstable surfaces (Cressey et al. 2007; Oberacker et al. 2012), although a minority have found no differences (Maté-Muñoz et al. 2014).

This suggests that lower body training on unstable surfaces may not transfer as well the same exercises performed on the ground to common tests of athletic ability, such as vertical jumping.

Summary of results

• Unstable surface training does improve strength on stable surfaces to a similar extent as stable surface training in untrained subjects. However, this may not apply to trained individuals.

• Unstable surface training may not improve common tests of athletic ability as well as the same exercises performed on the ground.

 

Written by Chris Beardsley for Strength and Conditioning.

Looking to bring awareness to adding stability drills to strengthening,

Dr. Phil Kotzan, DC