Exercises of dynamic stability under unstable conditions increase muscle strength and balance ability in the elderly

Abstract

The purpose of this study was to assess the effectiveness of a specific exercise intervention of mechanisms to control dynamic postural stability under unstable conditions in old adults. Forty-seven old adults (65-80 years) were assigned to 2 experimental groups (muscle strength group, n = 15; perturbation-based group, n = 16) and a control group (n = 16). The strength group performed resistance exercises for leg and trunk muscles, while the perturbation-based group exercised mechanisms of dynamic stability under unstable conditions. The training duration was 14 weeks, with training sessions twice a week for 1.5 hours. Muscle strength, balance ability, and balance recovery performance were investigated before and after the interventions using maximal isometric plantar flexion and knee extension contractions, the approach of the center of pressure to the anterior limits of stability and simulated forward falls. Both interventions increased balance recovery performance in simulated forward falls (81%, d = 1.50 and 80%, d = 1.08 in the muscle strength and perturbation-based group, respectively), while the control group did not show any changes. Plantar flexor strength increased 20% (d = 0.72) in the muscle strength and 23% (d = 1.03) in the perturbation-based group, while muscle strength of the knee extensors increased only in the muscle strength group (8%, d = 0.76). On the other hand, only the perturbation-based group showed a significant improvement of standing balance ability (38%, d = 1.61). We conclude that a perturbation-based training program focusing on exercising mechanisms of dynamic stability in unstable conditions has the potential to enhance muscle strength as well as sensory information processing within the motor system during sudden and static balance tasks and, as a consequence, reduce the risk of falls in old adults.

The relation between cognitive impairment severity and postural stability in the elderly

“…in the anteroposterior balance control, a major role is played by muscles of the lower extremity, mainly the quadriceps femoris and the triceps surae muscles [17]. Among older people, the strength of the quadriceps femoris muscle significantly affects the correct balance control and when weakened, it significantly lowers the postural stability in this group [18,19].…”

Follow-up efficacy of physical exercise interventions on fall incidence and fall risk in healthy older adults: a systematic review and meta-analysis

“…It might be argued that training balance control mechanisms using challenging conditions might improve the feedforward and feedback control of stability [ 68 , 108 – 112 ] in an intensity-related manner, improving recovery performance following subsequent exposure to sudden perturbations during daily life situations. Moreover, it has recently been shown that specific strenuous balance exercises on unstable surfaces (challenging postural conditions) improved both recovery performance and muscle strength [ 113 ], thus increasing the efficiency of the intervention. The authors of the latter study suggested that the instability might increase muscle activation during exercising, which might stimulate strength gains alongside balance control mechanism improvements [ 113 – 115 ].…”

Does the Fatigue Index Induced in Athlete’s Affect Static Balance?

“…Several studies reported positive effects of balance training on static and dynamic balance (Granacher, Mueulbauer, Doerflinger, & Strohmeier, 2011;Yu & Yang, 2012;Mettler et al, 2015;Çankaya et al, 2015;Baccouch, Rebai, & Sahli, 2015;Zemkova et al, 2017;Hamed, Bohm, Mersmann, & Arampatzis, 2017;Simpson et al, 2017). More specifically, static balance exercises are suggested as more effective in balance performance than dynamic balance exercises (Erdoğan et al, 2017).…”