Functionally Designed Resistance Exercise With the Aim of Improving Balance, Muscle Strength, Muscle Mass and Physical Function of the Elderly: a Randomized Controlled Study

Background:

Falls and fall-related injuries are major health concerns for elderly individuals; they cause functional decline and increased mortality, as well as incurring vast health care costs for society. Occurrences and consequences of falls are expected to increase globally with the growing number of elderly individuals. Hence, the improved detection of potential fall risk markers is of importance when predicting individuals at risk for falls and subsequently for improving strategies in fall-prevention. Falling can be the end result of intrinsic and extrinsic factors negatively affecting an individual's ability to maintain balance, which are often revealed during sequences of body movement. Balance can be both dynamically and statically measured, the latter involves having the individual in a stationary standing position, from which results researchers have proposed impaired postural stability as a risk factor for falling. However, evidence regarding the association of postural instability with prospective falls is limited, and population-based cohort studies in this field are scarce. Other shortcomings of previous studies include the use of retrospective study designs, which increase the risks of recall bias and the identification of risk factors as the result of falls.

Postural instability is preferably investigated using objective measures of posturography, which has advantages over regular clinical assessments since it reduces test performance variability and avoids the subjective nature of scoring systems. Recently, researchers has analyzed the performance of the Wii Balance Board (WBB) as an instrument for measuring postural instability, revealing excellent concurrent validity and an ability to complement existing fall assessments. However, these findings needed to be evaluated in a population-based sample with a rich set of covariates. Hence, the investigators performed a prospectively observational study to investigate how objective measures of postural sway predicted prospective falls in a cohort of more than 1800 community-dwelling men and women, all of whom were 70 years of age at the time of the investigation.

The results revealed that impaired postural stability can increase the risk of incident falls by 75 to 90% among older adults in the highest quintile of postural sway, measured during trials of both eyes open and eyes closed. One of the conclusions was that it would be valuable to examine the clinical utility of the investigated parameters in future studies, compare performance to established clinical balance tests, and to investigate whether strategies to improve balance would reduce the fall risk. Thus, in a follow-up study the investigators examined wether they could reduce the increased postural sway of participants who was identified as having abnormal balance values, based on previous measurements. The investigators also examined participants' functional balance through Time-Up-and-GO (TUG) performance, together with measures of muscle strength and validated questionnaires on Fear of Falling and Falls Efficacy. This follow-up study was conducted as a randomized intervention study, with a total of 52 individuals recruited from the existing HAI study cohort, with measures of postural sway in the 5th quintile, which indicated impaired balance function. The intervention group performed three supervised group training sessions a week, consisting of 30 minutes of balance training for 4 weeks while the control group received a health consultation highlighting the importance of physical activity and balance exercise. Preliminary data indicated that the exercise intervention had little to no effect on selected measures on balance, strength and physical function. Thus, it may seem that a exercise volume of 4 weeks of progressive balance exercise, 3 sessions per week, might be to low to produce beneficial effects.

The results from this previous study indicated the need for a more comprehensive exercise program in order to produce beneficial effects on balance, strength and physical function, and in the long term, fall prevention. Previous research has shown that low muscle strength together with low muscle mass, also known as sarcopenia, independently predicts falls, fractures and overall poor health. However, a growing body of evidence also indicates that older individuals are able to counteract the trend of age-related loss of muscle mass, as well as improve dynamic balance, through the use of resistance exercise. For older individuals, it is recommended that the exercise regimen lasts for 10-12 weeks, with 3 exercise sessions each week, in order to produce effects on muscle strength, muscle mass and physical function, which is a higher total exercise volume than what was used in the balance exercise study.