The strength of the knees and ankles of a group of nursing home residents with a history of falls was compared to age-matched controls. Peak torque (PT) and power (POW) were recorded at two limb velocities (60 degrees/s and 120 degrees/s) on a Cybex II Isokinetic dynamometer for four muscle groups: knee extensors, knee flexors, ankle plantar flexors and ankle dorsiflexors. The PT and POW of fallers were significantly decreased for all four muscle groups in comparison to controls, with the ankles showing the greatest decrements. Although POW in fallers was significantly lower at the higher velocity in both joints, the decrease was most prominent in the ankles. Dorsiflexion POW production in fallers was the most affected of all the motions (7.5 times less than the control value). At the higher, more functional limb velocities, ankle weakness particularly involving the dorsiflexors appears to be an important factor underlying poor balance.

Balance training meaningfully improved all balance measures by restoring performance to a level analogous to an individual 3 to 10 years younger: LOB = -2.0 +/- 0.3 (adjusted paired differences, P < .005 ANOVA); SST = 7.0 +/- 1.2 sec; and FBOS = 9.0 +/- 2.0% of foot length (P < .05). Strengthening increased ISOK by 1.1 +/- 0.1 Nm kg-1 (P < .005). There was no interaction between balance and strength training. Significant gains persisted after 6 months of Tai Chi, although there was some decrement.

Using dynamic posturography, we studied the balance of 234 community-dwelling elderly subjects (mean age, 76 +/- 5 years) as well as 34 young controls (mean age, 34 +/- 12 years). Almost all measures of balance were worse in elderly subjects compared with young controls. The decrements in older persons indicate a diminished capacity to process conflicting sensory input as well as a possible narrowing of the limit of stability (or, alternatively, an increase in sway). We propose that this occurs most likely as a result of biomechanical or central processing changes as opposed to diminished sensory or vestibular input. Furthermore, with difficult tasks sequentially presented, the performance of the older subjects improved, suggesting that balance, at least in the short term, adapts to stressful conditions. In these elderly subjects screened for age-related diseases affecting balance, only small decrements of balance occurred between the ages of 70 and 85 years. This nominal decrease over a 15-year span suggests that clinically significant balance impairment is the result of age-related disease rather than an inevitable consequence of aging and is therefore potentially treatable.

We evaluated the gait of 49 nursing home residents (27 of whom had a history of recent falls), and 22 controls. Measures consisted of stride length and walking speed, as well as a videotape-based analysis of 16 facets of gait. The study demonstrates that stride length, walking speed, and the assessment of videotaped gait correlated well with each other and were significantly impaired in fallers compared to controls. Arm swing amplitude, upper-lower extremity synchrony, and guardedness of gait were most impaired in fallers. Although subjects who fell were more often demented than controls, it is likely that this represents a selection bias in nursing homes. Visual rating of gait features in the nursing home population is a simple and useful alternative to established methods of gait analysis.