Task-specific training reduces trip-related fall risk in women.

PURPOSE: The potential of task-specific training as a fall-prevention intervention was studied. The primary purpose of the study was to determine the extent to which a task-specific training protocol decreased the number of falls by middle-age and older women after a laboratory-induced trip. Secondary purposes were to explore the ability of trunk kinematics during the initial recovery step and the length of the initial recovery step to correctly classify the trip outcome and to quantify the extent to which the training protocol affected these variables. METHODS: Healthy community-dwelling women (n = 52) were assigned to either a training group or a control group that received no training. Training group women participated in an individually tailored, task-specific training protocol during which forward-directed stepping responses were necessary to avoid a fall after treadmill-delivered postural disturbances. Following the protocol, the ability to avoid a fall after a laboratory-induced trip was assessed. The primary outcome variable was the success (recover) or failure (fall) of the posttrip stepping response. RESULTS: Compared with the control group, there were fewer falls by the trained women after the laboratory-induced trip (P < 0.001; odds ratio = 0.13). Using logistic regression, falls and recoveries after the trip were sensitively classified by trunk flexion angle at the completion of the initial recovery step and the length of the initial recovery step (sensitivity = 0.67, specificity = 0.98), the former of which improved as a result of the task-specific training protocol. CONCLUSIONS: The task-specific training protocol significantly reduced the number of falls after a laboratory-induced trip. Prospective study is required to determine whether this task-specific training reduces falls in the community and, consequently, may complement currently used exercise-based fall prevention intervention methods.

Neural mechanisms underlying balance control in Tai Chi.

BACKGROUND AND AIMS: The efficacy of Tai Chi (TC) to improve neuromuscular response characteristics underlying dynamic balance recovery in balance-impaired seniors at high risk for falling was examined during perturbed walking. METHODS: Twenty-two subjects were randomized into TC or control groups. Nineteen subjects (68-92 years, BERG 44 or less) completed the study. TC training incorporated repetitive exercises using TC's essential motor/biomechanical strategies, techniques, and postural components. Control training used axial exercises, balance awareness/education and stress reduction. Groups trained 1.5 h/day, 5 days/week for 3 weeks. After post-testing, controls received TC training. Subjects walked across a force plate triggered to move forward 15 cm at 40 cm/s at heelstrike. Tibialis anterior and medial gastrocnemius responses during balance recovery were recorded from electromyograms. Four clinical measures of balance were also examined. RESULTS: TC subjects, but not controls, significantly reduced tibialis anterior response time from 148.92 +/- 45.11 ms to 98.67 +/- 17.22 ms (p < or = 0.004) and decreased co-contraction of antagonist muscles (p < or = 0.003) of the perturbed leg. All clinical balance measures significantly improved after TC. CONCLUSIONS: TC training transferred to improved neuromuscular responses controlling the ankle joint during perturbed gait in balance-impaired seniors who had surgical interventions to their back, hips, knees and arthritis. The fast, accurate neuromuscular activation crucial for efficacious response to slips also transferred to four clinical measures of functional balance. Significant enhancement was achieved with 3 weeks of training.

A Tai Chi Chuan training model to improve balance control in older adults.

The first goal of this article is to present nine Tai Chi Chuan training principles and incorporate them into a current model of motor control and motor learning theory. The second goal is to present a Tai Chi Chuan training model. The third goal is to construct a theory as to how Tai Chi Chuan principles may improve balance and motor skills in an aging population. Evidence from the areas of motor control, biomechanics, and human physiology are drawn upon to build a theory of motor skill learning and construct a Tai Chi Chuan training model.

Trunk kinematics and fall risk of older adults: translating biomechanical results to the clinic.

This paper reviews some of our experiences over nearly 15 years of trying to determine modifiable factors that contribute to the high incidence of fall by older adults. As part of our approach, we have subjected healthy young and older adults to very large postural disturbances during locomotion, in the form of trips and slips, to which rapid compensatory responses have been necessary to avoid falling. For both trips and slips, the ability to limit trunk motion has consistently discriminated older adults who fall from both younger adults and older adults who have been able to avoid falling. We have shown that the ability to limit trunk motion can be rapidly acquired, or learned, by older adults as a result of task-specific training. The learned motor skill has demonstrated short-term retention and has been shown to effectively decrease fall-risk due to trips. Collectively, we believe the works strongly suggests that the traditional exercise-based fall-prevention and whole-body, task-specific training can synergize to reduce falls and fall-related injury in older adults.

How Tai Chi improves balance: biomechanics of recovery to a walking slip in impaired seniors.

BACKGROUND AND AIMS: This study examined the effect of Tai Chi (TC) training on biomechanical responses to large, fast walking perturbations in balance-impaired seniors. METHODS: Twenty-two seniors (age 68-92, BERG 44 or less) with surgical interventions to knees, hips, and back were randomly divided into control or TC groups. Groups trained 1.5h/day, 5 days/week for 3 weeks. Controls received TC training after post-control testing. Subjects walked across a force plate triggered to move forward 15cm at 40cm/s at right heel strike (RHS). Kinematics, center of pressure (COP) and center of mass (COM) responses were measured. RESULTS: TC but not control training significantly reduced tripping (p

Neural mechanisms underlying balance improvement with short term Tai Chi training.

BACKGROUND AND AIMS: Though previous research has shown that Tai Chi reduces falls risk in older adults, no studies have examined underlying neural mechanisms responsible for balance improvement. We aimed to determine the efficacy of Tai Chi training in improving neuromuscular response characteristics underlying balance control in balance-impaired older adults. METHODS: Twenty-two balance-impaired older adults were randomly divided into Tai Chi (TC) or control groups. Nineteen subjects (age 68-92, BERG 44 or less) completed the study. TC training included repetitive exercises using TC motor and biomechanical strategies, techniques, and postural elements. Control training included axial mobility exercises, balance/awareness education and stress reduction. Groups trained 1.5 hours/day, 5 days/week for 3 weeks. After post-testing the control group received TC training. Subjects walked across a force plate triggered to move forward 15 cm at 40 cm/sec at heel strike. Tibialis anterior (TA) and medial gastrocnemius (GA) responses during balance recovery were measured with electromyograms (EMGs). Four clinical measures of balance were also recorded. RESULTS: TC subjects, but not controls, significantly reduced both TA response time from 148.92 +/- 45.11 ms to 98.67 +/- 17.22 ms (p < or = 0.004) and occurrence of co-contraction of antagonist muscles (p < or = 0.003) of the perturbed leg. Clinical balance measures also significantly improved after TC. CONCLUSIONS: TC enhanced neuromuscular responses controlling the ankle joint of the perturbed leg. Fast, accurate neuromuscular activation is crucial for efficacious response to slips or trips.