Trip Recovery Training Without a Specialized Treadmill

Study Overview
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Brief Summary
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The goal of this study is to investigate the effects of a novel form of balance training called trip training. Trip training typically involves repeatedly exposing an individual to trip-like losses of balance on a specialized treadmill. This repeated exposure can lead to improvements in responses to trips while walking in the future, thereby reducing the risk of falling after a trip. Trip training typically is commonly conducted using a costly specialized treadmill. This study will evaluate the efficacy of a trip training protocol that does not require a treadmill. Adults age 65-80 will be assigned to either 1) non-treadmill trip training, 2) treadmill trip training, or 3) no intervention. The investigators hypothesized that responses to laboratory-induced trips would be better after non-treadmill trip training compared to no intervention, and that there would be no statistical difference between responses to laboratory-induced trips after non-treadmill trip training and treadmill trip training. The results from this work will advance the use of trip training, and may enable its wider use by establishing a protocol that does not require a costly treadmill.

Official Title
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Trip Recovery Training Without a Specialized Treadmill: A Pilot Randomized Controlled Trial

Conditions
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Accidental Fall

Intervention / Treatment
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* Behavioral: non-treadmill trip training
* Behavioral: treadmill trip training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 65-80 years old willing to use wearable sensors for 2-3 weeks (for a separate study) no lower limb amputation not weigh over 250 pounds pass a telephone interview related to cognitive status Exclusion Criteria: participants must pass a health screening involving a questionnaire that will be reviewed by a health care specialist. participants must not have clinical osteoporosis as indicated by a bone mineral density of the lumbar vertebra and proximal femur of t<-2.0 as obtained from dual energy x-ray absorptiometry (DEXA), or a DEXA scan completed within the last year.

Ages Eligible for Study
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Minimum Age: 65 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: non-treadmill trip training<br>Two training sessions per week will be completed for three consecutive weeks. Each training session will last 0.5-1 hour with an active training time of 30 minutes per participant. Training will involve repeated volitional and reactive stepping movements that mimic the movements necessary to recover balance after tripping while walking. | Behavioral: non-treadmill trip training<br>* Participants practice volitional and reactive stepping responses that mimic those needed when recovering balance after tripping.<br>|
| Experimental: treadmill trip training<br>Two training sessions per week will be completed for three consecutive weeks. Each training session will last 0.5-1 hour with an active training time of 30 minutes per participant. Training will involve repeated exposure to simulated trips on a treadmill. To simulate a trip, participants first stand on the stationary treadmill belt. A sudden and unexpected increase in backward treadmill belt speed induces a forward loss of balance similar to when tripping. Participants are then required to take steps to recover balance and establish a stable gait pattern before the trial ends. Trials are repeated using pseudo-random speeds that provide variability and are individualized to each participant's capabilities. | Behavioral: treadmill trip training<br>* Sudden treadmill changes in speed (from standing) induce trip-like losses of balance, after which participants take steps to recover balance and establish a stable gait pattern. This is repeated over a range of speeds to both provide training variability and to individualize training to each participant's capability.<br>|
| No Intervention: Control<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Trunk angle at touchdown of the first recovery step | After a laboratory-induced trip: Angle from vertical of a line connecting midpoint of greater trochanter markers and midpoint of the acromion markers | during the week after the 3-weeks of intervention | 
| Trip outcome | This is a binary variable that has a value of either fall or recovery. After a laboratory-induced trip, trip outcome will be assign to one of the following two values: fall if a participant is fully and continuously supported by the harness as observed from video, or if the harness force applied to the participant, integrated over time from trip onset until 1 second after touchdown of the first recovery step, is greater than 40% of body weight * seconds. The harness force will be measured by a uniaxial load cell. recovery if the harness force applied to the participant, integrated over time from trip onset until 1 second after touchdown of the first recovery step, is less than 40% of body weight * seconds. The harness force will be measured by a uniaxial load cell. | during the week after the 3-weeks of intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Trunk angular velocity at touchdown of the first recovery step | After a laboratory-induced trip: time derivative of trunk angle, and its value at the instant of touchdown of the first recovery step. | during the week after the 3-weeks of intervention | 
| Recovery step length | After a laboratory-induced trip, the distance between a lateral malleolus marker of the stance limb and a lateral malleolus marker of the stepping foot at touchdown | during the week after the 3-weeks of intervention | 
| Minimum hip height after trip onset | After a laboratory-induced trip, the minimum distance between the walkway and the greater trochanter marker on the non-tripping limb during trip recovery. | during the week after the 3-weeks of intervention | 
| Gait speed | The average forward speed of the participant prior to the laboratory-induced trip. | during the week after the 3-weeks of intervention | 
| Average step speed | After a laboratory-induced trip, the distance between a lateral malleolus marker of the stance limb and a lateral malleolus marker of the stepping foot at touchdown divided by the time from impact with the trip obstacle and touchdown of the initial recovery step. | during the week after the 3-weeks of intervention |