Mobility and Falls in the Elderly

The Biomechanics of Mobility and Falls is aimed at developing methods to reduce the injury risks, especially in the elderly population. Current research projects in this field include:

Muscle Strength Training

Knee extensor muscle weakness has been shown to increase the risk of falls in the elderly four-fold.  In order to prevent these falls, we need to determine the most efficient way to increase the knee extensor strength in the elderly.  Progressive resistance training with higher muscle force while the muscle is lengthening (referred to as Lengthening Contraction Training or LC Training) has shown promise as a more effective form of strength training.  However, the mechanisms driving muscle adaptation in this training are poorly understood.  Our research, conducted at the single muscle fiber, whole muscle, and whole body level, is to better understand the mechanisms leading to muscle strength gain at any age.

Primary Investigator: Dr. James Ashton-Miller
Graduate Student Researcher: Mark Gordon
 (sponsored by Institute of Gerontology Pre-Doctoral Fellowship)

Falls in Adult Patients with Peripheral Neuropathy

Peripheral Neuropathy (PN) is caused by the death of the longest nerves in the body, i.e those that innervate the feet and hands. PN is common in patients with diabetes and heavy metal poisoning. Due to their difficulties with balance, patients with PN have 20 times the rates of falls and 6 times the rate of fractures compared with healthy controls. This research, funding by an NIH R01 grant, is aimed at determining whether the major impairment is sensory, motor, or sensorimotor. Using randomized underfoot perturbations during level gait, we are identifing the effect of PN on short and long loop reflexes during gait. Biomechanical modeling is used to understand how delays in these reflexes cause instablility and falls during gait. We are also investigating various interventions that can be used to help reduce fall related injuries in these patients.

Primary Investigator: Dr. James Ashton-Miller
Graduate Student Researcher: Hogene Kim

Effect of Age and Gender on Upper Extremity Muscle Strength

Fall-related injuries can have a devistating effect on the elderly’s quality of life. Indeed, more elderly die from injuries as a result of a fall than from motor vehicle accidents. Our research is aimed at investigating the biomechanics of falls and developing methods to reduce the injury risk from falls, especially in the elderly.  If we could obtain insights that certain arrest strategies can significantly lower the risk for hip and wrist fracture, for example, then those insights could form the basis for future injury prevention programs, perhaps even starting in children.  In a forward fall the elbow and shoulder muscles must be strong enough to arrest the momentum of the head and trunk before they strike the ground.  Having enough strength may be a particular problem for elderly women.  The goals of this research are to determine the effect of age and gender on the resistance of the elbow and shoulder extensor muscles to the large impulsive loads associated with arresting a fall to the ground.

Primary Investigator: Dr. James Ashton-Miller
Graduate Student Researcher: Yunju Lee

Developing a Safe Falling Technique for the Elderly

Hip fractures in the elderly are a significant socioeconomic problem: up to 20% of those who fracture their hip die within a year and another 20% never regain mobility.  Statistics predict the number of people affected by this injury to increase as life expectancy and the elderly population increase.  Research shows that sideways falls with impact to the greater trochanter of the femur cause most hip fractures.  Our goal is to capitalize on insights obtained by Joshua Lo in his recent PhD thesis conducted in the laboratory. Specifically, we are developing a safe fall technique that we can teach others to minimize hip fracture risk.

Primary Investigator: Dr. James Ashton-Miller
Undergraduate Student Researcher: Sarah Ilkhani-Pour