Muscle atrophy and weakness greatly increase the risk and incidence of falling in community dwelling older individuals with normal cognition. Hence, improving the muscle conditioning of an elderly individual at high risk of falling via a multi-component exercise fall reduction program (MCEFRP) may decrease the incidence of falls. Muscle conditioning often requires considerable effort, yet many elderly individuals lack the energetic reserves required for maximizing muscle conditioning, i.e., via high-intensity exercise. However, those who do participate in low-intensity exercise have blunted benefits (compared to high intensity) in muscle conditioning and falling risks. We have explored the safety and feasibility of a high-intensity Resistance Exercise via Negative, Eccentrically-induced Work (RENEW) in multiple groups of deconditioned elderly males and females, many characterized as being at a high fall risk. In contrast to traditional resistance exercise (TRAD), RENEW is novel and advantageous in that RENEW: is a high-intensity exercise for muscle, yet requires little effort (resulting in high levels of adherence);induces unprecedented muscle conditioning (by increasing size, strength and power) and finally;decreases falling risks (by improving balance, mobility and confidence). This proposal is unique and timely because it is unknown if RENEW's amplified muscle effects translate to a decreased incidence of falls. This R01 application is the natural next step in determining the "proof of concept" regarding RENEW and how resistance exercises are designed in elderly rehabilitation and wellness settings, and specifically as part of a MCEFRP. A determination of the mediating influence of muscle conditioning on falling risks and fall incidence, will also direct "best-practice" patterns which impact muscle conditioning. In order to test the mediating influence of muscle conditioning and its effect on falling risks and fall incidence following 3 months of RENEW or TRAD this randomized, blinded, pre/post, longitudinal, phase II clinical trial in at-risk older individuals will address the following specific aims: 1) test whether RENEW's effect is different than Trad's effect on muscle conditioning, (muscle size, strength and power);2) test whether the effects of RENEW on falling risks (balance, mobility and confidence) is mediated by muscle conditioning;and 3) determine if RENEW lowers fall incidence more than TRAD. As well, we will explore if the direct and indirect mediating effects of muscle conditioning are sustained up to 1 year, i.e., following 3 and 9 months of no formal training.
A fall in an older individual is a major health care and societal problem, stemming in large part from muscle weakness and mobility limitations. An exercise that is easy to perform and can address muscle and mobility deficits may lessen the number of falls that occur. Eccentric muscle exercise has lessened fall-risk and this trial will determine if it actually reduces fall occurrences.
|Smith, Jessica W; Marcus, Robin L; Tracy, Brian L et al. (2016) Stance time variability during stair stepping before and after total knee arthroplasty: A pilot study. Hum Mov Sci 45:53-62|
|Chung-Hoon, Kaiwi; Tracy, Brian L; Dibble, Leland E et al. (2016) The Association Between Knee Extensor Force Steadiness, Force Accuracy, and Mobility in Older Adults Who Have Fallen. J Geriatr Phys Ther 39:1-7|
|Marcus, Robin L; LaStayo, Paul C; Ikizler, T Alp et al. (2015) Low Physical Function in Maintenance Hemodialysis Patients Is Independent of Muscle Mass and Comorbidity. J Ren Nutr 25:371-5|
|Jacobs, Janelle L; Marcus, Robin L; Morrell, Glen et al. (2014) Resistance exercise with older fallers: its impact on intermuscular adipose tissue. Biomed Res Int 2014:398960|
|Marcus, R L; Addison, O; LaStayo, P C (2013) Intramuscular adipose tissue attenuates gains in muscle quality in older adults at high risk for falling. A brief report. J Nutr Health Aging 17:215-8|
|Yoshida, Yuri; Marcus, Robin L; Lastayo, Paul C (2012) Intramuscular adipose tissue and central activation in older adults. Muscle Nerve 46:813-6|
|Lastayo, Paul C; Larsen, Stephanie; Smith, Sheldon et al. (2010) The feasibility and efficacy of eccentric exercise with older cancer survivors: a preliminary study. J Geriatr Phys Ther 33:135-40|