The primary purpose of this paper was to compare the effect of reversing the direction of step initiation in Parkinson's disease. Forward (FDS) and backward (BDS) oriented stepping initiation analyses were conducted on combined kinematic and kinetic data recorded on Parkinsonian patients (PD) and healthy age-matched subjects. Two successive phases were examined: a postural phase from T1 (onset of the center of pressure [CP] displacement) to T2 (onset of the malleolus displacement), which was followed by a stepping phase from T2 to T3 (end of the malleolus displacement; i.e., the end of the step). In healthy subjects, the duration of the postural phase remained unchanged regardless of the direction in which the step was initiated. The stepping phase duration and the first step length were reduced in BDS in comparison with FDS. In both tasks, the absolute value of the horizontal force in sagittal plane (Fx) remained unchanged. The maximal velocity of the iliac crest marker (estimated whole body center of gravity [CG]) in the sagittal plane (Vmax CG) remained within the same range regardless of direction of stepping. In Parkinsonian patients, the duration of the postural phase was markedly prolonged in both tasks in comparison with healthy subjects. The mean duration of stepping phase was approximately the same as in normal subjects, but the first step length was considerably reduced, as were horizontal force (Fx) and Vmax CG. This impairment, which was due to a decrease in the propulsive forces, was significantly more pronounced in BDS that in FDS.
Nikolai Gantchev, François Viallet, Roselyne Aurenty and Jean Massion
Anamica Batra, Stefany Coxe, Timothy F. Page, Michael Melchior and Richard C. Palmer
Despite the well-known benefits of exercise, only 50% of U.S. women met recommended physical activity levels in 2014. To combat this issue, the Healthy Aging Regional Collaborative of South Florida has been offering the EnhanceFitness (EF) program in community-based settings since 2008. In the current study, we examined the factors associated with the program completion among older women (≥ 60 years). During the first 4 years, 3,829 older women attended EF sessions. Of these, 924 (24.2%) attended the recommended 32 sessions within first 4 months. Results revealed that women who lived in Miami-Dade County, were ≥ 80 years, and did not report depression and/or risk factors for chronic conditions were more likely to complete EF. Black women were less likely to complete the program. Recognition of these factors might help identify at-risk individuals. More efforts are needed to improve completion rates. Theory-based interventions would allow comprehensive understanding of all factors and, therefore, should be explored in the future.
Jennifer L. Copeland and Dale W. Esliger
Despite widespread use of accelerometers to objectively monitor physical activity among adults and youth, little attention has been given to older populations. The purpose of this study was to define an accelerometer-count cut point for a group of older adults and to then assess the group’s physical activity for 7 days. Participants (N = 38, age 69.7 ± 3.5 yr) completed a laboratory-based calibration with an Actigraph 7164 accelerometer. The cut point defining moderate to vigorous physical activity (MVPA) was 1,041 counts/min. On average, participants obtained 68 min of MVPA per day, although more than 65% of this occurred as sporadic activity. Longer bouts of activity occurred in the morning (6 a.m. to 12 p.m.) more frequently than other times of the day. Almost 14 hr/day were spent in light-intensity activity. This study demonstrates the rich information that accelerometers provide about older adult activity patterns—information that might further our understanding of the relationship between physical activity and healthy aging.
Sunday Azagba and Mesbah Fathy Sharaf
In spite of the substantial benefits of physical activity for healthy aging, older adults are considered the most physically inactive segment of the Canadian population. This paper examines leisure-time physical inactivity (LTPA) and its correlates among older Canadian adults.
We use data from the Canadian Community Health Survey with 45,265 individuals aged 50–79 years. A logistic regression is estimated and separate regressions are performed for males and females.
About 50% of older Canadian adults are physically inactive. Higher odds of physical inactivity are found among current smokers (OR = 1.52, CI = 1.37–1.69), those who binge-drink (OR = 1.24, CI = 1.11–1.39), visible minorities (OR = 1.60, CI = 1.39–1.85), immigrants (OR = 1.13, CI = 1.02–1.25), individuals with high perceived life stress (OR = 1.48, CI = 1.31–1.66). We also find lower odds of physical inactivity among: males (OR = 0.89, CI = 0.83 to 0.96), those with strong social interaction (OR = 0.71, CI = 0.66–0.77), with general life satisfaction (OR = 0.66, CI = 0.58–0.76) and individuals with more education. Similar results are obtained from separate regressions for males and females.
Identifying the correlates of LTPA among older adults can inform useful intervention measures.
J.A. Goon, A.H. Noor Aini, M. Musalmah, M.Y. Yasmin Anum, W.M. Wan Nazaimoon and W.Z. Wan Ngah
The biochemical mechanisms involving oxidative stress to explain the relationship between exercise and healthy aging are still unclear.
Tai Chi participants and matched sedentary volunteers age 45 and above were enrolled. Glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities; levels of DNA damage using the comet assay; and malondialdehyde (MDA) and advanced glycation end products (AGE) were determined at 0, 6, and 12 months.
Tai Chi subjects had decreased normal and increased mildly damaged DNA with elevated GPx activity after 6 months (n = 25). Plasma MDA and AGE concentrations decreased significantly after 12 months (n = 15) accompanied by increased SOD activity. This may be attributed to the hormesis effect, whereby mild induction of oxidative stress at the first 6 months of exercise resulted in stimulation of antioxidant defenses. These parameters were unchanged in the sedentary subjects in the first 6 months (n = 27) except for elevated SOD activity. After 12 months, the sedentary subjects (n = 17) had decreased normal DNA and increased severely damaged DNA with unaltered MDA and AGE levels while SOD and GPx activities were significantly elevated.
Regular Tai Chi exercise stimulated endogenous antioxidant enzymes and reduced oxidative damage markers.
Ram Haddas, Steven F. Sawyer, Phillip S. Sizer, Toby Brooks, Ming-Chien Chyu and C. Roger James
Recurrent lower back pain (rLBP) and neuromuscular fatigue are independently thought to increase the risk of lower extremity (LE) injury. Volitional preemptive abdominal contraction (VPAC) is thought to improve lumbar spine and pelvis control in individuals with rLBP. The effects of VPAC on fatigued landing performance in individuals with rLBP are unknown.
To determine the effects of VPAC and LE fatigue on landing performance in a rLBP population.
Cross-sectional pretest-posttest cohort control design.
A clinical biomechanics laboratory.
32 rLBP (age 21.2 ± 2.7 y) but without current symptoms and 33 healthy (age 20.9 ± 2.3 y) subjects.
(i) Volitional preemptive abdominal contraction using abdominal bracing and (ii) fatigue using submaximal free-weight squat protocol with 15% body weight until task failure was achieved.
Main Outcome Measure(s):
Knee and ankle angles, moments, electromyographic measurements from semitendinosus and vastus medialis muscles, and ground reaction force (GRF) were collected during 0.30 m drop-jump landings.
The VPAC resulted in significantly earlier muscle onsets across all muscles with and without fatigue in both groups (mean ± SD, 0.063 ± 0.016 s earlier; P ≤ .001). Fatigue significantly delayed semitendinosus muscle onsets (0.033 ± 0.024 s later; P ≤ .001), decreased GRF (P ≤ .001), and altered landing kinematics in a variety of ways. The rLBP group exhibited delayed semitendinosus and vastus medialis muscle onsets (0.031 ± 0.028 s later; P ≤ .001) and 1.8° less knee flexion at initial contact (P ≤ .008).
The VPAC decreases some of the detrimental effects of fatigue on landing biomechanics and thus may reduce LE injury risk in a rLBP population.
Eric Tsz-Chun Poon, John O’Reilly, Sinead Sheridan, Michelle Mingjing Cai and Stephen Heung-Sang Wong
Weight-making practices, regularly engaged in by horse racing jockeys, have been suggested to impair both physiological and mental health. This study aimed to assess bone health markers, nutritional intake, bone-specific physical activity (PA) habits, and quality of life of professional jockeys in Hong Kong (n = 14), with gender-, age-, and body mass index-matched controls (n = 14). Anthropometric measurements, serum hormonal biomarkers, bone mineral density, bone-specific PA habits, nutritional intake, and quality of life were assessed in all participants. The jockey group displayed significantly lower bone mineral density at both calcanei than the control group (left: 0.50 ± 0.06 vs. 0.63 ± 0.07 g/cm2; right: 0.51 ± 0.07 vs. 0.64 ± 0.10 g/cm2, both ps < .01). Thirteen of the 14 jockeys (93%) showed either osteopenia or osteoporosis in at least one of their calcanei. No significant difference in bone mineral density was detected for either forearm between the groups. The current bone-specific PA questionnaire score was lower in the jockey group than the control group (5.61 ± 1.82 vs. 8.27 ± 2.91, p < .05). Daily energy intake was lower in the jockeys than the controls (1,360 ± 515 vs. 1,985 ± 1,046 kcal/day, p < .01). No significant group difference was found for micronutrient intake assessed by the bone-specific food frequency questionnaire, blood hormonal markers, and quality of life scores. Our results revealed suboptimal bone conditions at calcanei and insufficient energy intake and bone-loading PAs among professional jockeys in Hong Kong compared with healthy age-, gender-, and body mass index-matched controls. Further research is warranted to examine the effect of improved bone-loading PAs and nutritional habits on the musculoskeletal health of professional jockeys.
Giovanni Mario Pes, Maria Pina Dore, Alessandra Errigo and Michel Poulain
British twins ( Cherkas et al., 2008 ) and the Louisiana Healthy Aging Study ( Frisard et al., 2007 ; Johannsen et al., 2008 ) showed that, in addition to a significant decrease in mortality, regular exercise was associated with improved late-life physical function. The association between moderate
Beatriz H. Thames and Stacey L. Gorniak
fingertips in a type II diabetes patient cohort previously evaluated by our lab. As such, the working hypothesis of the study is that type II diabetes patients will exhibit μ changes at the fingertips as compared to healthy age- and sex-matched controls. Methods Study Participants Ten (10) individuals with
Marcus Colon, Andrew Hodgson, Eimear Donlon and James E.J. Murphy
highlight the importance of exercise and exercise intensity in healthy aging. TL has previously been shown to contribute to mortality in age-related diseases such as heart and infectious diseases ( Cawthon, Smith, O’Brien, Sivatchenko, & Kerber, 2003 ); these results show that exercise could represent a