Joyce E. Ballard

PRESS-related statistics : regression tools for cross-validation and case diagnostics

In the health science literature, a common approach of validating a regression equation is data-splitting, where a portion of the data fits the model (fitting sample) and the remainder (validation sample) estimates future performance. The R2 and SEE obtained by predicting the validation sample with the fitting sample equation is a proper estimate of future performance, tending to correct for the natural upward bias of the R2 and SEE obtained from fitting sample alone. Data-splitting has several disadvantages, however. These include: 1) difficulty, arbitrariness, and inconvenience of matching samples; 2) the need to report two sets of statistics to determine homogeneity; and 3) the lack of equation stability due to diluted sample size. The PRESS statistic and associated residuals do not require the data to be split, yield alternative unbiased estimates of R2 and SEE, and provide useful case diagnostics. This procedure is easy to use, is widely available in modern statistical packages, but is rarely utilized. The two methods are contrasted here using a simulation from original data for predicting body density from anthropometric measurements of a group of 117 women. The PRESS approach is particularly appropriate for smaller datasets; methods of reporting these statistics are recommended.

Bone Mineral Density in Hispanic Women: A Review of the Literature with Implications for Promoting Culturally Relevant Osteoporosis Education

Osteoporosis is a disease that primarily affects postmenopausal women of all ethnicities. Demographic projections indicate that the number of Hispanics over age 65 in the U.S. will increase from 2.9 million currently, to 17.5 million in 2050. A majority will be women. Recent research has increased understanding about biocultural correlates of osteoporosis in Hispanic women, and indicates that their risk for the disease is about equal to that of non-Hispanic White (NHW) women. Although Hispanics living in the U.S. share many biological and cultural characteristics with the general population, there are important differences in disease pre-disposition and associated morbidity that present challenges to osteoporosis prevention efforts. The purpose of this article is to provide a review of selected bone density studies that have included Hispanic women, to summarize the findings, and to discuss implications of these findings for osteoporosis prevention education for this population.

Perceptions of older women with cancer participating in an exercise programme: a mixed methods pilot study

Fourteen women over the age of 55 years with a history of cancer were followed during and after completion of a monitored exercise programme intended to improve body strength, functional performance, balance, activities of daily living and quality of life. A sequential explanatory mixed methods design was employed. The quantitative strand utilised a quasi-experimental, pretest/posttest design. The qualitative strand involved individualised interviews 2–3 months following completion of the intervention. The main outcomes were (a) physical characteristics of participants; (b) resistive tests; (c) functional ability; (d) cancer-related fatigue and (e) quality of life. Both study strands indicated that all participants showed significant improvement in resistive tests, functional ability and activities of daily living. Though quantitative results of fatigue and quality of life were statistically nonsignificant, qualitative findings indicated clinically significant improvement.

Tai Chi Exercise on Muscle Strength and Physical Function in Peripheral Neuropathy Patients: 2578 Board #101 June 3, 9: 30 AM - 11: 00 AM.

Tai Chi Exercise on Muscle Strength and Physical Function in Peripheral Neuropathy Patients Joyce E. Ballard1, Arturo A. Arce-Esquivel1, Barbara K. Haas2, Melinda L. Hermanns2, Carol Rizer2, Gary T. Kimmel3, and Yong T. Wang2 1Department of Health and Kinesiology and 2School of Nursing, The University of Texas at Tyler. 3Cancer Foundation for Life, Tyler, Texas An estimated 20 million people in the U.S. suffer from peripheral neuropathy (PN). Patients with PN develop gait abnormalities. Foot pain is one of the factors affecting walking ability. As a result, a large number of individuals with PN suffer from a reduction in daily physical activity and reduced quality of life. Tai Chi appears to be safe and effective in promoting strength and functional capacity in older patients with other chronic disabilities. Purpose: This study aimed to assess the effects of Tai Chi on muscle strength and physical function in patients with PN. Methods: Thirty seven participants (men=21, women=16) were randomly assigned to either Tai Chi exercise (Ex, n=20, age: 71 ± 9.50 years) or control group (Con, n=17, age: 75 ± 9.02 years). Exercise training consisted of 12-week progressive Tai Chi (i.e., Yang Style), offered 3 times per week, 60 minutes each time. Before and after training, muscle strength [One repetition maximum (1RM) for leg extension and leg curl] and physical function [time of 8-foot up-and-go; TUG] were evaluated. Results: Muscle strength increased significantly in the Ex group [leg extension: pre = 26.76 ±16.05; post = 46.12±25.55 kg; leg curl: pre = 28.69±13.51; post = 44.22±13.97 kg; (p<0.05)]. In addition, the TUG decreased significantly in the Ex group [pre = 12.34±5.73; post = 7.43±2.87 sec, (p<0.05)]. No significant changes were observed in the Con group. Conclusions: Clearly, these findings demonstrated that Tai Chi was capable of increasing lower extremity muscle strength and physical function among PN patients. Interestingly, the exercise training program was able to reduce the risk for loss of functional mobility (i.e., decreased 8-foot up-and-go time) among the participants.

Effect of Tai Chi on Vascular Function Among Patients with Peripheral Neuropathy

Foot pain due to Peripheral Neuropathy (PN) is one of the factors affecting walking ability. It has been reported that diminished vascular function contributes to a decrease in physical function in individuals with PN. Microvascular disturbances have been reported in humans with neuropathic pain. Tai Chi, a Chinese conditioning exercise, has been associated with enhanced endothelial function. However, the effect of Tai Chi training on microvascular function in patients with PN has not been studied. This study aimed to assess the effects of Tai Chi on vascular function (i.e., vascular reactivity) and functional exercise capacity among patients with PN. Thirty-seven participants (men = 21, women = 16) were randomly assigned to either Tai Chi exercise (Ex, n = 20, age: 71 ± 9.50 years) or control group (Con, n = 17, age: 75 ± 9.02 years). Exercise training consisted of 12-week progressive Tai Chi (i.e., Yang Style), offered 3 times per week, 60 minutes sessions. The Con group didn’t participate in any exercise activity. Before and after training, vascular function [fingertip Digital Thermal Monitoring (DTM) of vascular reactivity] and functional exercise capacity [Six-Minute Walk test (6MW)] were evaluated. The Ex group experienced a significant 25% increase in Vascular Reactivity Index (VRI) from baseline [1.93 ± 0.43 to 2.41 ± 0.47, (p < 0.05)]. In addition, the 6MW test increased significantly in the Ex group by 28% [pre = 392 ± 93; post = 503 ± 105 m, (p < 0.05)]. In the control group no significant changes were observed in either vascular function [1.83 ± 0.43 to 1.81 ± 0.37] or in the 6MW test [393 ± 142 to 398 ± 149 m]. Participants experienced no complications and/or falls as a result of the intervention. These findings demonstrated that in patients with PN, a 12-week progressive Tai Chi exercise program was capable of increasing not only vascular function, specifically vascular reactivity index, but also of increasing the distance covered during the 6MW test. Clearly, this study underlies the importance of Tai Chi as an effective and safe exercise intervention suitable for patients with PN. Received Date: August 03, 2016 Accepted Date: October 26 2016 Published Date: November 03, 2016 Citation: Arce-Esquivel, A.A., et al. Effect of Tai Chi on Vascular Function among Patients with Peripheral Neuropathy. (2016) J Heart Cardiol 2(4): 16.

Effects of Resistance Training on Bone and Muscle Mass in Older Women: A Review

Aging is associated with declines of different physiological systems. These reductions are directly related to loss of mobility in older individuals, reducing the independence and quality of life for this population. Regular physical activity (e.g, resistance training, RT), has been shown to decrease mortality and age-related morbidity in older adults, including women. A fracture is closely related to the typical decline in bone mass (i.e, osteoporosis) especially in postmenopausal women. In fact, up to 30% of postmenopausal females have osteoporosis. In postmenopausal women the rate of bone mineral density loss progressively increases with age. In addition, decreases in muscle tissue (i.e, sarcopneia) may begin to occur before the fourth decade and gradually worsens through the later stages of adulthood. Sarcopenia, is characterized by low muscle mass, low muscle strength, and low physical performance, which can lead to disability, risk of falls and fractures, and death. Further, sarcopenia occurs to a greater degree in older women than men. Menopause is characterized by important changes in hormonal status and these changes have a significant effect on body composition (i.e, bone mass density, muscle mass, and body fat). Importantly, RT is effective in increasing bone and muscle mass and improving measurements of physical performance. Thus, this review is intended to summarize the effects of RT on bone and muscle mass in older postmenopausal women.

Body composition alterations consequent to an exercise program for pre and postmenopausal women

The purposes of this study were: (a) to evaluate the effects of an exercise program upon the body composition of premenopausal (no. 43) and postmenopausal (no. 66) women, aged 35-70 years, and (b) to compare exercise Ss with age matched control Ss. Body composition was assessed by skinfold measurement and hydrostatic weighing. Exercise Ss walked or jogged and performed light resistive exercise for 60 minutes per day three times per week for 24 weeks. Control Ss remained sedentary. ANOVAs revealed: (a) no significant (p greater than or equal to .05) differences in exercise training effects between premenopausal and postmenopausal Ss, and (b) exercise Ss exhibited less body fatness while control Ss possessed more body fat as represented by significant changes (p less than or equal to .05) for the exercise and control Ss, respectively in: body density (+.002 g/cc, -.001 g/cc); % fat (-1.2%, +.6%); fat weight (-.4 kg, +1.1 kg); suprailiac skinfold (-.3 mm, +7 mm); and abdominal skinfold (-.3 mm, +1.5 mm). It was concluded that: (a) menopausal status did not alter the effects of exercise in this study, and (b) exercise training produced a positive effect in the exercise Ss by reversing body composition trends associated with a sedentary lifestyle.

Abstract sectionBody composition alterations consequent to an exercise program for pre and postmenopausal women : J. Sports Med. Phys. Fitness 1990 30/4 (426–433)

The purposes of this study were: (a) to evaluate the effects of an exercise program upon the body composition of premenopausal (no. 43) and postmenopausal (no. 66) women, aged 35-70 years, and (b) to compare exercise Ss with age matched control Ss. Body composition was assessed by skinfold measurement and hydrostatic weighing. Exercise Ss walked or jogged and performed light resistive exercise for 60 minutes per day three times per week for 24 weeks. Control Ss remained sedentary. ANOVAs revealed: (a) no significant (p greater than or equal to .05) differences in exercise training effects between premenopausal and postmenopausal Ss, and (b) exercise Ss exhibited less body fatness while control Ss possessed more body fat as represented by significant changes (p less than or equal to .05) for the exercise and control Ss, respectively in: body density (+.002 g/cc, -.001 g/cc); % fat (-1.2%, +.6%); fat weight (-.4 kg, +1.1 kg); suprailiac skinfold (-.3 mm, +7 mm); and abdominal skinfold (-.3 mm, +1.5 mm). It was concluded that: (a) menopausal status did not alter the effects of exercise in this study, and (b) exercise training produced a positive effect in the exercise Ss by reversing body composition trends associated with a sedentary lifestyle.

Body composition alterations consequent to an exercise program for pre and postmenopausal women : J. Sports Med. Phys. Fitness 1990 30/4 (426–433)

The purposes of this study were: (a) to evaluate the effects of an exercise program upon the body composition of premenopausal (no. 43) and postmenopausal (no. 66) women, aged 35-70 years, and (b) to compare exercise Ss with age matched control Ss. Body composition was assessed by skinfold measurement and hydrostatic weighing. Exercise Ss walked or jogged and performed light resistive exercise for 60 minutes per day three times per week for 24 weeks. Control Ss remained sedentary. ANOVAs revealed: (a) no significant (p greater than or equal to .05) differences in exercise training effects between premenopausal and postmenopausal Ss, and (b) exercise Ss exhibited less body fatness while control Ss possessed more body fat as represented by significant changes (p less than or equal to .05) for the exercise and control Ss, respectively in: body density (+.002 g/cc, -.001 g/cc); % fat (-1.2%, +.6%); fat weight (-.4 kg, +1.1 kg); suprailiac skinfold (-.3 mm, +7 mm); and abdominal skinfold (-.3 mm, +1.5 mm). It was concluded that: (a) menopausal status did not alter the effects of exercise in this study, and (b) exercise training produced a positive effect in the exercise Ss by reversing body composition trends associated with a sedentary lifestyle.