Biomedical subjects

Taylor J Marcell

Publications and source records attributed to Taylor J Marcell.

6 recordsLinked to original sources

PubMed2006

Endurance exercise and leg strength in older women.

Quadriceps strength and mass peak in the third decade of life, plateau, and then decline from the fifth decade on. To examine the influence of chronic endurance training and age on lean mass and leg strength, women runners (n = 62, age 43-69 years) and sedentary participants (n = 33, age 43-66 years) were divided into 40-, 50-, and 60-year age groups. Absolute isokinetic concentric torque did not differ between runners and sedentary women (97.9 +/- 19.5 and 104.6 +/- 22.7 N . m, respectively, p = .18) but was different between age groups independent of exercise status (107.6 +/- 18.4, 97.1 +/- 19.9, and 90.1 +/- 21.4 N . m, for 40s, 50s, and 60s, respectively, p < .05). Lean body mass also differed by age group (p < .05) but did not change differently among runners and sedentary women. These findings suggest that chronic endurance training might not influence the loss of muscle mass and muscle strength that occur with aging.

Adult↗

PubMed2006

Chronic exercise and skeletal muscle power in older men.

We sought to determine the effects of age and chronic exercise on muscle power in older males. We examined 32 older males 60-74 years of age and grouped as sedentary (CON, n = 11), chronic endurance trained (ET, n = 10), and chronic endurance trained + resistance training (ET + RT, n = 11). Exercise history was obtained by questionnaire. Absolute strength and power measures were obtained by the one-repetition maximum method. Relative strength and power were determined by dividing the absolute measure by the muscle mass involved in the exercise. Total and regional muscle mass was measured by DXA. Absolute and relative leg power were not significantly different among the 3 groups. In contrast, absolute leg press strength was greater in ET + RT compared with CON, and relative leg press strength was greater in ET and ET + RT compared with CON. Chronic running combined with resistance training may therefore enhance absolute and relative muscle strength in older adults, but does not influence muscle power. Endurance exercise may inhibit the ability of resistance exercise to positively influence skeletal muscle power.

Age Factors↗

PubMed2005

Exercise training is not associated with improved levels of C-reactive protein or adiponectin.

The purpose of this study was to determine the effect of exercise training on the levels of C-reactive protein (CRP) and adiponectin, and to assess whether exercise-induced changes in insulin resistance could be explained in part by changes in these inflammation markers. Study participants included 51 middle-aged (45.3+/-8.3 years; mean+/-SD), overweight (33.7+/-4.8 BMI), insulin-resistant, nondiabetic individuals. Subjects had their insulin sensitivity, body fat, CRP, and adiponectin levels measured, and their predicted maximal fitness calculated before and after 16 weeks of moderate, intense, or no exercise training. Modest improvements in fitness, body composition, and insulin sensitivity were observed, but these changes were not associated with decreased CRP or increased adiponectin levels, even when subjects were stratified by their change in fitness or obesity. Regression analysis demonstrated that the change in percentage of body fat was significantly related to changes in insulin sensitivity, whereas changes in VO2 MAX, CRP, and adiponectin were not. Participation in moderate to intense exercise was not associated with improved measures of chronic inflammation markers, as measured by CRP and adiponectin. Moreover, improvements in insulin sensitivity resulting from exercise or modest weight loss did not appear to be related to changes in these markers.

Adiponectin↗

PubMed2003

Sarcopenia: causes, consequences, and preventions.

With the onset of advancing age, muscle tissue is gradually lost, resulting in diminished mass and strength, a condition referred to as sarcopenia. The sequela of sarcopenia often contributes to frailty, decreased independence, and subsequently increased health care costs. The following was adapted from an introduction to the conference "Sarcopenia, Age-Related Muscle Loss-Causes, Consequences, and Prevention," sponsored by the Kronos Longevity Research Institute in June 2002. This brief review will introduce potential mechanisms that may contribute to sarcopenia, although no one mechanism has yet, and may not completely, define this process. The only agreed-upon intervention from these proceedings was regular physical exercise, stressing weight-training for elderly men and women. However, even those individuals who maintain their fitness through exercise do not appear to be immune to sarcopenia.

Aging↗

PubMed2003

Exercise and the master athlete--a model of successful aging?

Exercise as a therapeutic or prophylactic measure is a topic of particular interest in sarcopenia research. Clearly, exercise can be effectively utilized in the treatment of sarcopenia to recover muscle mass and muscle function in older adults. However, perhaps a more important question is the role of exercise in the prevention of age-related decrements in physiological capacities and function. The master athlete has been proposed as an ideal model to determine successful aging due to his or her chronic participation in high-intensity exercise. While extensive research has been conducted describing the age-related decrements in maximal aerobic capacity, the influence of chronic exercise on muscle mass and muscle function has not been as extensively studied. This article reviews the existing evidence concerning the influence of chronic exercise on body composition and skeletal muscle mass, and proposes areas that remain unstudied.

Aging↗

PubMed2003

Longitudinal analysis of lactate threshold in male and female master athletes.

PURPOSE: The lack of relationship between lactate threshold (LT) and running performance in older runners, and the increase in LT with age, has not been previously studied in a longitudinal design. We evaluated the cross-sectional and longitudinal changes in LT with age and compared the changes in LT with changes in performance variables. METHODS: Fifty-one male and 23 female runners (39-77 yr) performed two graded treadmill exercise tests with minute-by-minute venous blood lactate analysis, separated by 5.8 +/- 1.6 yr (mean +/- SD). Body composition was determined by hydrodensitometry and training history by questionnaire. RESULTS: There was no change in LBM over time, but significant decreases in [OV0312]O(2max) and training volume irrespective of age and gender (P < 0.05). LT as a percent of [OV0312]O(2max) increased with age (P < 0.05), demonstrated poor stability over time (r = 0.29, P = 0.01) compared with other parameters measured, and changes in LT were not related to changes in fitness or performance. CONCLUSION: Based upon these findings, we conclude that the LT may be less precise than [OV0312]O(2max) or performance in the prescription of exercise intensities or as an evaluation tool in older individuals.

Adaptation, Physiological↗