To assess age and gender differences in muscle strength, isometric, concentric (Con), and eccentric (Ecc) peak torque was measured in the knee extensors at a slow (0.52 rad/s) and fast (3.14 rad/s) velocity in 654 subjects (346 men and 308 women, aged 20-93 yr) from the Baltimore Longitudinal Study of Aging. Regression analysis revealed significant (P < 0.001) age-related reductions in Con and Ecc peak torque for men and women at both velocities, but no differences were observed between the gender groups or velocities. Age explained losses in Con better than Ecc peak torque, accounting for 30% (Con) vs. 19% (Ecc) of the variance in men and 28% (Con) vs. 11% (Ecc) in women. To assess age and gender differences in the ability to store and utilize elastic energy, the stretch-shortening cycle was determined in a subset of subjects (n = 47). The older women (mean age = 70 yr) showed a significantly greater enhancement in the stretch-shortening cycle, compared with men of similar age (P < 0.01) and compared with younger men and women (each P < 0.05). Both men and women showed significant declines in muscle quality for Con peak torque (P < 0.01), but no gender differences were observed. Only the men showed a significant decline in muscle quality (P < 0.001) for Ecc peak torque. Thus both men and women experience age-related losses in isometric, Con, and Ecc knee extensor peak torque; however, age accounted for less of the variance in Ecc peak torque in women, and women tend to better preserve muscle quality with age for Ecc peak torque. In addition, older women have an enhanced capacity to store and utilize elastic energy compared with similarly aged men as well as with younger women and men.

To determine the differences between arm and leg muscle quality (MQ) across the adult life span in men and women, concentric (Con) and eccentric (Ecc) peak torque (PT) were measured in 703 subjects (364 men and 339 women, age range 19-93 yr) and appendicular skeletal muscle mass (MM) was determined in the arm and leg in a subgroup of 502 of these subjects (224 men and 278 women). Regression analysis showed that MQ, defined as PT per unit of MM, was significantly higher in the arm ( approximately 30%) than in the leg across age in both genders (P < 0.01). Arm and leg MQ declined at a similar rate with age in men, whereas leg MQ declined approximately 20% more than arm MQ with increasing age in women (P

Objective-To evaluate longitudinal changes in prostate-specific antigen (PSA) levels in men with and without prostate disease.Design-Case-control study of men with and without prostate disease who were participants in a prospective aging study. Setting-GerontologyResearch Center of the National Institute on Aging; the Baltimore (Md) Longitudinal Study of Aging.Patients-Sixteen men with no prostate disease (control group), 20 men with a histologic diagnosis of benign prostatic hyperplasia (BPH), and 18 men with a histologic diagnosis of prostate cancer.Outcome Measures-Multiple PSA and androgen determinations on serum samples obtained from 7 to 25 years prior to histologic diagnosis or exclusion of prostate disease.Results-Changesin androgen levels with age did not differ between groups. Control subjects did not show a significant change in PSA levels with age. There was a significant difference in the age-adjusted rate of change in PSA levels between groups (prostate cancer>BPH>control; P<.01).At 5 years before diagnosis when PSA levels did not differ between subjects with BPH and prostate cancer, rate of change in PSA levels (0.75 μg/L per year) was significantly greater in subjects with prostate cancer compared with control subjects and subjects with BPH. Also, rate of change in PSA levels distinguished subjects with prostate cancer from subjects with BPH and control subjects with a specificity of 90% and 100%, respectively. Conclusions-The most significant factor affecting serum PSA levels with age is the development of prostate disease. Rate of change in PSA levels may be a sensitive and specific early clinical marker for the development of prostate cancer.PROSTATE-SPECIFIC ANTIGEN (PSA) is a serine protease produced by both benign and malignant prostatic epithelium that can be measured in serum samples by immunoassay. 1 Cross-sectional analysis of serum PSA levels in men with and without prostate discent studies suggest that PSA may be useful in the early detection of prostate cancer, 3,4 it is known that PSA elevations occur in men with BPH 2,5,6 and that men with prostate cancer can have normal PSA levels. [4][5][6] are not specific for prostate cancer, and a normal PSA level does not exclude the presence of cancer.The longitudinal changes in PSA that occur with age in men with and without prostate disease have not been reported previously. In addition, although it is well known that PSA is under the influence of androgen, 7,8 the influence of age-related decreases in androgen levels on PSA has not been studied. To better understand the factors that affect PSA levels and potentially improve the use of this valuable clinical marker in men with prostate disease, we evaluated PSA levels in a longitudinal, casecontrol study. METHODS Study GroupsThree groups of men were identified from subjects participating in the Baltimore Longitudinal Study of Aging (BLSA). The BLSA is an ongoing, long-term,prospective aging study of the National Institute of Aging, Bethesda, Md, which has as its goal the study of ...

To determine the effects of strength training (ST) on muscle quality (MQ, strength/muscle volume of the trained muscle group), 12 healthy older men (69 +/- 3 yr, range 65-75 yr) and 11 healthy older women (68 +/- 3 yr, range 65-73 yr) were studied before and after a unilateral leg ST program. After a warm-up set, four sets of heavy-resistance knee extensor ST exercise were performed 3 days/wk for 9 wk on the Keiser K-300 leg extension machine. The men exhibited greater absolute increases in the knee extension one-repetition maximum (1-RM) strength test (75 +/- 2 and 94 +/- 3 kg before and after training, respectively) and in quadriceps muscle volume measured by magnetic resonance imaging (1,753 +/- 44 and 1, 955 +/- 43 cm3) than the women (42 +/- 2 and 55 +/- 3 kg for the 1-RM test and 1,125 +/- 53 vs. 1,261 +/- 65 cm3 for quadriceps muscle volume before and after training, respectively, in women; both P < 0.05). However, percent increases were similar for men and women in the 1-RM test (27 and 29% for men and women, respectively), muscle volume (12% for both), and MQ (14 and 16% for men and women, respectively). Significant increases in MQ were observed in both groups in the trained leg (both P < 0.05) and in the 1-RM test for the untrained leg (both P < 0.05), but no significant differences were observed between groups, suggesting neuromuscular adaptations in both gender groups. Thus, although older men appear to have a greater capacity for absolute strength and muscle mass gains than older women in response to ST, the relative contribution of neuromuscular and hypertrophic factors to the increase in strength appears to be similar between genders.