The primary focus of this study was to determine basal levels of myogenic (MRF4, myogenin, MyoD), proteolytic (FOXO3A, atrogin-1, MuRF-1), myostatin, and mitochondrial (PGC-1α & Tfam) mRNA in elderly women before and after aerobic training. This approach was taken to gain insight into the molecular adaptations associated with our observed increases in whole muscle cross sectional area (CSA) (11%, p<0.05), knee extensor muscle function (25%, p<0.05) and aerobic capacity (30%, p<0.05) with training. Nine elderly women (71±2y) underwent muscle biopsies obtained from the vastus lateralis before and after 12-weeks of aerobic training on a cycle ergometer. Post training biopsy samples were acquired 48 hours after the last exercise session. Aerobic training reduced (p < 0.05) resting levels of MRF4 by 25% while myogenin showed a trend to decrease (p = 0.09) after training. FOXO3A expression was 27% lower (p < 0.05) while atrogin-1 and MuRF-1 were unaltered after training. Additionally, myostatin gene expression was decreased (p < 0.05) by 57% after training. Lastly, aerobic training did not alter PGC-1α or Tfam mRNA. These findings suggest that aerobic training alters basal transcript levels of growth related genes in skeletal muscle of older women. Further, the reductions in FOXO3A and myostatin indicate the aerobic training induced muscle hypertrophy in older women may be due to alterations in proteolytic machinery. / School of Physical Education, Sport, and Exercise Science

The purpose of this study was to compare muscle strength and psychomotor performance measures in healthy (n = 18) and frail (n = 21) groups of elderly women utilizing movements requiring various amounts of strength and ballistic action. Subjects were community-dwelling females ranging in age from 66-92 years. Evaluations of functional assessment of motor skills and grip strength occurred. Psychomotor performance was measured through production of aiming movements on a Digitizing Tablet. RT, MT, and movement kinematics (e.g., peak velocity, deceleration, movement adjustments) were evaluated. Differences between groups were apparent in quantity and quality of movement. Healthy subjects were stronger and faster than frail subjects, producing smoother movements with fewer adjustments. Strength appears to differentially affect healthy and frail samples and merits further exploration.

The aim of this research was to investigate myogenic (i.e. growth) and proteolytic (i.e. breakdown) gene expression (GE) in skeletal muscle of young and old women. Myogenic (MyoD, MRF4, Myf5, myogenin, myostatin) and proteolytic (Atrogin-1, MuRF-1, FOXO3A) genes were examined in the basal state and after resistance exercise (RE). Six old women (OW: 85 ± 1 y) and eight young women (YW: 23 ± 1) performed 3 x 10 knee extensions at 70% of 1-repetition-maximum. Muscle biopsies were obtained from the vastus lateralis (i.e. thigh) before and 4 hours after RE.In the basal state, OW expressed higher levels (p<0.05) of MyoD, MRF4, myf5, myogenin, myostatin, FOXO3A and MuRF-1 compared to YW. Fiber type specific GE analysis in the OW showed that slow-twitch muscle fibers (MHC I) expressed higher levels (p<0.05) of myogenin and Atrogin-1, compared to fast-twitch (MHC Ila) fibers. In response to RE both YW and OW increased (p<0.05) mRNA levels of MyoD and MRF4, while a decrease (p<0.05) was observed for myostatin. MuRF-1 mRNA increased (p<0.05) in both age groups, while there was an age-specific induction (p<0.05) of Atrogin-1 after RE. Fiber type specific GE after RE in the old women showed that MHC Ila fibers did not induce myogenic GE. Robust increases (p<0.05) in MyoD, MRF4, and myogenin were only observed in the MHC I fibers. Both fiber types decreased (p<0.05) myostatin, and increased Atrogin-1 with RE. MuRF-1 mRNA levels increased specifically in MHC Ila fibers. In summary, skeletal muscle of OW expresses higher levels of mRNA for most selected genes at rest. With RE, aging skeletal muscle retains the ability to induce myogenic GE, although exclusive to MHC I fibers. After RE, proteolytic GE induction is greater in OW and most pronounced in MHC Ila fibers. Collectively, these data suggest that an imbalance exists in the regulation of the myogenic and proteolytic program in aging skeletal muscle. This research also provides the first evidence of intrinsic molecular differences between MHC I and MHC Ila fibers in OW, and may, in part, explain the MHC Ila atrophy apparent in sarcopenic muscle. / School of Physical Education, Sport, and Exercise Science

The purpose of this investigation was to comprehensively examine the influence of progressive aerobic exercise training on whole muscle size and function in older women (65-80 yr). Three sedentary, healthy, females (66±1 yrs, 167±2 cm, 70±7 kg) performed 12 weeks of supervised progressive cycle training (42 training sessions 3-4 sessions/week up to 80% HRR). Subjects were tested before and after training for maximum aerobic capacity (VO2max), quadriceps cross sectional area (CSA), whole muscle specific tension, concentric 1-RM, maximum voluntary contraction (MVC), and concentric peak power (wafts). On average, the three subjects improved VO2max (34%), quadriceps CSA (10%), MVC (37%), whole muscle specific tension (25%), and concentric peak power (19%). These positive changes indicate that aerobic exercise may positively influence muscle size and function in the elderly. / School of Physical Education, Sport, and Exercise Science