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An investigation was conducted to determine if laryngeal valving economy, as reflected in measures of laryngeal airway resistance during vowel production, varies across adulthood. Toward this end, sixty healthy men were studied, ten from each of six age groups--25, 35, 45, 55, 65, and 75 years (± 2 years). Results showed that there are age-related differences in laryngeal airway resistance during vowel production, and that these differences are characterized by a lower mean resistance in 75-year-old men than in younger men of the ages studied. This finding provides insight into mechanisms regarding the impact of age on laryngeal function and has important clinical implications for the evaluation and management of men with voice disorders.

Several studies have reported that rating of perceived exertion (RPE) covaries more with blood lactate concentration (BLC) than other measures of relative exercise intensity. If BLC is used as the intensity criterion, then RPE could be used as a valid tool for exercise prescription. However, few have shown the relationship between RPE and BLC across a variety of graded exercise tests (GXTs) and exercise training settings. The purpose of this study was to determine if differences exist in RPEs at matched BLC between two GXTs and steady state exercise in the field setting. Thirteen healthy males (25 ± 5.3 yrs) completed two maximal treadmill protocols (Bruce and Balke) and one steady state exercise trial on a treadmill at two intensities which lasted approximately 7 minutes each. The intensities (40% & 70% max heart rate reserve) were below and above their ventilatory threshold. RPEs were recorded during the last minute of each workload of the field trial (FT). Immediately following the end of each workload, blood samples were collected for BLC analysis. RPEs from the FT were compared with RPEs from the GXTs at matched BI-Cs using a repeated measures ANOVA across exercise trials. The results show that there were no significant differences in RPEs at a matched BLC of 1.5 mM between the FTand and the Bruce and Balke GXT at the lower intensity, with the RPEs being 9.6 ± 1.7, 9.8 ± 2.6, and 10.2 ± 2.4, respectively. However, at the higher intensity, RPEs at a matched BLC of 3.0 mM were significantly different, with the FT < Bruce < Balke (11.9 ± 1.9, 13.5 ± 2.2 and 15.2 ± 2.0, p < 0.05). These results suggest that the relationship between RPE and BLC established during a GXT may not be transferable to the exercise training setting at exercise intensities in the typical prescription range of 50-85%. Therefore, using RPE for exercise prescription may not be an effective method for regulating exercise intensity according to BLC. / School of Physical Education

The purpose of this study was to determine if mild heat stress induced by wearing a wet suit while swimming in relatively warm water (25.4 ± 0.1°C) increases the risk of heat injury during the subsequent cycling and running stages. Specificlly, during an Olympic distance triathlon in a hot and humid environment (32°C & 65% RH). Five male triathletes randomly completed two simulated triathlons (Swim=30 min; Bike=40 km; Run=10 km) in the laboratory using a swimming flume, cycle ergometer, and running treadmill. In both trials, all conditions were identical, except for the swimming portion in which a full length, sleeveless neoprene wet suit was worn during one trial (WS) and a competitive brief swimming suit during the other (SS). The swim portion consisted of a 30 min standardized swim in which oxygen consumption (V02) was replicated, regardless of WS or SS. During the cycling and running stages, however, the subjects were asked to complete the distances as fast as possible. Core Temperature (T) was not significantly different between the SS and WS trials at any time point during the triathlon. However, mean skin temperature (TSk) and mean body temperature (Tb) were higher (p<0.05) in the WS at 15 (TSk=+4.1°C, Tb=+1.5°C) and 30 min (TSk=+4°C, Tb=+1.6°C) of the swim. These TSk and Tb differences were eliminated by 15 min of the cycling stage and remained similar (p>0.05) through the end of the triathlon. Moreover, there were no differences (p>0.05) in V02, heart rate (HR), rating of perceived exertion (RPE), or thermal sensation (TS) between the WS and SS. Additionally, no significant differences were found in cycling (SS=1:14:46 ± 2:48 vs. WS=1:14:37 ± 2:54 min), running (SS=55:40 ± 1:49 vs. WS=57:20 ± 4:00 min) or total triathlon times (SS=2:40:26 ± 1:58 vs. WS=2:41:57 ± 1:37 min). Therefore, the primary finding was that wearing a wet suit during the swimming stage of an Olympic distance triathlon in 25.4°C water does not adversely affect the thermal responses or the triathlete's ability to perform on the subsequent cycling and running stages. / School of Physical Education

The purpose of this study was to establish an exercise protocol that demonstrated a relationship between rest-interval duration and the exercise induced human growth hormone (hGH) response. Ten recreationally trained male subjects (23 ± 0.9 yrs) performed three leg extension trials on an Eagle — Cybex leg extension machine that consisted of 4 sets of 10 repetitions. The workload and volume was kept constant, but each trial had different rest-interval durations. Rest-interval durations between sets were at: 30 sec intervals (T-30), 60 sec intervals (T-60), or 120 sec intervals (T-120). Blood samples were obtained pre- and 0 — 30 minutes post-exercise and analyzed for lactate and hGH. All blood lactates rose significantly above baseline after exercise, with no differences in time of occurrence between trials. Blood lactates were significantly greater after the T-30 trials, compared to that of the T-60 and T-120 trials. There was no significant difference in hGH concentrations between trials. However, the data did suggest a relationship between rest-interval duration and the variability of hGH responses. The T-30 trials yielded significantly greater variation in hGH concentrations than the T-120 trials, and the T-120 trials showed significantly less variation than both the T-30 and T-60 trials. Although significant differences were found in these variations between trials, they did not prevent any significant differences in concentrations between trials from being found. In summary, the results of this study demonstrated an exercise related increase in lactic acid that had an inverse relationship to the length of the rest-intervals. hGH data on the other hand, did not show a relationship between rest-interval duration and the hGH concentrations. The connection between rest-interval duration and variability of hGH responses could possibly suggest that hGH values may have been significantly different if an exercise protocol higher in volume were utilized. Additionally, the results indicate that there is no direct relationship between blood lactate and hGH concentrations, as others have suggested. / School of Physical Education, Sport, and Exercise Science

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Graduation date: 1999

High impact loading activities such as jumping, performed during childhood is advocated as one preventive method for increasing peak bone mass. Thus, we conducted a randomized intervention to examine the effect of high impact loading on bone mass in 34 pre-pubescent boys and girl over a seven month period. Participants meeting all inclusion criteria were randomized into either a jumping (n=18) or stretching group (n=16), both of which exercised three times per week for 15 minutes. The jumping group completed 100 jumps off 24-inch boxes each session, while the stretching group performed low impact flexibility exercises. Attrition was 85% (6 drop outs), with an overall attendance rate of 95%. Bone area and bone mineral content (BMC) was assessed using dual energy x-ray absorptiometery (Ho logic QDR 1000/W) for the left hip (femoral neck, greater trochanter, total hip), and lumbar spine (L[subscript 2-4]). Other measures were body composition (Lang skinfold calipers); physical activity (self-report questionnaire); and calcium intake (food survey). All measurements were assessed at baseline and 7 months. Significance is denoted as p<.05. Analysis of variance (ANOVA) revealed no baseline difference between groups for age, height, weight, body fat, physical activity, or calcium intake (p>.05); however, gender differences were found for FN BMC at baseline (p<.05). Repeated measures ANOVA identified significant group differences for FN BMC (p=.015), with a trend for significance for FN area (p=.055). No significant differences in BMC or bone area were found at all other skeletal sites (p>.05). No group by gender interactions were found at baseline or at the completion of the seven month intervention. No significant differences between groups were identified for body composition, physical activity, or calcium intake in repeated measures ANOVA analyses (p>.05). In conclusion, 100 jumps performed 3 times per week at approximately 8x body weight were sufficient to stimulate an osteogenic response at the femoral neck in pre-pubescent boys and girls. Implementing jumping exercises into regular physical activity programs during pre-pubescent growing years may increase peak bone mass and potentially reduce the onset of osteoporosis. / Graduation date: 1999

Graduation date: 1995