Running an ultramarathon distance requires exceptional physical endurance, mental preparation, determination and perseverance, however the requirements are elevated when performing this feat in extreme heat and with an amputated limb. PURPOSE: To monitor the physiological response of a world class female marathon runner attempting to complete a 135 mile (216 km) ultramarathon in Death Valley, California. METHODS: A sub 3 hr transtibial amputee marathoner volunteered to undergo physiological monitoring during her quest to complete a 135 mile ultramarathon distance in the extreme heat of Death Valley. Two support teams assisted in the ultramarathon and obtained saliva samples for Cortisol content every 6 hrs, body mass and ambient temperature each hour, core temperature and heart rate every 30 seconds by Cortemp (ingested continuous monitoring), and urine specific gravity every 3 hrs, RESULTS: During the 37 hours of walk/running, in which the subject completed 97 miles (156 km), ambient temperature ranged from 28-51° C, core temperature ranged from 37-39 ° C, Cortisol peaked at 18 hrs (.650 ug/dL), urine specific gravity ranged from 1.0040 to 1.0435 g/cc, HR ranged from 110-160 b/m, and body mass ranged from 55.6 to 57.9 with a mean of 57 kg. CONCLUSION: Core temperature fluctuated little despite large changes in ambient temperature, which may be attributed to adequate hydration, minimal changes in body mass, and careful monitoring by the athlete and the support team. Premature termination of the ultramarathon was due to second/third degree burns sustained on her residual limb from the subject's voluntary continuation of prolonged exposure to extreme ambient temperatures at the metal/skin interface. Cortisol levels reveal limited endocrine stress, despite extended exercise in a harsh environment, which indicate that her physiological response was no greater than the response of biped athletes.
Physical fitness characteristics of college students today are purportedly diminished compared to normative data established in the 1960‘s. PURPOSE: The purpose of this study was to compare a range of physiological characteristics of college students enrolled in entry level physical fitness classes to norms established almost 50 years ago. METHODS: 84 male (ht 177 ± 6.6 cm, body mass 80.4 ± 17.4 kg) and 135 females (ht 162.8 ± 6.0 cm, body mass 63.5 ± 13.8 kg) students, age 19.9 ± 1.7 yr enrolled in personal fitness classes at a medium size private university were assessed by well-trained laboratory staff prior to initiating cardiovascular, metabolic and resistance stimulus intervention. Blood pressure (BP) was obtained at rest. Three minute curl-up (CU) and hand grip (HG) dynamometer were used to assess muscular endurance and strength, respectively. Flexibility was assessed by the Wells Sit and Reach test (F) and body composition by skinfold technique (%fat). Cardiovascular function was assessed in the mile run (MR) and extrapolated to estimated max VO2. RESULTS: BP 127/77 and 117/72 mmHg, CU 54.9 ± 20.2 and 44.3 ± 21.6, sum of HG 64.1 ± 15.7 and 27.7 ± 10.2 kg, F 39.9 ± 10.7 and 44.9 ± 10.4 cm, body fat 14.6 ± 7.6 and 27.7 ± 6.9 % fat, MR 8.86 ± 2.6 and 11.81 ± 2.8 min, and max pred VO2 42.8 ± 8.2 and 34.1 ± 7.4 mL/kg-m-1 for males and females, respectively. With the exception of flexibility for both sexes and percent body fat of the females, all characteristics were classified as average or better. Relative to muscular endurance (CU) and max VO2, both males and females were classified as good. CONCLUSION: This 2008 sample of college age students reveals that with the exception of female body composition, there is little difference in physiological characteristics compared to data accrued from college age students almost 5 decades ago.
The obesity epidemic has facilitated some commercial beverage manufactures to include claims for weight loss and caloric expenditure in their advertising. One commercial beverage claims a rise in caloric expenditure of 100 calories within three hours following consumption of the beverage. This purported boost in metabolism would be advantageous for anyone with a positive caloric balance. PURPOSE: The purpose of this study was to evaluate the effects of three commercial beverages on caloric expenditure during a basal metabolic state. METHODS: 8 female and 4 male college-age students (age 21.5 ±1.2 yrs, height 169.4 ±11.1 cm, body mass 67.4 ±14.8 kg) volunteered to participate in a double blind crossover study. Subjects adhered to basal metabolic rate (BMR) conditions and reported to the lab for BMR assessment by open circuit spirometry. Following BMR, subjects randomly ingested 355 mL of beverage (B) 1 (10 kcal CHO, 200 mg caffeine), B2 (15 kcal CHO, 110 mg caffeine), or B3 (placebo; no kcals or caffeine). After ingestion, metabolic rate was measured continuously for 15 of 30 min for 3 hrs. There was a minimum of 7 days between trials. RESULTS: Statistical analysis by ANOVA (p<0.05) revealed a significant, but small, increase in oxygen consumption above BMR for the caffeine containing beverages of B1 for 30 min, and of B2 for 120 min. During the three hour post-ingestion period, the total additional caloric expenditure above BMR was 23.7, 29.3, and 17.1 kcals for B 1, 2, and 3, respectively, with no significant difference among the beverages. CONCLUSION: The subtle increase in caloric expenditure of caffeine and calorie- containing beverages, was not significantly greater than the placebo beverage, thus the thermic effect was similar. The meager thermogenesis above BMR is insufficient for clinical standards of weight loss, and is therefore ineffective as a lone strategy in weight management.
Carbon fiber feet prostheses (aka, dynamic response feet) permit an amputee to run at speeds that here-to-fore were impossible on traditional rigid shank prosthesis. With the advent of this technology, amputee athletes have exceeded previous barriers. PURPOSE: To compare the energy cost of transtibial runners to predictions of energy cost at various speeds METHODS: 12 runners (7 male, 5 females, ht. 174.6 ± 7.9 cm, body mass 67.2 ± 12 kg, max VO2 48.5 ± 7.4 mL/kg-m [range 35-60]) with unilateral transtibial amputation performed a treadmill max VO2 speed protocol starting at 161 m/min with increments of 14.3 m/min per 3 min stage to volitional exhaustion, while using their prescribed prosthetic carbon fiber foot stiffness. AnT occurred at 85% of max VO2 between 188-281 m/min. All subjects were fitted by the same prosthetist and performed the maximal test following 48 hrs of taper. RESULTS: At speeds of 161, 174, 188, 201, 215, 228, 241, 255, 264, and 281 m/min subjects exhibited VO2 of 33.5, 35.3, 37.6, 40.3, 42.8, 44.9, 47.7, 51.2, 54.2 and 58.0 mL/kg-m, respectively. Mean VO2 was 41.7, 42.5 and 45.2 mL/kg-m for measured VO2, amputee predicted VO2, and ACSM prediction VO2, respectively. Statistical analysis by ANOVA at p<.05 revealed significant difference among actual vs predicted VO2. CONCLUSION: Energy cost of amputee running is similar to biped running, but less than the ACSM's run speed prediction equation by one MET. Energy cost of prosthesis running with dynamic response feet can be estimated using the ACSM prediction equation or our amputee prediction equation of VO2 mL/kg-min = speed (m/min) ×.19 + 2.913.
Group exercise sessions seldom involve vigorous upper body exercise, but often contain a myriad of calisthenics and light resistance apparatus. In an effort to provide a substantial upper body stimulus for use in a group exercise setting, we used an arm crank exercise cycle with independent crank arms, a short (170 mm) crank arm length and a narrower crank axis, than most upper body exercise cycles. These characteristics allow for a variety of movement patterns and a faster cadence than previously observed on upper-body exercise. PURPOSE: The purpose of this study was to determine the cardiovascular and metabolic response to arm cranking at cadences of 80, 100, and 120 rpm at a fixed resistance. METHODS: Familiarization trials were conducted to ensure compliance to a split crank position of 180 degrees and within 2 rpm of the assigned cadence. One female and nine male subjects (age 26.2 ± 7.1 yr, body mass 92.4 ± 15.7 kg and ht. 179.5 ± 6.7 cm.) were randomly assigned to perform steady state trials of 80, 100 and 120 rpm using open circuit spirometry. Pilot testing revealed that smaller subjects (<70 kg) fail to achieve steady state at any cadence at the fixed resistance (∼40% of maximal resistance). RESULTS: ANOVA revealed no significant difference (p<.05) in BR, HR, RER and RPE among all cadences, but significant differences in Ve (64 vs 84 and 97 l/min), and VO2(26.2 vs 32.7 and 35 ml/kg/min-1) at 80 rpm versus 100 and 120 rpm, respectively. Intensity ranged from 80% to 89% of APMHR, with 120 rpm eliciting the highest intensity. CONCLUSION: Arm cycle exercise can elicit substantial metabolic demand of 7.3 to 9.8 METS at cadences between 80 to 120 rpm, respectively.
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