published_or_final_version / Sports Science / Master / Master of Science in Sports Science

An attempt was made to evaluate the applicability of a theorized model concerning plasma lactic acid kinetics to running performance assessment. This model incorporated two distinct lactate thresholds identified as the aerobic threshold (AerT) and the anaerobic threshold (AT). Two groups of males with different levels of fitness were tested. Group 1 (n = 5) consisted of recreational athletes (͞X VO₂ max = 49.3 ml/kg•min⁻¹) who ran less than 20 miles per week, while Group 2 (n = 6) were highly trained runners (͞X VO₂ max = 65.5 ml/kg•min⁻¹) who all ran at least 40 miles per week. All subjects participated in two incremental work load (IWL) and four constant work load (CWL) tests that consisted of horizontal treadmill running at different speeds. The IWL tests elicited linear increases in VO₂ and were highly correlated for both Group 1 (r = .986) and Group 2 (r = .999). However, three unbiased observers found the identification of both AerT and AT, using independent lactate and respiratory gas exchange "breakpoints," very subjective in nature. The test-retest reliablity was generally poor and varied considerably among both the observers and the individual predictor variables. The validity of the respiratory gas exchange predictors was then evaluated against the criterion lactate thresholds using the estimates of a fourth, more experienced observer. The resultant correlation coefficients were generally not high, while t-test evaluation demonstrated significant (p < .05) differences in fifty percent of the cases. This same observer then pooled all of the ventilatory predictors in an effort to better estimate both AerT and AT indirectly. These indirect ventilatory estimates consistently underpredicted the criterion lactate thresholds. This finding suggests that increases in running speeds may confound the normal associate between plasma lactate and ventilation at increasing work levels. Arbitrary lactate concentrations of 2mmol/2 and 4 mmol/L were further evaluated as threshold predictors. This methodology consistently overpredicted the criterion lactate thresholds in terms of VO₂. When any of these AerT and AT threshold estimates were compared to the lactate responses during the appropriate CWL test, no meaningful relationship were found. These observations question the physiological significance of both AerT and AT evaluation during treadmill running, as well as pointing out the difficulty in reliably detecting both plasma lactate thresholds regardless of the methodology.

No description available.

No description available.

There were two primary goals in this investigation. The first goal was to determine if inter-individual variability in time to exhaustion at the velocity associated with V02max (Tlim at Vmax) was explained by anaerobic capacity (AC), Vmax, anaerobic threshold (AT), and/or a combination variable in the form [AC • (Vmax - vAT)^-1]. The second goal was to determine if AC could be predicted from Tlim at Vmax, AT, and/or a combination variable in the form [Tlim • (Vmax - vAT)].

Typescript (photocopy). / Digitized by Kansas Correctional Industries

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A modified version of the Rockport Fitness Walking Test (RFWT) has been determined to be reliable for persons with mental retardation. Previous investigations have used one pacer for each participant. While this protocol may be reliable, it is not likely feasible in most school or community-based settings. Therefore, the purpose of this study is twofold: first to evaluate the reliability of a modified version of the RFWT using one pacer per five participants; second, to determine the agreement among the one to one protocol and the proposed five to one protocol. This study compared the end completion times and mean peak heart rates of three different one-mile walking sessions of 35 participants with mild mental retardation. Eighteen females (21.1 �� 2.7 yr.) and 17 males (19.7 �� 2.8 yr.) participated in each testing session. Each participant randomly completed two sessions of walking with one pacer per five participants and one session of one pacer per participant on an indoor surface 1/9th of a mile long. Results from ANOVA indicated end completion times and mean peak heart rates did not differ based on gender (p=0.798), sessions (p=0.053), and gender x sessions (p=0.855). To determine agreement, intraclass correlation coefficients (ICC) were calculated for end completion times for the first five to one and the one to one (R=0.83) and the second five to one and the one to one (R=0.85). ICC's were calculated for mean peak heart rates for the first five to one and the one to one (R=0.95) and for the second five to one and the one to one (R=0.93). The results support that the five to one modified walking protocol produces results similar to the results using the one to one testing. / Graduation date: 1998

published_or_final_version / Sports Science / Master / Master of Science in Sports Science

published_or_final_version / Sports Science / Master / Master of Science in Sports Science