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Biomedical subjects

T R McConnell

Publications and source records attributed to T R McConnell.

5 recordsLinked to original sources
PubMed1988

Treadmill protocols for determination of maximum oxygen uptake in runners.

Four testing protocols were completed by each of 10 runners using a common speed for protocols 1 and 2 (P1 and P2), each runner's training pace for protocol 3 (P3) and a speed selected manually by the runner for protocol 4 (P4). Stages were increased by 2.5% grade every 2 min for each protocol except for P1, which had 1 min stages. There were no significant differences in maximum oxygen uptake (VO2 max) between protocols (P1, 65.0 +/- 5.6 ml.kg-1 min-1; P2, 64.5 +/- 5.3 ml.kg-1 min-1; P3, 66.2 +/- 3.9 ml.kg-1 min-1; P4, 64.7 +/- 5.8 ml.kg-1 min-1). Treadmill time was significantly less for P1 than for the other protocols. The rate of perceived exertion obtained at maximal exercise during P1 was less than that obtained during the other three protocols. Heart rate was significantly lower (P less than 0.05) at any level of submaximal VO2 during P3 than during the other protocols. We recommend a testing protocol using speeds approximating the runner's training pace and 1 min stages. This may result in lower perception of difficulty and HR throughout the test and shorter testing times.

Adult↗
PubMed1988

Practical considerations in the testing of VO2max in runners.

Maximal oxygen intake (VO2max) may be the most physiologically significant and, therefore, the most commonly measured parameter in the physiological assessment of well trained runners. To insure valid and reliable VO2max values, there are a number of practical concerns that must be addressed. An exercise modality must be selected that activates the specific muscle mass and duplicates the motion utilised in the runners' training programme. Motorized treadmill running has been shown to allow the most efficient, valid and reproducible VO2max values in a controlled testing environment. A testing protocol must be used that is easily administered, comfortable for the runner, allows test completion within 10 minutes, uses grade increments at a constant speed, and is reproducible. Speeds should be selected that approximate the runner's training pace. The criterion for the attainment of VO2max include the levelling off of VO2 with an increase in work stage, the onset of extreme exhaustion, the respiratory exchange ratio exceeding 1.1, blood lactate levels approaching or exceeding 10 mmol/L, and ratings of perceived exertion of 19 or 20. Quality control in terms of standardisation of procedures and calibration and maintenance of equipment is essential for the minimisation of technological error. Measurement equipment must be affordable, dependable, easily calibrated, yield reproducible data, and be within the technical skill levels of the operating personnel.

Exercise Test↗
PubMed1984

Exercise and temperature effects on human sperm production and testosterone levels.

Five subjects exercised at an ambient temperature of 6.2 degrees C, five exercised at 37.7 degrees C, and five served as non-exercise controls. Each subject in the exercise groups performed one 45-min treadmill run a day for five consecutive days at heart rates that represented 80% of their maximum capacity. Sperm production was quantified the week preceding treatment and from 6-10 wk post-treatment. Plasma testosterone levels (PTL) were measured before each exercise test and immediately, 30 min, and 60 min after the first and fifth tests. The initial pre-exercise sample was taken immediately preceding the first test. Rectal temperature (Tre) and heart rate were monitored during all tests. No significant differences were found for sperm production. Plasma testosterone levels were 32.9% greater on the fourth and fifth day of testing than they were on day one (P less than 0.018). The 6.2 degrees C group (1202.7 ng%) had higher resting PTL than either the 37.7 degrees C (897.3 ng%) or the control (968.8 ng%) groups throughout the exercise period (P less than 0.001); PTL were 46.6% greater on day 5 than they were on day 1 for the 6.2 degrees C group (P less than 0.021). The change in Tre attributed to exercise was significantly greater in the 37.7 degrees C group (2.5 degrees C) when compared to the 6.2 degrees C group (1.1 degrees C; P less than 0.001). In summary, the changes in PTL and Tre that occurred as a result of 5 d of heavy exercise did not affect sperm production rates in humans.

Adult↗