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Biomedical subjects

R Hugh Morton

Publications and source records attributed to R Hugh Morton.

5 recordsLinked to original sources
PubMed2006

Contrast water immersion hastens plasma lactate decrease after intense anaerobic exercise.

The benefits of rapid recovery after intense exercise are widely recognised, and lactate elimination is one indicator of recovery rate. This study examined the effect of contrast (alternating hot and cold) water immersion (CWI) on the rate of plasma lactate decrease during recovery after intense anaerobic exercise. Eleven subjects on each of two occasions undertook four successive 30-s Wingate tests separated by 30-s rest periods. On each occasion, plasma lactate concentration during recovery was measured 5 min post-exercise and thereafter at 5 min intervals for 30 min. On one occasion (determined randomly), the subjects recovered passively (PR) on a recovery bed and, on the other, they alternated partial body immersion in hot (36 degrees C) and cold (12 degrees C) water baths. Plasma lactate concentrations were analysed by repeated measures analysis of variance and by fitting a linear regression model, allowing for both gender and recovery mode differences. The rate of decrease in plasma lactate concentration over the 30-min recovery period was significantly higher (p<0.001) in CWI; 0.28(+/-0.02) mmol L(-1) min(-1) (CWI) compared to 0.22(+/-0.02) mmol L(-1) min(-1) (PR). These values do not differ significantly between males and females. Contrast water immersion is a valid method of hastening plasma lactate decrease during recovery after intense anaerobic exercise for both males and females. An approximately 1.8 mmol L(-1) difference between the two conditions may be expected after 30 min. With differences among elite competitors as little as 1-2%, this reduction may be of practical significance.

Adult↗
PubMed2005

The critical power and related whole-body bioenergetic models.

This paper takes a performance-based approach to review the broad expanse of literature relating to whole-body models of human bioenergetics. It begins with an examination of the critical power model and its assumptions. Although remarkably robust, this model has a number of shortcomings. Attention to these has led to the development of more realistic and more detailed derivatives of the critical power model. The mathematical solutions to and associated behaviour of these models when subjected to imposed "exercise" can be applied as a means of gaining a deeper understanding of the bioenergetics of human exercise performance.

Anaerobiosis↗
PubMed2005

On repeated measures designs: hierarchical structures and time trends.

The basic anatomy of an experimental design is used as an expository introduction to the examination of several repeated measures experiments described in recent pages of this and other journals. This examination reveals problematic issues concerning some common design and analysis features of such experimental designs. In particular, the hierarchical structures and/or presence of time trends is highlighted. These issues are discussed in an attempt to assist researchers to recognize such problems, to avoid the associated difficulties in the future, and to exploit the advantages of sound design with appropriate, efficient and informative analysis. While alternate reanalyses of the data of these experiments might reveal the conclusions to be unaffected by such issues, researchers should still be cautious. In retrospect, such occurrences should be seen as fortuitous, not as justification for inefficient or less informative analyses. More importantly, such reanalyses could reveal more enlightening information, and I argue that if a design permits such information to be discovered, then it behoves researchers to perform such analyses and to make such discoveries.

Bicycling↗
PubMed2003

The critical power model for intermittent exercise.

This paper develops and illustrates the critical power model for intermittent work. Model theoretic development reveals that total endurance time is always a step function of one or more of the four independent variables: work interval power output ( P(w)), rest interval power output ( P(r)), work interval duration ( t(w)), and rest interval duration ( t(r)). Six endurance-trained male athletes recorded their best performances during the season in 3-, 5-, and 10-km races, and performed three different intermittent running tests to exhaustion in random order, recording their total endurance times. These data were used to illustrate the model and compare anaerobic distance capacities (alpha) and critical velocities (beta) estimated from each type of exercise. Good fits of the model to data were obtained in all cases: 0.954< R(2)<0.999. Critical velocity was found to be significantly less when estimated using an intermittent versus continuous running protocol.

Algorithms↗