Biomedical subjects

J M McKay

Publications and source records attributed to J M McKay.

8 recordsLinked to original sources

PubMed1997

Psychophysiological stress in elite golfers during practice and competition.

This study examined self-reported state anxiety (cognitive anxiety, somatic anxiety and self-confidence) measured by the Competitive State Anxiety Inventory-2 (CSAI-2; Martens, Vealey, Bump, & Smith, 1990) and physiological responses (salivary cortisol concentration and heart rate) in elite golfers prior to, during and on completion of a tournament and practice round. The relationships between psychophysiological variables were investigated by comparing physiological and psychological responses during competition and practice to each other, and to performance. Performance was determined for each player as the difference between 18 hole score and handicap. Fifteen male Professional Golfing Association (PGA) trainees (aged 21-25 years) competed in a PGA sanctioned tournament and a practice round on the same, or similar golf course. Players completed the CSAI-2 and collected saliva for cortisol analysis on four occasions: prior to tee off, and after completing holes 6, 12 and 18. Cortisol concentration was corrected for circadian variations in cortisol secretion, using baseline cortisol measures. Within-subject analysis revealed elite golfers experienced elevated cortisol, heart rate, cognitive and somatic anxiety, and lower self-confidence during competition compared to practice. For both game conditions, the highest cortisol response was measured prior to the commencement of play, whilst state anxiety measures did not change significantly during the golf rounds. Univariate and multivariate analyses failed to reveal significant correlations between the psychophysiological variables and golf performance. In conclusion, competition and practice were clearly discriminated by the psychophysiological variables, but none of these predicted performance.

Adult↗

PubMed1994

Physiological tolerance to uncompensable heat stress: effects of exercise intensity, protective clothing, and climate.

This study determined the influence of exercise intensity, protective clothing level, and climate on physiological tolerance to uncompensable heat stress. It also compared the relationship between core temperature and the incidence of exhaustion from heat strain for persons wearing protective clothing to previously published data of unclothed persons during uncompensable heat stress. Seven heat-acclimated men attempted 180-min treadmill walks at metabolic rates of approximately 425 and 600 W while wearing full (clo = 1.5) or partial (clo = 1.3) protective clothing in both a desert (43 degrees C dry bulb, 20% relative humidity, wind 2.2 m/s) and tropical (35 degrees C dry bulb, 50% relative humidity, wind 2.2 m/s) climate. During these trials, the evaporative cooling required to maintain thermal balance exceeded the maximal evaporative capacity of the environment and core temperature continued to rise until exhaustion from heat strain occurred. Our findings concerning exhaustion from heat strain are 1) full encapsulation in protective clothing reduces physiological tolerance as core temperature at exhaustion was lower (P < 0.05) in fully than in partially clothed persons, 2) partial encapsulation results in physiological tolerance similar to that reported for unclothed persons, 3) raising metabolic rate from 400 to 600 W does not alter physiological tolerance when subjects are fully clothed, and 4) physiological tolerance is similar when subjects are wearing protective clothing in desert and tropical climates having the same wet bulb globe thermometer. These findings can improve occupational safety guidelines for human heat exposure, as they provide further evidence that the incidence of exhaustion from heat strain can be predicted from core temperature.

Adult↗

PubMed1991