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Biomedical subjects

M W Craib

Publications and source records attributed to M W Craib.

6 recordsLinked to original sources
PubMed1996

Short-term changes in 10-km race pace aerobic demand and gait mechanics following a bout of high-intensity distance running.

Following treadmill accommodation and a 3-day period of tapered running, ten well-trained male distance runners [x maximum oxygen uptake (VO2max) = 71.3 ml.kg-1.min-1] performed two 10-min level treadmill runs designed to assess running economy at 90% VO2max. Video recordings were obtained during the last minute of each run to quantify selected gait descriptors. Two to 3 days following the second economy run, each subject completed 30 min of high-intensity (HI) running at 90% VO2max. One 2, and 4 days after the HI run, subjects repeated the 10-min economy runs. Compared to pre HI-run values, no significant change (P > 0.05) in running economy was observed during the post-HI runs. Biomechanical analyses also revealed that running style remained unaltered after the HI run. These results support earlier findings obtained on moderately trained subjects featuring measurement of running economy and gait mechanics at less-demanding intensities and suggest that among well-trained athletes, 30 min of HI running does not elicit an increase in VO2 or disrupt gait mechanics over the short term in subsequent distance runs performed at near-maximal speeds.

Aerobiosis↗
PubMed1996

The association between flexibility and running economy in sub-elite male distance runners.

The purpose of this study was to examine the association between nine measures of limb and trunk flexibility and running economy. Within a week prior to running economy assessment, and after 10 min of jogging at 3.13 m.s-1, 19 well-trained male sub-elite distance runners underwent two complete sets of lower limb and trunk flexibility assessments. Runners then completed two 10-min running economy assessment sessions on consecutive days at 4.13 m.s-1 following two 30-min sessions of treadmill accommodation at 4.13 m.s-1. Intraclass correlation coefficients indicated that the repeated flexibility measurements were highly reliable (X R = 0.92 +/- 0.09), as were the two running economy appraisals (R = 0.99). Correlational analyses revealed that dorsiflexion (r = 0.65) and standing hip rotation (r = 0.53) were significantly (P < or = 0.05) associated with the mean aerobic demand of running, such that runners who were less flexible on these measures were more economical. Although speculative, these results suggest that inflexibility in certain areas of the musculoskeletal system may enhance running economy in sub-elite male runners by increasing storage and return of elastic energy and minimizing the need for muscle-stabilizing activity.

Adult↗
PubMed1994

Daily variability in exercise ventilation.

The purpose of this study was to quantify daily variability in ventilation (VE) during submaximal exercise and establish the number of testing sessions required to produce stable exercise ventilation measures. Following 60 min of treadmill accommodation, four male (M) and four female (F) distance runners completed 5 weeks of daily treadmill testing at the same time of day while engaged in a normal routine of training and racing. During each test session, subjects completed three 6-min level treadmill runs at either 3.13, 3.57, and 4.02 m.sec-1 for F or 3.57, 4.02, and 4.47 m.sec-1 for M. Measures of VE were obtained during the last 2 min of each 6-min run. Results indicated that the mean coefficient of variation (CV) for VE across speeds was 4.33%. Reliability analyses examining all possible combinations of testing days over the 5-week period revealed that 97% of the variation in mean VE was accounted for in either 2 consecutive or non-consecutive days, while 98% of the variation in mean VE was accounted for in 5 consecutive days. These data suggest that when treadmill exposure and circadian variation are controlled, intraindividual differences in exercise VE are relatively small in male and female subjects following an unrestricted program of training and competitive racing. Additionally, acceptably stable VE values in this cohort can be derived by averaging duplicate measures obtained from consecutive or non-consecutive testing sessions.

Adult↗
PubMed1991

Peak running velocity, submaximal energy expenditure, VO2max, and 8 km distance running performance.

The purposes of this study were to examine (1) if the peak running velocity achieved during maximal treadmill testing is related to 8 km distance running performance (DRP) and (2) if the relationship between selected physiological determinants are consistant for two 8 km races within a competitive season. Seven members of a University cross-country team (mean +/- SE) (age, 19.4 +/- 0.5 years, VO2max 67.0 +/- 1.0 ml/kg/min were tested 2-3 days following a mid-season race (Race M) and the season-ending conference championship (Race C). Despite similar weather and terrain, Race C (29:22 +/- 1:22 min:sec) was significantly (p less than 0.05) slower than Race M (28:31 +/- 0:58 min:sec). However, no significant differences (p greater than 0.05) were observed between testing sessions for calculated energy expenditure heart rate oxygen consumption and RER during submaximal running (248 and 268 m/min), postsubmaximal run lactate, peak running velocity, and VO2max. A significant correlation (p less than 0.05) was observed for Race M with with calculated energy expenditure during submaximal running at both speeds (r = 0.85) and with peak running velocity (r = -0.76). Regression analysis revealed that 92% of the total variance for Race M was accounted for by calculated energy expenditure during submaximal running and VO2max. No significant correlation or regression relationship was observed for any variables with Race C. These results suggest that peak running velocity, calculated energy expenditure during submaximal running, and VO2max can be associated with 8 km running performance. However, the relationship between 8 km DRP and the variables measured can differ for two races over a competitive season.

Adult↗