Biomedical subjects

V S Newbury

Publications and source records attributed to V S Newbury.

4 recordsLinked to original sources

PubMed1995

Lactate response to uphill roller skiing: diagonal stride versus double pole techniques.

The purpose of this experiment was to investigate the lactate responses to roller skiing with double pole and diagonal stride techniques in eight collegiate or national level cross-country ski racers. Four-minute exercise stages were performed on a ski treadmill at 67, 94, 121, 148, and 174 m.min-1 on a 1.7% grade and at 67, 94, and 121 m.min-1 on a 7.1% grade. Whole blood lactate concentration, heart rate, oxygen consumption (VO2) and rating of perceived exertion (RPE) were determined at each exercise stage. Blood lactate concentrations were not significantly different between double poling and diagonal striding at the 1.7% grade. However, the blood lactate concentrations were higher during double poling at the 7.1% grade for all speeds. Blood lactate concentrations were also higher for double poling at the 7.1% grade when compared with diagonal striding at 70% of technique specific peak VO2, a heart rate of 145 and a RPE of 12. We conclude that blood lactate concentrations do not offer physiological justification for choosing one technique over the other when skiing on low grades, but low blood lactate concentrations may provide a physiological advantage for diagonal striding on steep grades.

Exercise↗

PubMed1994

Physiological comparison of uphill roller skiing: diagonal stride versus double pole.

The physiological responses to treadmill roller skiing with the double pole (DP) and diagonal stride (DS) techniques were compared at 1.7% and 7.1% grades among eight cross-country ski racers. Oxygen uptake (VO2) requirements were found to be lower (P < 0.05) for DP at the 1.7% grade, but similar at the 7.1% grade. In contrast, ratings of perceived exertion (RPE) and percentages of technique-specific peak VO2 were similar between techniques at the 1.7% grade, and lower (P < 0.05) for DS at the 7.1% grade. RPE and percentages of technique-specific peak VO2 were strongly correlated (r = 0.89). The primary findings indicate that 1) the economies for DP and DS are dependent upon the incline, 2) it is possible for the economy of DP to be greater than DS although the percentages of technique-specific peak VO2 are similar, and 3) the perceived effort associated with the use of DP and DS reflects the percentage of technique-specific peak VO2.

Adipose Tissue↗

PubMed1993

Physiological responses to specific maximal exercise tests for cross-country skiing.

The present study attempted to quantify differences in peak physiological responses to pole-striding (PS), double poling on roller skis (DP), and diagonal striding on roller skis (DS) during maximal exercise. Six expert cross-country ski racers (3 M, 3 F) with a mean age of 20.2 +/- 1.3 yrs served as subjects. Testing was conducted on a motorized ski treadmill with a tracked belt surface. Expired air was analyzed continuously via an automated open-circuit system and averaged each 20 s. Heart rate was monitored via telemetry and arterialized blood was collected within 1 min of test termination and analyzed immediately for lactate. Peak values for heart rate and blood lactate did not differ among techniques. Peak oxygen uptake was higher for PS and DS versus DP whereas no difference was found between PS and DS. The VO2peak for DP was 77 and 81% of VO2peak for PS and DS, respectively. It was concluded that despite similar peak heart rate and blood lactate values, DP elicits a lower VO2peak than DS or PS and that PS responses appear to closely reflect those of DS.

Adult↗

PubMed1992

The effect of Alpine mountaineering on acute erythrocyte hemolysis.

The purpose of this study was to determine whether erythrocyte hemolysis occurs during a mountain ascent over snow and ice to 3285 meters. Data were collected from six experienced recreational mountaineers, 2 females and 4 males, who participated in a six-day ice climbing seminar and peak ascent in the North Cascades mountain range of the United States. Blood samples were collected from an antecubital vein at sea level (S1), in a base camp at 1515 m prior to the summit ascent (S2), on the summit at 3285 m after 6.5 hours of climbing (S3), at base camp immediately after the descent (S4), and at sea level following a trail descent from the base camp (S5). Whole blood samples were chilled and analyzed for complete blood count including hemoglobin (Hb) concentration, hematocrit (Hct), and white blood cell count (WBC). Serum was frozen and later analyzed for serum haptoglobin (Hapt). No significant changes were found for Hct and Hb among the samples. Mean (+/- SEM) Hapt values were 125 (+/- 28), 113 (+/- 25), 100 (+/- 18), 103 (+/- 32), and 109 (+/- 23) mg.dl-1 for S1 through S5, respectively. No significant differences were found among the Hapt values. Plasma volume changes (% PVC) were calculated from Hct and Hb. Mean estimated % PVC were -4.16 (+/- 1.55), -2.54 (+/- 3.93), 7.46 (+/- 4.86), and 4.80 (+/- 3.49) percent between S1 and S2, S2 and S3, S3 and S4, and S4 and S5, respectively. Total body haptoglobin (TBH) was estimated from Hapt and % PVC in an attempt to correct for the plasma volume change effect on haptoglobin concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗