The influence of graded exercise test selection on Pmax and a subsequent single interval bout

• Published in: Journal of exercise physiology online Vol. 8; no. 6; pp. 10 - 17
• Main Authors: Peiffer, J J, Quintana, R, Parker, D L
• Format: Journal Article
• Language: English
• Published: 01.12.2005
• ISSN: 1097-9751; 1097-9751

Due to the inconsistency in GXT protocols in cycling research, it is necessary to examine the affect of GXT selection on the determination of Pmax and subsequent affects on the time needed to achieve VO sub(2)max. Subjects consisted of 8 trained male cyclists (age: 26 plus or minus 7 yrs, height: 179.1 plus or minus 8.2 cm, weight: 74.4 plus or minus 5.0 kg, VO sub(2)max: 63.3 plus or minus 6.5 ml/kg/min) who completed two GXTs. Both tests started at 70 Watts with one increasing 35 Watts/min until volitional fatigue, and the other increasing 50 Watts/3min until volitional fatigue. Pmax was recorded as the lowest power output that coincided with the initial plateau in VO sub(2)max, defined as a change of no more than plus or minus 2 ml/kg/min from a previous recording. Peak aerobic power (Paerobic) was also determined. Subjects then completed two endurance tests at different Pmax values. During the endurance test, time to achieve VO sub(2)max (Tmax), total duration, and the total amount of work were recorded. Pmax as well as Paerobic were significantly lower during the 3 min stage duration GXT (387 plus or minus 27 vs. 342 plus or minus 25 Watts), (424 plus or minus 29 vs. 368 plus or minus 28 Watts)(p<0.05). The percent of Tmax needed to elicit VO sub(2)max was not significantly different between endurance tests (61.80 plus or minus 7.00 vs. 62.10 plus or minus 10.50 %). Total work performed was significantly lower when using Pmax values from the 1 min stage duration GXT (5614.95 plus or minus 1509.48 vs. 9625.57 plus or minus 2244.05 kg/m/min)(p<0.05). GXT protocol had a significant influence over the determination of Pmax and Paerobic. Increases in Pmax lead to substantially lower total interval times. Either GXT produced Pmax values that elicit VO sub(2)max in 60 % of Tmax.