Interrater reliability of a customized submaximal cycle ergometer test.

PURPOSE: Graded exercise testing (GXTs) is used to determine maximum oxygen uptake ([Formula: see text]). Recently, customized submaximal exercise testing (CSET) completed on both treadmill and cycle ergometry were validated. METHODS: Interrater reliability of the CSET for cycle ergometry was examined. Thirteen participants (age 31 ± 10.2 y, weight 77.9 ± 10.5 kg, height 176.2 ± 9.9 cm, body mass index 25.1 ± 2.9) completed the 2-stage × 3-min CSET protocol performed by two separate testers. True [Formula: see text] was determined using the highest value derived by a GXT and verification bout. Skeletal muscle oxygen saturation ([Formula: see text]), measured using near-infrared spectrometry on the medial gastrocnemius muscle, and [Formula: see text] were monitored during each CSET; whereby, [Formula: see text] kinetics were modeled breath-by-breath data for each 3-min stage. Measurement agreement was quantified using intraclass coefficient (ICC), typical error (TE), and coefficient of variation (CV). RESULTS: "True" [Formula: see text] (ml·kg-1·min-1) between the GXT (41.3 ± 10.5) and verification (42.5 ± 11.5) was established (ICC = 0.98, TE: 0.98, CV 2.1%). Estimated [Formula: see text] by tester 1 (42.5 ± 9.8) and tester 2 (42.7 ± 8.9) did not differ from "true" [Formula: see text] (F2,36 = 0.02, p = 0.98, ηp2 = 0.00). The second stage evoked a [Formula: see text] slow component of 194 ± 124 ml·min-1 that corresponded with a time-dependent decline of [Formula: see text]. The mean [Formula: see text] from the two CSET testers were highly correlated (ICC = 0.91, TE: 4.1%, CV = 8.9%). CONCLUSIONS: The CSET is a reliable and valid procedure and [Formula: see text] is a useful tool for corroborating the second stage is in the heavy-intensity domain.

Critical speed and finite distance capacity: norms for athletic and non-athletic groups.

PURPOSE: Two parameters in particular span both health and performance; critical speed (CS) and finite distance capacity (D'). The purpose of the present study was to: (1) classify performance norms, (2) distinguish athletic from non-athletic individuals using the 3-min all-out test (3MT) for running, and (3) introduce a deterministic model highlighting the relationship between variables of the 3MT. METHODS: Athletic (n = 43) and non-athletic (n = 25) individuals participated in the study. All participants completed a treadmill graded exercise test (GXT) with verification bout and a 3MT on an outdoor sprinting track. RESULTS: Meaningful differences between non-athletic and athletic individuals (denoted by mean difference scores, p value and Cohen's d with 95% confidence intervals) were evident for CS (- 0.74 m s-1, p < 0.001, d = - 1.41 [1.97, - 0.87]), exponential growth time constant ([Formula: see text]; 2.75 s, p < 0.001, d = - 1.29 [- 1.45, - 0.42]), time to maximal speed ([Formula: see text]; - 2.80 s, p < 0.001, d = - 0.98 [- 1.51, - 0.47]), maximal speed ([Formula: see text]; - 1.36 m s-1, p < 0.001, d = - 1.56 [- 2.13, - 1.01]), gas exchange threshold (GET; - 5.62 ml kg-1 min-1, p < 0.001, d = - 0.97 [- 1.50, - 0.45]), distance covered in the first minute (1st min; - 81.69 m, p < 0.001, d = - 1.91 [- 2.52, - 1.33]), distance covered in the second minute (2nd min; - 52.02 m, p < 0.001, d = - 1.71 [- 2.30, - 1.15]) and maximal distance (- 153.78 m, p < 0.001, d = - 1.27 [- 1.82, - 0.74]). The correlation coefficient between key physiological and performance variables are shown in the form of a deterministic model created from the data derived from the 3MT. CONCLUSIONS: Coaches and clinicians may benefit from the use of normative data to potentially identify exceptional or irregular occurrences in 3MT performances.

Analysis of square-wave bouts to verify VO2max.

Submaximal and supramaximal square-wave bouts have been reported to consistently verify 'true' VO2max. Although a direct comparison between both protocols exists, knowledge on the statistical consistency between the protocols using the same group of participants is lacking. The purpose of this study was to conduct an analysis of the submaximal and supramaximal verification bout performed shortly subsequent to a graded exercise test (GXT). On 2 separate occasions, 6 males and 7 females (age: 29±9 years) completed a GXT protocol and an exhaustive, square-wave bout at either end-GXT power minus 2-stages or 105% end-GXT power. No differences (p>0.05) in VO2max were observed between the GXT and square-wave bouts. The typical error (ml/kg/min) for submaximal (1.09) and supramaximal (1.04) trials was similar. Likewise, similar relative measures of consistency were observed for the submaximal (ICC α=0.97, CV=2.4%) and supramaximal trials (ICC α=0.95, CV=2.3%). For a GXT lasting ~10-12 min, the submaximal or supramaximal protocols appear to be equally effective.

3-min all-out exercise test for running.

A 3-min all-out exercise test (3 MT) estimates critical power and the curvature constant for cycle ergometry validly; however, the mode of running has not been studied. We examined the efficacy of a running 3 MT, using global positioning sensor data, to predict outdoor racing performance. Women distance runners (n=14) were tested at preseason within a month prior to competing officially in either short or middle distance races. Critical speed (CS) (4.46±0.41 m/s) estimated from the 3 MT did not differ (p>0.05) from the mean speed of gas exchange threshold and maximum oxygen uptake (50%Δ), as derived from a custom treadmill graded exercise test (4.55±0.24 m/s). Runners with higher curvature constants (D'), estimated from the 3 MT, raced at higher speeds above CS (R2 ranging 0.63-0.99). Race speeds for 800 m exceeded the speed for 150 s of all-out running, rendering 800 m estimates less accurate. Conversely, predicted times for the other distances yielded strong intraclass correlations (α) and low coefficients of variation (%) values (α=0.74/1.7% and α=0.87/2.1%, for 1 600 and 5 000 m, respectively). Use of the running 3 MT for performances ranging ~2.5-18 min is recommended.

Validity of 3 protocols for verifying VO2 max.

The verification bout has emerged as a technique for confirming 'true' VO2 max; however, validity during a single visit is unknown. We evaluated 3 different GXT durations with severe intensity verification bouts. On 3 separate days, in counterbalanced order, 12 recreational-trained men completed short (9±1 min), middle (11±1 min), and long (13±2 min) duration GXTs followed by exhaustive, sine wave verification bouts during the same visit. Intensities for verification were set at speeds equivalent to 2-stages minus end-GXT speed. No differences (p<0.05) in VO2 max (mL/kg/min) were observed between short (49.1), middle (48.2), and long (48.8) protocols. In addition, no differences in verification bout duration occurred between protocols (3±1 min). Validity of VO2 max was strongest for the middle duration protocol (ICC α=0.97; typical error=1 mL/kg/min; CV=2%). A small, but significantly higher HR (max) (∼1-2 bpm) was observed for the long protocol. Maximum respiratory exchange ratios were inconsistent (ICC α ranged 0.58-0.68). Our findings indicate GXT-verification bout testing during a single visit is a valid means of measuring 'true' VO2 max. The 10 min target for GXT duration was the optimum.