All-out exercise testing (AOT) has emerged as a method for quantifying critical speed (CS) and the curvature constant (D'). The AOT method was recently validated for shuttle running yet how that method compares with linear running is unknown. In the present study, we utilized a novel bi-exponential model that derives CS and D' with additional new parameters from the AOT method. Fourteen male athletes (age = 21.6 +/- 2.2 years; height = 177 +/- 70 cm; weight = 83.0 +/- 11.8 kg) completed a graded exercise test (GXT) to derive maximum oxygen uptake ((V) over dotO(2)max) and the average speed between gas exchange threshold and (V) over dotO(2)max (s Delta 50%), a linear AOT, and two shuttle AOTs. Measurement agreement was determined using intraclass correlation coefficient (ICC alpha), typical error (TE), and coefficient of variation (CV). The gamma-asymptote (S-0) of the speed-time curve (3.52 +/- 0.66 m.sec(-1)) did not differ from s Delta 50% (3.49 +/- 0.41 m.sec(-1)) or CS (3.77 +/- 0.56 m.sec(-1)) (P = 0.34). Strong agreement was observed for estimates of CS (ICC alpha = 0.92, TE = 0.18 m.sec(-1), and CV = 5.7%) and D' (ICC alpha = 0.94, TE = 16.0 m, CV = 7.6%) with significant (P < 0.01) correlations observed between (V) over dotO(2)max and CS and between S-0 and (V) over dotO(2)max (r values of 0.74 and 0.84, respectively). The time constant of the decay in speed (tau(d)) and the amplitude between maximal speed and S-0 (A(d)) emerged as unique metrics. The A(d) and tau(d) metrics may glean new insights for prescribing and interpreting high-intensity exercise using the AOT method.

PURPOSE:To compare critical speed (CS) derived from all-out testing (AOT) for linear and shuttle running with metrics from a graded exercise test, the Yo-Yo Intermittent Recovery Test  Level 1 (YYIR1), and estimation of an 800-m-shuttle time trial.METHODS:Twelve male rugby players completed a graded exercise test, the YYIR1, a linear AOT, shuttle AOTs of 25 and 50 m, and an 800-m-shuttle time trial consisting of 32 × 25-m shuttles.RESULTS:Strong linear correlations were observed between maximum oxygen uptake ( V˙O2max ) and CS (m·s-1) derived from the linear AOT (3.68 [0.62], r = .90, P < .01) and 50-m-shuttle AOT (3.19 [0.26], r = .83, P < .01). Conversely, V˙O2max showed lower correlations with speeds evoking CS from 25-m AOT (2.86 [0.18], r = .42, P = .18) and YYIR1 (4.36 [0.11], r = .55, P = .07). The 800-m time trial (213.58 [15.84] s) was best predicted using parameters from the 25-m AOT (r = .93, SEE = 6.60 s, P < .001).CONCLUSIONS:The AOT is a valuable method of assessing performance-specific fitness, with CS from linear and 50-m-shuttle AOTs being strong predictors of V˙O2max , rivaling metrics from the graded exercise test. The YYIR1 offered limited utility compared with the AOT method.

All-out, non-steady state running makes for difficult comparisons regarding linear and shuttle running; yet such differences remain an important distinction for field-based sports. The purpose of the study was to determine whether an energetic approach could be used to differentiate all-out linear from shuttle running.

How parameters derived from oxygen uptake [Formula: see text] kinetics relate to critical speed is not fully understood, and how such parameters relate to more sport-specific performances, such as shuttle running, has not been investigated. Therefore, the primary aims of the present student were to examine the [Formula: see text] kinetics during all-out linear and shuttle running and compare physiological variables of all-out running to variables measured during a graded exercise test (GXT). Fifteen male soccer players performed a graded exercise test (GXT) and the [Formula: see text] kinetics from a series of three different 3-min all-out tests (3MT's) were evaluated. [Formula: see text] achieved during the GXT did not differ from maximal [Formula: see text] achieved during the all-out tests (F = 1.85, p = 0.13) (overall ICC = 0.65; typical error = 2.48 ml∙kg-1∙min-1; coefficient of variation = 4.8%). A moderate, inverse correlation (r = -0.62, p = 0.02) was observed between τ (14.7 ± 1.92 s) and CS (3.96 ± 0.52 m∙s-1) despite the narrow SD for τ. No differences (p > 0.05) were observed for any of the [Formula: see text] kinetics between continuous and shuttle running bouts. The linear running 3MT (r3MT) represents a viable surrogate to the GXT and data beyond CS and D' may be gleaned by using the bi-exponential speed-time model.