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Introduction: Load carriage is an inherent part of tactical operations. Critical speed (CS) has been associated with technical and combat-specific performance measures (e.g., loaded running). The 3-min all-out exercise test provides estimates of CS and the maximal capacity to displace the body (D') at speeds above CS. The current study investigated the contributions of CS, D', lean body mass (LBM), thigh lean mass (TLM), and lower body isokinetic strength and endurance parameters related to load carriage time trials (LCTTs)., Methods: Twenty-two Reserve Officers' Training Corps cadets (6 = females, age = 20.82 ± 1.59 years) underwent various assessments that included a running 3-minute all-out test to determine CS and D', isokinetic knee extension (KE) muscle strength and endurance, body composition assessed by dual-energy X-ray absorption, and two 21-kg LCTTs of 400 and 3,200 m, respectively. Pearson's product-moment correlations investigated relationships between selected predictor variables. Stepwise multiple linear regression analyses were used to determine the relationship between variables that predicted LCTT performance., Results: Significant correlations were as follows: LBM and CS (r = 0.651, P < .001), KE endurance work and CS (r = 0.645, P < .001), TLM and CS (r = 0.593, P < .05), and KE peak torque and CS (r = 0.529, P < .05). The stepwise regression analyses indicated that CS and LBM contributed significantly to predicting 3,200-m LCTT (F [2,19] = 81.85, R2 = 0.90, P < .001) with standardized β coefficients (-0.723 and -0.301, respectively). Thigh lean mass contributed significantly to predicting the 400-m LCTT (F [1,20] = 46.586, R2 = 0.70, P < .001) with a standardized β coefficient (-0.836)., Conclusion: The results of this study highlight that CS and LBM were the best predictors of the 3,200-m LCTT, and TLM was the best predictor of the 400-m LCTT. The findings of this study support that CS and LBM, including TLM, are important in predicting load carriage task completion in the time trial tasks., (© The Association of Military Surgeons of the United States 2025. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

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] (F 2,36  = 0.02, p = 0.98, η p 2  = 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., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Tactical professionals often depend on their physical ability and fitness to perform and complete occupational tasks to successfully provide public services or survive on the battlefield. Critical speed (CS), or maximal aerobic steady-state, is a purported measure that predicts performance, prescribes exercise, and detects training adaptions with application to tactical professionals. The CS concept has the versatility to adapt to training with load carriage as an integrated bioenergetic system approach for assessment. The aims of this review are to: (1) provide an overview of tactical populations and the CS concept; (2) describe the different methods and equipment used in CS testing; (3) review the literature on CS associated with tactical occupational tasks; and (4) demonstrate the use of CS-derived exercise prescriptions for tactical populations.

The purpose of this study was to evaluate the effects of using the critical velocity (CV) concept to prescribe two separate high-intensity interval training (HIT) exercise programs aimed at enhancing CV and load carriage performance. 20 young adult participants (male = 15, female = 5) underwent a 4-week training period where they exercised 2 d   wk -1 . Participants were randomly assigned into two groups: (1) HIT or (2) Load Carriage-HIT (LCHIT). Pre- and post-training assessments included running 3-minute All-Out Test (3MT) to determine critical velocity (CV) and distance prime ( D ') and two load carriage tasks (400 and 3200 m). There were significant increases in CV ( p  = 0.005) and velocity at V ˙ O 2max ( v V ˙ O 2max ) ( p  = 0.037) among the sample but not between training groups. Improvements were observed in 3200 m load carriage performance time ( p  < 0.001) with a 9.8 and 5.4% decrease in the LCHIT and HIT groups, respectively. Practitioner summary: Critical velocity has shown efficacy as a marker for performance in tactical populations. With the addition of load carriage, there is a reduction in the individual's CV. The CV-concept-prescribed exercises (HIT and LCHIT) 2 days per week for 4 weeks showed improvements in CV, v V ˙ O 2max and load carriage performance. The use of the CV concept provides a method to prescribe HIT to increase running and load carriage performances in tactical populations.

Maximal oxygen uptake (VO 2max ) and critical speed (CS) are key fatigue-related measurements that demonstrate a relationship to one another and are indicative of athletic endurance performance. This is especially true for those that participate in competitive fitness events. However, the accessibility to a metabolic analyzer to accurately measure VO 2max is expensive and time intensive, whereas CS may be measured in the field using a 3 min all-out test (3MT). Therefore, the purpose of this study was to examine the relationship between VO 2max and CS in high-intensity functional training (HIFT) athletes. Twenty-five male and female (age: 27.6 ± 4.5 years; height: 174.5 ± 18.3 cm; weight: 77.4 ± 14.8 kg; body fat: 15.7 ± 6.5%) HIFT athletes performed a 3MT as well as a graded exercise test with 48 h between measurements. True VO 2max was determined using a square-wave supramaximal verification phase and CS was measured as the average speed of the last 30 s of the 3MT. A statistically significant and positive correlation was observed between relative VO 2max and CS values (r = 0.819, p < 0.001). Based on the significant correlation, a linear regression analysis was completed, including sex, in order to develop a VO 2max prediction equation (VO 2max (mL/kg/min) = 8.449(CS) + 4.387(F = 0, M = 1) + 14.683; standard error of the estimate = 3.34 mL/kg/min). Observed (47.71 ± 6.54 mL/kg/min) and predicted (47.71 ± 5.7 mL/kg/min) VO 2max values were compared using a dependent t-test and no significant difference was displayed between the observed and predicted values ( p = 1.000). The typical error, coefficient of variation, and intraclass correlation coefficient were 2.26 mL/kg/min, 4.90%, and 0.864, respectively. The positive and significant relationship between VO 2max and CS suggests that the 3MT may be a practical alternative to predicting maximal oxygen uptake when time and access to a metabolic analyzer is limited.

Prescribing the frequency, duration, or volume of training is simple as these factors can be altered by manipulating the number of exercise sessions per week, the duration of each session, or the total work performed in a given time frame (e.g., per week). However, prescribing exercise intensity is complex and controversy exists regarding the reliability and validity of the methods used to determine and prescribe intensity. This controversy arises from the absence of an agreed framework for assessing the construct validity of different methods used to determine exercise intensity. In this review, we have evaluated the construct validity of different methods for prescribing exercise intensity based on their ability to provoke homeostatic disturbances (e.g., changes in oxygen uptake kinetics and blood lactate) consistent with the moderate, heavy, and severe domains of exercise. Methods for prescribing exercise intensity include a percentage of anchor measurements, such as maximal oxygen uptake ([Formula: see text]), peak oxygen uptake ([Formula: see text]), maximum heart rate (HR max ), and maximum work rate (i.e., power or velocity-[Formula: see text] or [Formula: see text], respectively), derived from a graded exercise test (GXT). However, despite their common use, it is apparent that prescribing exercise intensity based on a fixed percentage of these maximal anchors has little merit for eliciting distinct or domain-specific homeostatic perturbations. Some have advocated using submaximal anchors, including the ventilatory threshold (VT), the gas exchange threshold (GET), the respiratory compensation point (RCP), the first and second lactate threshold (LT 1 and LT 2 ), the maximal lactate steady state (MLSS), critical power (CP), and critical speed (CS). There is some evidence to support the validity of LT 1 , GET, and VT to delineate the moderate and heavy domains of exercise. However, there is little evidence to support the validity of most commonly used methods, with exception of CP and CS, to delineate the heavy and severe domains of exercise. As acute responses to exercise are not always predictive of chronic adaptations, training studies are required to verify whether different methods to prescribe exercise will affect adaptations to training. Better ways to prescribe exercise intensity should help sport scientists, researchers, clinicians, and coaches to design more effective training programs to achieve greater improvements in health and athletic performance.

Objectives: Health and wellness coaching (HWC) interventions have been reported to improve health outcomes for individuals with chronic diseases such as diabetes, cardiovascular disease, or cancer. However, HWC also holds potential as an effective intervention within a biopsychosocial chronic pain management framework. The aim of the present study was to evaluate the effects of HWC on individuals with chronic pain., Methods: Participants were referred by their primary care provider or insurance company to a comprehensive telephonic 12-month pain management HWC program. Relationships between pain outcomes and physical and psychological factors were retrospectively analyzed. Mixed linear-effects modeling explored whether physical and psychological variables were associated with pain outcomes over time., Results: Four hundred nineteen participants (female, 58.9%; mean age, 54.8) enrolled in the program and 181 completed the intervention. After 12 months in the program, statistically and clinically significant reductions were observed for pain intensity (Hedges' g = 1.00) and pain-related interference (Hedges' g = 1.13). Linear mixed-effects modeling indicated that improvements in physical functioning and psychological factors were associated with improvements in pain intensity., Discussion: Our results provide a novel analysis on the effects of HWC on chronic pain and pain-related interference. HWC appears to be a promising intervention to improve pain-related outcomes in a population with chronic pain. Further investigation of HWC as an intervention for chronic pain is warranted., Competing Interests: The authors have declared that no competing interests exist.

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.

Saari, A, Dicks, ND, Hartman, ME, and Pettitt, RW. Validation of the 3-minute all-out exercise test for shuttle running prescription. J Strength Cond Res 33(6): 1679-1685, 2019-A 3-minute all-out exercise test (3 MT) for running has been developed to determine critical speed (CS) and finite capacity for running speeds > CS (D') which allow for the prediction of time limits (TLIMs) associated with running different distances. Most team sports require shuttle running; however, the 3 MT was validated for uninterrupted, track running and not shuttle running. The purpose of this study was to examine the efficacy of shuttle running 3 MT to determine CS and D'. A total of 12 subjects were tested using a baseline 3 MT along with 3 separate distance time trials of all-out shuttle running to determine true CS and D'. The 3 MT (2.94 ± 0.39 m·s) and the true CS (3.00 ± 0.36 m·s) for shuttle running did not differ (p = 0.71) and had a coefficient of variation (CV) of 7.7%. Conversely, D' from the 3 MT exceeded true D' by 42 m (p = 0.04, CV = 36%). The TLIMs estimated for the 3 different distances were within ∼2-6% (p = 0.60). Based on these outcomes, the shuttle run 3 MT may offer a suitable method for prescribing shuttle running interval training.

CrossFit ® began as another exercise program to improve physical fitness and has rapidly grown into the "sport of fitness". However, little is understood as to the physiological indicators that determine CrossFit ® sport performance. The purpose of this study was to determine which physiological performance measure was the greatest indicator of CrossFit ® workout performance. Male ( n = 12) and female ( n = 5) participants successfully completed a treadmill graded exercise test to measure maximal oxygen uptake (VO 2max ), a 3-minute all-out running test (3MT) to determine critical speed (CS) and the finite capacity for running speeds above CS (D'), a Wingate anaerobic test (WAnT) to assess anaerobic peak and mean power, the CrossFit ® total to measure total body strength, as well as the CrossFit ® benchmark workouts: Fran, Grace, and Nancy. It was hypothesized that CS and total body strength would be the greatest indicators of CrossFit ® performance. Pearson's r correlations were used to determine the relationship of benchmark performance data and the physiological performance measures. For each benchmark-dependent variable, a stepwise linear regression was created using significant correlative data. For the workout Fran, back squat strength explained 42% of the variance. VO 2max explained 68% of the variance for the workout Nancy. Lastly, anaerobic peak power explained 57% of the variance for performance on the CrossFit ® total. In conclusion, results demonstrated select physiological performance variables may be used to predict CrossFit ® workout performance.

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 ˙ O 2 max ) 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 ˙ O 2 max 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 ˙ O 2 max , rivaling metrics from the graded exercise test. The YYIR1 offered limited utility compared with the AOT method.

The search for variables involved in the regulation and termination of exercise performance has led to integrative models that attribute a central role to the brain and utilize an array of psychological terms (e.g. sensation, perception, discomfort, tolerance). We propose that theorizing about exercise regulation would benefit from establishing cross-disciplinary bridges to research fields, such as affective psychology and neuroscience, in which changes along the dimension of pleasure-displeasure are considered the main channel via which homeostatic perturbations enter consciousness and dictate corrective action (slowing down or stopping). We hypothesized that ratings of pleasure-displeasure would respond to the severity of homeostatic perturbation and would be related to time to exhaustion during exercise performed at an unsustainable intensity. In a within-subjects experiment ( N =15, 13 men and 2 women, age 23.4±2.2 years; maximal oxygen uptake 46.0±8.0 ml kg -1  min -1 ), we compared the slope of ratings of pleasure-displeasure (acquired every 1 min) during cycling exercise at a power output 10% above critical power until volitional termination under glycogen-loaded and glycogen-depleted conditions. As hypothesized, ratings of pleasure-displeasure declined more steeply under glycogen depletion ( P =0.009, d =0.70) and correlated closely with time to exhaustion under both glycogen-loaded ( r =0.85; P <0.001) and glycogen-depleted conditions ( r =0.83; P <0.001). We conclude that in exercise, as in other domains, changes in pleasure-displeasure may be the main channel via which homeostatic perturbations enter consciousness. This proposal may have important implications for conceptualizing and identifying the neurobiological mechanisms of the sense of exertional physical fatigue., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2019. Published by The Company of Biologists Ltd.)

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 ˙ O 2 max ) and the average speed between gas exchange threshold and V ˙ O 2 max (sΔ50%), a linear AOT, and two shuttle AOTs. Measurement agreement was determined using intraclass correlation coefficient (ICC α ), typical error (TE), and coefficient of variation (CV). The y-asymptote ( S 0 ) of the speed-time curve (3.52 ± 0.66 m·sec -1 ) did not differ from sΔ50% (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 α  = 0.92, TE = 0.18 m·sec -1 , and CV = 5.7%) and D' (ICC α  = 0.94, TE = 16.0 m, CV = 7.6%) with significant (P < 0.01) correlations observed between V ˙ O 2 max and CS and between S 0 and V ˙ O 2 max (r values of 0.74 and 0.84, respectively). The time constant of the decay in speed ( τ d ) and the amplitude between maximal speed and S 0 ( A d ) emerged as unique metrics. The A d and τ d metrics may glean new insights for prescribing and interpreting high-intensity exercise using the AOT method., (© 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

Purpose: 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., Methods: Fifteen male field-sport athletes volunteered for the study (means ± SD): age, 21.53 ± 2.23 years; height, 1.78 ± 0.68 m; weight, 83.85 ± 11.73 kg. Athletes completed a graded exercise test, a 3-min linear all-out test and two all-out shuttle tests of varied distances (25 m and 50 m shuttles)., Results: Significant differences between the all-out tests were found for critical speed (CS) [F(8.97), p < 0.001), D' (finite capacity for running speeds exceeding critical speed) [F(7.83), p = 0.001], total distance covered [F(85.31), p < 0.001], peak energetic cost ([Formula: see text]) [F(45.60), p < 0.001], peak metabolic power ([Formula: see text]) [F(23.36), p < 0.001], average [Formula: see text] [F(548.74), p < 0.001], maximal speed [F(22.87), p < 0.001] and fatigue index [F(3.93), p = 0.027]. Non-significant differences were evident for average [Formula: see text] [F(2.47), p = 0.097], total [Formula: see text] [F(0.86), p = 0.416] and total [Formula: see text] [F(2.11), p = 0.134]., Conclusions: The energetic approach provides insights into performance characteristics that differentiate linear from shuttle running, yet surprising similarities between tests were evident. Key parameters from all-out linear and shuttle running appear to be partly interchangeable between tests, indicating that the final choice between linear and shuttle testing should be based on the requirements of the sport.

This study examined the relationship between subjective ratings of overall wellness and neuromuscular performance throughout a 6-week intensive offseason strength and conditioning program. Thirty experienced NCAA Division II baseball players completed all phases of the program. A comprehensive wellness rating and 5 countermovement jumps (CMJ5) were measured and averaged for 4 phases of training. Pre- and post-testing measures of strength and speed also were evaluated. Internal consistency of the wellness rating for each phase ranged α = 0.77-0.92, and CMJ5 velocities had decent consistency (ICC α = 0.88, TE = 0.19 m·s -1 , CV = 5.90%). The training program evoked significant (p < 0.01) improvements in front squats ( d = 0.55), trap bar deadlifts ( d = 0.62), chin ups ( d = 0.39), 30-yd dash ( d = 0.39), with no change in the 300-yd dash (p > 0.05), where d is the treatment effect size. Average CMJ5 velocities (m·s -1 ) were similar for the preparation phase (1.90 ± 0.25), eccentric phase (1.91 ± 0.28), strength & power phase (1.91 ± 0.24), and recovery phase (1.91 ± 0.30; F = 0.04, p = 0.99, η p 2 = 0.001). No significant correlations were observed for pre-or post-testing measures of wellness ratings in comparison to any performance measures, including a composite standardized score from each performance test at pre-testing ( r = 0.22, p = 0.26). The CMJ5 exhibited too high of a typical error to determine a change in neuromuscular status. Additionally, the wellness rating did not reflect changes in relation to performance.

Introduction: A customized submaximal exercise test for cycle ergometry was reported as a superior estimate of maximum oxygen uptake (VO 2max ) in comparison to the traditional YMCA ergometry test., Purpose: Following similar methodology, we sought to validate a customized submaximal treadmill test (CustomTM) compared with the widely used Bruce submaximal protocol., Methods: Participants (29 women and 21 men; age = 31.37 ± 11.44 year, BMI = 24.02 ± 3.03) performed a graded exercise test (GXT) with a subsequent exhaustive, square-wave bout for the verification of "true" VO 2max . In counterbalanced order, subjects then completed submaximal protocols. The CustomTM protocol consisted of two 3-min stages estimated at 35 and 70% of VO 2max , where VO 2max was estimated with a linear regression equation utilizing sex, BMI, age, and self-reported physical activity., Results: VO 2 values from the GXT and verification bout were 47.2 ± 7.7 and 47.0 ± 7.7 ml kg -1  min -1 , respectively (ICC = 0.99, CV = 2.0%, TE = 0.83 ml kg -1  min -1 ), with the highest value used as "true" VO 2max (47.7 ± 7.7 ml kg -1  min -1 ). Neither the Bruce (45.95 ± 6.97 ml kg -1  min -1 ) nor the CustomTM (47.3 ± 9.4 ml kg -1  min -1 ) protocol differed from "true" VO 2max . The CustomTM had a "very large" measurement agreement with "true" VO 2max (ICC = 0.78, CV of 9.1%, TE = 4.07 ml kg -1  min -1 ). Bruce had a "large" measurement agreement with "true" VO 2max (ICC = 0.62, CV of 10.0%, TE = 4.51 ml kg -1  min -1 )., Conclusion: The CustomTM was superior to the Bruce protocol, because it included a stage below and above gas exchange threshold, yielded a better measurement agreement for "true" VO 2max , and was more time efficient.

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., Competing Interests: The authors have declared that no competing interests exist.

We investigated the validity of a recently developed equation for predicting sprinting times of various tactical loads based upon the performance of a running 3-min all-out exercise test (3MT). Thirteen recreationally trained participants completed the running 3MT to determine critical velocity (CV) and finite running capacity for running velocities exceeding CV ( D '). Two subsequent counterbalanced loaded sprints of 800 and 1000 m distances with 20 and 15% of their body mass, respectively, were evaluated. Estimated times (t, sec) for running 800 and 1000 m with a tactical load was derived using t = (D - D ')/CV. Critical velocity adjusted for an added load using the following regression equation: original CV + (-0.0638 × %load) + 0.6982, D was 800 or 1000 m, and whole percentage load was ~15 or 20% of the participant's body mass. From the 3MT, CV (3.80 ± 0.5 m·s -1 ) and D ' (200 ± 49.88 m) values were determined. The typical error of predicting actual times for the 800 and 1000 m loaded sprints were 5.6 and 10.1 s, with corresponding ICCs of 0.95 and 0.87, and coefficient of variations of 2.9 and 4.3%. The effect size differences between estimated and actual sprint times were small (0.27) and moderate (0.60) for 800 and 1000 m, respectively. The adjustment to CV through the regression equation yields small to moderate overestimates of maximally loaded sprint times for distances of 800 and 1000 m. Whether such errors remain pervasive for prescribing high-intensity interval training is unclear and requires further investigation.

Kramer, M, Clark, IE, Jamnick, N, Strom, C, and Pettitt, RW. Normative data for critical speed and D' for high-level male rugby players. J Strength Cond Res 32(3): 783-789, 2018-The critical speed (CS) concept helps characterize the aerobic and anaerobic fitness of an athlete. Rugby players should, hypothetically, have modest CS values but extremely high curvature constant (D') values, yet, normative data are currently unavailable. To develop normative data of CS and D' for high-level male rugby players, a total of 30 male rugby players were recruited from the Eastern Cape of South Africa. All subjects performed the running 3-minute all-out exercise test (3 MT) using global positioning system (GPS) technology to determine CS and D'. The GPS data were used to determine the total distance and velocities performed, and to examine for pacing effects. Summary statistics of mean ± SD are provided. High total running speeds for the initial 150 seconds (S150s = 5.79 ± 0.59 m·s), and total distance (3 MT distance = 871.5 ± 71.9 m) were observed. A total of 13 of 30 subjects surpassed the 300 m D' value (mean D' = 288.2 ± 49.1 m). The CS of the total group was 3.87 ± 0.55 m·s. All 3 MT-derived data were categorized using standard nine (stanine) tables that allowed for the generation of normative data with which future performances, performances across similar sporting domains, and more accurate contrasts across the literature can be compared. Skewing of CS and D' was observed between forwards and backs, therefore, between-group differences in neither CS nor D' were observed (p > 0.05). Comparisons with previous literature indicate that male rugby players have higher CS values than female rugby players. When compared with Olympic distance runners, male rugby players have markedly higher D' values and markedly lower CS values. The 3 MT provides a useful procedure for assessing and prescribing high-intensity interval training for rugby athletes.

Natural physique competitions are based on subjective judgments of how a competitor appears on show day. Prior to competition, there is a prolonged dieting phase referred to as contest preparation. The primary goal is to reduce body fat levels while maintaining skeletal muscle mass. The study tracked the physiological and psychological changes for a 24 year old female preparing for a physique competition., Purpose: The study was conducted to describe the physiological and psychological changes of a female physique competitor who engages in long-term contest preparation., Methods: Diet, body composition, blood work, energy expenditure, mood, and performance were evaluated through contest preparation., Results: The participant lost 10.1kg throughout contest preparation in a strong weekly linear pattern (R 2 =0.97). Body fat was reduced from 30.45% to 15.85% while fat free mass was maintained. Mood for the participant remained stable until month five, when an observed variation occurred, with performance maintaining., Conclusions: Contest preparation was successful in reducing the body fat in the participant while having a minimum effect on both performance and fat free mass. For athletes looking to lose large amounts of body fat with minimal performance decrements a prolonged diet period with moderate exercise and food restriction can be an effective solution.

The use of personal records (PRs) for running different distances may be used to derive critical speed (CS) and the finite capacity for running speeds exceeding CS (D'). Using CS and D', individualized speed-time and distance-time relationships can be modeled (ie, time limits associated with running at a given speed or a given distance can be derived via linear regression with a high degree of accuracy). The running 3-min all-out exercise test (3 MT) has emerged as a method for estimating CS and D' on a large group of athletes in a single visit. Such a procedure is useful when PRs are not readily available (eg, team-sport athletes). This article reviews how to administer and interpret the running 3 MT, how CS and D' can inform racing strategy, and how CS and D' can be used to prescribe and evaluate high-intensity interval training (HIIT). Directions for deriving HIIT bouts using either fixed distances or fixed speeds are provided along with CS dose-responses to short-term HIIT programs.

Load carriage is a necessary burden for tactical athletes. A combination of training modes, including aerobic conditioning and progressive load carriage, may lead to improved performance. The critical speed (CS) concept enables the practitioner to prescribe high-intensity interval training (HIIT) time limits (TLIMs) from a single 3-minute all-out exercise test (3 MT). We sought to examine the effect of a standard load carriage (18.86 kg) on CS and the finite running capacity > CS (D'). A group of trained subjects (age: 26 ± 5 years, height: 181 ± 4 cm, body mass [BM]: 90 ± 14 kg) completed a loaded and unloaded (UL) 3 MT. The CS was reduced by 0.66 ± 0.24 m·s (p < 0.01) in the loaded condition. There was a small nonsignificant increase in D' (21.25 ± 39.53 m, p = 0.07). The higher the % load carriage relative to BM is, the greater decline in CS (r = 0.83, p < 0.01). A revised CS with load carriage from the UL 3 MT may be calculated using: adjusted CS = original CS + ([-0.0638 × %load]) + 0.6982. Our results indicate that revised CS and TLIMs for fixed distance, fixed time, or fixed speed HIIT prescriptions may be derived from a UL 3 MT. Such calculations would enable more expeditious training for tactical athletes. We recommend further research involving implementation of HIIT using this new method.

The 3-minute all-out exercise test (3MT) has emerged as a useful procedure for identifying critical power (CP) and the finite work capacity above CP (W') within a single visit. The CP concept enables for the prediction of exhaustive time limits (T(LIMs)) for a wide range of severe intensity power outputs and is a method for prescribing high-intensity interval training (HIIT). Road cyclists often use the CompuTrainer for indoor HIIT. The purpose of this study was to validate the 3MT for use on the CompuTrainer. On 4 separate visits, 10 competitive cyclists performed a 3MT, and three separate constant-load bouts projected to yield exhaustive T(LIMs) of 3, 6, and 9 minutes, respectively, using the Computrainer. Actual CP and W' were calculated using the linear work-time (W-t) and power-inverse time (1/t) models. The results for CP (W) from the 3MT (215 ± 40), the W-t model (212 ± 36), and the 1/t model (213 ± 36) did not differ (F = 2.96, p = 0.11, η2(p) = 0.43). Similarly, the results for W' (kJ) for the 3MT (11.2 ± 4.0), the W-t model (12.1 ± 6.5), and the 1/s model (11.7 ± 6.3) did not differ (F = 2.40, p = 0.15, η2(p) = 0.375). We conclude that use of the 3MT and the CP concept for performance assessment and HIIT prescription on the CompuTrainer is a valid procedure.

Purpose: To investigate a new power-to-body-mass (BM) ratio 3-min all-out cycling test (3MT(%BM)) for determining critical power (CP) and finite work capacity above CP (W')., Methods: The gas-exchange threshold (GET), maximal oxygen uptake (VO2max), and power output evoking VO2max (W(peak)) and GET (W(GET)) for cycle ergometry were determined in 12 participants. CP and W' were determined using the original "linear factor" 3MT (3MT(rpm^2)) and compared with CP and W' derived from a procedure, the 3MT(%BM), using the subject's body mass and self-reported physical activity rating (PA-R), with values derived from linear regression of the work-time model and power-inverse-time model (1/time) data from 3 separate exhaustive square-wave bouts., Results: The VO2max, VO(2GET), W(peak), and W(GET) values estimated from PA-R and a non-exercise-regression equation did not differ (P > .05) from actual measurements. Estimates of CP derived from the 3MT(%BM) (235 ± 56 W), 3MT(rpm^2) (234 ± 62 W), work-time (231 ± 57 W), and 1/time models (230 ± 57 W) did not differ (F = 0.46, P = .72). Similarly, estimates of W' between all methods did not differ (F = 3.58, P = .07). There were strong comparisons of the 3MT(%BM) to 1/time and work-time models with the average correlation, standard error of the measurement, and CV% for critical power being .96, 8.74 W, and 4.64%, respectively., Conclusion: The 3MT(%BM) is a valid, single-visit protocol for determining CP and W'.

Unlabelled: The maximal oxygen uptake (VO2max) is deemed the highest predictor for all-cause mortality, and therefore, an ability to assess VO2max is important. The YMCA submaximal test is one of the most widely used tests to estimate VO2max; however, it has questionable validity., Purpose: We validated a customized submaximal test that accounts for the nonlinear rise in VO2 relative to power output and compared its accuracy against the YMCA protocol., Methods: Fifty-six men and women performed a graded exercise test with a subsequent exhaustive, square wave bout for the verification of "true" VO2max. In counterbalanced order, subjects then completed the YMCA test and our new Mankato submaximal exercise test (MSET). The MSET consisted of a 3-min stage estimated at 35% VO2max and a second 3-min stage estimated at either 65% or 70% VO2max, where VO2max was estimated with a regression equation using sex, body mass index, age, and self-reported PA-R., Results: VO2 values from the graded exercise test and square wave verification bout did not differ with the highest value used to identify "true" VO2max (45.1 ± 8.89 mL · kg(-1) · min(-1)). The MSET (43.6 ± 8.6 mL · kg(-1) · min(-1)) did not differ from "true" VO2max, whereas the YMCA test (41.1 ± 9.6 mL · kg(-1) · min(-1)) yielded an underestimation (P = 0.002). The MSET was moderately correlated with "true" VO2max (ICC = 0.73, CV of 11.3%). The YMCA test was poorly correlated with "true" VO2max (ICC = 0.29, CV of 15.1%)., Conclusions: To our knowledge, this is the first study to examine submaximal exercise protocols versus a verified VO2max protocol. The MSET yielded better estimates of VO2max because of the protocol including a stage exceeding gas exchange threshold.

Epidemiological studies suggest that prolonged sitting increases all-cause mortality; yet, physiological causes underpinning prolonged sitting remain elusive. We evaluated cardiometabolic function during prolonged sitting (5 h) in 10 adults with and without 30 min of moderate exercise leading up to the sitting. Mean arterial blood pressure (MAP), heart rate (HR) and posterior tibial artery blood velocity were measured at baseline and every hour subsequently. Blood glucose was measured at baseline, 3 and 5 h, with consumption of a caloric beverage at 1 h. Seated MAP and HR values were ~17 mmHg (P < 0.001) and ~4 bpm (P < 0.05) higher for the moderate exercise versus sitting conditions. A ~ 4 cm·s(-1) (16%) (P < 0.05) decline in posterior tibial artery blood velocity from prolonged sitting was observed, with no benefit conferred from moderate exercise. Postprandial glucose metabolism was not different between conditions (P > 0.05). We conclude prolonged sitting may be related to decreased posterior tibial artery blood velocity. Moreover, an acute bout of moderate exercise does not seem to attenuate cardiometabolic function during prolonged sitting in healthy, young adults.

As advances in protective equipment are made, it has been observed that the weight law enforcement officers must carry every day is greatly increasing. Many investigations have noted the health risks of these increases, yet none have looked at its effects on officer mobility. The primary purpose of this study was to examine the influence of both the weight of officer safety equipment, as well as a lateral focal point (FP), on the stride length, stride velocity, and acceleration of the first six strides of a short sprint. Twenty male law enforcement students performed two maximal effort sprint trials, in the participating college's gymnasium, from each of four starting positions: forwards (control position), backwards, 90° left, and 90° right. Subjects placed in the FP group (n = 9) were required to maintain focus on lateral FP during the 90° left and 90° right trials, and a forwards FP during the backwards trials. On a second testing date, subjects repeated the sprint tests while wearing a 9.07 kg weight belt, simulating officer equipment and protective gear. The belt averaged 11.47 ± 1.64% of subject body mass. A significant main effect of weight belt trials was found (F = 20.494, p < 0.01), in which significant decreases were found for velocity and acceleration. No other significant effects were found as a result of starting position or focal point and no significant interactions were found between independent variables. Conclusively, the results of this study show the increasing weights of duty gear and protective equipment have detrimental effects on officer velocity and acceleration, impeding their mobility, which may be dangerous in use of force or threatening situations., (Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.)

The critical velocity (CV) model offers an opportunity to prescribe and to test empirically different velocity-time (V-t) configurations of high-intensity interval training (HIIT); however, such experiments are lacking. We evaluated a group of competitive, female soccer players (age = 19 ± 1 years, height = 168 ± 6 cm, mass = 61 ± 6 kg) completing 1 of 2 different HIIT regimes: a short group (n = 6) completing higher V and shorter t configurations, and a long group (n = 10) completing lower V, longer t configurations. Both groups trained 2 d·wk for 4 weeks. For each workout, both groups ran at velocities exceeding CV and designed to deplete identical fractional percentages of the finite work capacity above CV (D'). The metrics of CV and D' were evaluated at pretraining and posttraining using the 3-minute all-out exercise test on an indoor track using video digitizing of displacement relative to time. Despite differences in the V-t configurations, both groups increased their CV (+0.22 m·s, +6%) and decreased their D' (-24 m, -13%; p < 0.05). We conclude that 2- to 5-minute HIIT bouts are suitable for increasing CV, in previously trained athletes, but they result in a decline of D'. To increase D', we suggest examining HIIT of intensities that are <2 minutes and >130% of maximum oxygen uptake.

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., (© Georg Thieme Verlag KG Stuttgart · New York.)

Quantifying the maximal work capacity (W') above the aerobic critical power (CP) has emerged as a method for estimating anaerobic work capacity. Slower cadence, lower-load resistance training (RT), colloquially referred to as high-intensity training (HIT), is purported to be a better metabolic stressor than faster cadence higher-load RT, but to date, this belief has not been supported by research. We compared the acute effects of HIT and traditional RT bouts on average power within a 150-second time period (P(150 s)), CP, and W', as measured from a 3-minute all-out exercise test using cycling ergometry (3 MT). Eight recreationally active male subjects (mean ± SD: age 22 ± 2 years, body mass 85 ± 14 kg, and height 18 ± 9 cm) completed a baseline 3 MT 10 repetition maximum testing on leg press and leg extension machines, and post-bout 3 MTs after an HIT (4:2 second cadence) or a traditional RT bout (1:1 second cadence). Measurements of CP from the 3 MTs were similar between the baseline, post-HIT (α = 0.96), and post-traditional RT bouts (α = 0.98). Neither HIT (269.2 ± 51.3 W) nor traditional RT (275.1 ± 51.3 W) evoked depreciations (p > 0.05) in P(150 s) from the baseline (275.1 ± 45.4 W). Moreover, estimates of W' at the baseline (8.3 ± 3.2 kJ) were unaffected (p > 0.05) either by the HIT (7.6 ± 2.3 kJ) or by the traditional RT (8.3 ± 1.3 kJ) bouts. These data indicate that the 4:2 cadence is insufficient to exhaust a person's capacity for high-intensity work. Longer RT durations, either by slower cadences or by multiple sets, are necessary to evoke substantive declines on W' and should be investigated.

The cycling 3-minute all-out exercise test (3 MT) provides the measures of critical power (CP) and the curvature constant (W') for the relationship between power and time limit to exhaustion in the severe exercise domain. The original procedures for the 3 MT required a preliminary graded exercise test (GXT) to establish the linear factor and the fixed load for the test. We evaluated a new procedure of establishing the load for the 3 MT using a percentage of body mass (% BM). Fifteen subjects of varied fitness levels completed a custom GXT-verification protocol to establish the gas exchange threshold and V[Combining Dot Above]O2max, a 3 MT using a load derived with the linear factor, and a 3 MT using a % BM. The subjects also completed a subsequent exhaustive bout at 10% above CP. The CP and W' estimated from either protocol did not differ. The CP estimates were consistent (α = 0.97, SEM = 7.1 W, coefficient of variation = 4%); however, W' was less reliable, a finding true of any method of measuring W'. The V[Combining Dot Above]O2 evoked during the 3 MT was lower than the values evoked by the exhaustive GXT-verification bouts and the 10% above CP bout after the 3 MT. All individual V[Combining Dot Above]O2 values in the 10% above CP bout were "≥" values measured in the 3 MT. Our findings indicate that several viable procedures for administering the 3 MT are plausible.

Energy drinks (EDs) such as Red Bull (RB) are marketed to enhance metabolism. Secondary ingredients of EDs (e.g., taurine) have been purported to improve time trial performance; however, little research exists on how such secondary ingredients affect aerobic metabolism during heavy exercise. The purpose of this study was to investigate the effect of the secondary ingredients of RB on aerobic metabolism during and subsequent to heavy exercise. In double-blind, counterbalanced, and crossover fashion, 8 recreationally trained individuals completed a graded exercise test to determine the gas exchange threshold (GET). Subjects returned on 2 separate occasions and ingested either a 245 ml serving of RB or a control (CTRL) drink with the equivalent caffeine before engaging in two 10-minute constant-load cycling bouts, at an intensity equivalent to GET, with 3 minutes of rest between bouts. Accumulated liters of O2 (10 minutes) were higher for the first bout (17.1 ± 3.5 L) vs. the second bout (16.7 ± 3.5 L) but did not differ between drinks. Similarly, excess postexercise oxygen consumption was higher after the initial bout (RB mean, 2.6 ± 0.85 L; CTRL mean, 2.9 ± 0.90 L) vs. the second bout (RB mean, 1.5 ± 0.85 L; CTRL mean, 1.9 ± 0.87 L) but did not differ between drinks. No differences occurred between drinks for measures of heart rate or rating of perceived exertion. These results indicate that the secondary ingredients contained in a single serving of RB do not augment aerobic metabolism during or subsequent to heavy exercise.

Standardized graded exercise test (GXT) protocols are ineffective for testing endurance athletes. Scientists have called for the abandonment of traditional techniques for corroborating "true" maximum oxygen uptake (VO2max), as measured during a GXT. Instead, a new technique, the verification bout subsequent to the GXT, has emerged for establishing the "true" VO2max. The addition of the verification bout reframes how the GXT should be viewed. In this article, we summarize the methods for developing custom GXT protocols, identifying threshold and interpolating power or outdoor running velocity, and implicating the verification bout.

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., (© Georg Thieme Verlag KG Stuttgart · New York.)

Unlabelled: The 3-min all-out exercise test (3 MT) is purported to estimate critical power (CP) and anaerobic work capacity (W') and serve as an exercise mode for measuring maximum oxygen uptake (VO(2max)). Reliability analysis of the 3 MT has been confined to CP, not W', and verification of "true" VO(2max)was exclusive to a graded exercise test (GXT)., Purpose: We conducted a reliability analysis of the 3 MT and compared VO(2max)values from the 3 MT with a GXT and an exhaustive square-wave verification bout., Methods: Upon completion of a custom GXT and square-wave verification protocol, 11 subjects of various aerobic powers completed two 3 MTs (separate visits). CP, W', average power during 150 s from the 3 MT, and VO(2max)values were assessed using typical error (TE), coefficient of variation (CV), and intraclass correlation (α)., Results: CP (W) (trial 1 = 206 ± 47, trial 2 = 206 ± 42) did not differ between 3 MT trials (P = 0.37) and was reliable (TE = 15 W, CV = 7%, α = 0.93). W' was less reliable (TE = 2864 J, CV = 28%, α = 0.76) but did not alter power-duration estimates from the two 3 MTs (P > 0.05). Variability for VO(2max)(TE (mL·kg(-1)·min(-1)) between the GXT and the verification bout (1.16) was more consistent than the first (2.03) or second (2.69) 3 MT., Conclusions: The 3 MT yields reliable estimates of CP and consistent estimates of the power-duration relationship. Power for 150 s, in comparison with W', is a more reliable metric of short-term power performance. The square-wave protocol is recommended over the 3 MT for verifying true VO(2max).

Firefighters are required to perform a variety of strenuous occupational tasks that require high levels of both aerobic and anaerobic fitness. Thus, it is critical that firefighters train at an appropriate intensity to develop adequate levels of aerobic and anaerobic fitness. Circuit training is a unique training method that stresses both energy systems and therefore may be a viable training method to enhance firefighter preparedness. Thus, the purpose of this study was to compare the aerobic and anaerobic intensities of a circuit-based workout to physiological data previously reported on firefighters performing fire suppression and rescue tasks. Twenty career firefighters performed a workout that included 2 rotations of 12 exercises that stressed all major muscle groups. Heart rate was recorded at the completion of each exercise. Blood lactate was measured before and approximately 5 minutes after the workout. The workout heart rate and post-workout blood lactate responses were statistically compared to data reported on firefighters performing fire suppression and rescue tasks. The mean circuit-training heart rate was similar to previously reported heart rate responses from firefighters performing simulated smoke-diving tasks (79 ± 5 vs. 79 ± 6% maximum heart rate [HRmax], p = 0.741), but lower than previously reported heart rate responses from firefighters performing fire suppression tasks (79 ± 5 vs. 88 ± 6% HRmax, p < 0.001). The workout produced a similar peak blood lactate compared to that when performing firefighting tasks (12 ± 3 vs. 13 ± 3 mmol·L(-1), p = 0.084). In general, the circuit-based workout produced a lower cardiovascular stress but a similar anaerobic stress as compared to performing firefighting tasks. Therefore, firefighters should supplement low-intensity circuit-training programs with high-intensity cardiovascular and resistance training (e.g., ≥85% 1-repetition maximum) exercises to adequately prepare for the variable physical demands of firefighting.

Complex training is characterized by pairing resistance exercise with plyometric exercise to exploit the postactivation potentiation (PAP) phenomenon, thereby promising a better training effect. Studies on PAP as measured by human power performances are equivocal. One issue may be the lack of analyses across multiple sets of paired exercises, a common practice used by athletes. We evaluated countermovement vertical jump (CMJ) performance in 19 women, collegiate athletes in 3 of the following trials: (a) CMJs-only, where 1 set of CMJs served as a conditioning exercise, (b) heavy-load, back squats paired with CMJs, and (c) hang cleans paired with CMJs. The CMJ vertical displacement (3-attempt average), as measured with digital video, served as the dependent variable of CMJ performance. Across 3 sets of paired-exercise regimens, CMJ-only depreciated 1.6 cm and CMJ paired with back squats depreciated 2.0 cm (main effect, p < 0.05). Conversely, CMJ paired with hang cleans depreciated 0.30 cm (interaction, p < 0.05). Thus, the best complex training scheme was achieved by pairing CMJs with hang cleans in comparison to back squats or CMJs in and of themselves. Future research on exercise modes of complex training that best help athletes preserve and train with the highest power possible, in a given training session, is warranted.

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., (© Georg Thieme Verlag KG Stuttgart · New York.)

Inferential statistics help the strength and conditioning specialist to determine if a team is responding to a strength and conditioning program overall; however, such statistics do not detect unusual responses among individuals such as those who may be overtraining. This article introduces the standard difference score (SDS), a new statistic for evaluating strength and conditioning programs. The SDSs are standard scores (z score) derived from a change in a raw strength and conditioning performance score. They are simple to calculate and sort, easy to plot, and can be aggregated to detect athletes exhibiting extreme performance changes from a battery of tests. Standard difference scores, when evaluated with skewness, can be substituted for conventional exploratory statistics generated with higher end statistical software programs.

Postactivation potentiation (PAP) has been hypothesized previously to occur during voluntary, concentric actions. We tested the hypothesis that one of at least three different intensities of conditioning exercises would evoke potentiation of power during the concentric, bench press throw (BPT). Twelve men (age = 22.9 ± 2.7 years, bench press 1 repetition maximum (1RM) = 1.20 ± 0.12 kg·kg -1 body weight) completed five isotonic conditioning presses at ~55, 70, and 86% 1RM, in counterbalanced order, and on separate days. Average and peak power of the BPT using a load of 55% 1RM along with surface electromyography (EMG) of the triceps brachii were collected prior to and 4-minutes following each conditioning bout. Both average and peak power and EMG values (mean ± SD), respectively, were evaluated using two-way analyses of variance with repeated measures. Significant main effect decreases (p < 0.05) in average (-18.6 ± 4.9 W) and peak power (-37.4 ± 9.9 W) occurred across the three different intensities evaluated. No main effects or interactions were observed with the EMG data. Contrary to the previously reported hypothesis, we were unable to demonstrate that conditioning exercise, with three different intensities, can evoke potentiation of power using a load equating to that which is optimum for power production.

Overestimates of oxygen uptake (VO2) are derived from the heart rate reserve-VO2 reserve (HRR-VO2R) model. We tested the hypothesis that adjusting for differences above and below gas exchange threshold (HRR-GET model) would tighten the precision of HR-derived VO2 estimates during heavy exercise. Seven men and 7 women of various VO2 max levels, on 2 separate days, cycled for 6 min at intensities equal to power at GET, 15% the difference between GET and VO2 max (15% above), and at 30% above GET. A second bout at 15% above GET (15% above (bout 2)) after 3 min of recovery was performed to assess estimates during interval training. Actual VO2 was compared with estimates derived from the HRR-VO2R and the HRR-GET. VO2 values were summed over the 6 min duration of data collection (6 min LO2) and compared with Bland-Altman plots. HRR-VO2R yielded 6 min LO2 (+/-2 SD) overestimates of 2.0 (+/-2.5), 1.9 (+/-2.7), and 1.3 (+/-3.3) for GET, 15% over, and 30% over, respectively, whereas corresponding 6 min LO2 difference values for the HRR-GET model were -0.42 (+/-1.6), -0.23 (+/-1.1), and -0.55 (+/-1.8), respectively. For 15% above (bout 2), the 6 min LO2 difference for HRR-VO2R was 1.8 (+/-2.9), whereas the difference for HRR-GET was 0.17 (+/-1.4). The 6 min LO2 values relative to the subjects' VO2 max did not vary (r=0.05 to 0.36); therefore, fitness level did not affect estimates. Sex did not affect accuracy of either estimate model (sex X estimate model interaction, p>0.95). We observed accurate estimates from the HRR-GET model during heavy exercise.

While ice massage (IM) is a rapid cooling technique used to facilitate therapeutic movements in the rehabilitation process, evidence of its efficacy over alternative therapeutic protocols is scarce. We determined whether dabbing the skin surface dry during a standard IM treatment would lead to greater rate of skin temperature reduction in comparison to without dabbing; and whether dabbing the skin would lead to an acute change in flexibility. Sixteen healthy volunteers received a "dabbing" and "non-dabbing" 7-minute IM treatment over the surface of each triceps surae muscle. Minute-by-minute temperature change in skin surface was evaluated using an infrared thermometer. Active (AROM) and passive (PROM) range of motion were evaluated via hand-held goniometer and passive stretch force was evaluated with an algometer. Dependent variables (reported as Mean ± SD) were tested with two-way analysis of variance with repeated measures. Skin temperature (°C) was reduced to with dabbing (5.8 ± 1.1) in comparison to without dabbing (6.8 ± 1.4), evoking significantly greater cooling at 1-min of ice massage (group X time interaction, p<0.01). However, after two minutes of IM, each method of application evoked similar surface temperatures. There was no significant difference in AROM, with dabbing (-0.63 ± 2.55°) in comparison to without dabbing (1.18 ± 2.90°), and no significant difference in passive-length tension relations (p>0.05) for either IM group. The dabbing protocol resulted in more rapid rate of temperature drop at 1-minute, however, both IM techniques are sufficient in cooling surface temperature after 2-minutes of IM. Further study is warranted to determine the clinical significance of the dabbing procedure.

High-risk stress fractures require precise assessment and treatment because of their propensity for delayed union, nonunion, or complete fracture and their resulting disabling complications. Proper diagnosis necessitates a thorough clinical evaluation, centering on the patient's diet and history, particularly the training regimen. For a definitive diagnosis, plain radiography, ultrasound, bone scintigraphy, magnetic resonance imagery (MRI), and computed tomography (CT) are helpful, and each plays a specific role. High-risk stress fractures typically require aggressive treatment such as nonweight-bearing immobilization coupled with therapy and often surgery.

The repeated bout effect (RBE) is a phenomenon characterized by less delayed onset muscle soreness (DOMS) and torque deficit after the second of 2 separate eccentric exercise bouts. Previous investigators have reported that shifting of optimum angle after an initial bout of eccentric exercise mediates the RBE. We hypothesized that an RBE for elbow extensor exercise occurs after an initial bout performed at long (starting position of 50 degrees to an end position of 130 degrees) but not short (starting position of 0 degrees to an end position of 80 degrees) muscle length because strain at long length evokes a shifting of the optimum angle to a longer length. Untrained women performed an initial bout at either long or short length (n = 9 per group) followed 1 week later by a repeated bout (RB) through the full ROM (0-130 degrees). Extensor torque and optimum angle was evaluated before, immediately after, and 2 days after each bout. A mechanical transducer depressed on the triceps brachii quantified DOMS. Torque deficits were 3% and 7% after exercise at short vs. long length, respectively. Two days after the RB, torque deficit was 8% and 1% for those previously exercising at short vs. long length (group x bout, p < 0.05). Greater DOMS (N) was observed after exercise at long (16 +/- 3) vs. short (23 +/- 2) length; whereas greater DOMS occurred for the short-length (17 +/- 2) vs. long (26 +/- 3) group after the RB (group x bout, p < 0.05). Optimum angle shifted to a longer length after exercise at long (+10 +/- 4 degrees) vs. short (+1 +/- 3 degrees) length (group x bout, p < 0.05). After the RB, those exercising previously at short length experienced a shift of +15 +/- 4 degrees (main effect, p < 0.05). The findings of this study indicate that the repetitive strain at long but not short muscle length evokes both immediate and sustained shifts in optimum angle to longer lengths, and that this shifting mediates (r(2) = 0.71) the RBE.