Comparison of the Gauntlet Test With Standard Laboratory Measures of Aerobic Fitness

Abstract

Burnsed-Torres, ML, Wichmann, TK, Clayton, ZS, and Hahn, ME. Comparison of the Gauntlet test with standard laboratory measures of aerobic fitness. J Strength Cond Res XX(X): 000–000, 2019—The purpose of this study was to validate whether the Gauntlet test (GT) can accurately estimate individual aerobic endurance performance compared with standard laboratory-based physiological tests. The GT required athletes to complete 5 maximal effort running stages, with a 1-minute break between each stage, with the goal of achieving the best overall time. Eighteen men (n = 9) and women (n = 9) (age, 23.5 ± 4.13 years; body mass index, 23.1 ± 7.62 kg·m⁻²; 5k time, 22 ± 7 minutes; 10k time, 47 ± 15 minutes; $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, 52.3 ± 8 ml·kg⁻¹·min⁻¹) completed a lactate threshold test and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max test (laboratory measures). Four to 14 days later, subjects completed the GT on an outdoor track. Blood lactate (bLa), $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, and heart rate (HR) were recorded during the laboratory session. Blood lactate, HR, stage completion time, and overall completion time were recorded during the GT. Linear regression correlation analyses revealed a significant inverse association between $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max (mL·kg⁻¹·min⁻¹) and GT completion time (r = −0.88, P < 0.0001). In addition, there were significant correlations between $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max maximum HR and GT maximum HR (r = 0.89, P < 0.0001) and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max 3-minute post bLa and GT 3-minute post bLa (r = 0.63, P = 0.0029). Sex-specific analysis showed significant inverse associations between female and male GT completion time and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max (r = −0.70, P = 0.0352; r = −0.94, P < 0.0002). Bland-Altman plots were used to evaluate concordance between GT completion time, $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, maximum HR, and 3-minute post bLa. Results suggest the GT is a valid assessment to accurately estimate aerobic endurance performance similar to standard laboratory methods.

Introduction

For sporting populations, the ongoing assessment of aerobic endurance performance can be beneficial for monitoring training programs, assessing recovery from injury or be used as part of a selection process (29). The standard test for assessing aerobic endurance performance is the measurement of an individual’s maximal oxygen uptake ($\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max) which reflects the ability of the cardiovascular system to deliver oxygen to the working muscles (21).

In addition to measurement of $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, measuring blood lactate (bLa) to identify lactate threshold (LT) is well correlated with endurance performance (9,12,27). Research shows that healthy trained individuals had LT values that were 84% of $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, supporting the notion that LT can be a good predictor of aerobic endurance performance (9).

Although the values obtained for $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max and LT are considered the “gold standard” for the measurement of aerobic endurance performance (1,5,23), the procedures require laboratory time, expensive equipment, and trained personnel. Consequently, such measurements are not feasible for routine fitness testing, creating a demand for a predictive field-based test that will elicit the same physiological responses to a $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max test indicating an individual’s level of aerobic endurance.

Commonly used aerobic fitness tests include the 20-meter (m) multistage shuttle run test (MST), Yo-Yo intermittent endurance test (YIET), and the Yo-Yo intermittent recovery 1 and 2 (IR) tests (13,14,17,21). These field tests require running at different speeds across 20- to 40-m distances with frequent dynamic twisting and changing of direction (1). The difference between the 2 tests is that MST involves continuous running while the YIET and Yo-Yo IR tests have varying time specific recovery periods after each 20- to 40-m shuttle run. Performance measures from both field tests have been validated against laboratory-based $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max tests (1,13,14,18). Blood lactate concentrations and heart rate (HR) collected in studies using the Yo-Yo IR tests, YIET, and MST were at levels reflecting maximal performance efforts which would suggest the tests are a valid representation of aerobic endurance performance (2,7,14,25).

The Gauntlet test (GT) is a field-based fitness test that has been shown to be a convenient and predictive screen for potential lower-body injuries among female soccer athletes but has yet to be validated against laboratory-based physiological tests (19). It consists of individuals running stages of 1600, 800, 400, 200, and 100 m intermittently with a 1-minute break in between each stage with the goal of completing each distance as quickly as possible for a best effort overall time (28). The necessary equipment needed by a coach or practitioner to administer this test is a stopwatch and a track or the appropriate distances marked out. Currently, there are no universal stratifications established that associate the GT overall completion time or stage completion time with set levels of fitness; thus, the goal of this test is to have athletes perform the assessment at their maximal effort.

However, coaches and practitioners can establish time cutoffs and relative rest periods for each distance and overall completion time as it relates to their athletes and sport or an individual’s fitness goals. The GT is unique to currently validated field tests, such as the YEIT, MST, and Yo-Yo IR, by requiring athletes to run a variety of distances at maximal effort, rather than 20- to 40-m sprints coupled with dynamic movements (i.e., cutting and change of direction) and set passing levels. Most commonly, but not limited to, the GT has been used by team sports to determine the fitness level of athletes during pre-season, in-season, and post-season.

Given the limited access to ambulatory devices for indirect calorimetry and limited ability to measure bLa in many non-laboratory environments, there is a need for accurate alternative assessments that can be easily performed in the field. Therefore, the purpose of this study was to validate the performance measures collected during the GT against comparable performance measures collected during standard laboratory-based physiological tests. It was hypothesized that the GT time to completion would provide a means of estimating $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$ value equal to the gold standard laboratory-based physiological tests. In addition, we hypothesize that 3-minute post bLa and maximum HR of the GT would be significantly correlated with both the laboratory and field fitness test.

Methods

Experimental Approach to the Problem

An observational crossover controlled trial was implemented to determine whether the GT can accurately estimate aerobic endurance performance similar to standard laboratory methods, across male subjects and female subjects. Each subject visited the Bowerman Sports Science Clinic on 2 separate occasions 4–14 days apart from each other. Each subject completed: (a) an LT test followed by a $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max test on day one and (b) the GT on the track of Hayward Field on day 2. Before testing for both visits, researchers recorded height, body mass (shoes on), age, and resting HR. Blood lactate was assessed in duplicate at baseline, intermittently during the tests and 3 minutes after exercise for the LT, $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, and the GT. Heart rate was recorded throughout both visits using a chest strap monitor (Polar H7, Kempele, Finland). In preparation for testing, subjects were instructed to maintain their current workout regimen and refrain from strenuous or vigorous activity at least 24 hours before the tests. In addition, subjects were advised to maintain their typical dietary intake and dietary supplement regiment throughout their participation in the study.

Subjects

Eighteen (9 male and 9 female) healthy, recreationally active subjects enrolled in this study (Table 1). Subjects were required to be nonsmokers, without lower-body injuries within the past year, the ability to run a 5k ≤28 minutes, and be within 18–35 years of age. The study power for this sample size (n = 18) was estimated at 0.97 based on a minimal detectable change in GT completion time of 13.3 seconds per unit change in $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, using Schoenfeld’s sample size estimation and power calculation method (24). The study and informed consent documents were approved by the Institutional Review Board and Research Compliance Services at the University of Oregon: 09232016.025. Informed oral and written consent was obtained from all subjects before participating in the study.

Table 1.

Subject characteristics.^*†

Subject N = 18	Male	Female
Sex	9	9
Age (y)	27.7 ± 2.8	21.2 ± 2.1
Height (cm)	179.3 ± 4.3	170.5 ± 6.2
Body mass (kg)	78.6 ± 7.6	64.9 ± 7.1
BMI (body mass (kg)·height (m)−2)	24.4 ± 1.6	22.2 ± 1.4
5k (min)	21.3 ± 3.2	23.4 ± 2.2
10k (min)	46.7 ± 8.1	49.7 ± 4.6

^*BMI = body mass index.

^†Mean ± SD. 5k and 10k times were self-reported.

Procedures

Visit 1: LT and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2\max$ Test.

Before starting the submaximal LT test, subjects had the opportunity to perform a self-selected warm-up for 5 minutes, which could include but was not limited to static stretching, dynamic stretching, and jogging. After the warm-up, subjects were outfitted with an HR monitor, and oxygen consumption was assessed using the continuous indirect calorimetric Parvo Medics TrueOne 2400 metabolic measurement system (Parvo, Sandy, UT) (6). A high speed treadmill (Woodway, Waukesha, WI) was set at 1% grade throughout the test to simulate overground running (11). Before the onset of running, subjects stood on the treadmill for 3 minutes to acclimate and allow metabolic values to stabilize. The test was started with a treadmill speed that was 5 km·h⁻¹ slower than each subject’s reported 5k/10k pace; then, the speed was increased by 1 km·h⁻¹ every 3 minutes for 6 to 7 stages. Each stage was separated by a 30-second rest period, during which blood samples were obtained from the finger and analyzed for bLa concentrations using handheld meters (Lactate Plus Meters, Waltham, MA). Pulmonary gas exchange and HR data were collected in 15-second averages. In response to the progressive incremental exercise, subjects’ bLa exponentially increased until LT was exceeded which typically occurred between the sixth-seventh stage, and bLa reached ~8mMol. Lactate threshold was determined by the Dmax method, proposed by Cheng et al. (4), which uses a third-order polynomial function of bLa vs. $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$ to determine the critical LT inflection point. Once the LT test was completed, subjects were given a 10-minute recovery period before starting the $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max test. Subjects were allowed to choose their method of recovery (i.e., walk, jog, sit, etc).

The $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max test used the same equipment as previously described for the LT test. The protocol was a graded test where speed was held constant while the grade increased 1% each minute until volitional exhaustion. Test speed was determined by using the speed 2 stages before the last completed stage during the LT test. Subjects were verbally encouraged by the researchers to run as long as they could and to try to reach a true maximal effort. Handrail support was not allowed during the test. The criteria used to determine $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max were an increase in $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$ of less than 2.1 ml·kg⁻¹·min⁻¹ on 2 consecutive stages, a respiratory exchange ratio greater than 1.1, or an HR ± 10 b·min⁻¹ of the maximal age-predicted HR. A final bLa sample was collected 3 minutes after the test was completed.

Visit 2: The Gauntlet Test.

The GT was completed in lane 8 on the track of Hayward Field at the University of Oregon. Lane 8 was chosen to reduce interference of the collegiate program’s training sessions. The test consisted of 5 stages, with a 1-minute break in between each stage: stage 1: 1,814.64 m, stage 2: 907.32 m, stage 3: 453.66 m, stage 4: 226.83 m, and stage 5: 100 m. These distances were the exact distances traveled based on the start and finish positions being constrained to the beginning and end of the straightaway, to simplify the start and finish positions for consistency in each stage. Total GT completion times for stages 1 through 4 were normalized to represent the prescribed distances for the GT protocol (stage one: 1600 m, stage 2: 800 m, stage 3: 400 m, and stage 4: 200 m). This normalization simply used the average velocity of the measured distance for each stage (i.e., 1,814.64 m) divided into the value of the standard distance (i.e., 1,600 m). Heart rate and bLa measures were collected during the first 30 seconds of every 1-minute break between each stage for a total of 5 collections. Subjects were verbally encouraged by the researchers to run as fast as they could and to try to reach a true maximal effort for each stage. A final bLa sample was collected 3 minutes after completion of the final stage of the GT.

Statistical Analyses

Descriptive statistics (sample mean and SD) were calculated. The Pearson correlation coefficient (R) was calculated from a regression analysis for comparison of: (a) GT completion time relative to $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max; (b) GT maximum HR relative to $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max maximum HR; (c) GT 3-minute post bLa relative to $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max 3-minute post bLa Paired, 2-tailed t-tests were used to test for significance of each association. Data were analyzed using GraphPad Prism version 7 for windows (GraphPad Software; La Jolla, CA), with significance set at P ≤ 0.05. In addition, Bland-Altman plots were used to evaluate concordance between GT completion time and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, GT maximum HR and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max maximum HR, and GT 3-minute post bLa and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max 3-minute post bLa.

Results

Twenty subjects enrolled in this study. Two subjects were not able to complete testing, reducing the sample to 18 subjects (Table 2). Correlation analysis revealed significant inverse association between GT completion time and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max (r = −0.88, p < 0.0001) and positive associations between GT maximum HR and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max HR (r = 0.80, p < 0.0001) and 3-minute post-GT bLa and 3-minute post-$\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max bLa (r = 0.63, p = 0.0029) (Figure 1A-C). In addition, sex-specific associations were analyzed, showing significant inverse associations between female GT completion time and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max (r = −0.70, p = 0.0352) and male GT completion time and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max (r = −0.94, p < 0.0002) (Figure 2A, B).

Table 2.

Laboratory-based $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max values, Gauntlet total completion time, and stage completion time.^*

Subject	$\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max (mL·kg−1·min−1)	Gauntlet (s)	Stage 1 (s)	Stage 2 (s)	Stage 3 (s)	Stage 4 (s)	Stage 5 (s)
S01	43.19	1,184	497	252	116	52	26
S02	53.10	1,071	432	225	104	49	21
S03	48.99	1,017	427	210	92	36	13
S04	55.42	971	406	195	82	34	13
S05	61.79	883	351	170	76	33	13
S06	54.48	930	366	188	82	38	16
S07	41.96	1,057	425	230	101	42	19
S08	38.33	1,181	491	277	129	31	13
S09	49.40	954	393	184	83	38	16
S10	56.40	897	347	178	85	32	15
S11	64.72	827	320	154	70	30	13
S12	48.30	959	377	192	90	42	17
S13	62.80	920	362	181	85	36	16
S14	66.20	781	291	143	63	30	14
S15	52.50	933	374	188	80	36	15
S16	47.20	1,090	460	241	93	40	16
S17	45.30	1,010	416	205	93	40	16
S18	51.01	1,000	423	201	86	34	16
Mean ± SD	52.3 ± 8	397.8 ± 55.2	397.8 ± 55.2	200.8 ± 34.0	89.3 ± 15.7	37.4 ± 6.2	16 ± 3.3

^*Gauntlet stage distances, performed in lane 8 with 4 one-minute breaks between each stage. Time values were normalized to standard distances; stage 1 = 1600 m, stage 2 = 800, stage 3 = 400, stage 4 = 200 m, and stage 5 = 100 m.

Figure 1.

Correlation between $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max and GT completion time (A), $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max maximum HR and GT maximum HR (B), and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max 3-minute post bLa and GT 3-minute post bLa (C). Bland-Altman plots for the average and differences between $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max and GT completion time (D), $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max maximum HR and GT maximum HR (E), and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max 3-minute post bLa and GT 3-minute post bLa (F). Solid lines denote linear trend, and dashed lines denote the 95% confidence interval, P < 0.05, for (A–C). Solid lines denote the mean of the differences, and dashed lines denote the 95% confidence interval for (D–F). GT = Gauntlet test; HR = heart rate; bLa = blood lactate.

Figure 2.

Correlation between $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max and GT completion time for male (A, closed circle) and female (B, open circle) subjects. Solid line denotes linear trend, and dashed lines denote the 95% confidence interval, p < 0.05. GT = Gauntlet test.

Discussion

The findings indicate that GT completion time is significantly and inversely correlated with $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max. In addition, maximum HR during the GT is significantly correlated with maximum HR during a $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max test, and 3-minute post-GT bLa is significantly correlated with 3-minute post-$\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max bLa. This is the first study to compare performance variables such as HR and bLa from the GT against a laboratory measurement of aerobic endurance. Physiological metrics associated with performance such as bLa and maximum HR are indicators of aerobic fitness; therefore, we compared both metrics during the GT and the laboratory-based assessments to gain a better insight into the GT’s ability to be an alternative to laboratory-based assessments. Although laboratory testing using calorimetry is considered the most accurate method to determine maximal aerobic capacity, the procedure is time-consuming, expensive, and requires the subject to have adequate motivation to perform maximally during the test. There is a need for indirect methods that are inexpensive and easy to administer which provide an estimation of aerobic capacity. Currently, the MST, YIET, and Yo-Yo IR tests are commonly implemented field fitness assessments used within endurance sports. Based on evidence from this study, the GT can offer an alternative assessment to provide accurate estimation of aerobic fitness among those who are recreationally trained.

It is known that $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max is a predictor of an individual’s aerobic endurance capacity. In the current study, significant correlations were found between GT total completion time and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max. Furthermore, subjects with higher $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max also had faster stage-by-stage completion times for the GT. The GT evaluates an individual’s ability to repeatedly perform intermittent exercise with a high aerobic component. The results from this study indicate that the GT is able to produce a strong aerobic response, similar to that elicited from a treadmill test. Previous research on the MST and Yo-Yo IR level 1 and 2 tests has shown significant correlation between field test time and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max with varying amounts of correlation per study (r = 0.67–0.92) (3,13,16,20,21,26). A study conducted by Aziz et al. (1) compared the Beep test and YIET with $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, to determine what test would best measure endurance performance. They found that neither field test was significantly correlated with measured $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max demonstrating a need for a more accurate field measure of aerobic capacity.

Heart rate increases in direct proportion to exercise intensity until maximum HR is reached. The direct method for determining maximum HR is to exercise at increasing intensities until a plateau in HR is achieved despite the increasing work rate (22). In the current study, maximum HR values obtained from traditional laboratory-based tests were significantly correlated with GT maximum HR values. These results suggest that the GT maximally stimulates the aerobic system, accurately providing the maximal HR of an individual. Such measurements are useful for estimating exercise intensity and evaluating the level of aerobic fitness. The variation observed between compared values could be due to the treadmill-based $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max test limiting the subjects’ ability to change their pace as they approach failure. In comparison, the GT was performed overground on a track, and the subjects could adjust their pace/intensity to complete the test.

It is widely accepted that bLa accumulation during incremental exercise is a criterion measure for aerobic endurance performance (8). Overall bLa levels are known to be influenced by depleted glycogen stores preceding exhaustive exercise (8), in this case induced by a graded incremental exercise test. The bLa values collected 3 minutes after testing for both the GT and the $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max test were significantly correlated, suggesting that the GT maximally stimulated the aerobic system. This correlation also provides evidence that the GT can provide an estimated evaluation of aerobic endurance performance in the field without having to collect blood for lactate analysis.

Male and female subjects were matched for total work performed; however, variations were observed between the GT completion time and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max for male and female subjects. The correlation between these values were significant for both sexes; however, the male subjects had a higher correlation coefficient compared with the female subjects. In a study conducted by Laurent et al. (15), the effects of sex on repeated, maximal-intensity intermittent exercise was investigated. They reported that women exhibited significantly lower bLa concentration and significantly lower decrement in performance, suggesting increased resistance to fatigue. However, sex differences in moderate to intense exercise appear to be primarily due to contractile and metabolic differences between men and women and related to maximal power or torque; the precise mechanisms of these differences are still unknown (10). With a larger sample size, it is possible we would observe a stronger correlation among the female subjects reflecting a similar trend to the male subjects. Regardless, from these initial findings, it is apparent that the GT, independent of sex, is able to accurately estimate aerobic performance.

The main limitation to this study was the relatively small sample size. A larger sample size would increase the statistical power and likelihood of observing stronger correlations than those observed in the current study. Also, some subjects performed the GT in winter weather (cold and wet), and others performed the test in more moderate conditions (sunny and dry). The variable weather conditions could have had an effect on performance. Future studies could follow the methodology of the current study and directly compare the GT, MST, and YIET, along with a $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max, to determine which field test is a more accurate measure of aerobic fitness. Since the current study is the first to analyze the physiological responses elicited from the GT, follow-up studies could further examine the reliability and validity of this test as an assessment of aerobic endurance performance. In conclusion, based on the results from this study, the GT can be considered an accurate method to assess an individual’s aerobic fitness.

Practical Applications.

The practical application for the GT can provide strength and conditioning coaches with a cost-effective field-based assessment of aerobic fitness for athletes, which requires minimal equipment and time. $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max and LT are considered the “gold standard” for the measurement of aerobic endurance performance; however, the procedures require laboratory time, expensive equipment, and trained personnel. With strong correlations between data from the laboratory-based assessments and GT, the findings of this study are generalizable because the GT time to completion was strongly correlated across a broad range of fitness levels. Since we observed strong correlations between the maximum HR and 3-minute post bLa collected during the GT and $\stackrel{.}{\mathrm{V}}{\mathrm{o}}_2$max and LT tests, this suggests the GT elicits a comparable physiological response we would expect to see during laboratory-based assessments. Thus, practitioners at a minimum can use maximum HR from the GT and total completion time to assess the aerobic fitness level for their athletes. These data suggest that the GT is a valid evaluation of aerobic fitness and can be implemented as a tool to assess and track an athlete’s aerobic fitness in lieu of laboratory-based assessments. For example, practitioners can implement the GT to establish a baseline aerobic fitness level for their athletes to track progress during pre-season, in-season, and post-season training. From the data collected during the GT (maximum HR and completion time), practitioners will gain insight into their athlete’s aerobic fitness which they then can use to help generate an athlete-specific training protocol. Results of this study suggest the GT can accurately estimate an individual’s fitness level, independent of sex and fitness level. Thus, coaches and fitness professionals can use the GT test as a generalizable assessment of fitness without the need for expensive laboratory-based equipment and trained personnel.