The ability to generate power is an essential component in achieving optimal performance in several track and field events, particularly the throws (18,19,27), sprints (22,25), and jumps (2,14). The definition of power is relatively simple—the applied force multiplied by the velocity of the movement (16,24). However, power is a complex property of the neuromuscular system and its meaning will often change depending on the action or event in which the power is being produced. Track and field sprinters, for instance, rely heavily on the ability to not only generate high amounts of power but to be able to do so repeatedly with every stride of the race. Conversely, throwers need to generate maximal power, not repeatedly, but rather in a single explosive motion. Track and field jumpers, must be able to do both, repeated powerful strides down the runway or across the apron, concluding with a final, single maximal explosive jump.
These differences in performance outcomes necessitate specificity of training. Each of these 3 types of power athletes will incorporate variations of running, jumping, and weight-room techniques to elicit gains in power output (15). Sprinters will generally rely most on sprinting, while also incorporating plyometrics and power-specific lifts in the weight room, such as snatch, power-cleans, and speed squats (28). Throwers will rely far more on the resistance training and plyometric movements and much less on running activities (12,30). Jumpers again occupy the middle ground, with a more balanced approach among the 3 training techniques (7). Although these are all “power” events, the differences among the training methods and the variations of power used by the athletes can make it difficult to objectively test each athlete's power capacities and capabilities.
The Wingate anaerobic test (WAnT) is a widely used standardized test of anaerobic power and capacity (1). The WAnT is performed using a cycle ergometer and consists of an individual maximally pedaling against a predetermined resistance for 30 seconds. This test has been shown to be both reliable and valid in measuring peak power (PP), mean power (MP), and percent fatigue (fatigue index [FI]) (1). However, the WAnT lacks specificity to most sport skills with the exception of cycling. In addition, the test requires expensive specialized equipment and can take considerable time when used in a team setting. For these reasons, more practical tests of anaerobic power, such as sprinting, jumping, and stair climbing, are often used (29).
In track and field, the WAnT may be generalizable to the running component of training due to running's cyclical nature, however, it is likely not the most appropriate power test for addressing the more linear weightlifting and jumping components. A lift-specific power test could allow for a more comprehensive assessment of the trained status of sprinters and jumpers than a cyclic test alone. In addition, such a test could specifically address the resistance training component used by sprinters and jumpers, and favored by throwers.
The Kansas squat test (KST) is a repetitive lifting test that has been designed to measure similar indices of power as the WAnT (8). The KST is performed by completing 15 repetitions of a barbell back squat at a rate of 1 repetition every 6 seconds. Measures of power are determined through the use of an external dynamometer tethered to the barbell. Relative to the WAnT, the KST is a much more practical test. It can be conducted in the weight room, using equipment and an exercise that the athletes are already familiar with. And while the dynamometer does have a cost, it is less expensive compared with the equipment required for the WAnT. In addition, its use is not limited to the KST, as it can be used in various other ways in training athletes (20). For athletes who train power with an emphasis on weight training, this lift-specific power test may be more practical and advantageous for monitoring training adaptations than the WAnT.
Fry et al. (8) found the KST to be a reliable indicator of anaerobic power. Although they observed significant correlations between the KST and the WAnT on 2 measures of anaerobic power in recreationally trained males: peak power (r = 0.775, p ≤ 0.05) and mean power (r = 0.752, p ≤ 0.05) (8), they did not put forward the prospect of validity. Therefore, a purpose of this study was to determine concurrent validity of the KST as a test of lower-body anaerobic power by comparing it to the WAnT as the criterion measure. In addition, this study aimed to demonstrate the KST as a practical test of lower-body anaerobic power for collegiate track and field power athletes, both men and women.
Experimental Approach to the Problem
Concurrent validity is a type of criterion-related validity in which correlation coefficients are calculated between a true criterion measure and an alternative measure (23). Previous research has demonstrated the use of this method to determine the validity of new tests of upper-body power (6) and lower-body power (4,5,10). This study was designed to determine concurrent validity of the KST by examining correlations with the established and validated 30-second cycle WAnT on measures of lower-body peak power (PP), mean power (MP), percent power drop (relative fatigue index [FI]), and posttest lactate (HLa).
Participants reported to the laboratory on 5 separate occasions. The first 3 visits were for baseline measurements and familiarization of the WAnT and KST. Each of these 3 occasions was on a separate day within the first week of the study. The final 2 visits were for the actual tests and their respective data collection. These 2 visits were separated by 1 week, each occurring on the first day of the week after a weekend of rest. The experiment was conducted during the fall preseason training of the track and field team.
The track and field program was a part of the Intercollegiate Athletics Department at a midwestern regional university. Permission to conduct the study was granted by the university's Institutional Review Board. The track and field coaching staff agreed to the recruitment of participants from the team and allowed for the necessary modifications to be made to the practice days on which testing would take place. Details of the study were verbally explained to the athletes by the principal investigator at squad meetings. In total, 23 athletes volunteered to be participants (mean ± SD; 20.1 ± 1.0 years; 77 ± 16.8 kg, 175.6 ± 8.7 cm). The group consisted of 7 males (20.7 ± 0.7 years; 72.9 ± 10.0 kg, 180.7 ± 4.0 cm) and 7 females (19.8 ± 0.9 years; 64.4 ± 5.1 kg, 171.6 ± 3.6 cm) from the sprinter and jumper squad, as well as 5 males (19.8 ± 0.8 years; 94.6 ± 23.9 kg, 183.1 ± 4.8 cm) and 4 females (20.3 ± 1.5 years; 81.9 ± 11.3 kg, 164.0 ± 10.0 cm) from the throwers squad. Each volunteer signed an informed consent document. All were deemed healthy and able to participate by the university's medical and athletic training staff.
Baseline Measurement and Familiarization
Participants reported to the laboratory on 3 separate occasions for baseline data collection and test procedure familiarization. During the first visit, participants completed a 1RM back squat test on a Smith machine. In the second and third visits, participants completed familiarization sessions with the WAnT and KST, respectively (Figure 1).
One Repetition Maximum Squat Procedures
Participants completed a 1RM back squat test on a PSM144X Smith machine (Body-Solid Incorporated, Forest Park, IL, USA) following strength-test protocols set forth by Kraemer et al. (17). For future reference in the KST, participants' foot placement during the 1RM was measured using a marked grid, which was located at the base of the Smith machine. These measurements were recorded to ensure that participants' used the same stance during the 1RM and the KST familiarization and testing sessions.
Kansas Squat Test Procedures
Before the squat test, each participant's body mass was measured using a Tanita WB-3000plus Digital Physicians Scale (Arlington Heights, IL, USA). A test-specific warm-up with free-weight barbell squats for 3 sets of 5 repetitions (1 × 5 at 30% 1RM, 2 × 5 at 50% 1RM) (8) was completed. The KST was performed in a Smith machine at a load equivalent to 70% of each participant's system mass, which was calculated by summing the load of their 1RM and their body mass as measured just before the test (System Mass = 1RM + BM). Depth of each repetition was monitored with the use of a Safety Squat monitor (Bigger Faster Stronger, Salt Lake City, UT, USA). This device projects a distinct audible tone when it becomes parallel to the ground. The Safety Squat was strapped around the participant's right leg at the approximate midpoint of the thigh. Participants were informed that the tone would be used as an indication that the decent of a repetition had achieved sufficient depth (i.e., anterior thigh parallel with the ground) and that after a momentary pause, the ascent could begin. Foot placements from the 1RM tests were replicated. The KST consisted of 15 speed squat repetitions at a cadence of 1 lift·6·s−1. The cadence was paced with the use a programmable digital timer (Chronomix, Sunnyvale, CA, USA), which was set to count down from 6 seconds and automatically repeat the sequence 15 times. The timer provided a large visible display of the cadence to the participants as well as an audible beep each time a new repetition was to begin. The timer was started by the investigator as soon as the participant began the first repetition. Each repetition consisted of lowering the weight in a volitionally controlled manner until the Safety Squat device emitted a tone, which indicated that the lower end of the squat range had been achieved. The participant then paused briefly and then maximally accelerated upward through the concentric phase of the squat. Participants were instructed not to jump or raise their heels off of the ground. Each repetition was completed when the participant returned to the starting position and the next repetition began when the timer beeped and started a new countdown. This pattern was followed until the 15 repetitions were completed.
To measure power output during the KST, the Smith machine barbell was tethered to an external dynamometer (Fitrodyne; Bratislava, Slovakia) (11) through the device's spooled nylon thread. The device was interfaced with a laptop computer with the Tendo Weightlifting Analyzer software program (Fitrodyne; Bratislava, Slovakia) installed, which recorded the linear velocity of the tethered thread as it moved through the range of motion of each KST repetition. Power measures were calculated from the collected data and the participants' system mass in the same manner as in the initial KST study. Briefly, the mean bar velocity measured by the dynamometer was multiplied by the system mass (barbell load + body mass) to determine mean repetition power (8). For a detailed discussion on these calculations, see Fry et al. (8).
Wingate anaerobic test Cycle Testing Procedures
Before the WAnT, each participant's body mass was measured using the same scale as was used for the KST. A test-specific warm-up was completed by lightly pedaling on a stationary cycle interspersed with two 5-second sprints. Once the warm-up was complete, a standard 30-second WAnT sprint cycle test was then performed using a Monark 894E Peak cycle ergometer (Monark, Stockholm, Sweden). The WAnT required that participants pedal maximally against a load equal to 0.07 kg·kg−1·BM−1 for the 30-second duration (1).
Power output was measured during the test through Monark Anaerobic Test Software (ATS) computer program (Monark), which was interfaced with the 894E ergometer. Peak power, mean power, and fatigue index were calculated on completion of the test by the ATS program.
The data collection sessions for the KST and WAnT were conducted at the beginning of track practice after the standard team warm-up. These sessions took place on the first day of practice for the week, following a 2-day weekend of rest and recovery. The KST was performed at the first session and the WAnT followed 1 week later (Figure 1). The testing procedures for both tests followed those used in the familiarization sessions as described above.
Blood Lactate Analysis
In addition to the data collected directly from the 2 tests, blood lactate was also measured to compare the physiological response of the anaerobic energy system between the WAnT and the KST, as was done by Fry et al. (8). Finger prick blood samples were taken just before the warm-up and analyzed using a hand held Lactate Scout (SensLab, Leipzig, Germany). This procedure was repeated again at approximately 5 minutes posttest.
Pearson correlation coefficients and paired-samples t-tests for maximum test power, mean test power, and relative fatigue were performed to examine the relationship between the WAnT and the KST, as well as the posttest blood lactate values from each assessment. PASW Statistics 18 was used for analysis, and the level of significance was set at 0.05 for all tests.
The concurrent validity was determined by correlating the outcome variables between the KST and the WAnT. When all athletes were examined together as a single group (n = 23), correlation coefficients indicated that there were significant relationships between the KST and the WAnT on measures of peak test power (r = 0.920, p < 0.01; Figure 2) and mean test power (r = 0.929, p < 0.01; Figure 3), but not for relative fatigue (r = 0.030, p = 0.891). The posttest lactate response also lacked a significant relationship (r = −0.062, p = 0.779). These relationships were also present when athletes were examined in subgroups of male athletes (n = 12), female athletes (n = 11), throwers (n = 9), and sprinters and jumpers (n = 14).
Paired-samples t-tests indicated that while peak power and mean power were significantly higher for the KST (p ≤ 0.01), relative fatigue and lactate were both significantly higher for the WAnT (p ≤ 0.01), when all athletes were examined together as a single group. These significant differences between test measures were similar in the subsequent subgroupings of the athletes. Complete results of the total squad and all subgroupings are located in Table 1.
A purpose of this study was to determine the concurrent validity of the KST. Fry et al. (8), who published the initial KST study, determined the KST to be a reliable measure of lower-body power. In addition, they found the KST to be significantly correlated with the WAnT on 2 measures of anaerobic power: peak (r = 0.775, p ≤ 0.05) and mean (r = 0.752, p ≤ 0.05), although they did not indicate that they were establishing validity of the KST (8). The results of this study (Table 1) support those initial finding. In addition, the correlations between the KST and the criterion WAnT were sufficiently strong enough to indicate that the KST is a concurrently valid measure of lower-body peak and mean power.
Fry et al. (8) had demonstrated that the KST was highly correlated with the WAnT in measurement of peak power in recreationally trained males (r = 0.775). This value is higher than correlations found between the WAnT and other anaerobic tests such as the 50-m sprint test, the Margaria stair test (24), as well as leg press power (25). This study, which used trained collegiate track and field power athletes, found an even higher correlation (r = 0.920) than the study by Fry et al. (8). This stronger correlation is likely due to the power-specific nature of the training of the track and field athletes.
This notion is also supported by a small unpublished study that used a population of recreationally trained males (n = 8) and females (n = 8), who had little to modest weight training experience (9). In comparing 3 tests of peak anaerobic power, Graham et al. (9) concluded that the KST was not an adequate replacement for the WAnT. In examining the results of Graham et al. (9), Fry et al. (8), and this study, it seems as if the training status and experience of the population in question may be a factor in the successful use of the test. Therefore, the KST may be best suited as an alternative to the WAnT as a test of lower-body anaerobic power with those who have a history of using barbell squats as a means of training power.
As in the initial study (8), the current investigation found a very low correlation with the WAnT in measuring relative fatigue (r = 0.030 vs. r = 0.174). Likewise, the t-tests on the posttest lactate measurements also indicated a significantly lower value for the KST than the WAnT in this study (p < 0.01). A possible explanation for this is that these tests do not place the same metabolic demand on the individual being assessed. Although the WAnT has been shown to be associated closely with the lactic acid production of fast glycolysis (1), the lower levels and lack of correlation of lactate with the KST indicate that the anaerobic glycolytic system is likely not the primary energy pathway used during the test. It is more likely that the phosphagen system is the principle energy contributor during the KST. This could be due to the longer duration of the KST to the WAnT (90 seconds vs. 30 seconds), which means that the total session power is lower in comparison, although a similar amount of work is performed (8). Also, the KST uses repeated intermittent activity compared with the continuous action required by the WAnT. The alternating periods of high- and low-energy demands during the KST could allow for the phosphagen system to maintain its ability to provide energy for the test duration, whereas in the WAnT, the phosphagen system is quickly exhausted and energy production shifts to the fast glycolytic system. Fry et al. (8) also speculated that the differences in each test's mode of contraction (KST—concentric and eccentric vs. WAnT concentric only) may also play a role in the observed metabolic differences.
Although both the present investigation and the initial study by Fry et al. (8) found similarly low correlations in the fatigue indices between the KST and the WAnT, which may be metabolically explained, there is another possible explanation. The relative fatigue experienced by the recreationally trained participants during the KST in the study by Fry et al. (8) was 20.4 ± 13.9%. Whereas the collegiate track and field athletes in this study had relative fatigue indices of only 4.9 ± 4.9%. Relative fatigue for the KST, as defined by Fry et al. (8) is “the percent difference between the highest single repetition power (i.e., maximum test power) and the last single repetition power.” Given this definition, it would seem as if there was very little power lost during the KST for the athletes in this study. Yet, this was not the case. The relatively low FI is more likely due to some of the athletes not experiencing their lowest power repetition on the final repetition of the test, but rather in one of the repetitions only near the end of the test. If the data are analyzed by using the difference between the highest single repletion power and the lowest single repetition power (rather than the last repetition power), the difference for the team increases to approximately 15.9%. This percentage is nearer to the FI experienced by the recreationally trained athletes in the study by Fry et al. (8). It is possible that some of the athletes in the current study were pacing during the test, rather than giving maximal effort with every repetition as directed. If so, this may account for the lower FI in this study. This observation stresses the importance for the participants to attempt maximal effort for each repetition of the KST.
Collegiate track and field power athletes train for power using a combination of techniques. Training protocols encompass methods from increasing maximal strength (e.g., squat 1RM), explosive power (e.g., cleans, plyometrics), and speed (e.g., sprints). Although these are each generally used, each athlete or squad will favor the methods that are most specific to their event and allow for the greatest transfer of power to their skill (26). Although performance in an event is certainly a way to gauge successful training, it can be beneficial to also test each training variable when possible.
There are a wide variety of tests for lower-body power, some which are very applicable to training methods of track and field power athletes, such as the Bosco anaerobic jump test (3), the Margaria-Kalamen test (13,21), and the Running Anaerobic Sprint Test (31). However, until the development of the KST, there has not been a lower-body anaerobic power test that assesses power in a manner that is specific to the externally loaded squat weight training protocols that are used by most track and field power athletes at some point in their training programs. Furthermore, the KST can be conducted with nonspecialized equipment that can be used by coaches and athletes in other aspects of their training programs (20), making the KST a feasible practical alternative to the WAnT.
This study demonstrates that the Kansas squat test is a concurrently valid, practical, lift-specific assessment of lower-body peak and mean power. When incorporated into a testing battery, the KST may aid in providing a more comprehensive and valid analysis of track and field athletes' power status. This information could be useful to strength and conditioning coaches and their track and field athletes in designing, monitoring, and modifying training programs and protocols.
The authors thank the Emporia State University track and field team and coaches for their time and efforts in this study. They also express their gratitude to Keith Pfannenstiel for his assistance with data collection.
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